Was this IT? Road to Most Powerful Two Stroke
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- Опубліковано 30 вер 2024
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Hey man, i’ve made hundreds of pipes for 2-strokes id suggest using backing gas next time! Will get rid of a lot of blowouts and result in a smoother weld on the inside.. And a way more neat weld outside :) love it how i was screaming at the videos a couple of months back “ITS THE PIPE” but i knew you’d probably never see the comment.. Hope you see this one tho!
Anyone who has welded stainless would know how important backing gas is.
Also I'm not sure if he is using a foot pedal. It made a HUGE difference for me in welding school back in 1982. It's a must. I bet that is one of the issues on his welding if he don't have one.
I'm a retired certified millwright but I also have a basic welding ticket.
pretty sure it doesnt matter in his application@@canadianoddy8504
Even mild steel welding a lot better with backing gas. Putting a peace of copper behind the welding helpt the result.
No need for purging with welding mild steel. Just correct amperage and gun speed.
agree@@GlobalSLO
I’m a little worried that your dyno may not be recording horsepower correctly. She sounds good, maybe try a friends bike that was tested on a commercial dyno to compare results??
Too, in last Vid i thought that he actually did it. For me it sounded really well...
I think so too. Think about how often things changed during process and how many things went bad iver time, this could pappen tonthis self made dino too. I understand that the dino is not the Target of this orogress but it could be a restricting factor
Back when I was young I had 3 dirt bikes I would ride on the same day. Started with the YZ490 then when I was beat up enough jump on the YZ250. Would finish the day with a Suzuki 125 to just put around. I can tell the sounds of a good 2 stroke.
As long as rpm is reading correctly and the weight of the roller is correctly calibrated the hp should be correct. Maybe recalibrate after multiple runs with close hp figures and see if it changes.
last vid was almost on the pipe for me. almost
Others have mentioned aspects of dyno loss - here's a summary of what I see:
1) 3+hp lost at high rpm after you pull the clutch - that's JUST the transmission, chain, rear axle, and tire/roller interface, not the belt drive
2) Loss in a transmission/driveline has multiple factors, one of them is torque dependent due to the friction in the gear teeth and bearings/bushings. Force vector on a gear tooth is the same as on the bushing/bearing, but the torque loss can be higher due to the bigger radius of application (depends on level of gear tooth friction relative to bearing/bushing friction). You don't see realistic torque-dependent loss during a spin down, so factor #1 above is an underestimate of the loss when you're full throttle. Hard to estimate, but let's guess additional 1hp lost due to torque through the drivetrain.
3) Inertia of the roller is accounted for, but what about inertia of the wheel/tire? Some additional loss here, but probably pretty small, I'll ignore it.
4) BELT DRIVE: who knows? try to measure it! Belt with an idler with significant tension will have some real torque loss, when you consider you're about 4-5Nm at the crank, and that the torque loss in the belt is constant (or maybe even rising) with rpm, that can be a big hp killer! Maybe 20% there alone, so potentially another 3hp!
5) I thought I had one more item, but can't remember - I'll add a comment if I can think of it.
So, in total, you could be losing something like 7hp total, so you may already be looking at closer to 18-19hp at the crank already.
Also, subjectively, the last runs with the bigger stinger, the last 2000rpm or so are happening FAST!!! I think you're making a lot of power just before you hit the wall, and the wall hits too soon. I think you're getting really close!
Nice guess. But he needs a dedicated engine dynamometer to eliminate all of the other crap.
@@davidgierke7582he has one. He also has an interial dyno that works great, so in the interest of chasing one bone at a time, he’s using it.
I've said it before, but I think he should go back the old dyno bench with load cell, but change the truck break for a hydraulic pump. It's simple and doesn't have a bunch of maybes and ifs. Swedish Tvåtaktsmeken has used a really nice one a long time and has made another reasently with some improvements.
ua-cam.com/video/24RMh4JUuZM/v-deo.html
All guesses aside - he did mention two videos back that on the same dyno, his 80cc metrakit AM6 delivers 13hp, so in any case he has the same power with all the transmission losses as a quite potent 80cc! But to me 13hp from a nicely tuned 80cc am6 is much too low numbers..? Reading some forums it seems that this kind of setup should make at least 15.5-16 hp, but probably more. Hell, most 70cc make about 15.5 hp!
