Excellent video, but i feel there is something missing from this conversation that ultimately changes all of the variables you presented, and that's the difference in fuel types. The combustion profiles for pump gas, oxygenated gasoline, E85, ethanol and nitromethane are all going to be different, not only for their individual burn qualities but also for the optimum volume used with each fuel. Also, just adding something to the argument, my experience with nitromethane would put me in agreement with Steve. Whether tuning for blown or N/A, the ignition lead stays constant at approximately 55 degrees for a dual plug or 65 for single plug application...this in a 426 style engine with 175cc combustion chamber. There is a difference in static compression between the two types of engines, but all else being equal (bore, stroke, cam profile) the duration of burn is the main factor and not how the chamber is pressurized.
I got here from Steve's short also. Over the years I have learned so much about engines and tuning, especially after buying a dyno. I would say over 99% of the engines I have tuned are exactly what you are explaining here Ben, I have always had to retard timing with boost.... The one engine I was very surprised on though, was a turbocharged Gen 1 SBC in a drag race S10 pickup. Single turbo, low compression, conventional 23 degree head. I got involved when he made the switch to EFI, and had a local shop tune it (this was before I owned a dyno). He was disappointed with the power and resulting trap speeds when he got it to the track for the first time. He ran it like that for a while then asked me for help. I started adding timing and the trap speeds kept on getting better. I was coming from a pump gas turbocharged import background at the time and was extremely reluctant and uneasy about the numbers in the timing table. However, I knew that if it was going faster, "give it what the engine wants, not what you THINK it wants". We ended up right at what the NA engine liked all the way up to 30 psi boost pressure (we are at about 1,000ft. above sea level). Plugs showed the timing was right in the sweet spot as well. This particular engine really opened my mind up, and I'm grateful to have created a friendship with the owner and have drag raced with him ever since. Another thing to just mention about this particular engine that is interesting is that we went through 3 different single turbo setups, ultimately ending with a big 98mm Garrett GTX5533R. We ran it up to 54psi boost, and up there it STILL wanted a lot of timing. I later figured out why when we installed back pressure sensors... The single was choking the exhaust too much and effectively diluting the mixture and requiring more ignition lead, just as you talk about here Ben. It still went faster, but the power gain per pound of boost was really plateauing. We ended up switching to a twin 80mm turbo setup, and made the same power at only 42psi boost pressure, just because of the more open exhaust. It took less timing as well, and as an added benefit we stopped having to replace spark plugs after 4 runs. Anyways, that's already too much info in a UA-cam comment, but thank you for the great video Ben!
@@EFIU_Ben Since you're compressing MORE air, the cylinder pressure... and therefore the temperature will be far greater than n/a. The higher temps alone should dictate less timing. Now I'll watch your video and see if you come up with the same theory... but that's what jumped out at me while watching his.
When I live in Japan I worked for a Japanese manufacturer's internal engine builder and parts maker for their racing programs. We also made prototype parts for future models. We had our own data from grA, GT300, GT500, Dakar rally, 24hr LeMans, Pikes Peak, etc... While I was there we started making street parts based on those programs. Our oil pumps, headgaskets, pistons, rods, cams, turbos and other parts were exactly the same as race version. But we added some cam options, oil pumps, water pumps and other parts based on racing but for street. Anyway, every single engine required less timing as we increased boost. We produced our own ecu and software too. It's not uncommon for our engine programs to have 30+ degrees at 0psi boost tapering down to 20 or even 12 degrees at 21psi and 28psi. We could add a few degrees after peak torque but didn't bother on most. That's on about 94-95 octane (USA rating) with pentroof 4 valve. If we wanted more boost then we'd remove the quench pads or use race gas. Keep in mind we could run 13:1 and extremely high egt for 30+ minutes with no damage. Of course we ran 11:1-12:1 and low egt for safety. These were 2.6 & 2.8 in line 6, 8.5:1 compression making 450-800+hp at the wheels. Oh and the pressure delta varied greatly between turbos. We even used old school clipped turbine wheels on some setups to reduce back pressure. Nonclipped would spool 1bar just before 3,000rpm and clipped version kick in at 4,500-5,000rpm lol. It ruined turbine efficiency but helped VE. They would run like big displacement NA engines from 5,000 to 8,000 rpm. I can't imagine running the same timing at different boost. That said if engine makes peak power at 30 degrees and 0psi. But it could also run at 40psi and 0psi without ping then theoretical maybe it can make peak power at 30 degrees and 21psi were as our engines did at 20 degree. I wanna say air-cooled Porsche make peak power NA at something crazy low like 20 degrees but don't ping till 35+ degrees. And that's like Steve is saying. The combustion shape is limiting factor not fuel. Need a "hotter" combustion design. But then again on air-cooled you probably can't keep cylinder head temperature under control if the combustion design was pushed harder
Remove the quench pads for more boost? Internet says no quench causes detonation sooner? Remove pads to lower compression? A 2jz ge , with a gte head gasket will have lower compression but you have too much space on the quench pads for them to work. If I want high h.p. boost, do I run no quench on the ge (thicker gasket ) or run quench with stock gasket thickness giving higher compression?
2.6L and 2.8L inline 6's commonly running 8.5:1 compression in those series with a manufacturers internal engine builder... so Nismo RB26's 🥳hell yeah, thanks for sharing that.
@@jasonschreiber6458 its not that no quench makes detonation happen sooner(it doesn’t), improper quench does. Theres a middle ground between good quench and no quench where you run into detonation issues. The chamber is shaped much different for a no quench build
@EFIU_Ben really enjoyed it and was interesting to go into so much detail and things I've never thought about. Would love to see you team up with Steve to do some testing
@@EFIU_Ben IMO, it would have everything to do with quality of the air fuel ratio. This would effect a naturally aspirated engine the same as a boosted engine. IMO, changes in the air fuel ratio AND the quality of atomization is the root of the timing differences. (I'm thinking the routing of the air/fuel mixture to the combustion chamber causing the fuel to drop out of suspension) Just my guess. BTW, I LOVED this thought process!
When you talk about 426 hemi. When Dodge wanted the old men to run the new hemi instead of the 392 that everyone else was using. Gar couldn't get it run hard like the old one , in frustration he cranked the timing up, way up, said Gar, well that was what was missing way more than they ran in the 392. Ask him
the reason he cranked the timing up in the first pace was he wanted to blow up the engine so he could go back to the 392 Hemi. the car went something like 210 at 40 degree's timing and the nhe upped it to 50 and it was even faster.
True; but i think it was becauce nitro fuel burns extremely slow. Not sure why the 426 was so much different than the 392 using the same fuel.....maybe larger chamber?
The wrong cam will also act like EGR, I have guys come up to me at car shows and tell me about overheating problems that they just cannot fix. My first question I always ask, have you looked into the intake manifold for your problem. Never thinking the engine is eating it own exhaust, so the intake is black all the way back to the base plate of the carb.
BINGO ! If you look at the posts in Steve's video, I said the only way to properly set timing was via cylinder pressure. Finally someone using real science instead of folklore. Great video.
It's crazy that people with this much leverage can say whatever they want without using the basics of engines 101. I always checked out his timing maps and it amazes me that there where no more than 3 different numbers in the whole timing map. Good for you educating us with proper info!
There isnt as much of a need for timing change in a methanol drag engine thats built to handle 5000hp. We pull timing in average street engines because the fuel and engine assembly cant handle it, his engines on meth can handle it
I like that you ended up with the same conclusion as me and a humble attitude at the end. What he said is definitely a good rule of thumb and seems like it was mostly said to get people out of the old way of thinking: “pull lots of timing if you have lots of boost”
Excellent video Ben. I admire you for being at the top echelon top be able to get in cylinder pressure data - it so interesting to us engineering nerds!
Flame front propagation across a large piston .............. we find that alive and well in the 1939 technology of your aircraft engine. Another great video!
THANK YOU for doing what I wish I had the resources to do!! This is the comment I posted on Steve's video: "My answer to your question, "why do we need to decrease timing when going from NA to boosted?" The mixture will be extremely tightly packed in the same size chamber as before. Oxygen molecules will be very close together and when the flame front starts, it will propagate VERY quickly when compared to a more sparsely distributed mixture. Peak cylinder pressure will then occur much earlier/sooner/faster - so you take away timing to keep that peak pressure occurring at the correct time. If this is untrue I might as well throw my engineering degree in the garbage." As you'd expect, he did not reply.
