How to make the perfect 2 Stroke Ignition Curve - 100 MPH Moped Challenge

[@thedarkknight1971]

Great to hear that progress is coming on nicely, it seems like you and Alex ('2 Stroke Stuffing' channel * ) have had a lot to work out of late. But, as always, 🤞 to the both of you achieving our goals! Looking forward to the speed test runs too! I take it you sorted the 'Potential' rear tyre/dyno rub issue? 😏 * For anyone not in the know, Alex is a guy who has hand built a 50cc 2 stroke motor and is trying to make the most powerful motor for land speed attempt. If successful, it'll be a supercharged Nitro run 50cc. He HAS had 24ish BHP, but is working on a redesign, go check him out as well as this fine gent here! 👍 😎🇬🇧

[@AutoBeta2T]

Cheers Mate - yes getting there now. Tyre rub issue all sorted. I fixed the wheel chock to the dyno and all is well. I did do back to back tests and it didn't increase power but I think as the power goes up it would have been a problem.

[@teltwosheds2972]

Alex does go off on tangents though 😅

[@HPRaceDevelopment]

The timing tells you a lot about the pipe length to port timing relationship - and some about the head - as it's all tied in together. In my opinion - this is telling you the pipe is a little short for the port. Im not a pipe expert like some people - but adding a little length to your belly would be an easy start to this theory - and see if you can find your peak torque at 10-13 deg timing rather than 22 ish. If you add length and reduce timing - you *might* find a better combo. Addtionally - if you add compression it will be similar to more timing. What the timing really does is alter pipe temp. All bulk power is made via the pipe's influence on the egine - so what we often 'have happen" is we tune variables such that our engine is making the pipe happiest to trap the most air. Nice work - keep plugging away!

[@AutoBeta2T]

Cheers Derek. I want to try getting the trapped compression back up to where it was before along with a few other things then I will have a play with the pipe length again and the timing. The problem with two strokes is you change just one thing and it affects 3 or 4 other things... Such a simple design but massively complex in actual operation. 🙂 I guess that's what makes them interesting.

[@ASoftaaja]

The 15 degree peak power recommendation is meant for some crazy hp engines which are far from our typical moped-base tuning candidates. The burn rate gets faster the more mixture you can get crammed in the chamber and the advance must be less, but it takes a lot to make the cylinder that good. I have also found that 18-20 degrees at peak power is quite good. I have tested removing the lower piston ring a couple of times and it did not seem to have any negative effect at all even though the groove is open. The engine sounded more eager to rev but at that time I didn't have a dyno so the result is subjective 😁Some guys have plugged the groove with a spring pin. Another technique I heard of is to heat the lower ring red hot in a mandrel so it loses the springiness and just rides in there with minimal friction.

[@AutoBeta2T]

ASoftaaja - Thanks for that info about the timing. I think ill keep the max advance to 20 degrees for the min then. I am worried if it will be too much under load at 100 mph? Something to worry about in the summer I guess when I can get to do some actual speed runs. I want to do a few more tests before I attack the exhaust duct so I do want to do a quick 2 ring v 1 ring back to back test in mine - it will be interesting :) I'm pleased the Ignitec has worked for you in your last video - a good result :)

[@sidecarbod1441]

"The burn rate gets faster the more mixture you can get crammed in the chamber and the advance must be less"....YES, this what I have been saying.

[@ASoftaaja]

Once you find the best advance for maximum power, there is no reason to back it off for reliability reasons. It means the engine is working efficiently. There must be other ways to prevent overheating. In an aircooled 2T it is always a challenge 😁 I would get a good air blower in front of the dyno (you probably already have) and then experiment with cylinder/head air ducting and a CHT sensor to improve the cooling. Using a richer carburetor tune also helps to cool it down. I would keep the compression ratio also low. I have found that high compression increases thermal load a lot but improves power only a little. @@AutoBeta2T

[@AutoBeta2T]

Cheers @ASoftaaja. The front fans are about 1 KW from memory. I'm interested to see how much difference there is from the dyno CHT/EGT to road testing CHT/EGT? Yes, air(fuel)cooled engines are a pain. What sort of compression ratio would you recomend?

[@sidecarbod1441]

8:30 You are not dealing with a huge increase when you look at the raw numbers but that is partly because the 'before' and 'after' numbers are both fairly small, its still a 4% increase and that is worth having.