This is an assumption, but if this assumption is correct, and the 50cc is making the same power, that's not bad at all.
Finally someone who knows that rundown is not realistic loss. Usually when I mentioned that to some dyno operators (people who just have dyno), they start fuming haha.
I don't have any idea on two strokes so take this with a grain of salt, but I'm studying musical composition, and we have acustic related subjects. What if the actual resonance of the pipe hits the initial power band at arround 11000rmp and what you are seing at almost double that is an harmonic of that resonance? It would make sense since when you get past that point the pulses just inmidiatly die.
bang on Adrian. 2 stroke pipes are all about resonance. The stronger the pulses the shorter the resonance period.
What gets complicated is balancing the resonance to the temperature, the speed of sound and therefore the resonance change with the temperature and the temperature depends on how well tuned the engine is along with how well the pipe is doing it's job.
2 stroke balancing act.
I find great assurance when your constantly making 3 steps forward and 2.5 steps back. Whenever I take on a project it goes exactly the way yours does. Thank you for sharing the pain and success.
I have given you my advice already, but maybe with the number of comments you did not notice yet. Run a couple of curves with different fixed ignition values. Take the best run for each ignition value and put them together in one diagram. Then you will see, which engine speed needs which spark and you have your new curve, that should be validated in a final run....
it is a great idea for fine tuning, but at this point, there is an issue with the engine that prevent it from getting its full power. So this should be adressed first and that's what he is trying to do.
Just a dumb thought have you double checked your setup on the dyno. Could wrong ratios in the setup cause off results. Love watching your videos and see how your mind works.
I thought the same. If the rpm is still not calculated correctly by the dyno it could also explain why the timing curve does not work as well as it should.
@@bomberjuli dyno is based on weight and rotation+radius?
@@bomberjuli The amount of rpm he is getting it seems like it should be making more horsepower. That or the motor is barely making any torque.
A 50cc, If you can get to rev that high, would be at 20hp or over.
@@richr161revs those not always mean hp
@@alexrodensjo348 Your right, but 17k rpm at 11hp would mean the motor is making less torque than a stock 50cc bike.
HP= Torque+RPM.
Or simply how hard your piston is pushing down and how fast the motor is turning.
Hey Brother , I used to build pipes for several expansion chamber companies , J&R, T&M Eng, S&S headers, FMF ,and DG . I have never seen such a small diameter stinger on such a small motor but I think you know what you are doing . It sounds great .
That is right and personally i think the stinger should have a lenght at least 5x of the initial exhaust diameter, so that it can build a more precise wave, otherwise it's gonna get messy
My KTM 380 MXC has a stinger ID of 1.13"...it flies down the track nice...
It sounds like another chapter can be started...
Sort out the gas tank...take your 12.5 HP Aprilla...out for a spin...
You know your approximate weight....the bike could be weighed...
Run down a 1/4 mile the get an ET...
Maybe it will do the quarter mile in 12 secs at 99 mph....
Then a HP calculation can be done
Good job getting her to run this good
My daughters KTM 50 has an SXS pipe on it. Very hard to get that pipe these days. It's got a 16mm stinger. I had to scratch build a muffler for it since it's so much smaller than stock. The stinger is a LOT longer on that pipe compared to what has been made here.
I need to get you to repair my silencing can on my kart pipe.
@@bkh5746 hey brother I would be happy to do that for you but I don’t have a torches or any of the tools I need to do that anymore I wish I did you should be able to just buy a piece of mild steel tubing the desire you want and cut the old one off with a hacksaw I’m just have somebody will the new one on
Hello
I come from Germany and am following your shipments with interest. I find you very brave to keep going after disappointments. Yes, 50cc is interesting. There already is
50ccm with 20hp. So keep going, you can do it.
FYI if your carburetor is flattening out on the flow meter then you will not get any more RPM or peak horsepower out of it at any rpm
Is the spark strong enough for those rpm’s? That’s a lot of timing advance. I hope you decide to start reading comments again even to consider what folks are saying and question it. I wish you luck on your adventure in any case
The exhaust gasses are exiting the cylinder exhaust port at supersonic speed AFAIK. It appears the abrupt shape change in the ex port to pipe adapter could be reflecting a large amount of spent gasses back into the cylinder at very high velocity thus completely disrupting the much slower moving intake charge distribution and exchange within the cyl. This would disrupt cyl scavenging in a massive way if my idea is sound. Just throwing out my thoughts upon a very brief view of the part I'm discussing.