Going with the LS example here, your engineering degree can be binned. Obviously it is more complicated than your training tells you or that test wouldn't have had the result it did. There are many variables to how an engine functions, as shown here, there is not a one size fits all answer. I can see why he didn't reply, nobody likes a know-it-all commenter.
I think you are missing one point which I believe may be part of the basis for Steve’s comment. While I agree that a mixture with more densely packed molecules will burn faster. In a boosted application you have a lot more molecules that have to burn. So while the mixture may be burning faster it may end up taking close to the same amount of time to burn all the molecules as it did in the na version with a less dense mixture.
SM is running mostly methanol fueled engines under high boost....so the additional cooling you get from increasing the amount of fuel in the chamber tends to offset the potential faster burn rate. In his engines....and LOTS of dyno development....they just don't need ignition retarding at higher boost levels on methanol. Also remember that they are not running the engines at the ragged edge of timing....stay safely away by reading the sparkplug ground strap colors. There's no need to run dangerous amounts of timing because all of his really powerful setups need to be tamed down in the car just to get through a pass without blowing off the tires. Many 'it depends' here and Steve was only saying what HIS engines like and there are NO 'Universal Truths' being violated.
How does spark plug gap affect the whole thing. We had an engine with MSD ignition and the plugs were .025. Opened them up to .055 and it ran much much better.
Resistor type plugs need a decent gap to build up a resistance so when the spark occurs its fat, as if it was being held back. If the gap is too close on the resistor plug the gap is easily achieved and the weak spark makes it across before optimal resistance is achived. Kind of like setting a pressure regulator to low for the injectors, when the injector opens not much pressure. Set high pressure on the regulator, when the injector finally opens, bamm! Not a perfect analogy but tried another way to describe it if the main concept didnt connect.
Greg's Airplanes just did a similar video. Its rather interesting that NACA did studys on this to improve aviation engine efficiency back in the 40s. It would be cool to see your burn time data with just changing air fuel ratios and fuel types.
@@EFIU_Ben Actually, they kind of didn't. That's why they had to do all those studies and testing, just like you're doing now, so they could learn and now we all know what we're doing, all thanks to them.
@EFIU_Ben Yeh. I just realized that the testing data gose back as far as 1925. If you think about it, the data in general makes sense. If you look at the air fuel ratio and disregard the boost. The burn time of a set air to fuel ratio is going to be the same regardless of boost pressure well to a point.What you said about the hemi makes sense it. It literally quenches the air fuel mixture, causing a slower burn. I think that is how the term quench area came about.
Seems like Steve gave you the parameters of his statement, safe fuel ie quality race fuel, safe compression and boost levels, and safe combustion chamber design and safe timing numbers. I think it's important to recognise that Steve Morris builds drag and drive engines, not max effort, race engines and what he finds an engine needs to put thousands of miles on the road and race is different to a rebuild every x number of runs. So, in conclusion, as you stated when you build an engine the way Steve does you get the same results and when you do different engine designs and intended use you get different results. From your results it seems like air and fuel prefers somewhere in the .8 to 1.1 time range to complete a combustion event regardless of variables
Great video Ben! What is your opinion on mixture motion inside the combustion chamber prior to ignition. High swirl /tumble heads & tight quench-high mixture motion, vs low swirl/ tumble & chamber softening-less mixture motion. Thank you.
Newly Subbed from SM. Have you got any data on port water/meth injection and its effect on cylinder pressure, detonation and timing ? Love to see a video on that.
Well if memory serves Steve was sayings boost vs non boost on his motors, not all motors, so that eliminates many of the variables that change. You make good sense and is not surprising that different configs need different adjustments. I was taught that with cylinder pressure, that the math is stable regardless of motor (as long as it was a piston pushing on a crank thru a rod) that peak cylinder pressure at 12ish degrees after TDC was universally desirable. So, back calculate from that the combustion time, at different RPM and Boost etc to back calculate your ideal ignition map. Have you ever indexed your data to the peak pressure vs crank position?? Thoughts?? Thanks!
We look at peak pressure amount, and crank locations but more importantly, we look at the area under the curve and how much % of mixture has been burned at certain crank locations. Typically we look at the value for "CA50" or the crank angle where 50% of the mixture has been burned, because this is a much more reliable indicator than peak pressure locations such as "X number of degrees after TDC"
True but just want to point out, he builds and dynos a lot of stuff other than just his own engines. BBCs, SBCs, LS, Hemis, heck even Rotax and Lamborghini.
@@EFIU_Ben Thanks Ben for the reply. I know my info is getting dated, I wish I could be uber familiar with and testing and learning this stuff even as a hobby. I think its fascinating.
Where the spark plug is located, what type of plug, and AFR. A fatter mix burns slower BUT it creates more pressure. If you pack it up you make it denser, thus it burns faster, but if you add more fuel, it burns slower again. If you run it rich you create carbon deposits inside the chamber which then heat up and cause pre-detonation. If you add more fuel and boost, reduce the advance, you end up with unburnt liquid inside the chamber that doesn't compress, lifting the head from quench area. Then there's cam timing. When your exhaust valve opens, the leftover pressure escapes. this pressure spins the turbo fan and heats it up. This heat travels through the turbo heating up your oil and your compressor fan. If you have overheated your cold side before, this heating fan expands and makes it tighter, heats up your intake air, showing more boost on your gauge. Then you cool the temp down with your fuel, but your AFR is still out of whack and your flame front is escaping into your exhaust. Also your liquid fuel flushes your piston rings creating more friction, making them lose tension, while the hydro lock collapses your ring lands. When the blow by escapes into your crank case the flame front follows welding your rings into your piston. Then your piston heats up, so does your rod, your rod expands, and your piston sticks to your cylinder bore. Rod gives up, piston shoots up into your valves and the run is done.
The only factors I have in question are camshaft profiles and temp of the cylinder before, after and during the combustion process. Was the sorceress different because of water flow and the cam profile it runs?
I feel there is alot of actually important factors omitted in the video that would help explain why ignition timing may not or may need to be adjusted based on the cylinder charge. 1. MFB50 and its relationship with MBT and their joined relationship with the engines geometry 2. The resultant pressure curve vs engine geometry in relations to timing 3. No engine is "NA" , without a turbo or supercharger or n2o the atmospheric pressure is the power adder 4. No mention of IMEP and how it is derived, it would explain exactly why timing needs to be moved to alter the power output to reach the peak power output 5. All pressure on the pistons upwards stroke is a loss and all pressure on the downards stroke is a gain, that includes intake stroke. Geometry here dictates how that piston pressure translates into torque(the instantaneous torque at X crank angle) or torque loss. 6. Variability in turbulence, general understanding is that turbulence goes up with engine speed as well as higher density air charge. Here geometry of the combustion chamber comes heavily into play. Engines can need 15°BTDC ignition at 30psi and 40psi and that would entirely be due to turbulence coming down with higher air charge.
Agreed, I’ve seen the same with cars I’ve tuned some I was surprised that I didn’t have to pull timing but for most setups timing was pulled, never thought about the surface area though, that some good info (as always from you channel) I always attributed it to egr’ing from back pressure. Man I would love to see the ve and ign map from that supercharger LS after you installing this Kistler sensor, actually before and after if the maps were both boost to really the advantage of that data.
Back in the '90's, I read an article in a snowmobile magazine about a gentleman who was testing cylinder transducers in a two-stroke engine. As I recall, he was trying to eliminate the carburetor for a better EFI system regardless of load, temperature or altitude. Not sure how it ended but this sure rhymes
Yumm combustion dynamics, flame propagation. cylinder pressures, I love this stuff! Produced torque vs cylinder pressures is what I really like to look at. I want the highest torque with the lowest cylinder pressures. That is efficiency and longevity.
Wouldn't you also want to take into account exactly where peak pressure of the combustion event happens in relation to tdc? I get measuring the duration, but during that roughly 1 ms of combustion the peak pressure could be .4 ms or .6 ms from the start. I would think that would also determine where to set spark.