[@Scissors69]

Really good, methodical, testing. 👍

[@AutoBeta2T]

Cheers Dave

[@gerhardpotgieter9091]

Very nice!! The boat looks much more planted with the bigger props and you didn't lose any speed

[@AutoBeta2T]

Hi Gerhard, I think your comment was for another video?

[@julesvern-u4e]

I have an RD400 and put an ignition that had a curve in it and I was stunned at how much more power it made. Problem was it had the tiniest lightest flywheel.. it weighed nothing and I hated the way it make the bike feel.. and having to have a high idle just to stop it from stalling was annoying. I splurged and put in a VAPE and it has a large hefty flywheel and the bike idles and feels amazing.. This winter i will purchase the controller module so I can program in a safe curve and get all the torque I experienced, back.

[@AutoBeta2T]

Cool - sounds like a plan! I'm wanting to try the standard AR generator/flywheel on mine again too. Good luck with getting that torque back.

[@pirrracy]

Cheers for the intel. Planning on getting an HPI digital ignition for my 2T Suzuki 68cc. Appears the HPI software is a similar design, so this helps understand the concept. Still learning by myself. Good luck with your 100mph goal, friend. I'm chasing 100kmph on the 68cc, and I'm nearly there (94kmph).

[@billshiff2060]

Looking forward to your flow test video. That will be interesting.

[@AutoBeta2T]

Cheers Bill. It could be a little while... The data I measured goes into a program that gives a Time FlowArea (FTA). It correlated well with the Specific Time Area I had worked out for the port. Should be an interesting seeing what the transfer FTA gives.

[@johnnykjaersgaard7978]

Good video - and like the trial and error approach for the timing curve versus hp curve😊

[@AutoBeta2T]

Cheers Johnny :)

[@johnnykjaersgaard7978]

I could however imagine that with this approach as with the same approach for fuel mixture you can always take it to far in the chase for more HP 😛@@AutoBeta2T

[@AutoBeta2T]

Yep - but hopefully not until I find a spare barrel.

[@markaddy53]

great job lad keep at it im sure ul get there

[@AutoBeta2T]

Thanks Mark 😁

[@srerccustoms537]

Great video thanks keep them coming

[@AutoBeta2T]

Cheers mate and will do. Hopefully another this Sunday...

[@BEYTEK]

Supposw compression ratio between orher peoples and yours mean diffrent timing

[@AutoBeta2T]

Yep - I think each engine is different in what it wants and needs

[@sidecarbod1441]

Dude Please don't pay any attention to Derek Harris, he believes that the reason for retarding the ignition at high RPM is just to create heat in the pipe, You can see your 10 degree flat line test sent the pipe temperature through the roof but the power curve was crap! He thinks that the VE of the engine is not a factor in determining what the timing needs to be at any point in time. The real 'icing on the cake' for me was when he stated in a post that peak cylinder pressure should occur at TDC, this is total nonsense, the likes of Ricardo Developments worked this out years ago, peak cylinder pressure needs to occur between 14-20 degrees ATDC. 7:05 Your timing 'curves' make perfect sense, you can see how the timing needs to advance as the revs rise up to around 8k RPM, this is because the RPM is going up but the VE of the engine is still fairly poor, (the engine is not 'on the pipe'), in this state the timing needs to advance to give enough time for the flame front to create peak pressure at 14-20 degrees ATDC. Then as the engine comes on the pipe the VE starts going up and up, the initial cylinder pressure before the plug fires is going up as the pipe and intake 'resonate' harder and harder, the initial cylinder pressure has a great bearing on the flame speed so the timing has to start retarding to compensate for this. A.G Bells book on 2 strokes explains why a 2 stroke runs an advance curve until the engine is making decent power and then it runs a retard curve once its in the powerband, its all to do with the VE! (The aim is ALWAYS to get peak cylinder pressure at the right point in degrees ATDC)

[@Hipsters_N_Hippies]

Uncle Tony’s garage, did a video called “ ignition timing how much and why” It’s worth a watch.

[@AutoBeta2T]

Hi Pete, Derek is a very smart guy. From what I have read he's very well educated in two strokes. I also believe that the ignition being retarded after peak increases the over rev by heating the pipe and allowing it to resonate at a higher rpm. As seen in my video with the 13 degree curve being better after peak and shown by the egt increase at that timing.