Based on my understanding, "line of sight" needs to be applied to your exhaust port to pipe adapter to reduce the tendency of wave reflection off a great deal of the cylinder ex port area. The functional area may be reduced to the "line of sight" from the pipe side looking into your adaptor.
Grab the lowest hanging fruits first. Please verify the validity of your dyno setup before dedicating time to test complex scenarios.
yes yes yes - sanity check with some stock-ish bike on that dyno would be very helpful!
Just a thought: The lower EGT means the speed of sound is lower, thus your shorter pipe will be targeting an even higher rpm than you designed it for, unless you're taking the lower EGT into account when doing your design.
Edit: I see you touched on this in your outro, I jumped the gun a bit on this comment hahaha
Is there a reason why the stinger is only 1 inch long ? I've never seen a pipe that the stinger is open to the atmosphere so abruptly most are 6 inches or more. I'm not saying its wrong but its just nothing like I've ever seen
This stinger is not a stinger. Much to short!
More like a baffle than a stinger
For dealing with kart engines an unspeakable amount of years: If you want higher temps less fuel would do it. At least on our 2 strokes (60-125cc) that would do it. Then again, if you had a taller gear it would strain for longer and push temps.
love it spent years in karts. Yeah EGT is the real mixture test. Ran 100cc piston port and reed at 1.1K at the end of the straight then would choke the f out of it and pull 600Deg of the piston temp under brakes. Mychron2 warning light set to 1.12K any higher would seize, if it got there then more high jet. Used head temp (air cooled) at 85Deg (from memory 15 years ago) and set low jet by it. My probes that he is using and they are top quality and spot on accurate for K Type. Made by Temperature Controls in Sefton Sydney with special clear high temp outer coating to stop the copper braid from degrading from the insane vibration up to 19K rpm. Plug always white back at the pits but it never locked doing this - was running 50:1 synthetic oil on 98 Octane
Drive chain does look extremely lose for just running it on the dyno
Its nearly impossible to guess pipe temps in the sim until you test in real world. Makes sim pipe development hard
You can model this probably close by lowering pipe temp in the sim to match rpm points
you will find that its hard to make power at low bulk pipe temps
as power increases the temp goes up - so chicken and the egg…
I also think you need a stinger outlet tube - it can play a nice role in tuning
I agree. Build a bunch of pipes, dyno them, sim them, dyno them, sim them. Give up on the sim for a while because you don’t trust it, go back to the sim because you are second guessing yourself not trusting it.
Nice!!!! You may want to consider "back purging" while welding the pipes. (Flowing shielding gas inside the pipe to prevent internal oxidation) May help with your issues. My TIG welding is horrible, so it is just a suggestion.
I think maybe the term you are looking for is "standing wave" this is what they call the captured shockwave in the intake of super sonic jets to slow down the air to sub sonic speed before it hits the jet compressor blades. If you have one of those developing in you tail pipe that would definitely cause a breakdown of the pulses you want.
Some good results Alex, in the right direction too.
As I've said I'm a boilermaker/welder, here's a tip when tig welding what you are with the new exhausts, you need to purge with the gas your tigging with, the internal side of what your tigging, use some light plate steel as end cover's for pipe sections, with a hole for a gas line, use tape to hold in place is good enough, doesn't have to be sealed totally, you don't need a lot of gas flow and not more than your using to tig with, just as long as there's gas there and not atmosphere air that contaminats the weld from behind, it will help flatten your internal weld faces, without purging, the weld face can have built up dags and lumps which would create little pulse wave echoes disturbing the pulse action, it'll also help a little with blow through too, that's because both side's of weld are shielded and no contamination from behind affecting the weld as you go, where as when your welding like you are, there's only one side that's shielded, I hope that makes sense mate.
PLEASE READ THIS. There's some serious SHAKING on the drive belt right at 17,4xx RPM on EVERY SINGLE high RPM RUN. Example 23:19. You can see it on the previous video as well. Watch on 1/4 speed if you have to. Also I saw multiple instances of a multi thousand rpm jump on the RPM readout. Perhaps that's a valid jump due to the Dyno refresh rate? Or maybe there's something else going on. Slip?
