Slant Six - Holley Vs. Weber Side Draft Carburetors
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- Опубліковано 16 лис 2021
- A video by a fellow UA-camr from Australia may have the ultimate answer to this debate based on something we observed during a dyno session with a 225 Slant Six.
WILD SLANT SIX - 225 Chrysler Build and Dyno | Iconic Engine Series : • WILD SLANT SIX - 225 C...
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#engines #mopar #265Hemi - Авто та транспорт
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I'm going to play devil's advocate- Just watched the Wild Slant Six video and believe the phenomena to be visible condensation in a low pressure area. If the temperature and dew point are close in that dyno room, then the air pressure drop in front of the carbs would chill that air and the moisture in that air would become visible. Something to consider.
Most of the "condensation" is originally from the venturies, watch closer
@@tinkersspeedshop8401 have you ever seen an airplane take off on a cool humid day? A cloud forms over the wings and dissipates at the trailing edge. I have seen it thousands of times with commercial planes, C17s, C141s, and all manner of fighter jets while I was in the USAF. It doesn't happen all the time, only when the conditions are right. C17s have a very high lift wing shape, so they did it far more often than other planes. You can see when a fighter flies through humid patches at the right temp in some videos, because clouds intermittently form over the wings and vanish, like someone is flipping a switch. Its really cool.
Its probably a combination of both reversion and low pressure areas to be noticeable.
He’s trying to justify doing what everyone in America like to do. If the big 3 had used side draft carbs. They would have save Americans millions of gallons of gas.
After using DCOE Webers on small block Chevy cross ram some 20+ years ago, I became a believer in the fantastic tunability that Webers have built into them with the jet stack, individual manifold length, and the ram tubes(velocity stacks) on the mouths of the carbs. You can do virtually anything with these beautiful carbs. When the Chevy was properly tuned with those carbs so many years ago, they would just MOAN when you stepped into them. The sound never failed to draw a crowd and run chills down your spine. A KEY PART of the tuning process is getting the velocity stacks and air cleaners (K&N in my case) the proper length/volume to deal with the "stand off" at the mouth of the carbs that leads to the loss of power or tuning of the torque at the wrong rpm for what you are trying to accomplish with the engine power range. If you combine the above with a header/collector that is set up for the rpm designed to pull the exhaust thru the motor at the proper range, you've got a winner. Good Luck to ya, Tony. Keep the Faith, Tom P.S. Using the Holley with the proper plenum volume is an attempt at the same effect.
That standoff is why the old air cooled vws had such a tall air cleaner assembly, the standoff could be like 5-6"
Will a set up like that work on the strip with an automatic or something more like a close ratio gear box?
I agree I ran triple webber's on my 2.8 datsun 240 z
@@moparsquid Bet that was a nice set-up.......wouldn't you love to have it back today?
If you like the moan of a DCOE, try putting it less than a foot from your ears like it is in my Europa. "We don't need no stinking stereos."
Never heard it called reversion before. When I was younger, it was called "stand-off", and ideally you wanted to be able to have intake trumpets long enough to enclose it if you had the space under the bonnet. Old Minis running a Weber DCOE tend to get quite a bit of standoff also, and i doesn't seem to be detrimental to power or torque output.
Agreed. You adjusted the runner length for the power band area you wanted to run, then the velocity stack length to prevent the reversion outside of the stack.That's why a lot of the Hilborn injectors used such tall stacks.
Well you call wrenches spanners too right? Boot and bonnet rather than trunk and hood.. Different words meaning the same thing depending on what country you live in.
@@SweatyFatGuy Well, yeah...but I've lived in the PA/NJ area for 30 years. Still never heard it called that. Not claiming it's wrong or anything, just odd I'd never come across that term before.
Reversion is just the general term for fuel-air charge coming back up the intake tract, even if it doesn't make it's way all the way outside the motor like the example given here. It's a large part of the reason why a big cam is "choppy" at low rpms and is a really common phenomenon, just not usually a visible one.
I looked up the Ram effect formula in the book “We We’re The Ramchargers”. It relates the length of the from plenum to valve head to the RPM at which the ram effect is desired L (inches)=84,000/RPM. So those stubby manifolds say 6”, are tuned to 14000 RPM. Hence the reversion
For an engine that HP peaks at 5700 RPMs and a way too big 7,500 RPMs cam for the available head flow...
