Turbocharging the Yan-clone L100: End of the Trail?

[larkout]

This http://tech.groups.yahoo.com/group/Biod ... ssage/1142 and this http://en.wikipedia.org/wiki/Cetane_number are interesting.

[Banzaibob]

I thought about adding kerosene to my fuel to bump up the cetane. I opted out of it because kerosene does not have the lubrication qualities that is required for the fuel pump.

[coachgeo]

I thought about adding kerosene to my fuel to bump up the cetane. I opted out of it because kerosene does not have the lubrication qualities that is required for the fuel pump.

adding a little BioD or even tiny amount of Straight Veg oil/ even a few spoon fulls in a small Bike tank would add enough luberocity

[tappy]

Have a look for the threads on butane / propane gas fumigation. By adding a little gas to the incoming air, it's well mixed by the time fuel is injected and helps the flame front spread faster and more completely.
If it's generating soot because of too little air flow however then it probably won't help much. Nitrous would help that tho'.

[tappy]

The more I think about it, the more I'm convinced that the pulsing nature of the exhaust flow out of the engine is a major part of the problem.

It's a reasonable assumption to assume that both the compressor and turbine have been matched to deal with the same mass flow going into and out of the engine. Yes the pressure, temperature and density will be different, but fundamentally the mass of gas is practically the same (tiny bit of fuel mass in there too).

A plenum has been used to smooth out the flow on the inlet side. At the average flow rate I calculated that the turbo is only just flowing as much as it would like to. If there was no plenum then for 540degree of engine rotation there would be zero flow from the turbo, and for 180 degrees (intake stroke) there would be a sudden flow. The plenum will help smooth this out, but it's possible that for say - 360degrees of engine rotation there is no flow, and then for 360 degrees there's about the flow the turbo was designed for. So on the inlet side at the moment, things might be OK.

Now turn to the exhaust. If the flow out the exhaust port were constant, then again we'd expect that the turbine was seeing just about enough flow to spin the compressor. But in practise we're seeing no flow for 540 degrees, and then 4 times the "average" flow for 180 degrees. Given that the exhaust valve doesn't open & close instantaneously, and the piston speed is sinusoidal, we might actually be seeing a peak of 6 times the average flow. This is probably too much for the turbine, so the turbine chokes and doesn't let the exhaust out.

So back pressure builds up in the engine, stopping fresh air in.
So it smokes like a bastard, and makes no more power despite reading 7psi manifold pressure.

SOOO, my previous advice stands - make an exhaust plenum too. And for both inlet and exhaust plenum reduce their pressure losses (I can probably advise), and consider a spot of intercooling.

[tappy]

Here's a diagram I made to help explain with fewer words:

[toyotaracer9]

That 10hp engine isnt flowing enough exhaust to get into the max turbine flow area, its not spinning the turbine fast enough to keep the wheel efficient. This turbo is made to flow up to 125hp so its like taking a turbo from a vehicle making 850hp and putting it on an engine making 100hp and wondering why it wont go. I do agree with everything else you are saying and like the way you explained it with the degrees of rotation without any energy being produced.

[Banzaibob]

That is indeed a cool graphic. Video of the bike as of today; http://www.youtube.com/watch?v=PfaaI7h5WjY

[sbes]

Is it possible that the exhaust valve timing on this engine favours no back pressure too much?
The reverse of this is often the case with removing the cat converter killing power and fuel mileage on modern car engines. The exhaust timing is set to favour a high backpressure in many modern engines. This is easy to fix on a DOHC engine, and ajustable to a degree on most cams, but would be hard to correct on this diesel where it affects injection timing as well.

Steve

[albertaphil]

Hi all, it's been a long time since I posted anything on this forum, but after several years of more important projects (housing and family) I'm getting back to the whimsy. And I have a vested interest in this topic as, in addition to my dieselbike project (honda cb400 with a ruggerini 654cc twin) awaiting completion, I have an L100 clone wanting to be put into a garden tractor, and it will require turbocharging to make it do what it will need to do. So here's what I think...