Peak pressure location is important, but we focus more on when the mixture is being consumed and adding "area under the curve"...we call out specific locations such as "CA50" where 50% of the mixture is burned
Can you also determine the exhaust stroke efficiency by using the combustion pressure sensor, and thus see if the engine had more egr in a boosted application vs na? also, no mention of the AFR target change when switching from boosted to na. a rich mixture will typically require more ign timing. Interesting mapping the combustion time data. Would is there an advantage in using peak pressure angle instead, or a combo of both? (one is used to map the other) If the inlet pressure is elevated, and the exhaust pressure is not would the intake port velocity increase and possibly create a state of poor atomization in some applications? Could touch on inlet temps as well. lots and lots of things contribute to the ideal ignition timing for a given combo. one more thought here, the duration of a pull is also important in finding MBT. If an engine took 12 seconds to make a run, the chamber temp will be elevated more than an engine making a run in 5 seconds. The shorter duration run would tend to want more ignition timing do to the lower chamber temp, valve temp, plug temp etc.
I was told the LT-5 has one of the best combustion chamber designs of its time. They respond really well to additional timing. I wonder what technology Lotus was using back then in the mid 80's because they seemed to have nailed it with that engine.
I started in the engine reconditioning game when I was 16, that was 1985, I have worked in the performance race engine world, for many many years I was tuning engines, race engines, be it on a engine dyno or a chassis dyno, before retirement , I owned a performance motorcycle shop, with a motorcycle chassis dyno, building turbo bikes, nitrous and all motor engine. I can tell you from a life long experience, Steve Morris is wrong a lot of the time. I remember watching that video and his claims about ignition timing . Building peak pressure at a specific degrees after top dead centre is vital for engine performance and longevity. Many factors affect this, boost, fuel octane and burn rate, atmospheric pressure, humidity etc. I used computer models to determine at what degrees after top dead centre would be best for peak torque and what cylinder pressures would be there at or before that point. On the dyno we play with ignition timing to find these peak torque figures and determine a safe ignition timing figure for the fuel we are using. Steve videos only show again and again what he doesn’t know! One of my old bosses use to say, a “ EXPERT” Is a drip under pressure! Steve is just a drip under pressure. His videos look great for those who don’t know , for us that do, those videos just show us, he knows very little and has almost zero technical knowledge. The proof is how he tries to babble around a technical issue . Then have a look at the stuff that stumps him! Again proof he lacks the technical knowledge. He is nothing more than an experimenter and knows what he knows by his failed attempts. This is a costly way to learn, and it’s costly for his customers ! And that engine he sold to Cleetus, that had the main cap failure, look at all those sharp edges, just waiting to start a crack. This is 101 of race engine building, remove all stress points. Radius all sharp edges. Not Steve and look at how they failed! And in earlier videos he showed a main cap failure and states the crack started and the sharp edge, yet in that later Cleetus video he say he never seen that before. That engine sold to Cleetus was just a grenade waiting to happen, I look forward to seeing how this engine goes in Val’s Camaro.
You are the best at figuring out how to measure, record, display, and explain what an engine is doing. Kudos! Those pressure transducers can be so formative!
If too much surface area is a problem, how does it affect piston domes? So domes are actually more inefficient than we think, besides the airflow limitation is also impacts.
Awesome video Ben. I'm a DataHolic that's been racing and tuning motorcycles for 50+ years and in the end, it's always been about giving each engine what is wants/needs. I'm shocked that you don't have more subs but I'm guessing that number is rising tonight 👍
So if you didn’t have the different wet maintained grass mixed with the ratty dry grass, you’d have a better burn. The more efficient a combustion chamber, the less timing will be required. Boost situations have the probability of changing chamber efficiency. Treat every engine the same way only different. Ignition timing is very important. I watched a video of magnetos coming off and tumbling down the track from a top fuel dragster that was still firing down the quarter
I'm surprised that timing could end up back at the same place as NA. Can you do timing for E85 vs pump gas? I'm tired of hearing of the "cooling effect" being the source of increased power.
beside “cooling effect”，the only main factor for timing chose is how much fuel mixture speed up the flame font and the water be brough into chamber that slow down the burn
Not sure Steve and others understand timing number we use is negative work done. IE making crank go slower. But there is more being done when after TDC but is it enough to where average power is higher. The goal should be most power not stuck on a certain number. You won’t ever use 40° on a twin plug engine…and make more average power post TDC.
76 PSI of boost reacts differently from 20 PSI. The number of molecules present, the temperature differential between the air and fuel molecules, and the time it spends under those conditions are quite different.
This is a great channel for people that want to really learn things about how engines really work. I enjoy the science aspect of how he describes these processes. The ability to gather all this data and be able to come to meaningful conclusions that really describe what is going on inside the cylinder is terrific. We never stop learning.
fuel tolerance is what i got out of that from Steve, what you can get away with potentially. awesome data sir. thank you for letting such expensive hard learned data out to us plebs.
Seems like a segway into you and steve doing some testing together? I think that would be a awesome series. You guys beating on a motor with different setups with his motor skills and your data skills alot could be learned.
There’s a way to do this without drilling into the head Had a set of 8 spark plugs that were made by drilling into the nut and comes out into the combustion chamber had a jeweler micro weld a stainless tube onto it and ran it through an expansion coil to even out the pulses and it gives a better reading and you can save the heads and collect the data on several different platforms without ruining the heads it was really cool to see and cost all of $800
The only way I can see that it's physically possible for what steve said to be true is if the volatility of the mixture was unchanged between the two test conditions. I'd go so far to say that if it still takes the same timing after adding boost, its because you have added unfavorable conditions when you increased the boost, probably in the form of an EGR effect from an exhaust that has become more of a restriction.
I have been looking for a channel like this for a very long time and I immediately subscribed. As a former race engine builder and cylinder head porter I have always wondered how the effect of intake port design and specifically combustion chamber roof and floor design (piston dome or dish) effects the speed of combustion. There has been some books written about these theroies of combustion swirl in diesel engines but a gasoline burning high RPM engine is a far cry from a low speed larger stroke (IE. slow mechanical event ) diesel engine. has there been any test data thats available to study on this subject.? TY
I’m glad you found the channel! It is something we are working on! We do sell some videos on cylinder pressure measurement on our website and also discuss these topics and many others weekly as part of our Delta Lambda Fraternity you can learn more here: www.efi101.com
I always thought higher octane meant more of a resistance to burn, where there are more short octane bonds that are harder to break versus a lower octane fuel's greater presence of the longer easier to break heptane bonds. Therefore more resistance to burn equals more timing needed. At least this is what the famous calibrator Greg Banish mentions in his books. You mentioned octane is resistance to detonation and that makes perfect sense, but isn't that essentially the same thing as "resistance to burn" just another way of stating that any burn (whether intentional from spark or unintentional from detonation/preignition) will be harder to begin with higher octane, and thus require more ignition advance for ample time to burn? I understand the other factors you mentioned that influence timing requirements, I just thought octane was one of them based on literature from other professionals.
It's the same exact reason we run vacuume advance to advance the timing at part throttle... less air and fuel in the chamber takes longer to burn needs lit earlier. As for the gen III Hemi, they like less advance than LS engines and it's why Chevy tuners break hemi pistons when they try to find them like an LS.
Just gotta love when someone rips out the cylinder pressure data and shows the fuel mass burn time etc! Combustion efficiency is where we find the good stuff 🤌
Thank you Ben. I really enjoyed your Drag Racing school last year in Bowling Green. When are you coming back? Enjoyed the video. Thanks for using “real world” experience and data to set the record straight. Frank
This is very interesting and will clear up some misinformation and help people to understand it in the full spectrum. Thanks brother. Back in the day with leaded fuel my old 327 / 350 not modified 32 degrees all in with Dist advance curve with vacuum source was the max I could go before it hard cranked and that`s when I knew to back it off just a bit and get rid of the ping.
I think terms like , flame propagation, flame front and flame hatching out should be added to this discussion. And you are burning faster if you burning more in the same time frame hp.
Absolutely brilliant. Very well explained, with actual data to let us understand exactly what's going on. Your data driven approach is very refreshing, and reminds me of Gale Banks approach.
Basically, the flame speed goes as the air density, so it follows that higher density reduces the Time to peak pressure....The efficiency of a system can be judged by how much advance is necessary to get peak power....Mostly....
Measuring and comparing air density, air flow volume, fueling rate, combustion temperature,and exhaust pressure should show how much EGR effect/cylinder evacuation there is. I think Steve needs some combustion sensors!
Hey Ben. I just wanted to say this is absolutely amazing info! Really gets me thinking. I do have a question. Are you going to go into further depth on this topic? I just had an idea. Maybe covering burn rate and timing for say an open chamber head vs closed and ls vs hemi? Just a thought. Awesome job and great info! I wish I had the equipment to do all this because I most definitely would!