Weber DCOE or Dellorto DHLA is the way to go ultimately. Every aspect of tune is adjustable, including adjustable VENTURI sizes(adjusts velocity wherever you would like it) and fuel EMULSION tube variables for mixture settings high/low, and everywhere in between. 4bbls are just a cheap & convenient way to dump a shit ton of un-atomized fuel in a V8.
Don't talk crap fanboi.
4bbls do atomize the fuel properly.
I can see that because you don't like 4bbls then anyone elso who likes them is ignorant.
The 4bbl dual booster venturi has been out now for at least 50 years - Please! You geese crack me up. You remind me of a those religious idiots that knock at your door on the weekend.
Glenn Everett is awesome. Absolutely a great bloke. Ran a dyno and performance shop but has been firstly tv and now UA-cam for around 10 to 12 years now and an absolute wealth of knowledge on not only aussie cars but many others too.
Webers on an inline motor normally have a very short intake manifold. On a motor that spins fast, like an Alfa Romeo that's probably fine, they run best at high RPM. On a Slant I'm thinking you'd want them longer to match the lower RPM range.
I'm no engineer but I'd bet neither are the folks that designed the Slant Six Weber manifold.
In Australia, we had a (non-slant) straight 6 Hemi from the factory with 3 side-draught Webers. With the Slant having the head leaning to the right and the carb on the left of the engine bay, there should be room for significantly longer manifold runners.
Remember to keep the entire length of the carb and inlet stack in mind.
@@aussiebloke609 the 'hemi 6' was in the vg's on ,
about 69ish from memory,
chyrisler aust was playing with tripple Weber's on 'hemi's' since 68 ish
tbf, the runner length on this Slant is MUCH longer than an Alfa Romeo DCOE runner. The last time I had my hands on a Fiat DCOE intake, the short part of the runner was about an inch long, the long part was about 2" long (the manifold to head surface has a 45 degree angle, it's a straight shot from the tip of the velocity stack to the downward curve to the valve inside the head)
His slant dropped off at 5700 RPMs, a Fiat or Alfa motor will easily rev to 7500, but I don't recommend doing it on a mountain road in Oregon when you're more than 2500 miles from home....
@@alt7488 Yeah, VG was the first hemi 6 - in '70. But the VG Pacer only came in 2 bbl (regular Pacer and E32) and 4 bbl (E34 only)...the 6-pack didn't come along until the '71 VH Charger E38 and E49, and the 225 slants in Oz ('69 VF and before) never came with a multi-carb setup at all. I know there's a fair few Pacers these days with 6 packs (or sometimes just 6-pack badges), but that never came from the factory - even the VH Pacer that hit showrooms alongside the Charger weren't offered with the triple carb setup.
PS: I remember this stuff mostly because my first car when I was a kid was a VG Pacer hardtop, so I really got into the Mopar stuff at the time while I was going to tech. Hard to believe I bought that car for $200. And sold it for $350 a few years later. _AND_ thought I'd gotten a good deal. :-P
Are we sure that the cloud isn’t moisture condensing in front of the stacks because of the drop in air pressure changing the point of water vapour saturation at a given temperature? F1 engines have this happen as well when dyno'd
depends on ambient temp and humidity if clouds form in a low pressure area.
Commonly seen as a sheet flashing transiently on the top of airliner wings. Airliners can also produce a water vapor trail from the wingtips or other places where there is transiently a low pressure created.
Usually seen during takeoff or landing with full flaps when higher angles of attack of the wing occur.
Thats how I see it
That's not reversion. It's the air losing pressure in front of each runner as it gets 'sucked' into the carb. As it loses pressure, the amount of moisture the air can hold decreases; it causes the moisture in the air to condense. What you're seeing is essentially mist. My guess is it was a humid day when they dynoed.
Exactly; fuel backpulses would vary approx. linearly with rpm. Condensation would have more of a threshold at the dew point, which is exactly what you see fairly dramatically above 5500. If you were really interested, you could shoot a laser pointer through it and measure the refraction angle. Gas has a higher refraction index (1.42 vs. 1.33 for water) and will bend the beam more.
Like the vortexes on the wing tips of a fighterjet pulling up like crazy?
I quit my job of 2 years & 3 months to smoke weed on my UA-cam channel full time haha
Glen Everett has one of the best channels out there, professionally made videos, yet not a huge amount of subs for the work put into it
The Aussie hemi 6 pack… there’s your starting point
He just got another sub!
I enjoy most of your shows, but the educational part is my favorite. I love you sharing your knowledge and experience.