I think that's when he lets of the gas, what do you think? (I've only noticed this one example you've provided.)
@@raycar1165 Impossible to say from this angle, It seems like his clutch hand and throttle hand move at the same time after RPM stops moving. To me it sounded like a WOT soft rev limiter like on a modern car. It just hit a wall of resistance. Maybe it's some sort of harmonic on the belt that suddenly kills torque.
The madness will probably never end
It won’t
I imagine he would over engineer a ham and cheese sandwich
I hope it doesn't
10+ for making Own exhaust bit bigger 👍🏻.
Now only need some more fuel Petrol.
Becase it want too die in high RPM.
So Larger nozzle or petrol needle.
That need too by the Good Key.
That's all as far as I know it should work.
Maybe a different toothing so that it probably works better.
Well done so far 👍🏻
Greetings from Finland, love your videos. They are a true inspiration. For sheet metal joints I often use Silicon Bronze (CuSi) tig wire. It doesn't make boogers inside the joint and it's gas tight.🙂
I had the DG pipes (and ported heads) on my RD400. Loved them and hated them. Loved the power, hated the droning and loud sound while on a long ride. Plus, they garnered a LOT of unnecessary attention. They absolutely worked. They were longer than the stock Yammie pipes, so there's something to be said for length too. I remember Team Yammie and Suzuki running very long chambers on their RGs etc back in the 70s and 80s.
Best thing I ever did to my RD400C was find some stock pipes and stock airbox and put them on. I can not believe how much more torque the damn thing made off idle and into mid rpm.. exactly where youd need it when bombing around town. Luckily my cylinders had never been ported. Also, the dg's and pod filter was so insanely loud and that DRONE it made was mind numbing.. I dont miss them at all. The bike has become such a pleasure to take out on the weekends now, I love it. Something i can do now is leave it in 6th and slow right down for a corner then just feed in some throttle and the bike just pulls with no complaints. I could never do that the with pipes and pod filter.
I remember my chum's RD400; a real basket-case, but had standard pipes; As the revs climbed and it came into the power, it just lifted the front wheel so smoothly. Sounded so good - without the attention-grabbing Micron's on my RD125 twin.
Here in England 🇬🇧 we soon discovered that even at a high rate of tuning and porting the standard Chambers gave best all round power.
@@ianmangham4570 Like a ""FACTORY PIPE"" doesn't get HOURS & HOURS of R&D & should work the best. I NEVER could understand the ""MIX & NOT MATCH"" toss it up on the wall & see if it sticks, hap-hazard garage hop-ups that just seemed to create totally un-ridable, LOUD & horrid bikes, most of the time after spending half again the cost of the STOCK BIKE, trashing all the STOCK PARTS & ending up with DOO-DOO!!!
The gas is faster than the sound
2-taktere er som en religion. Er så glad for å få være med på reisen! Du gjør en kjempegod jobb, både filmatisk og mekanisk. Heier på deg!
Look into an S shaped expansion chamber. When i switched to that type, the power gains were extremely higher than conventional straight expansion chamber. 100%
Any thoughts toward "ok, i got the pipe and iggy peaking, but egt is low. Lean the carb to increase egt to more ideal levels"? Run all the variables you can control on any single mod, THEN mod further? My thought is more heat is less dense, so the inertial conflict of colliding waves will wander up the curve, possibly dragging your peak with it?
👍 Leaner carb is next up, in tandem with building a new pipe.
Came here to say this - clearly there's still something fundamentally wrong happening, reflected in the low EGT (some is sensor lag, though, takes some duration of heat to get the probe heated up, even if it's open tip probe, so it's likely reading lower than actual). Would also love to see the 16mm stinger with the curve!
Could you put slip sections in your pipe in order to vary the reflection timing in the exhaust? Also, why is your header pipe so short? 👍👍
Try cutting open a commercially available exhaust pipe. A lot of them have a baffle were the straight pipe transitions to the expansion chamber to redirect the waves so they are not directly aligned with the inlet flow.
I've read on the internet that smaller diameter pipe headers increase torque because of the increase in velocity. Also, I heard from a former KTM Racing mechanic from Protugal that bigger diameter pipe, full exhaust, makes more better torque because of the increase airflow but slower velocity. I wonder what is your opinion on this one?