@@EFIU_Ben yea sadly your right. I got a little too excited after seeing this video and thinking of all the possibilities. It would be a big undertaking to do a bunch of engines. What can I say I guess I really like to see the data!
Good arguments I,m wondering what your pressures would be in a nitro engine ours we run approximately 60 degrees timing due to slow burning of nitromethane
I haven't measured one (YET!) but I'm told their cylinder pressures aren't necessarily way higher...they just last for a REALLY long time after TDC and continue pushing the pistons down HARD!
@@jeffthomson1777 I believe it but it's still crazy to me because I used to build a VERY different style of race engine and yes, measuring rods was a constant thing to monitor. But that's because they got LONGER, not shorter. 30k rpm can stretch anything, LOL
The one example you used that didn’t follow said the blow off valve was open. Was it turbo or blower car? I’m sure that it won’t follow every situation but it was news to me when steve said that!! I was always told to remove 1* per pound of boost…but I also thought that was too much. Crazy to think it may be way far off haha
@ ok that makes sense. Turbos would still be generating some back pressure but with no positive manifold pressure it would have a disproportionate amount of exhaust gas still remaining in the cylinder…slowing the burn significantly as you mentioned. Then with the boost, it returns it to a more normal ratio. I’m sure if you had very high pressure ratios, you would also see the need for reduced back pressure and changes to timing. Do you have any examples that are not turbo cars? This has me very curious.
I heard Steve say as long as your fuel is "Tolerant" also. I figured yes Methanol is Tolerant, Steve's preferred fuel. A BBC requires a lot of timing. In your example "Boost Fixes Everything", so you needed less timing. How about another video on a GENII HEMI? You also didn't mention AFR, a lean mixture will detonate especially under boost. Anyway I just Subscribed. Thank you.
Informative video. However, you forgot to mention that not all fuels have the same volatility, and some fuels are heavier than other fuels for this very reason. You kinda missed that, and I feel that it's truly important to mention. Lots of factors in what Steve said. Steve jist didn't go into the details as to why.
@ ok....because its kind of another story with diesel....since its the injection of the fuel that make the combustion you need to add timing as rpm increase to have the combustion happening in a conservative degree of rotation of the crank....and even more as boost come up
I remember that in that video Steve was using/tuning on methanol. At the time I was triggered as well about his statement, but in the particular case of very high octane (usually alcohols, ethanol/methanol) and considering the cylinder pressure those engines can make for the given boost interval as well as the volume/bore of the cylinder in those engines... his statement probably was not been too much further from the truth.
I think I have left a comment or two (don't remember) on Steve's channel about the Sorceress, and of course your work at EFI-U. So, what's new for the Sorceress in '25?? They have been silent ... Great video, per usual.
Ben, one thing I've always struggled with as a tuner is twin plug setups. I've never had one on the dyno but I'm currently turbocharging a motorcycle with 2 plugs. I see in the video you have data for some of these engines, does it usually lead to an increased probability of knock?
I had decent computer software to simulate this back in 2005 and it wasn’t cheap, but it ment I could experiment in software not on an expensive customers engine . Steve is a hack!
@@busarob1969so where's your multi million dollar engine building business that makes your own engines with a cnc machine? You sound really jealous. Calling him a hack is beyond a stretch.
I remember EGR was introduced as a response to preignition from the crap gas we could get at the time. Sound like you are saying the opposite, EGR was there so they COULD advance the timing.
Very interesting and informative. I was under the impression that a hemi required less timing advance than a wedge due to a more centrally located spark plug cutting the distance of the flame travel essentially in half? Anyone?
I guess what Steve stated could be described as being (basically) right, but for the wrong reasons. Another example in this industry is the claim that LSA in and of itself determines engine behaviour. And just like the physical realities of creating working cam profiles mean that a given LSA on a given duration more or less correspond to given valve opening times (what matters), the physical realities of cramming more A/F into a given cylinder mean slower initial ignition (due to more mass needing to be plasma'd by the same energy spark) and an increase in exhaust remnants - which, like you mentioned, lowers the burn speed. By themselves and of course combined, these factors result in a longer combustion time than what "should" be and thus the need for more ignition advance than what "should" be needed. These circumstances mean that statements that make absolutely no sense when looking at them from a basic theory, chemistry and/or physics angle still can correlate to real world results - which in turn are where Steve, and the LSA guys, got their beliefs from: they've done it in the real world, they've seen what it did, they've (hopefully) thought about it and they've drawn their conclusions.
And remember that not all PSI’s are created equal. Boost doesn’t equal horsepower, boost is not a measure of power, more boost does not equal more power, more boost doesn’t equal a power number, boost doesn’t really say much at all…. Engines pump their own displacement every two revs, at any fixed RPM the engine CFM pumped is constant. The boost pressure does not increase the engine CFM, it increases the density of that CFM. It takes pounds of air not pounds of boost to burn pounds of fuel 🥳
Great demonstration Ben! Question, was the same fuel used in both the LS tests boosted and non boosted? If so what? Just curious if say a C14 or C15 was used N/A and how it would compare to say M1 boosted.
Excellent video, but i feel there is something missing from this conversation that ultimately changes all of the variables you presented, and that's the difference in fuel types.
The combustion profiles for pump gas, oxygenated gasoline, E85, ethanol and nitromethane are all going to be different, not only for their individual burn qualities but also for the optimum volume used with each fuel.
Also, just adding something to the argument, my experience with nitromethane would put me in agreement with Steve. Whether tuning for blown or N/A, the ignition lead stays constant at approximately 55 degrees for a dual plug or 65 for single plug application...this in a 426 style engine with 175cc combustion chamber. There is a difference in static compression between the two types of engines, but all else being equal (bore, stroke, cam profile) the duration of burn is the main factor and not how the chamber is pressurized.
i think you're right, there was no data shared about different fuels and i think it would make a substantial difference
Dewey sent me!
😂
Shop dogs rule!!
@@MattyEngland I feel like if I went to the shop I'd spend half my time drooling over the engines and the other half patting and playing with Dewey
Me 4 🐾🐾
Haha same
I got here from Steve's short also. Over the years I have learned so much about engines and tuning, especially after buying a dyno. I would say over 99% of the engines I have tuned are exactly what you are explaining here Ben, I have always had to retard timing with boost....
The one engine I was very surprised on though, was a turbocharged Gen 1 SBC in a drag race S10 pickup. Single turbo, low compression, conventional 23 degree head. I got involved when he made the switch to EFI, and had a local shop tune it (this was before I owned a dyno). He was disappointed with the power and resulting trap speeds when he got it to the track for the first time. He ran it like that for a while then asked me for help. I started adding timing and the trap speeds kept on getting better. I was coming from a pump gas turbocharged import background at the time and was extremely reluctant and uneasy about the numbers in the timing table. However, I knew that if it was going faster, "give it what the engine wants, not what you THINK it wants". We ended up right at what the NA engine liked all the way up to 30 psi boost pressure (we are at about 1,000ft. above sea level). Plugs showed the timing was right in the sweet spot as well. This particular engine really opened my mind up, and I'm grateful to have created a friendship with the owner and have drag raced with him ever since.
Another thing to just mention about this particular engine that is interesting is that we went through 3 different single turbo setups, ultimately ending with a big 98mm Garrett GTX5533R. We ran it up to 54psi boost, and up there it STILL wanted a lot of timing. I later figured out why when we installed back pressure sensors... The single was choking the exhaust too much and effectively diluting the mixture and requiring more ignition lead, just as you talk about here Ben. It still went faster, but the power gain per pound of boost was really plateauing. We ended up switching to a twin 80mm turbo setup, and made the same power at only 42psi boost pressure, just because of the more open exhaust. It took less timing as well, and as an added benefit we stopped having to replace spark plugs after 4 runs.
Anyways, that's already too much info in a UA-cam comment, but thank you for the great video Ben!
Thanks for sharing your experience! It's great to hear from someone with hands-on knowledge like you.
@@EFIU_Ben Since you're compressing MORE air, the cylinder pressure... and therefore the temperature will be far greater than n/a. The higher temps alone should dictate less timing. Now I'll watch your video and see if you come up with the same theory... but that's what jumped out at me while watching his.