Love your show and your style. I'm GM all the way to the ground, but you cannot learn from someone you agree with. Your MOPAR focus, teaches me new things. Thanks, fun stuff.
We forgive you!
Hey man, no doubt these lessons could apply to a stout 292 that oughta put the slants to shame ;)
Just an FYI, the condition you have described of the cloud caused by reversion is called "fuel standoff." It was very common on VW air-cooled engines with Weber carbs. The solution? Run longer velocity stacks OR use a big air cleaner. Consider what happens at speed on the drag strip when air coming through the grill and radiator blows that cloud of fuel standoff away from the opening of the velocity stacks. Without containing the standoff, the engine will run lean.
That is exactly was I thought. A dyno and real life are two different things. I think a ram air loaded resonance chamber on the carb inlet side is the key to success.
1960's plymouth Hyper Pak looong runner intake manifold solves the reversion/stand off issue. I built my '67 slant .60 over, 250* cam, 10:1, pistons, Offy intake, and Clifford headers. The Dutra cast irons don't compare for bottom and mid range. I made an alumilum spacer 1.5 inch high to adapt a Holley 4 bbl mounted sideways so that on primaries, the fuel distribution would be more even. New bigger valves and hardened seats with minor matching was done on the heads. Mopar elect ign curved just right and a tightened 904 trans rounded out the build. I'm glad I did all that back in the 1980s when good American parts were still plentiful. Plenty of stories have been generated. My son used it in college or law school and got a few tickets. Oh yeah; it's a 4 door Dart.
Yeah I saw that, I am and Aussie like glens stuff , what a strong motor, big torque figure too and I mentioned you and he said he’s a fan and 6000rpm is pretty much there limit. They were using what look to be a healthy budget , with pretty good hardware and internals , interesting discussion 👍👌and something to compare too and see what you’re motor can achieve, using more stock internals and probably smaller budget
I’d like Glenn to to a video on why your engine failed..,
Sorry UTG, us Aussies stay together 😂🚀🇦🇺
Watching a "Holley Only" person try and tune in a Weber for the first time is always a treat...
NOPE... that's not an idle speed screw... keep those throttle plates completely closed... and figure it out ;-)
I love how you see something that works and say, hell I will do the exact opposite and expect better results.
The RamChargers developed a formula for intake runner length. According to the Interweb it is 17.8 cm @10,000 rpm peak torque. Add 4.3 cm for every 1,000 rpm less. So for 5,000 rpm peak torque the length is 15.47" from intake valve to carb butterfly. I see very short intake runners on lots of drag race in line 6's. Wondering if all of those guys are wrong.
They're probably running MPI.
Webers are a little harder to tune right
Bit once you get it on point the throtle response and torque down low is unreal
And they look badass of course
My friend has an engine shop he does many vintage road race motors such as Cosworth BDA and Alfa Romeos....It's very common to see fuel standoff in an Individual runner intake set-up. There is always compromises made in tuning and this standoff usually happens at a lower RPM.
The reversion struck me as well. I immediately started thinking about how to remedy this obvious problem. Glad we have Tony to help work these things out in our heads!
In electrical speak we call it a standing wave. Measured as VSWR. Where the tunnel ram is the transmission line.
I don't work on cars any longer but I still love watching your video's and learning all the time.
What I have experienced with my car was a revision happening with a restricted exhaust. I run a 514 cubic inch ford with a victor jr. intake and a 1050 dominator. the first time I put this motor in the car I put the exhaust port gaskets on backwards by accident. I didn't notice a fog out side the carburetor because the hood was on. But what I did see was a black soot in the throttle bores. When I change the gaskets and put them on the right way and not restricting the ports the soot went away. also a guy I know had the webber intake and stacks on his hot rod. They worked really well until he put zoomies on the car. After that te car ran like crap. He called webber and they told him the webbers need the scavenging effect from a collector.
i built a slant 6 in the late 50s and early sixties,i made my own intake out of aluminum and had 3 SU carbs,1 and a half inch off of MGs,no reversion but it was fast, lot of experimentation with different needle in the main jet, tryed th SUs cause they only worked off engine vacuum,,i run SUs on my 77 sportster and 96 inch 84 superglide
I had double SU on a slant too, worked good !
I watch that yesterday, that was a nice slant 6, It reminded me of our Australian built RT Charger with its row of Webbers on a 265 Hemi, just over 300HP and quarter mile time in the mid 14 s . There’s a classic photo of this engine when Chrysler ran it full noise for a crazy amount of hours with the extractors glowing yellow to orange, they checked its durability and didn’t blow up.