You know you are getting boost, which means that when the intake valve is open and the piston is traveling downward on the intake stroke, you are necessarily getting more fresh air into the engine to burn the fuel you are about to inject. As long as you are getting boost, you know that the turbo is spinning as it should.

You know what your smoke levels are, which are a good gauge of over-fuelling or under-fuelling, so you know that your air-fuel ratios are correct enough to give you added performance. That is: more boost+more fuel=more power.

Regarding intercooling: as I understand it, the reasons to intercool are twofold 1)reduce intake air temperature to increase the density of the intake air that has been heated due to compression in the turbo, and 2)reduce exhaust temperature so as not to melt down the important bits of the engine. Your engine is only running 9psi boost, which will only ever raise IAT so much. All the old VW diesels I've owned ran around 10psi, for 500,000km, and none were intercooled, so I doubt IAT or EGT were problems. Pretty much all newer diesels are intercooled, and they are also all running +15psi boost.

This leaves 2 areas of potential problem 1)injection timing, and 2)exhaust backpressure. banzaibob, you mentioned that when you added the turbo, you restored the injection timing to its original, advanced state. Have you tried retarding the timing with the turbo? Check out this video http://www.youtube.com/watch?v=gwNfhEUqfuY of a yanclone generator melting itself down (muffler glowing red hot until the engine grinds to a halt). Injection timing is the only thing I can think of that would cause this...the engine is working against itself, generating heat instead of mechanical energy.

I think tappy is onto something with his backpressure argument...just because you are "only" flowing x cfm, but the peak flow per millisecond could be overly restrictive with the total amount of exhaust you are flowing.

Do you have any idea what your EGT's are? Very high EGT could indicate advanced timing, could it not?

I would also shim your head or shave your piston or somehow reduce compression ratio. I know that, for instance, high output marine versions of the GM 6.5 diesel ran 18/1 compression ratios instead of the stock automotive 21.5/1. Presumably, you can get a turbo to jam so much air into the cylinder that you will, perhaps generate way more heat compressing the air than you need to for effective combustion, and it is robbing kinetic energy from the crankshaft to do it.

Like I said, I haven't been around here for a while, but BoxerOtto had a setup like yours in a bike he built, and the last thing I heard was that it was giving him the performance you are hoping for, and his bike was bigger and heavier than yours. Thundercougarfalconbird is his brother. Hey TCFB, how is your bro's bike?

Phil

[BoxerOtto]

indeed it has been a long time scince i have posted mostly for the similar reasons as yourself phil. the turboed engine maxed out at 106km per hour,but only on level ground the bike is not finished. what ive discovered is exactly what is being said . to much compression, to much heated air on the intake side.as the bike ran much stronger in the first 2 minutes of operation. egt was 610 degrees celcius. ibelive camshaft profile on exhaust side is holding it back plus the turbo is just to large to get in its optimum range. supercharging because its a single would probably work better. when i get time i'm going to build a different camshaft to try and optimize the flow.the other mod i did was lighten the flywheel 9 lbs. that mod works great and my idle only increased 100 rpm and was still easy to start. original fly wheel was 24 lbs.the intake plenum would get so hot it would burn the skin off your hand at 9lbs boost, it just wasn't putting through the cfm.

[albertaphil]

Hey Boxer, what happened if you limited the boost to, say, 5psi with the wastegate? Would performance still fall off?

Your brother very cryptically indicated that an intercooler and lowering the compression ratio is required. Shim the head gasket? It would sure be neat to make a small turboed engine viable...