Bingo @@n2omike
When I live in Japan I worked for a Japanese manufacturer's internal engine builder and parts maker for their racing programs. We also made prototype parts for future models. We had our own data from grA, GT300, GT500, Dakar rally, 24hr LeMans, Pikes Peak, etc... While I was there we started making street parts based on those programs. Our oil pumps, headgaskets, pistons, rods, cams, turbos and other parts were exactly the same as race version. But we added some cam options, oil pumps, water pumps and other parts based on racing but for street. Anyway, every single engine required less timing as we increased boost. We produced our own ecu and software too. It's not uncommon for our engine programs to have 30+ degrees at 0psi boost tapering down to 20 or even 12 degrees at 21psi and 28psi. We could add a few degrees after peak torque but didn't bother on most. That's on about 94-95 octane (USA rating) with pentroof 4 valve. If we wanted more boost then we'd remove the quench pads or use race gas. Keep in mind we could run 13:1 and extremely high egt for 30+ minutes with no damage. Of course we ran 11:1-12:1 and low egt for safety. These were 2.6 & 2.8 in line 6, 8.5:1 compression making 450-800+hp at the wheels. Oh and the pressure delta varied greatly between turbos. We even used old school clipped turbine wheels on some setups to reduce back pressure. Nonclipped would spool 1bar just before 3,000rpm and clipped version kick in at 4,500-5,000rpm lol. It ruined turbine efficiency but helped VE. They would run like big displacement NA engines from 5,000 to 8,000 rpm. I can't imagine running the same timing at different boost.
That said if engine makes peak power at 30 degrees and 0psi. But it could also run at 40psi and 0psi without ping then theoretical maybe it can make peak power at 30 degrees and 21psi were as our engines did at 20 degree. I wanna say air-cooled Porsche make peak power NA at something crazy low like 20 degrees but don't ping till 35+ degrees. And that's like Steve is saying. The combustion shape is limiting factor not fuel. Need a "hotter" combustion design. But then again on air-cooled you probably can't keep cylinder head temperature under control if the combustion design was pushed harder
So Nissan RB engines. Interesting.
SM is using methanol so that may change things.
Remove the quench pads for more boost? Internet says no quench causes detonation sooner? Remove pads to lower compression? A 2jz ge , with a gte head gasket will have lower compression but you have too much space on the quench pads for them to work. If I want high h.p. boost, do I run no quench on the ge (thicker gasket ) or run quench with stock gasket thickness giving higher compression?
2.6L and 2.8L inline 6's commonly running 8.5:1 compression in those series with a manufacturers internal engine builder... so Nismo RB26's 🥳hell yeah, thanks for sharing that.
@@jasonschreiber6458 its not that no quench makes detonation happen sooner(it doesn’t), improper quench does. Theres a middle ground between good quench and no quench where you run into detonation issues. The chamber is shaped much different for a no quench build
I love data as well. I don’t care who right or wrong I’m excited I found all this knowledge your willing to share.
I'm all about sharing the knowledge!
“you’re”
Chill Karen.
The fuel you choose changes everything with timing
Just saw Steves short about this so had to check it out
Love to hear what you think?
@EFIU_Ben really enjoyed it and was interesting to go into so much detail and things I've never thought about. Would love to see you team up with Steve to do some testing
@@EFIU_Ben IMO, it would have everything to do with quality of the air fuel ratio. This would effect a naturally aspirated engine the same as a boosted engine. IMO, changes in the air fuel ratio AND the quality of atomization is the root of the timing differences. (I'm thinking the routing of the air/fuel mixture to the combustion chamber causing the fuel to drop out of suspension)
Just my guess.
BTW, I LOVED this thought process!
just about to watch this, but Steve reckons you are all about Data 🤣 I think you can take that as a compliment
Ditto
Steve can be right and wrong. He can also divide by zero. Chuck Norris is the only other person to do this. Good job tho.
We need a temperature overlay. As there's a density shift and the speed of sound changes. Would love to see this. 👍
When you talk about 426 hemi. When Dodge wanted the old men to run the new hemi instead of the 392 that everyone else was using. Gar couldn't get it run hard like the old one , in frustration he cranked the timing up, way up, said Gar, well that was what was missing way more than they ran in the 392. Ask him
the reason he cranked the timing up in the first pace was he wanted to blow up the engine so he could go back to the 392 Hemi. the car went something like 210 at 40 degree's timing and the nhe upped it to 50 and it was even faster.
True; but i think it was becauce nitro fuel burns extremely slow. Not sure why the 426 was so much different than the 392 using the same fuel.....maybe larger chamber?
The wrong cam will also act like EGR, I have guys come up to me at car shows and tell me about overheating problems that they just cannot fix. My first question I always ask, have you looked into the intake manifold for your problem. Never thinking the engine is eating it own exhaust, so the intake is black all the way back to the base plate of the carb.
good point
BINGO !
If you look at the posts in Steve's video, I said the only way to properly set timing was via cylinder pressure. Finally someone using real science instead of folklore. Great video.
"real science" Don't forget your 37th booster shot! ha ha
And?
It's crazy that people with this much leverage can say whatever they want without using the basics of engines 101. I always checked out his timing maps and it amazes me that there where no more than 3 different numbers in the whole timing map. Good for you educating us with proper info!
Everyone can say whatever they want, no "leverage" needed!!
There isnt as much of a need for timing change in a methanol drag engine thats built to handle 5000hp. We pull timing in average street engines because the fuel and engine assembly cant handle it, his engines on meth can handle it
I like that you ended up with the same conclusion as me and a humble attitude at the end. What he said is definitely a good rule of thumb and seems like it was mostly said to get people out of the old way of thinking: “pull lots of timing if you have lots of boost”
Excellent video Ben. I admire you for being at the top echelon top be able to get in cylinder pressure data - it so interesting to us engineering nerds!
Glad you enjoyed it! It takes a lot of work to get that data.
Flame front propagation across a large piston .............. we find that alive and well in the 1939 technology of your aircraft engine. Another great video!
It's interesting to think about how these concepts apply to aircraft engines even from nearly 100 years ago!
@@EFIU_Ben, it's interesting to read Harry Ricardo's work and realise how nothing really has changed in _more_ than a hundred years. ;-)
THANK YOU for doing what I wish I had the resources to do!! This is the comment I posted on Steve's video: "My answer to your question, "why do we need to decrease timing when going from NA to boosted?" The mixture will be extremely tightly packed in the same size chamber as before. Oxygen molecules will be very close together and when the flame front starts, it will propagate VERY quickly when compared to a more sparsely distributed mixture. Peak cylinder pressure will then occur much earlier/sooner/faster - so you take away timing to keep that peak pressure occurring at the correct time. If this is untrue I might as well throw my engineering degree in the garbage." As you'd expect, he did not reply.
Sounds like you've got a good understanding!
Going with the LS example here, your engineering degree can be binned. Obviously it is more complicated than your training tells you or that test wouldn't have had the result it did. There are many variables to how an engine functions, as shown here, there is not a one size fits all answer. I can see why he didn't reply, nobody likes a know-it-all commenter.
I think you are missing one point which I believe may be part of the basis for Steve’s comment. While I agree that a mixture with more densely packed molecules will burn faster. In a boosted application you have a lot more molecules that have to burn. So while the mixture may be burning faster it may end up taking close to the same amount of time to burn all the molecules as it did in the na version with a less dense mixture.
SM is running mostly methanol fueled engines under high boost....so the additional cooling you get from increasing the amount of fuel in the chamber tends to offset the potential faster burn rate. In his engines....and LOTS of dyno development....they just don't need ignition retarding at higher boost levels on methanol.
Also remember that they are not running the engines at the ragged edge of timing....stay safely away by reading the sparkplug ground strap colors. There's no need to run dangerous amounts of timing because all of his really powerful setups need to be tamed down in the car just to get through a pass without blowing off the tires. Many 'it depends' here and Steve was only saying what HIS engines like and there are NO 'Universal Truths' being violated.
How does spark plug gap affect the whole thing. We had an engine with MSD ignition and the plugs were .025. Opened them up to .055 and it ran much much better.