This cloud is a known danger, actually. In the right conditions, a backfire will ignite this cloud and your engine bay is gone instantaneously. It is why a lot of people running this setup on Austin Healey's and MG's will actually run something that looks like a single cold air intake to the whole thing. If it backfires, it just belches out the nose.
In terms of reversion back in the 70's and 80's there were exhaust built with a "cone" shape on the mating surface to the head that reduced reversion considerably. The other trick for reversion is to have a small groove (circle) cut into the valve as this impeedes reverse flow. Another low budget option is to have a slight mis match in sizes from the exhaust port and the manifold (manifold needs to be bigger than the size of the port). Reversion effects are more pronounced in engines that have "siamese" intake ports, like the classic British Leyland Mini (A Series).
In terms of carbs you also have to bear in mind that on a Weber setup (or dellorto) because you are using an independent runner configuration every cylinder is fed by a single barrell. The setup you have there with the 650 DP means that every cylinder on that engine can "see" the 4 barrels of the holley, in that sense the common plennun approach gives you much more capacity (in cfm) than a weber would ever give you. Webers can be a winner in applications where you want to precisely tune where you want the resonance effect to have an inpact on the power band, and you can do this by adding more lenght to the velocity stacks (trumpets)
Some dual quads like the FOMOCO units for the 427 sideoiler are configured in such a way that every piston is able to draw air from both carbs (8 barrels in total!)
That haze at the end of the stacks is what we call "creating it's own atmosphere"...I thought you'd like that vid.
After watching the mentioned vid, it seems that one wants a “box” that the velocity stacks go into to collect those fumes. One could fit an air cleaner there between the collection box and the hood scoop.
That box is quite a common add on on full house modern race spec track cars fitted with Hemi 6's and tripple webbers here in Aus.
Would be interesting to hear what David Vizard has to say on the subject.
Carburation is neat! Physics is hard... that massive cloud of reversion is probably partially due to cam selection. As I understand it, Webers like a wide lobe separation with a less overlap. The typical rowdy street cam is generally a poor choice for that system. I'm confident those guys know that, but what can you get for a slant without a $$$ custom grind? Sweet engine no matter what.
Can you elaborate on why you think Webers like wide LSA?
I paused the video before hearing your answer Tony, the cloud of reversion was helping in a static environment, when on a running vehicle on the track it will get blown away, on the Dyno it can be sucked back in! Just saying I've watched videos of F1 Renault engines doing the same thing starting at around 14,000 RPM. In fact some of the injectors are "outside" the throttle bodies in open air!
Colin Chapman (owner and mastermind of Lotus) came up with the idea of a resonance chamber on the intake side of his engines back in the sixties. The chambered volume reflects the intake pulse and increased efficiency of engines substantially without parasitic losses. It was mounted on the intake side of the carbs. Truck intake manifolds combine long runners with resonance chambers to increase low end torque as far as I know. According to David Vizard, exhaust resonance chambers increase the scavenging effect without an increase of backpressure. I guess, because of the volume between runners and carb, the slant six intake manifold works somewhat like a resonance chamber.
I kept thinking that either longer intake runners or longer intake stacks would be good for that Oz engine - and I love it. The mopar guys in Oz have the inline 6 265 Hemi Six-Pack OEM engine as an example, with side-draft Webers like those. So I sure see why they like them, once they learn how to tune them.
Glen Everett Reversion is due to the headers not scavenging at their best. Then I’d play with the stack lengths.
agreed, I would like to see longer stacks on these. The nice thing about Webers is you an change everything on them.
Master of machines is awesome! Especially the 413 build.
Tony. I have seen that cloud form in the airbox of Ferraris. I believe the position of the Webers in the intake runners is important. The intake air pulses have a waveform caused by the rpm, bore/stroke, camshaft timing. It is important to position the Webers at a distance from the intake valve that provides a smooth vacuum signal to the venturi and contains the intake pulse within the Weber + intake runner combination. The intake roar, as a musical note, is affected by the combination. A ragged intake roar is a sign of a mismatch affecting the CFM flow through the engine. Mike
If I was building a slant 6, I’d go Triple Webbers.
I saw a guy that installed 6 50mm motorcycle carbs on 240z L28 engine. Not only did it look cooler than hell, it sounded amazing and ran perfect!