Finally got back to 12hp.... I feel like you should run the death bike on the dyno to see if it's reading correctly. Keep up the great work.... 😁👍
I really like the wide angle recording. I always watch YT in theater mode, so it's just really awesome to get that extra video around the edges. It's the little things like this that make me happy.
:)
I think you should rework the first third up to the diffuser. In my opinion that is far too big. 28mm starting at the cylinder brings improvement. The exhaust doesn't manage to suck properly
It was made that big to keep pulse intensity at bay, bleed off some energy. No help, seems to be two resonance systems fighting each other in such a short pipe - helmholtz and "normal" pressure waves.
I was thinking about this some. Make sure you always set that EGT at exactly the same distance from the piston face over your iterations. It will skew your data if you don't.
I am the only one who is thinking maybe the dyno dont show the correct numbers ?
Would be nice to try another dyno
Some people in the comments allready sayed come to my dyno the life near from you
I remember Back in the early 90 s F1 powerboat racing (Heavy tuned 2 stroke Methanol) they worked with spacer- rings on the sparkplugs to make it run good , just want to say it could make difference.
Required:- Telescopic centre section of expansion chamber + Adjustable Iris style stinger.
I would think about what your egt temps are so low, power seems to be increasing with pipe temperatures maybe poor atomization of mixture, or lots of exhaust gases staying in the combustion cylinder timing doesn’t seem like it has much affect on egt so I’m leaning towards a port velocity problem, the engine seems like it has plenty of flow but doesn’t seem to be building cylinder pressure like it should you possibly try heating the crank case to help atomize the fuel, the cylinder stuffer didn’t work which kind throws low transfer port velocity out the window, I think the exhaust port is probably working too well and pulling air fuel mixture out of the cylinder or secondary pressure waves canceling the initial wave out, making the transfer port less effective a little nitrous oxide would actually tell you quite a bit because the intake flow is less critical
You hear the sound of the exhaust, it's not the right sound. When the expansion chamber works optimally, it gets a metallic sound and you don't have that.
Did you design the pipe by simulating it in engmod? and if so did you remodel the engine as it is now?(with the lower exhaust floor, different angle transfers, rotaryvalve) or did you use an old unupdate model to design the pipe? cause i would think that things like angelarea and case volume would be important in pipedesign.
I put out a short video last week of the Northern Lights while I was visiting Norway. Lovely country by the way, despite being -12c. In that short I speculate that the Northern Lights is actually caused by unburnt 2T oil, so as this correlates with the timing of our dyno runs I guess the lower EGT is something to look at next! Great work Alex, keep it up, we're all behind you!
How more h.p. do you expect over all 50cc modified to date???, we see 50cc between 15hp to 25hp on the road yet.
Please familiarize yourself with “Taguchi excitement design”. It’s a simple engineering test that shows you which variables are important, how important they are, how they interact with each other, and where they should be set at.
It’s pretty easy to setup and it’d keep you from chasing a sea of variables that all affect each other in seemingly random ways.
I’d start with running a Taguchi L8 on 3-4 variables with your pipes.
first I learned of this,
seems very powerful
thank you
Watching you build an expansion chamber from scratch reminds me of 1970 when my friend Tommy Joe built his own expansion chamber using plans from motorcycle magazine.he. made mandrells on a wood lathe out of oak wood. This was on a 1970 125cc Yamaha Enduro.
It worked really well. He is an excellent gas welder.
3:30: when forming cylinders and other shapes, bend the ends slightly more than they need to be. when you get to join the ends together it's MUCH easier to reduce an over-bend, than it is to bend the ends inwards. (if you see what i mean - sorta tricky to explain..)
2nd time. Ill leave this message. Put a MAF on it just to see when you're drawing more air. You've got too many variables and no data as to whether it's drawing more air when you change things. You can remove the MAF when you're satisfied with flow.
Kinda wonder what will happen if you make the inside of the stinger into a slight cone shape? like from 14mm to 16mm.
I feel like some pressure transducers and a picoscope would really guide the development. Could even use in cylinder pressure and ignition trigger comparison to set timing.
I think now we’re on to something bcoz i havent seen your pants this dirty that even the snusbox shows its spot 😅
I think you should test using a proper length stinger. The very short one you are testing with will give way different results to a full length stinger.