[BoxerOtto]

there is no power in the air when it is hot ,so the best would be an intercooler of some type or maybe some type of injection, wether it is water or methanol or whatever. lowering the compression should help both heat and engine fighting the massive ratio when under boost. the compressor wheel intake side of turbo is so agressive, it stalls the turbo through the engine strokes when there is no exahust heat/pressure. so if you open the waste gate sooner on the exhaust side it still stalls. however one thing i never got around to trying is a pop off valve on boost side at a lower pressure to allow less load on the turbo. short of that working i would probably try a supercharger and large cooling capacity next. that same rhb31 turbo works extreamly well on my brothers punsun twin with twice the displacement.but it also feels the effects of compressed air heating and will be sporting an intercooler for this next round of research . if the single was a2 stroke it would definatly work the turbo.

[thundercougarfalconbird]

picture of intercooler partly installed, plumbing unfinished, pistons with material removed (lower compression), and lighter flywheel, will it be the answer? i have no idea, but will keep posting updates as they happen.

the turbo on the v-twin works very well when the outside temp is arond 4 or 5 degreec C, on a 25C day it was pointless.
i still need to make an adjustable wastegate controller.

http://img10.imageshack.us/img10/6821/coolerh.jpg

[albertaphil]

Looks good. Pictures of the RHB31 turbo on fleabay look like it has a wastegate. Is it not adjustable? Or are you talking about an on-the-go adjustable?

I love your bike...

[thundercougarfalconbird]

thanks, and the wastegate ontroler is fixed, need to build something different

[gearhead1951]

www.turboford.org has an equation page that gives you all you need to figure what you should expect from a turbo installation !

[coachgeo]

http://www.turboford.org has an equation page that gives you all you need to figure what you should expect from a turbo installation !

Just emailed them. Thanx for the link. Here is copy of what I sent them.

Just came across your Turbo calculation/ worksheet pages. Honestly have not looked close yet though.

Any thoughts on how your pages relate too:
. single cylinder engines!
. two cylinder engines
. diesel engines

Mucho thanx for everyone's efforts in putting your page together and opening them up to the mass gear heads.

[albertaphil]

Hmmm, a fixed wastegate. As though every engine that particular turbo might be mounted on requires the same amount of maximum boost. I wonder psi the wadtegate is set for...

What would the results be if we could simply limit the boost of the yanclone to 4 or 5 psi.

Years ado my dad was fiddling with his '85 jetta td, which had an adjustable wastegate and an adjustable popoff valve. Well, he kept tightening both adjustments because he just couldnt get the boost up...then he realized that the tube to his boost guage was crushed. The long and short of it was that he had been running his car briefly at upwards of 20 psi boost, and I could feel no increase in power over 11psi.
I wonder

[toyotaracer9]

Hmmm, a fixed wastegate. As though every engine that particular turbo might be mounted on requires the same amount of maximum boost. I wonder psi the wadtegate is set for..
I wonder

WG set for 10psi

[thundercougarfalconbird]

fixed as in non adjustable , need to build adjustable controler and adjust to where the engine runs its best

[toyotaracer9]

fixed as in non adjustable , need to build adjustable controler and adjust to where the engine runs its best

may be able to get a weaker spring in the vacuum dashpot to make it open sooner, then you can put a boost controller and turn it up from there.

[Dieselmonkey89]

I finally took my turbo Intercooled Yanmar clone diesel Suzuki out for its first test run today, and I was able to reach a top speed of 60mph. From what I've read, it seems that 60 is all this bike will ever reach. I'm running a 3.5:1 gear ratio with a comet 40 cvt. At 60 the engine seems to be pulling as hard as it can even though there is still more room on the cvt to move into a higher gear ratio. I think your best bet would be to calculate what rpm your wheel needs to be running at 60, and install a sprocket that matches that speed when the engine is running max rpm.

[DieselFly]

I always find they run their best just before the parts start flying through the case

fixed as in non adjustable , need to build adjustable controler and adjust to where the engine runs its best

[DieselFly]

I find the run their best just before the parts start flying through the case

fixed as in non adjustable , need to build adjustable controler and adjust to where the engine runs its best