Short intake runners and a lot of overlap will create stand-off until the motor climbs into its powerband. I’d bet the A/F ratio goes rich too, as the column of air picks up even more fuel on its way back into the motor.
I found a Chevy intake with 3 webbers and all the linkage at a pawnshop in 91. I remember they wanted 125 bucks.. I wasn't into cars yet so I had no idea what it really was. Wish I had bought it even just as a paper weight because it just looked so cool.
Here in Australia we had Chrysler Australia playing with the Hemi 265 back in the early 70’s
They had 3 dual side draft Weber’s in a limited production charger six pack
It out run the Ford 351 over the standing quarter in the day ....
No mean feat for a six cylinder against V8
Glen would have been using the same ideas for the 225
This is legendary in Australia
I watched the video. Very impressed. That was very interesting to see the fuel spray reversion go in and out of the stacks.
"Pulsating in Sympathy" Sounds like great name for an album. LOL Great video, Tony!
I had watched that same video just a cpl days prior. That build is awsum, and it looks super cool, but i do believe the long factory runners were there for a reason. I believe a bit longer runners on his setup would yield absolute excellence, and i bet the sound resonance in those trumpets would be baritone bliss
A friend of mine ran a '68 Camaro with a sbc running Webers. I suspect it was for the WOW factor when he opened the hood. However, at the drag strip, it fell flat on it's face. When he tuned the Webers for wide open throttle to run better at the track, the Camaro lost all drivability for the street. He replaced the Webers with a single 4 barrel. Same thing happened when a guy added mechanical Hilborne Fuel injection to his '67 Chevy II. I ran fine on the street but failed miserably at the drag strip.
I wondered how longer velocity stacks would have changed the dynamics of that Aussie engine when I first saw the video. I have to admit it was VERY impressive! Not sure about its economy on the street. Would love to be able to follow that engine for a year or two and see what happens.
I remember playing with sidedraft carbs back in the early 90's on short runner manifolds (less than 2") and yeah the reversion was terrible especially at wide open and anything less than full rpm's(6500-9000), the fuel usage was horrendous and the fuel smell made it a constant guessing game of when it was going to catch fire, but add trumpets of sufficient length and or lengthen the runner length and boom the drivability went through the roof and the fuel consumption dropped, add a common air filter or some sort of air box and it got even better.
ITB's are awesome but only if you put in the time as with anything with engines to tune then as a part of a larger system.
I like your theory. In the Weber vid he spent some breath describing how he figured part of the reasoning behind the slant six was for long intake runners. I look forward to finding your theory (and mine) backed up with higher dyno results.
A few years back a gentleman out west in Montana named Ron McCord was building dirtbike intakes for two strokes and four strokes on this exact principle. It was a specially modified carburetor with a hand built intake and a pulse tube that re-introduced to Pulse on the intake side of the carb needle.
I have a yz250 that does amazing things based on ram effect intake
Power everywhere
Reversion (blow back) is common to ALL high performance motorcycles.It's a combination of a very short intake track, individual carbs or throttle bodies and just as important aggressive camshaft profiles, specifically overlap.the five valve Yamaha Genesis engines exhibit this like crazy..I have been a motorcycle mechanic for over 30 years.Reversion isn't necessaryly a bad thing just look at how a two stroke expansion chamber works..As always when Uncle Tony talks listen,he knows his SH"T.
I see this when dyno tuning air-cooled race VW engines, 'fuel standoff' 'reversion', whatever you want to call it, is almost always present. Not street stuff, but normally aspirated 2hp/cubic inch VW drag race engines, with one carburetor barrel per hole. Like motorcycles, the Aussie slant 6 w/3 DCOE Webbers, my air=cooled VW's with dual 48IDA Webbers, those individual runner type intake designs are treated like 4 or 6 individual engines running on a common crank and camshaft. Were as a plenum intake, with it's uneven length runners, and 650cfm lump perched atop a bucket, act more like a team. The theory as I understand it, is the reversion pulses are still present, but they never make it out the carburetor velocity stack, they get 'held in reserve' inside the 'bucket' or plenum, in the form of a slight positive pressure. Then when one of the further away cylinders opens it's intake valve, an intake charge is there, ready to rush in, almost super charged. On and individual runner design, that pulse pushes out the low volume runner and through the carb, throwing it away as you point out. The Ramchargers guys were really on to something when they looked at runner length, which often missed it volume, and using it to augment the same effect at a given rpm. All things being equal, one isn't better than the other in my view, just different, and requires a different approach to tuning. Ok, plenum types have a better low rpm off-idle throttle response. I love your videos Tony
i twigged out over the same video...how a cloud of fuel that size can hover in front of a direct vacuum is an enigma.