[@AutoBeta2T]

Cool - I'll try to take a look

[@sidecarbod1441]

@@AutoBeta2T Yeah, fiddling around with the timing AFTER peak power RPM might extend the rev range by a few hundred RPM but really your main concern should be the power curve all the way up peak power, then after that anything else that you can gain after peak power is just a bonus. Like I said, the second that 'DH' stated that peak pressure should occur at 0 zero degrees (at TDC) my mind was made up. (I'll refrain from typing out what I actually think!) 🙂 Carefully set an engine up at exactly 0 degrees, then stand an elephant on the piston, no torque would be created at the crank! DESPITE your reference to Derek Harris I will still 'like' your video!

[@julesvern-u4e]

@@sidecarbod1441 What youre saying mimics what I have managed to learn about two-strokes over the last 30 years. Im not 100% sure but I imagine peak pressure at 0 degrees would be needlessly abusive to crank and rod bearings. There just no mechanical leverage to rotate the crank at 0 degrees either. It doesnt make any sense to me to do such a thing.

[@PetefromSouthOz]

New to your channel. Great stuff. I ran a Suzuki RGV 250 at Land Speed events in Australia for a few years and tuning a smoker for sustained Wide Open Throttle is an "interesting" challenge. What petrol/fuel are you running?

[@AutoBeta2T]

Hi Pete, I used to have an RGV 250 and wish I hadn't sold it now. Lovely bike. How fast do you get out of yours? Any top tips for sustained WOT?

[@AutoBeta2T]

I'm currently on Gulf Super Unleaded, 99 RON.

[@sidecarbod1441]

@@AutoBeta2T "Any top tips for sustained WOT"....a cylinder head temp gauge! 😛

[@AutoBeta2T]

Yep - I had one on my X7 - ignored it and the engine melted. I should have pulled in but had red mist

[@tinolino58]

Thanks

[@Patricks_Projects]

Nice work! In my tzr250 engine as i´ve converted to fuelinjection i just looked at how the curves are looking like in a highperformance twostroke, and saw that 'underneeth' where the pipe breathes they can take a lot of ignition, i´m running mine on E85 and have ~35 degrees down low, i´m running 20-21degrees at idle. Up top where the pipe is working i am comparing it to an boosted 4stroke engine, when the boost hits one need to lower the ignition. So, by this i´m saying that you can probably run much higher down low.(if needed) I honestly already ran this curve i programmed into maxxecu in my ignitech system before. But a thing to consider is that twostrokes is very sensitive, the rpms after are depending on the rpms before. If wanting a huge powerband one can sacrifice a couple of newtonmeters to gain some up top(pipe temp)

[@AutoBeta2T]

Cheers Patrick, what sort of timing are you at when at peak torque?

[@Patricks_Projects]

@@AutoBeta2T Around 22-24 degree from what i can remember from my mind(i am at work now) But remember i´m running E85 fuel also, on petrol i would think about 19-20 degrees.

[@AutoBeta2T]

@@Patricks_Projects does E85 burn slower than pump petrol? I'm assuming it does but I haven't looked into it.

[@Patricks_Projects]

@AutoBeta2T Maybe it does, but i do know that in 4stroke boosted applications you might end up at the same values running e85 or petrol, but e85 as it has more octane, it is more forgiving. I will actually do a test upcoming weekends and lower the ignition at max torque and see if i loose anything.

[@Patricks_Projects]

@@AutoBeta2T Go to my channel, you might be able to spot my ignitionmap in the latest video i released today. I´m running 15.5-1 in compressionration. Stay tuned for part III, i´ll try to reach 100ps to the tire in that one, adding Nitrous.

[@copisetic1104]

Try a cone in cone on the baffle cone, put a spring on the stinger so you can adjust the tuned length of the rear cone and fine tune the pipe at different rpm.

[@AutoBeta2T]

Hi, my baffle come is adjustable but it moves in the dwell section.

[@tinchomtv]

It would be nice to have some plugs pics after the runs with different timings

[@AutoBeta2T]

I'll see what I can do next time at the dyno

[@RACE.KART.PRODUCTS]

start the ignition curve tapering off(retarding) of your test curves a little earlier. You need to start building heat in the pipe just a tad bit sooner in your dyno pulls.

[@AutoBeta2T]

Okay. What is the reason for this?