Resistor type plugs need a decent gap to build up a resistance so when the spark occurs its fat, as if it was being held back. If the gap is too close on the resistor plug the gap is easily achieved and the weak spark makes it across before optimal resistance is achived. Kind of like setting a pressure regulator to low for the injectors, when the injector opens not much pressure. Set high pressure on the regulator, when the injector finally opens, bamm! Not a perfect analogy but tried another way to describe it if the main concept didnt connect.
if it's too big its like regarding the timing, the spark has to jump and the longer it takes the engine as turned more degrees,
Greg's Airplanes just did a similar video. Its rather interesting that NACA did studys on this to improve aviation engine efficiency back in the 40s. It would be cool to see your burn time data with just changing air fuel ratios and fuel types.
Those guys really knew what they were doing back then!
@@EFIU_Ben Actually, they kind of didn't. That's why they had to do all those studies and testing, just like you're doing now, so they could learn and now we all know what we're doing, all thanks to them.
@EFIU_Ben Yeh. I just realized that the testing data gose back as far as 1925. If you think about it, the data in general makes sense. If you look at the air fuel ratio and disregard the boost. The burn time of a set air to fuel ratio is going to be the same regardless of boost pressure well to a point.What you said about the hemi makes sense it. It literally quenches the air fuel mixture, causing a slower burn. I think that is how the term quench area came about.
@@wingracer1614 Actually we all kinda dont know what we are doing.
What we know now will become obsolete just like the knowledge gained in the 40's
Seems like Steve gave you the parameters of his statement, safe fuel ie quality race fuel, safe compression and boost levels, and safe combustion chamber design and safe timing numbers. I think it's important to recognise that Steve Morris builds drag and drive engines, not max effort, race engines and what he finds an engine needs to put thousands of miles on the road and race is different to a rebuild every x number of runs. So, in conclusion, as you stated when you build an engine the way Steve does you get the same results and when you do different engine designs and intended use you get different results. From your results it seems like air and fuel prefers somewhere in the .8 to 1.1 time range to complete a combustion event regardless of variables
Great video Ben! What is your opinion on mixture motion inside the combustion chamber prior to ignition. High swirl /tumble heads & tight quench-high mixture motion, vs low swirl/ tumble & chamber softening-less mixture motion. Thank you.
Newly Subbed from SM. Have you got any data on port water/meth injection and its effect on cylinder pressure, detonation and timing ? Love to see a video on that.
Thanks, I'm 65 and learned a lot from this....
Glad I could help!
An engine wants what an engine wants. Optimize the combination and what you get is all of its potential.
Well if memory serves Steve was sayings boost vs non boost on his motors, not all motors, so that eliminates many of the variables that change. You make good sense and is not surprising that different configs need different adjustments. I was taught that with cylinder pressure, that the math is stable regardless of motor (as long as it was a piston pushing on a crank thru a rod) that peak cylinder pressure at 12ish degrees after TDC was universally desirable. So, back calculate from that the combustion time, at different RPM and Boost etc to back calculate your ideal ignition map. Have you ever indexed your data to the peak pressure vs crank position?? Thoughts?? Thanks!
We look at peak pressure amount, and crank locations but more importantly, we look at the area under the curve and how much % of mixture has been burned at certain crank locations. Typically we look at the value for "CA50" or the crank angle where 50% of the mixture has been burned, because this is a much more reliable indicator than peak pressure locations such as "X number of degrees after TDC"
True but just want to point out, he builds and dynos a lot of stuff other than just his own engines. BBCs, SBCs, LS, Hemis, heck even Rotax and Lamborghini.
@@EFIU_Ben Thanks Ben for the reply. I know my info is getting dated, I wish I could be uber familiar with and testing and learning this stuff even as a hobby. I think its fascinating.
Where the spark plug is located, what type of plug, and AFR. A fatter mix burns slower BUT it creates more pressure. If you pack it up you make it denser, thus it burns faster, but if you add more fuel, it burns slower again. If you run it rich you create carbon deposits inside the chamber which then heat up and cause pre-detonation. If you add more fuel and boost, reduce the advance, you end up with unburnt liquid inside the chamber that doesn't compress, lifting the head from quench area. Then there's cam timing. When your exhaust valve opens, the leftover pressure escapes. this pressure spins the turbo fan and heats it up. This heat travels through the turbo heating up your oil and your compressor fan. If you have overheated your cold side before, this heating fan expands and makes it tighter, heats up your intake air, showing more boost on your gauge. Then you cool the temp down with your fuel, but your AFR is still out of whack and your flame front is escaping into your exhaust. Also your liquid fuel flushes your piston rings creating more friction, making them lose tension, while the hydro lock collapses your ring lands. When the blow by escapes into your crank case the flame front follows welding your rings into your piston. Then your piston heats up, so does your rod, your rod expands, and your piston sticks to your cylinder bore. Rod gives up, piston shoots up into your valves and the run is done.
An exciting run indeed..
"In God we Trust all others bring Data!"
Couldn't agree more!
I asked god about this he said its all wrong, so now what are you gonna do?
The only factors I have in question are camshaft profiles and temp of the cylinder before, after and during the combustion process. Was the sorceress different because of water flow and the cam profile it runs?
I feel there is alot of actually important factors omitted in the video that would help explain why ignition timing may not or may need to be adjusted based on the cylinder charge.
1. MFB50 and its relationship with MBT and their joined relationship with the engines geometry
2. The resultant pressure curve vs engine geometry in relations to timing
3. No engine is "NA" , without a turbo or supercharger or n2o the atmospheric pressure is the power adder
4. No mention of IMEP and how it is derived, it would explain exactly why timing needs to be moved to alter the power output to reach the peak power output
5. All pressure on the pistons upwards stroke is a loss and all pressure on the downards stroke is a gain, that includes intake stroke. Geometry here dictates how that piston pressure translates into torque(the instantaneous torque at X crank angle) or torque loss.
6. Variability in turbulence, general understanding is that turbulence goes up with engine speed as well as higher density air charge. Here geometry of the combustion chamber comes heavily into play. Engines can need 15°BTDC ignition at 30psi and 40psi and that would entirely be due to turbulence coming down with higher air charge.
Agreed, I’ve seen the same with cars I’ve tuned some I was surprised that I didn’t have to pull timing but for most setups timing was pulled, never thought about the surface area though, that some good info (as always from you channel) I always attributed it to egr’ing from back pressure.
Man I would love to see the ve and ign map from that supercharger LS after you installing this Kistler sensor, actually before and after if the maps were both boost to really the advantage of that data.
Lots to unpack there, I’ll see if I can get a video made to cover some of that!
Back in the '90's, I read an article in a snowmobile magazine about a gentleman who was testing cylinder transducers in a two-stroke engine. As I recall, he was trying to eliminate the carburetor for a better EFI system regardless of load, temperature or altitude. Not sure how it ended but this sure rhymes
Yumm combustion dynamics, flame propagation. cylinder pressures, I love this stuff! Produced torque vs cylinder pressures is what I really like to look at. I want the highest torque with the lowest cylinder pressures. That is efficiency and longevity.
Wouldn't you also want to take into account exactly where peak pressure of the combustion event happens in relation to tdc? I get measuring the duration, but during that roughly 1 ms of combustion the peak pressure could be .4 ms or .6 ms from the start. I would think that would also determine where to set spark.
Peak pressure location is important, but we focus more on when the mixture is being consumed and adding "area under the curve"...we call out specific locations such as "CA50" where 50% of the mixture is burned
Where did you get the software? This guy nailed it.
Great information thanks for sharing
Is there a trend for modern cylinder heads not needing timing changes?
not that I've seen
@EFIU_Ben have you seen any patterns that woukd allow you to predict when to change and when not to change?
Can you also determine the exhaust stroke efficiency by using the combustion pressure sensor, and thus see if the engine had more egr in a boosted application vs na? also, no mention of the AFR target change when switching from boosted to na. a rich mixture will typically require more ign timing. Interesting mapping the combustion time data. Would is there an advantage in using peak pressure angle instead, or a combo of both? (one is used to map the other) If the inlet pressure is elevated, and the exhaust pressure is not would the intake port velocity increase and possibly create a state of poor atomization in some applications? Could touch on inlet temps as well. lots and lots of things contribute to the ideal ignition timing for a given combo. one more thought here, the duration of a pull is also important in finding MBT. If an engine took 12 seconds to make a run, the chamber temp will be elevated more than an engine making a run in 5 seconds. The shorter duration run would tend to want more ignition timing do to the lower chamber temp, valve temp, plug temp etc.
I was told the LT-5 has one of the best combustion chamber designs of its time. They respond really well to additional timing.
I wonder what technology Lotus was using back then in the mid 80's because they seemed to have nailed it with that engine.