Every time I watch you I learn something and I’m 67 years old
Go with what you know and are comfortable with. But in terms of the cool factor. Yeah Webers are way cool looking. The first engine I ever remember actually seeing them on was a 343 or 390 in an AMX. Homemade tube intake in a cross ram set up
I sat in on the Ramchargers clinic a couple years ago at Carlisle. They talked about a cloud forming when dyne testing a hilborn setup back in the 60's. I think they said it happened depending on stack length. I can't exactly remember though.
I always liked the sound of a slant. I had another straight 6 that was so boring in sound it almost would make me sick on a long drive, but the slant always seemed to have a nice soothing effect as I drove...the perfect motor.
Cam characteristics can also cause some intake reversion. There's a guy on UA-cam who mounted 4 Quadrajet carbs to an Olds V8 cruiser,with all the carbs linked to open simultaniously. An in car camera catches the carbs in action (no hood) as the driver floors it & all 4 carbs open. It sounds great but there's big time reversion (fuel mist sprays the windshield).
This Offenhauser monifold runners appear to be short vs the ones I have seen at car shows (please note that I have not seen very many). The slant six config. allow the possibility to install very long runners, I’m surprised that Offy made a short runners version like this one we see on the table.
Weber's do that when tuned to rich, when it's calibrated right the "Fog" remains inside the Carberator throat, and they are very efficient at all rpms.
Old school Mercedes 190, 4 bangers have 4 sidedraft webers. Very simple and reliable carbs so long as you don't ever park it to long after using gasoline cut with ethanol.
They do tend to gum-up very quickly since the Gasoline refineries started adding that corn fuel additive.
Oh, I should add that having the 'fuel stand-off' cloud out in the breeze, letting it get disturbed by the air rushing over the car, is a bad thing, takes away power, and makes tuning for the top end of the drag strip next to impossible. I did some back to back experiments on a friend's drag race sand rail, under 90mph, the first 1/8th mile, didn't make a difference, but the second half, 1/8th to 1/4 mile we really saw significant improvements, 4-5 mph and 2 tenths ET if I remember right
I've seen that fog before on indy car dyno motor pulls I always thought it was a good thing. I thing it's also common with the velocity stack style setups that are revving to the moon..
Appreciate your decision on using what is available. I would suspect 6 inline carbs would surpass plenum/runner set-up due to the years of development & experience of UJM design alone. Otherwise Hayabusas would have some interesting runner/plenum 4bbl carb set-ups right from the factory. Intake & Exhaust witchcraft got really interesting in the early to late 1950's , especially in the racing motorcycle singles. Thanks for being a car guy who also likes bikes.
Cheers
Watching the WILD SLANT SIX video reminded me of my old 1982 Mercury Capri 5.0 that I was street racing from 1984 to 1988. Early in the modification process ( I was just out of high school and didn't have much of a budget - good thing cars were slow back then) I had an Edelbrock Performer non-emissions intake with the typical Holly 600 vacuum secondary carb with stock manifols and a "test pipe" to eliminate the catalytic converter. The car seemed to be running well. One day I read an article about "anti-reversion" headers. The article said that Ford 302s were notorious for the problem and to look for it just take of the carb and see of the plenum was black. It was. That was evidence of reversion, and adding a set of these new headers was supposed to reduce the problem. I got a set along with a cheap bolt on dual exhaust system with a set of cheap turbo mufflers. The car was much more responsive after installing them. After driving it to work for a week I took the carb of and the plenum was now clean. Apparently those headers worked as advertised. I can't help but wonder if a better exhaust setup would help of that slant. Too bad there doesn't seem to be room for one.
I witnessed this happening just a couple weeks ago when I was tuning my chainsaw. On a much smaller scale ofc.
I've noticed that and have concluded that an air filter will help contain that, a deeper velocity stack also helps.
I have been wondering how 6 motorcycle carbs might work on your drag slant .
Hey Tony, watch the Renault F1 engine on the dyno that runs fuel injectors at the top of the intake trumpets.
When they are at high rpm you can’t go past atomised fuel rules in the open air.
I know you may know but the 265 hemi six in the E49 charger ran Weber carbs and ruled at Bathurst race in Australia
It did very well against V8
Watching the suggested video helped me understand how an intake manifold like the SP2P Werks.