[@RACE.KART.PRODUCTS]

@@AutoBeta2T it will make power for longer past 12k

[@sidecarbod1441]

@@RACE.KART.PRODUCTS Do you know that the port timing of this engine will support 12k? Do you know whether the piston speed will not exceed the current accepted maximum value of around 25m/s? I guess what I am trying to say here is that you cannot just arbitrarily pick an RPM figure and then try and rev the engine to that RPM.

[@ferdiyurdakul]

You need to take a leaf out of a certain Norwegian 2T dude's book, and leave the best bit to the beginning of the next video, and leave on a cliffhanger. That dude has figured out how the algorithm works 😂 as for tuning, all i ever learned is that all the thinks we thought that helps actually does nothing. Best bang for buck is in port timing, pipes and lots of revs. Perhaps compression and ignition timing afterwards 🤔

[@AutoBeta2T]

Yeah, I know, Alex has got it figured. It's kinda how a soap opera works I think or just life in general - ups and downs. Or that will they won't they get together between a couple of the characters...? I'm sure i'll have some downs. If you look at some of my older vids there were a few failures such as leaks and ignition not working. I aggree - everything seems to be ports and pipes. I've done pipes a few times but this is my first proper go at the ports and I was shocked about how much power I gained. A massive influence. Cheers for watching and stay tuned :)

[@copisetic1104]

Ceramic coat the piston top and combustion chamber, also the expansion chamber. On V8s coated headers reduce heat immensely. Should retain the heat in the combustion gases and not the engine and pipe.

[@AutoBeta2T]

Hi, it's something I have considered... Sounds expensive mind!?

[@smiffie2002]

have you read "2 stroke performance tuning by A Graham Bell" this is pretty much my bible when building up an engine. using more premix will often gain power (up to a point), better lubrication, better ring sealing etc, what fuel are you using? loving the project, vaguely remember reading of this many moons ago. Subscribed ;)

[@AutoBeta2T]

Cheers Smiffie, and yes I have read Bell's book but it was some years ago... I need to get back into reading 2 stroke stuff. Someone else has mentioned oil/fuel ratios. Something for a video one day along with higher octane fuel.

[@sidecarbod1441]

Dave, what was the EGT when your engine was running timing that gave the best peak power and how does that compare to the flat 10 degree run? I'm going to 'stick my neck out' here! I bet it was no higher and possibly lower on the best power run compared to the 10 degree run.

[@AutoBeta2T]

Hi Pete I've not double checked but from memory the egt for 10 degrees was well over 100 degrees hotter. The temp difference for the different timings was significant. You could smell the heat at 10 degrees.

[@sidecarbod1441]

@@AutoBeta2T Cheers for the update, your reply does line up well with what I've been saying, i.e. you do not need a red hot exhaust in order to make power! 🙂 (I'm being a bit flippant here). Your dyno runs clearly show that your best power run was NOT when the exhaust was at its hottest, it totally goes against DH and his 'wonky' theory.

[@Seriouskai]

I'm eating a hamburger while watching this!

[@AutoBeta2T]

Enjoy :)

[@janeali1174]

Sir, I need such a help. I want to ask about the port of such a cylinder, how can we increase the speed from its port. Please help me. Please tell me.

[@AutoBeta2T]

Hi mate, I'd measure the port timings first and got from there. 190 exhaust and 130 degrees duration on the transfer ports can work well. But you need a pipe and look at the carburettor and ignition too.

[@mikemelbrooks]

What fuel are you using? Would a higher octane help prevent detonation?

[@AutoBeta2T]

Hi, it's pump petrol. Gulf 99 unleaded (E5). And yes higher octane fuel would in theory help but I'd need to take advantage with it by possibly increasing compression or advancing the ignition and then I'd have to shorten the pipe. I'd like to try some of the VP fuel. Saying that AvGas is still available and good. Or Methanol...?

[@stevenbusk539]

I'm using Renegade MX2 104Ron fuel in my Kawasaki KMX125. It allowed me to increase the compression and reduce the squish clearance to ~0.9mm. I think it picked up just over 1bhp from the changes when set up on the dyno and with the ignition curve tweaked to suit. Have you thought about an exhaust resonance chamber type power valve being added to the final pipe design? Maybe it would give more low-mid range power to help pull higher gearing without bogging down below the power band?