It would be very interesting to see how a bigger stinger would act?
The exhaust manifold length/shape matters a lot on smokers.
I had a RM 125 1986. I did shorten the expansion chamber according to mx action magazine to make a rocket pipe. I got a shorter poweband more power higher up in the rev range.
Good Video again! :D Aside from the dyno maybe not working correctly...How can you be sure, that your cylinder is getting filled as it should? because everything else looks good. The engine should produce that(or more) power independend of the pipe i guess. Those pipes cant be that wrong. Also you have to overthink/recalculate your Intake setup/timing when changing parameters of your exhaust system... Just some thoughts ;D Keep it up, best regards
Try solar flux type B mixed with alcohol and apply on the inside of your parts
You’ve used a lot of cool DIY techniques in this build it would be cool to see you use a pressure washer for hydro forming a pipe.
How about a sliding pipe like I e seen on go-carts before? Start long and shorten as the revs climb
It seems like your transmission losses are around 2.5hp, as can be seen when the dyno spins down. Unless there’s some weird software stuff, it seems like the dyno should be able to measure the loss just as accurately as hp gain, the drum is just spinning down instead of spinning up. The more loss, the faster the drum slows down.
Good call - there is also hysteresis to consider, especially with that belt drive primary. If I understand the setup correctly, the clutch is disengaged when he finishes the run, so we're seeing the spin-down numbers of the transmission only without the belt primary, so his loss is probably even higher than 2.5hp. Probably a safe bet that he's at least 15hp at the crank right now.
He should quit screwing around and obtain a dedicated 2-stroke engine dynamometer! How obvious can it be? @@MikeyAntonakakis
with a wide exhaust port the area the exiting gas encounters is larger and so that reduces the pressure at the beginning of the exhaust pulse, what is going into the pipe, and that results in less intense return waves for a less effective pipe. And no pipe modification can correct that. So obviously there is a limit to how wide the exhaust port can be made before this problem becomes too much.
Could be the problem 👍
Salut mec !
Pour ton pot
J’ai vu le gars de chez KRM faire les pots au chalumeau
Bon il faut un sacrée coup de main mais c’était ouff la qualité
Il soudait chaque tronçon comme toi
Après il surfaçait les tronçon sur une ponceuse à bande et enfin il les passais sur un cône métallique avec un marteau pour les mettre bien rond
Ensuite il soudait un tronçon à un autre et il le tapait sur une sorte de boule pour que le pot sois bien rond à l’intérieur et pas avec des facettes et ça permet aussi d’aplatir la soudure
Et enfin il soudait le coude à la fin
Awesome job on the pipe, your best welds happen when you are most comfortable, use a clamp or block to help position your torch hand. Been watching for a long time, thanks for bringing us along!
Nice to see some progress, but it seems to be still a long way to reach the benchmark of about 24hp. Keep on fighting 👍🏻
Would an outlet pipe tip extension make any change? Mabie more chamber gasses would be available for the power-band. Look at an 80's yz80 exhaust pipe. It has more chamber volume, and longer exit length
they also need room for a spark arrestor though, for mass production... standards, or whatever they call them.
Do you have the stinger pipe to extend into the pipe and terminate at the max pressure point? Adjusting the pipe length and its position makes a difference.
I think you said that your wrist pin hole might be opening a path from the intake port to the exhaust port near TDC.
Is that a correct understanding? I think that would really mess up your pipe tuning.
I think he plugged it already.
Because this is the internet someone is going to say "by the sound of you slapping the pipe your pipe is wrong in (palce x) by about (really precise number)".
I want to add my own little comment here about this whole fiasco. I been following for a long time now and the most powerful 2 stroke at 50cc is commendable. what kind of gear ratio are you running? It seems like you hit the top speed for this transmission pretty quick so for me its hard to tell. It's too bad this bike isn't ride worthy. It would be far more interesting to see some straight line pulls but I know we are a ways away from that. wind resistance alone would keep you from hitting the limit. And I thought you were aiming for 20k rpm? Seems to me that if your not getting accurate rpm measurements, you could be getting other measurements wrong as well. I'm not saying this is the case, just something to think about. Your still at the point where I think a length adjustable pipe is necessary. If you could change the pipe on the fly and ensure pipe resonance then you would be able to see if 50cc is really enough.