Tony, a while back I had a military 3/4 ton 68 Dodge flight line truck. Full two seat crew cab with 225 slant six and 4 speed with 3 and 4 close. It had a huge rectangular oil pan that was big as a bathtub. Like about 10 quarts big. I don’t know if it was special or if most trucks had one like that. Anyway, one of those with correct pickup and maybe pump would put you ahead of the game. If it doesn’t have a windage tray, there is certainly room for one. Good luck and take care.
That video showed on my Facebook feed a couple days ago. I watched it before work. That cloud was obvious. My thought was that the stacks needed about 6 inches of length and a common plenum to draw from. Think early 90s Ford Escort manifolding. The same effect is seen on Austin A engine dyno runs as the intakes are always way short due to the chassis they are put in. A pair of very long stacks alleviates the issue with more area under the curve although a bit of peak power is sacrificed.
Did you know down here in Australia we had a range of Chrysler straight six motors that were called Hemi’s . Had semi hemi heads , 265 ci and some had triple Weber’s and ran at Bathurst in Aussie valiant Chargers ( nothing like American Chargers ) and beat 351GT Cleveland’s etc . Have a squiz on UA-cam - we did some crazy stuff with mopars !!
Uncle Tony, webers used on individual runner manifolds often have those reversion clouds hanging above them especially with big overlap cams.
I think you are quite correct in saying the plenum plays a important role in utilizing that reversion in charging the other cylinders.
I think individual runners could often be improved by having a balance tube between cylinders that are opposite in the firing order to take advantage of that reversion rather than as you say letting it go to waste into the atmosphere.
his engine is definite artwork, not sure the reversion is much of anything fuel mix but seeing it would make me want longer trumpets and an air cleaner at least, which might create a self cooling intake situation. I do think the 650 with the jetting, spark plug choices after run reading etc will work as well or better overall.
I just watched that video this morning and noticed the cloud of vapor on the intake stacks too. Also wondered how much more torque would have improved with a set of long tube headers and longer intake stacks. I'm willing to bet there's at least another 15-20 foot pounds of torque to be had if the intake and headers were tuned properly for the power band.
Love any carb video you do.
Interesting stuff as always!
Master of Machines. Lol.
Took me back to my youth...
Black Sabbath, Volume 4, Wheels of Confusion...which leads into: Tomorrow's Dream.
Tony....that should be your Shop Music.
UTG: Mopar Arbitor
Completely unrelated to the topic of this video, but this makes me think of a mopar oddity I've heard of that was available in Australia, the 265 Hemi, which was a straight 6, but not a slant, that used 3 2bbl sidedraft webbers. If i remeber correctly, the engine was capable of horsepower and torque figures in the low 300's, but I could be wrong. I don't know about any other nieces and nephews out there, but I would love to see Uncle Tony do a video on this engine, I'm sure he knows a thing or two about it. How 'bout it Tony?
Yep we all need variable length inlet manifolds. Ford did it in OZ on their inline 6
My off the cuff guess is that the runners are not long enough, so the pulses are escaping out of the carbs before the intake valves can open again.
Ive run into reversion in the past. Long runner tubes feeding into a common plenum, then appearing in a large ball above the Holley 4V.
Happened only at a certain RPM, then the ball of fuel appeared to be sucked back into the engine above or below that RPM.
Engine ran fine. The only question was whether the pulse going back out of the carb was collecting additional fuel from the boosters, then would go into the engine with a rich A/F ratio in that narrow RPM range.
I just put the air cleaner cover (still wet with fuel on the bottom) back on and didnt worry about it.
There was a whole story about this type of thing in the Ramchargers book when they were setting up a 1st gen hemi to run in a Indy car. They had straight stacks on it and had to add the bell on each to keep from fogging the Dyno room.
All for nothing, as one of the first cases of the hemi being banned from racing, because offenhouser complained.
Wow tony your right.
We used to do this to hondas all the time but they never spit the fuel charge back out. Id say hes losing about 20% to atmosphere.
So when our hondas did this we capped the stacks. Merging all four into like a header colector.