I started in the engine reconditioning game when I was 16, that was 1985, I have worked in the performance race engine world, for many many years I was tuning engines, race engines, be it on a engine dyno or a chassis dyno, before retirement , I owned a performance motorcycle shop, with a motorcycle chassis dyno, building turbo bikes, nitrous and all motor engine.
I can tell you from a life long experience, Steve Morris is wrong a lot of the time. I remember watching that video and his claims about ignition timing . Building peak pressure at a specific degrees after top dead centre is vital for engine performance and longevity.
Many factors affect this, boost, fuel octane and burn rate, atmospheric pressure, humidity etc. I used computer models to determine at what degrees after top dead centre would be best for peak torque and what cylinder pressures would be there at or before that point.
On the dyno we play with ignition timing to find these peak torque figures and determine a safe ignition timing figure for the fuel we are using.
Steve videos only show again and again what he doesn’t know!
One of my old bosses use to say, a “ EXPERT” Is a drip under pressure! Steve is just a drip under pressure.
His videos look great for those who don’t know , for us that do, those videos just show us, he knows very little and has almost zero technical knowledge. The proof is how he tries to babble around a technical issue .
Then have a look at the stuff that stumps him! Again proof he lacks the technical knowledge. He is nothing more than an experimenter and knows what he knows by his failed attempts.
This is a costly way to learn, and it’s costly for his customers !
And that engine he sold to Cleetus, that had the main cap failure, look at all those sharp edges, just waiting to start a crack.
This is 101 of race engine building, remove all stress points. Radius all sharp edges. Not Steve and look at how they failed!
And in earlier videos he showed a main cap failure and states the crack started and the sharp edge, yet in that later Cleetus video he say he never seen that before.
That engine sold to Cleetus was just a grenade waiting to happen, I look forward to seeing how this engine goes in Val’s Camaro.
I'm thinking taking lot of timing out. Either there is a tuning problem or you are doing it on purpose to slow the car down?
You are the best at figuring out how to measure, record, display, and explain what an engine is doing. Kudos! Those pressure transducers can be so formative!
If too much surface area is a problem, how does it affect piston domes? So domes are actually more inefficient than we think, besides the airflow limitation is also impacts.
Awesome video Ben. I'm a DataHolic that's been racing and tuning motorcycles for 50+ years and in the end, it's always been about giving each engine what is wants/needs. I'm shocked that you don't have more subs but I'm guessing that number is rising tonight 👍
So if you didn’t have the different wet maintained grass mixed with the ratty dry grass, you’d have a better burn.
The more efficient a combustion chamber, the less timing will be required.
Boost situations have the probability of changing chamber efficiency.
Treat every engine the same way only different.
Ignition timing is very important.
I watched a video of magnetos coming off and tumbling down the track from a top fuel dragster that was still firing down the quarter
I'm surprised that timing could end up back at the same place as NA. Can you do timing for E85 vs pump gas? I'm tired of hearing of the "cooling effect" being the source of increased power.
beside “cooling effect”，the only main factor for timing chose is how much fuel mixture speed up the flame font and the water be brough into chamber that slow down the burn
4.0 in 660 feet Sir.
What's your tune up for ANTHING U own other than a pencil.
Real world is out there SIR.
Not sure Steve and others understand timing number we use is negative work done. IE making crank go slower. But there is more being done when after TDC but is it enough to where average power is higher. The goal should be most power not stuck on a certain number. You won’t ever use 40° on a twin plug engine…and make more average power post TDC.
76 PSI of boost reacts differently from 20 PSI. The number of molecules present, the temperature differential between the air and fuel molecules, and the time it spends under those conditions are quite different.
This is a great channel for people that want to really learn things about how engines really work. I enjoy the science aspect of how he describes these processes. The ability to gather all this data and be able to come to meaningful conclusions that really describe what is going on inside the cylinder is terrific. We never stop learning.
fuel tolerance is what i got out of that from Steve, what you can get away with potentially. awesome data sir. thank you for letting such expensive hard learned data out to us plebs.
Thanks, glad you found it useful!
Seems like a segway into you and steve doing some testing together? I think that would be a awesome series. You guys beating on a motor with different setups with his motor skills and your data skills alot could be learned.
Can you show data on thermal barrier coating when on head and piston
There’s a way to do this without drilling into the head
Had a set of 8 spark plugs that were made by drilling into the nut and comes out into the combustion chamber had a jeweler micro weld a stainless tube onto it and ran it through an expansion coil to even out the pulses and it gives a better reading and you can save the heads and collect the data on several different platforms without ruining the heads it was really cool to see and cost all of $800
What sensors did you use with that?
Wouldn't the additional volume of the coil cause issues?
So by injecting water, you made the fuel tolerant?
it dose slow burn prosses, but also make you benefit from greater expand rate to save fuel
Have y’all done any work with passive pre-chamber ignition?
Came over because of Steve Morris. Subscribing. I like data, though sometimes it's hard to understand.
Glad you came! Happy to have you here!
The only way I can see that it's physically possible for what steve said to be true is if the volatility of the mixture was unchanged between the two test conditions. I'd go so far to say that if it still takes the same timing after adding boost, its because you have added unfavorable conditions when you increased the boost, probably in the form of an EGR effect from an exhaust that has become more of a restriction.
Different octaine does not have different volitility? You said it does not have an effect? Just want to double check.
Curious on sizing on those 2 engines
Awesome video Ben. When I saw the Steve video I was in shock about his statement.
Thanks
I wonder if Steve is going to say something about your statement of superchargers causing more exhaust back pressure??
Totally agree with what you say, adding to that the stroke it will affect the timing as it will change the speed of compression and power time.
I have been looking for a channel like this for a very long time and I immediately subscribed. As a former race engine builder and cylinder head porter I have always wondered how the effect of intake port design and specifically combustion chamber roof and floor design (piston dome or dish) effects the speed of combustion. There has been some books written about these theroies of combustion swirl in diesel engines but a gasoline burning high RPM engine is a far cry from a low speed larger stroke (IE. slow mechanical event ) diesel engine. has there been any test data thats available to study on this subject.? TY
I’m glad you found the channel! It is something we are working on! We do sell some videos on cylinder pressure measurement on our website and also discuss these topics and many others weekly as part of our Delta Lambda Fraternity you can learn more here: www.efi101.com
I always thought higher octane meant more of a resistance to burn, where there are more short octane bonds that are harder to break versus a lower octane fuel's greater presence of the longer easier to break heptane bonds. Therefore more resistance to burn equals more timing needed. At least this is what the famous calibrator Greg Banish mentions in his books.
You mentioned octane is resistance to detonation and that makes perfect sense, but isn't that essentially the same thing as "resistance to burn" just another way of stating that any burn (whether intentional from spark or unintentional from detonation/preignition) will be harder to begin with higher octane, and thus require more ignition advance for ample time to burn?
I understand the other factors you mentioned that influence timing requirements, I just thought octane was one of them based on literature from other professionals.
It's the same exact reason we run vacuume advance to advance the timing at part throttle... less air and fuel in the chamber takes longer to burn needs lit earlier. As for the gen III Hemi, they like less advance than LS engines and it's why Chevy tuners break hemi pistons when they try to find them like an LS.
U send this to Richard Holdner?
Can you make a video discussing your thoughts on Cattledog Garage's camshaft LSA videos, especially after the Weingartner camshaft challenge?
I wish I could, but I haven't seen it and I'm probably not smart enough anyway!
@EFIU_Ben you are just being modest. The good part of the video starts about 30 minutes in and I would listen to it at 1.5x speed if I were you
Just gotta love when someone rips out the cylinder pressure data and shows the fuel mass burn time etc!
Combustion efficiency is where we find the good stuff 🤌
Thank you!
Thank you Ben. I really enjoyed your Drag Racing school last year in Bowling Green. When are you coming back? Enjoyed the video. Thanks for using “real world” experience and data to set the record straight. Frank
Thank you!
This is very interesting and will clear up some misinformation and help people to understand it in the full spectrum. Thanks brother. Back in the day with leaded fuel my old 327 / 350 not modified 32 degrees all in with Dist advance curve with vacuum source was the max I could go before it hard cranked and that`s when I knew to back it off just a bit and get rid of the ping.
Yes! The old school way of tuning is still super helpful!
I think terms like , flame propagation, flame front and flame hatching out should be added to this discussion. And you are burning faster if you burning more in the same time frame hp.