[@AutoBeta2T]

Cheers for the info Steven - sounds like a good gain. Reference ATAC chamber - it could be something to try if I struggle to stay on pipe. The ignitech could control it too 🤔

[@BorneoClassical]

Hello sir, greetings from Malaysia, I have some issues with the spark plug, the ring and the ground electrod were dark brown, but the electrode shows white colour. Please help

[@Patricks_Projects]

Too hot plug, but!! the porcelain should burn clean from deposits if taking new plug and do a couple of runs, only time dilutes them. What you should look at on the porcelain is down a the bottom of the porcelain you should have about 2mm wide black band. Later on when have been running all kinds of driving the plug will get that cacaobrown colour.

[@BorneoClassical]

@@Patricks_Projects yes sir, they all cocoabrown.. but the electrode center shows white colour. The porcelain also burns good imo, or is this causing from ignition degree too advance? Or the ignition too powerful?

[@thiswillprobhrt]

Here to let you know the thumbnail worked :D

[@AutoBeta2T]

Cool :) Sorry that no pistons were destroyed... That pic was of my Suzuki X7 race bike. I learnt a lot about two strokes that day!

[@humourless682]

Is Horse Power Race Development, linked to Horse Power Ignitions in any way?

[@AutoBeta2T]

Hi - I don't believe so.

[@humourless682]

@@AutoBeta2T Name sounded like they might be linked? Have you done anything to the transfer duct entrances on your Kawasaki cylinder?

[@AutoBeta2T]

Hi, no nothing to the transfers yet, I want to do some flow testing on then to see how well they do actually flow. Could be interesting.

[@duggers999]

Lots of good testing and technical appraisal. However, looking at the photos in the magazine, there might be something you have overlooked… The AR they used was green (and everyone knows the green Kwaks are the fastest). Time to get the rattle cans out!

[@AutoBeta2T]

Cheers and yes definitely - fast Kwackas are always green. I'll get painting 😁

[@sidecarbod1441]

@@AutoBeta2T Green is an unlucky colour according to the Japanese, Kawasaki painted their race bikes green in order to 'give the middle finger' to luck!

[@matthewfredrickmfkrz1934]

Can someone recommend a cdi for tuning

[@AutoBeta2T]

Hi I'm using the Ignitech at the min but I have used a Racetech Developments RTD www.racetechdev.co.uk/ before and they are excellent.

[@alanbirch9663]

What’s causing the 100 mph barrier is power/ weight and wind your trying to push . Just ride behind a car

[@AutoBeta2T]

Hi Alan - Drag and rolling resistance. I just need enough torque at the rear tyre at 100mph to achieve it.

[@rodffofficial7717]

I see you're mod your intake, next time try install an induction tube in your bike. The simplest is copy a Suzuki SIPC, you just need 2 metres of a 10mm hose. Please try it.

[@AutoBeta2T]

Hi :) I'll add it to the list of things to try!

[@rodffofficial7717]

@AutoBeta2T I hope it will increase more power & fuel efficiency to your engine.. Keep a good work sir👍

[@AutoBeta2T]

@@rodffofficial7717 many thanks 🙏

[@HPRaceDevelopment]

Hey that's me!!!

[@raywalsh5822]

bigger carb get more fuel in it

[@AutoBeta2T]

Hi Ray, I have a bigger one to try one day.

[@copisetic1104]

Fix your links

[@AutoBeta2T]

Which ones? I tested the two links I posted and they are fine.

[@sidecarbod1441]

SHIT! 😞

[@AutoBeta2T]

What's up?

[@sidecarbod1441]

@@AutoBeta2T From the thumbnail I thought you have blown your motor, is that not the case?

[@AutoBeta2T]

@sidecarbod1441 Narp Pete 😊 That's my Suzuki X7... Did that at Pembrey 2018. I learnt a few lessons from it mind... The AR is very well thanks... Just about to have a check over and the ready for more power.

[@sidecarbod1441]

@@AutoBeta2T Jeez, man, I thought you had been getting greedy with the ignition timing. Back in the day of my RD's and TZ's I had an impressive collection of 'paperweight' pistons. (I'm starting a new collection now with my KTM 300 EXC! )

[@AutoBeta2T]

@@sidecarbod1441 I have a bit... But all seems okay... Well for now.

[@DoSomething-]

Dude it’s not a moped! Stop

[@AutoBeta2T]

Technically it is 😉