The thing with the weber setups
Im a heavy smoker, i have problems with atomized air in front of me, sealed under hood and it making its way into the cabin. I agree the only thing that would be better than the ofenhouser is a manifold of tuned equal length. Great catch, i honestly thought webers were great, but after seeing that, theyre for decent power yes, but mostly conversation peices
What amazed me about that S 6, was that he got 6k rpm out of it. I've never seen one, even hopped up, go above 5k without hitting some wall (I assume flow) and won't go further. I did see that reversion and thought that can't be good for raw power
i've always wanted to test a "dynamic" ITB setup, not something with a plenum tune intake like the new corvette, but a true stack injection type deal with telescoping velocity stacks, it would be very over the top in the engineering department but to see an intake runner "shrink" like a trombone slide in distance from low RPM to high RPM in trying to achieve the flattest torque curve possible and the best high RPM horsepower output would be astonishing, obviously in the drag racing world this could be compensated with torque converter slip or other gearing measures but just from a hotrod/efficiency POV it would be cool to test
Tony your thought process reminds me of the old days on how we found that extra H.P.
Speaking of clouds coming off of intakes. Early 2000's F1 engines that revved just a little short of 20k rpm, had big clouds of fuel from it's injectors over the throttle bodies, there's a video of that on youtube
Master of Machines built an engine I dreamed of but I didn't know it would ever exist. If I may. With this perfectly straight side draft intake, there is way to much capacity for air. I think if you used slightly smaller diameter velocity stacks and perhaps adjusted the length. It would tune the intake and if done perfectly would eliminate the problem.
The reversion or standoff should be contained by an air filter. It's a non issue. However cam choice with regard to lobe centers, timing and overlap are important with Webers, AND a ZERO restriction exhaust is critical. That manifold setup contributed to the standoff.
I'm most of Tony's viewers would get bored but i would very much see Tony take the slant 6 naturally aspirated as far as he can experimenting with manifold carbs injectors various head lengths collectors etc.
Hey thanks for talking about this! I observed something similar coming out of the 460 in my f350 a couple days ago while I was playing with then ignition. I was like what the heck was that!?
Also I saw your video on adding extra timing on big bore engines. really put a lot more pep in my truck which previously had some serious lag. Previous owner bored it .040" and Changed the cam but put everything back together stock.
I wonder if putting a plenum around the stacks (similar to most modern motorcycles) would solve the problem. You wouldn't get to look at those pretty stacks, but on those engines it widens the powerband.
Love these Slanty vids...I've only drag raced a slant 6 once... unfortunately and unknowingly against a Indiana State Police 91ish RS Camaro...but that 86 Diplomat was one helluva car
*correction 81 Diplo...bought for $200...drove 6 blocks home from 2 doors down (would only turn left)...straightened frame w/ 30' log chain and 100 yr old oak
I don't really say much about my engine/dyno experience, but I watched that video Before you made this. Noticed the reversion immediately. It reminded me of 2006. Had 350 Chev that was built in south Carolina by a "pro engine builder". Trick Flow 190 heads, around 10:6 1 static compression. Had a Crane cam (which I'm not a fan of) on around a 114. This engine had a new Edelbrock low rise dual Quad manifold with with 600s I believe. Around 4500rpm there was a cloud of atomized air and fuel above the engine that looked like a Kansas tornado ready to touch down... initially I advanced the cam a few degrees. 2-4 ; it was slightly better. I think it was 340 hpish. That engine should have been over 400 IMO. I put an old Comp 280 magnum in it, 110, .480 lift straight up and made 370 hp. However, the reversion was there. Bolted a 2975 Victor jr on with a 4150 600 double on and pulled 424 hp at 6300. No cloud. Customer couldn't believe we pulled near 100hp out of it, he picked up over a full second in the quarter. And was so much better onto the street ..
The only other time I witnessed this was on a 389 tri power on the dyno.
Agreed that the combo is leading to reversion and pulse stand-off. Not uncommon in boat motors where you have worry about carb tuning issues, but also drawing in wet exhaust. Usually because of too much cam and not enough exhaust scavenging at a harmonic RPM ...
Idk man, I always loved this channel, but I love the small hole in the wall guys, like what road kill used to be like. Didn't want for anything an had no plans of going mainstream or getting TOO BIG. I hope the channel doesn't go that route. An sells out to sponsors an shit. An just turns into the same old dont forget to like an subscribe shit
Im pretty sure tony has said in the past that he would never sell out like that because he does this for fun and thats not what he wants from the channel. He will accept if a compant wants to give him things his stipulation is that he is going to be honest in his review
To see the sonic pulses in real time... MAGIC
Is there an intake manifold available in a "split style"? Like a three piece manifold where one piece covers two cylinders and is fed by one 2bbl carb. Or a single flange with six individual runners to use six one bbl carbs? Hey now that I think about it that would be an interesting test item.