Is your connection between the spigot and the pipe air tight? If you loose pressure there it could affect horsepower. I had a leaky pipe gasket on my 50cc 2 stroke and i felt a huge drop in power.
Yes, exhaust leaks have a big influence and cause a lot of power loss.
dont know..for amount of work u put in this engine..this power figures are disapointment
It's because I'm working on the edge, too many unknowns like conflicting resonance systems. I'm designing a pipe for peak at 14-16k, things should work out better. For real power we need a short high rpm pipe to work tho, and the low rpm pipe will only be to confirm the rest of the engine.
There's more than 25% primary, transmission, tyre losses here. I reckon 40%. Need to get this on a calibrated engine dyno with a known history of other bikes to compare.
Its odd. a 50cc at that rpm should be making more hp. That's around a stock 50cc with a pipe and carb territory.
at 17k it should be in the 20 hp range. Even if the motor is majorly down in torque i'd expect more.
Do you think that Alex needs an engine-dedicated dyno?
It seems like hydroforming a pipe from two sheets welded together with a grease pump would be a lot more efficient for making one-off pipes… there are how-to’s on YT that might be worth looking into.
What does a longer stinger do?
Love it! Keep grinding 👌
Why not build a slider pipe? I have been wondering about this for several years now. Plus couldn't you make it come apart so you could experiment with different cone designs?
Slider pipes were all the rage when I was growing up. If you had a slider you were a baller lol
I agree, but first he has to fix the obvious porting problem that's keeping the peak torque and bhp at virtually the same throughout the engine's rpm range. Usually, this condition is the result of poorly designed ports that won't allow the rpm to increase faster than the torque decreases. The late Dr. Blair dedicated a lifetime in research to this phenomena (among others), but Alex claims that he's had enough of theory. Really?
Nice to see the "tuning" has finally started!! ..I have a really good feeling about your progress! ..I have a good "ear" for engines and I do believe there is a good "jump" in power coming..I'm so happy for you!...👍👍👍🗽🇺🇸
Love the dyno testing from my experience if you have leaks at flange to cyl will run much worse interesting trying different stinger sizes also pipe length would be good is it possible to have the centre cone to slide an inch or 2 by sleeving it then having a big clamp to keep fixed kind of like a car exhaust fits together you could change overall length a few inches simply for dyno runs
I think me and a few others noticed 5-10 episodes back that it really needed a fresh properly designed pipe as the hacking and bodging of other stuff just wasn't working with it. I think the key is you realized all the geometry "errors" you made during the design of the cylinder and that let you design the correct pipe this time. Glad to see it responding well to that!
test with 20mm longer header , when your thoughts are correct the powerband should drop 500 RPM earlier.
I still think the pipe is a lot of it.............. go longer, rather than have a pipe looking like an insect pupa, been some very high powered two strokes none have had a pipe that looks anything like that .
there's very high powered and VERY high powered. was your two stroke a 50cc produced peak power around 15k rpm and doing more than 20-30hp at the wheel. extreme power takes extreme measures. obviously looking at the channel extreme measures don't guarantee success but if you're. it shooting for that high rpm you'll never make that kind of power
Have you used the flow meter on the intake the carburetion to find out how much flow your intake is receiving at what rpm
There exist programs, I believe for cellphones, which measure your vehicle acceleration, your displacement, and with input of vehicle mass (including rider), can calculate horsepower. Since you basically have a rideable bike, you might consider this method as a data for comparison to your inertia dyno and your bench dyno. Not suggesting this method for all your development, just as a reference value for validation.
It is already a big challenge to produce several equal dyno pulls in a controlled environment. Trying to produce multiple comparable pulls outdoors with all the external factors thrown in is as good as impossible, especially when the measured differences are as small as they are here. Those programs are nice for bragging rights if you own a muscle car but useless for developing purposes.
Dear Alex, in my opinion your engine sounds and rips great. With that kind of performance you should stand at 15-18 HP. I think, there ist something working not right with your dyno.
I just have the feeling that the expansion chamber needs more volume.