Are there anymore Sorceress videos coming out?
I'm sure there will be lots more to come!
@@EFIU_Ben Thank you! We would gobble up some spintron videos too 😁
Absolutely brilliant. Very well explained, with actual data to let us understand exactly what's going on.
Your data driven approach is very refreshing, and reminds me of Gale Banks approach.
Thanks!
ben go easy on the guys. you have the brains and brawn. i think we are lucky to have all of you! To every engine builder or machinist ect, salute.
Basically, the flame speed goes as the air density, so it follows that higher density reduces the Time to peak pressure....The efficiency of a system can be judged by how much advance is necessary to get peak power....Mostly....
Measuring and comparing air density, air flow volume, fueling rate, combustion temperature,and exhaust pressure should show how much EGR effect/cylinder evacuation there is. I think Steve needs some combustion sensors!
Hey Ben. I just wanted to say this is absolutely amazing info! Really gets me thinking. I do have a question. Are you going to go into further depth on this topic? I just had an idea. Maybe covering burn rate and timing for say an open chamber head vs closed and ls vs hemi? Just a thought. Awesome job and great info! I wish I had the equipment to do all this because I most definitely would!
Hard to get all the data for so many combos! But maybe we will look at trying to do something like that soon!
@@EFIU_Ben yea sadly your right. I got a little too excited after seeing this video and thinking of all the possibilities. It would be a big undertaking to do a bunch of engines. What can I say I guess I really like to see the data!
There's no substitute for data. Data is truth. Thank you.!! 🙏
Good arguments I,m wondering what your pressures would be in a nitro engine ours we run approximately 60 degrees timing due to slow burning of nitromethane
I haven't measured one (YET!) but I'm told their cylinder pressures aren't necessarily way higher...they just last for a REALLY long time after TDC and continue pushing the pistons down HARD!
@ yes pushes hard is an understatement we constantly measure the rods each pass as they get shorter due to pressures exerted on them
@@jeffthomson1777 I believe it but it's still crazy to me because I used to build a VERY different style of race engine and yes, measuring rods was a constant thing to monitor. But that's because they got LONGER, not shorter. 30k rpm can stretch anything, LOL
The one example you used that didn’t follow said the blow off valve was open. Was it turbo or blower car?
I’m sure that it won’t follow every situation but it was news to me when steve said that!! I was always told to remove 1* per pound of boost…but I also thought that was too much. Crazy to think it may be way far off haha
turbo...thats how we were able to keep ot from making boost as even with the gates all the way open it would still make some!
@ ok that makes sense. Turbos would still be generating some back pressure but with no positive manifold pressure it would have a disproportionate amount of exhaust gas still remaining in the cylinder…slowing the burn significantly as you mentioned. Then with the boost, it returns it to a more normal ratio. I’m sure if you had very high pressure ratios, you would also see the need for reduced back pressure and changes to timing. Do you have any examples that are not turbo cars? This has me very curious.
Id love to see you have a look at Adam Lz’s video about gains with bigger injectors at lower duty cycle in NA applications, its interesting
I heard Steve say as long as your fuel is "Tolerant" also. I figured yes Methanol is Tolerant, Steve's preferred fuel. A BBC requires a lot of timing. In your example "Boost Fixes Everything", so you needed less timing. How about another video on a GENII HEMI? You also didn't mention AFR, a lean mixture will detonate especially under boost. Anyway I just Subscribed. Thank you.
Air density requires less boost. As in single, or twin turbos.
Informative video. However, you forgot to mention that not all fuels have the same volatility, and some fuels are heavier than other fuels for this very reason. You kinda missed that, and I feel that it's truly important to mention. Lots of factors in what Steve said. Steve jist didn't go into the details as to why.
Very interesting...you have any data on diesel engine?
unfortunately, no...most of my work is on gasoline powered racing engines
@ ok....because its kind of another story with diesel....since its the injection of the fuel that make the combustion you need to add timing as rpm increase to have the combustion happening in a conservative degree of rotation of the crank....and even more as boost come up
I remember that in that video Steve was using/tuning on methanol. At the time I was triggered as well about his statement, but in the particular case of very high octane (usually alcohols, ethanol/methanol) and considering the cylinder pressure those engines can make for the given boost interval as well as the volume/bore of the cylinder in those engines... his statement probably was not been too much further from the truth.
I think I have left a comment or two (don't remember) on Steve's channel about the Sorceress, and of course your work at EFI-U. So, what's new for the Sorceress in '25?? They have been silent ...
Great video, per usual.
You and Richard Holdener should run for president and vice president and you can have Steve Morris as your defense secretary
Ben, one thing I've always struggled with as a tuner is twin plug setups. I've never had one on the dyno but I'm currently turbocharging a motorcycle with 2 plugs. I see in the video you have data for some of these engines, does it usually lead to an increased probability of knock?
I haven't seen any data that would suggest that having twin plugs affects the probability of knock.
@@EFIU_Ben That's great to know, thank you! I wasn't going to bother wiring both up, but I will now. Can't wait to get it on the dyno.
@@EFIU_Ben Twin plugs reduce the probability of knock, as there is less time for the end gases to heat to the point of detonation.
Great lesson! Combustion analysis for the win. Science, Not Speculation!
Spot on myth busting information from a guy who messes with an obscure flat twin hemispherical combustion chambered engine.
You nailed it!
Steve is simplifying it a lot, probably due to lack of knowledge.
Its nearly impossible to get access to this kind of actual data, so I wouldn't feel too bad if someone didn't know this stuff!
I had decent computer software to simulate this back in 2005 and it wasn’t cheap, but it ment I could experiment in software not on an expensive customers engine . Steve is a hack!
@@busarob1969so where's your multi million dollar engine building business that makes your own engines with a cnc machine? You sound really jealous. Calling him a hack is beyond a stretch.
@@EFIU_Ben A lot of what you are talking about is just plain old physics.
WOW THIS IS NUTS I GOT TO HAVE THESE SENSORS OR AT LEAST MY TUNERE DOES , THIS COULD REALLY CHANGE THE TUNNING PROCESS , AWSOME BROTHER
I remember EGR was introduced as a response to preignition from the crap gas we could get at the time. Sound like you are saying the opposite, EGR was there so they COULD advance the timing.
Very interesting and informative. I was under the impression that a hemi required less timing advance than a wedge due to a more centrally located spark plug cutting the distance of the flame travel essentially in half? Anyone?
I guess what Steve stated could be described as being (basically) right, but for the wrong reasons.
Another example in this industry is the claim that LSA in and of itself determines engine behaviour. And just like the physical realities of creating working cam profiles mean that a given LSA on a given duration more or less correspond to given valve opening times (what matters), the physical realities of cramming more A/F into a given cylinder mean slower initial ignition (due to more mass needing to be plasma'd by the same energy spark) and an increase in exhaust remnants - which, like you mentioned, lowers the burn speed. By themselves and of course combined, these factors result in a longer combustion time than what "should" be and thus the need for more ignition advance than what "should" be needed.
These circumstances mean that statements that make absolutely no sense when looking at them from a basic theory, chemistry and/or physics angle still can correlate to real world results - which in turn are where Steve, and the LSA guys, got their beliefs from: they've done it in the real world, they've seen what it did, they've (hopefully) thought about it and they've drawn their conclusions.
And remember that not all PSI’s are created equal.
Boost doesn’t equal horsepower, boost is not a measure of power, more boost does not equal more power, more boost doesn’t equal a power number, boost doesn’t really say much at all….
Engines pump their own displacement every two revs, at any fixed RPM the engine CFM pumped is constant. The boost pressure does not increase the engine CFM, it increases the density of that CFM. It takes pounds of air not pounds of boost to burn pounds of fuel 🥳
Awesome video! Awesome data. I watched the whole series on the Sorcerous. That was very interesting as well. Thanks for sharing the info.
Glad you enjoyed it!
I’m here for an actual answer. 😂 Yes/No? Right/Wrong? Both/Neither? 😂😂😂😂😂😂
Great demonstration Ben! Question, was the same fuel used in both the LS tests boosted and non boosted? If so what? Just curious if say a C14 or C15 was used N/A and how it would compare to say M1 boosted.
Yes it was
We used VP MS109 for both!
@@EFIU_Ben That's funny, just out of curiosity to see what the specs are I just check it out on VP web site and it says sold out 😁