I think smaller and a bit longer cones with less mid section between cones
@2STROKE STUFFING ALEX.. Here's an idea a friend did MANY years a go while 'Home tuning his Kawasaki AR125... He took a medium sized exhaust that had a wide-ish expansion chamber with a flat cylinder mid section, and then tune it, run it see what power, then, cut the pipe (at the mid section), trim off a 5mm/10mm band, reweld pipe back together (thus shortening the chamber by approx that length, tune the engine to match and see the results. Keep doing this till you find the IDEAL chamber size for the tune you want. My friend Steve did this repetitive job for quite a while with different heads (and modding those heads - back before computers n such, and made some NICE power gains with a decent power band!)...
SO, from a lowly 12BHP AR125 rotary (wasn't the best 125cc bikes compared to the TZR125,NSF/NSR125 & RG125 (which had 'Powervalves etc'), he managed to get up to around 25+BHP with the unrestricted Kawasaki AR125 Kit. Eventually though, he just replaced the motor with the one out of the Kawasaki traily bike the KMX200 and tuned that up instead. 🤔😏 It was a FAST AR, and though his other mates on their NSR125Rs and TZR125Rs thought they were the bees knees, his 'Lowly' Kwak, showed them something or two 👌
😎🇬🇧
I think you should start coneing your stinger and using a smaller hole and then going larger cutting it off as it goes up🎉
Time to put this engine in a bike and record sone acceleration runs to calculate hp.
On a serious note what if you get your exhaust gas temperature up and your air fuel ratio a little closer just asking
Next vid👍
Proud of you making pipes now bro.
Take the FARRRKN stuffers out!!! Show us your secondary intake now.
I just can't understand why you haven't made a pipe that you can easily change the resonant length quickly by slipping one
pipe inside another to get closer to the required set point for maximum power.
You did it again!!!!!! the stingerpipe MUST be at least 18cm long to prevent gas constelations !!! just look at 2strock bikes from the 80 man...My SBK Aprilia RS 125 34HP Arrow exhaust.. (with 19.5 cm stinger pipe before Endmuffler.... thats the secret...it was Valentino Rossi`s first Bike.......or KREIDLER FLORETT World champin 50ccm 213 Kmh..25HP from the 70ies I had one.....Or the Van Veen Kreidler sceene in Holland the last 15 Jears...just dooo reesearch.... 2strokeGURU from swizerland..bää..bääää...bäääääääääää
Hooray ❤! Making progress with hard work 💪. You sound like a WWWII aeronautics engineer bumbping against MACH DYYNAMICS 😮. ACHTUNG SCHNELL ! 😂 HAHAHA 😂🤣😂🤣 Good luck my friend .
doubt you have shockwaves but you probably have interference with the scavenging pulses from the exhaust pulses.
In cars, they usually take
1 degree of timing out for each PSI of boost..
Sounds like it might be time to get yourself an air/fuel ratio sensor and gauge.
Thanks for the vidio, your pipe looks high reving (short)and sharp rear cone(quick shut down)witch is normal for most.your porting may not like the pipe.ponder this my 250 has a 9000rpm std pipe around 1250mm.Revised port timing and head only .Now pulls hard to 11500 with around 10 more hp.just shows how sprint porting likes a stock pipe lengh.only mod to pipe stinger perforated tube from 24 to28mm just gave more everywhere.28mm is stock 500cc but 250s whith plus 55-65hp like 28mm helps dissipate cylinder heat.interresting stinger size of 16mm.
Now ive watched all the video, you need to experiment with variable length expansion chambers. Its not just the soundwave you manipulate..its the volume too.
Hi Alex! Maybe my question is dumb but, what about squish gap and CR? Less gap, more turbulence, better mix burning, more exhaust gas temperature... Also less burning time, that means less spark advance... Maybe you are in a "too safe zone". I dont remember the last yime You checked that... Anyway, great job man! I always learn something new in your videos, and inspire me for keep my own project alive. Thanks.
Awesome 👍😎‼️ I love your Channel and always be happy that you not give up 👍👍👍‼️The only thing that i did not see is Tape, because the most Racer hold together with Tape. I don't know if it for POWER or to hold all together or Aerodynamic?!? Without Ducttape the World brakes in Parts.
Greatings to you/family stay safe, healthy and share love!
Considering its a one cylinder 50cc, and is you theorize a engine at 500cc and said it has 10x the power this little 50cc has, it would be a pretty decent engine.
800cc snowmobiles have between 130-150hp, which is 10-12x the power your little 50cc has.
Relatively, it runs fucking good.