Turbo's on singles - effective or not?

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Turbo's on singles - effective or not?

Post by andrewaust » Fri Jul 31, 2009 1:59 pm

Last week I came across a small IHI clone turbo many are using for only $216 USD, I've always been curious if a turbo would work on a single diesel as many have no form of throttle valve, although some of the larger 4cyl engines have a vacuum dashpot due to the governor arrangement. As nearly all the engines we use do not have any restriction, a full volume of air is drawn into the engine, then expelled "but pulsed".

Diesel engines have a torque curve around 2200 rpm for smaller engines, truck engines etc can be much lower! So what has this got to do with a turbo on a single? To get good power, torque and efficiency from a diesel, boost should start at its torque curve or it will lag, being a real slug.

I set up the turbo today very crudely, nothing seemed to happen till I reached the high rpm limit of the engine, so results were not that impressive. At idle the turbine is hardly spinning that you can actually see the vanes spinning around.

I'm not that really concerned if I cannot get it to work as this little turbo will be used on another multi cylinder project, before I commit to going further I'd like to see how others have gone.

Maybe a small blower is more effective? That I'll leave for someone else to tinker with :).



A ;)

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Re: Turbo's on singles - effective or not?

Post by oldbmw » Fri Jul 31, 2009 9:13 pm

I think a small blower would be better, but whether blower or turbo, on a single you will get better results with a big airbox.
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Re: Turbo's on singles - effective or not?

Post by chevy43 » Sat Aug 22, 2009 5:01 pm

I think the problem mostly is that you don't have enough volume to spin the turbo fast enough to do anything. It probably needs about 1000cc's turing 2,500 rpm to start to build boost. Also I'm guessing you did the test with no load? If the engine is loaded that would help because the heat also makes more flow out the exhuast - spinning the turbo faster and then making even more exhaust flow.

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Re: Turbo's on singles - effective or not?

Post by pietenpol2002 » Sun Aug 23, 2009 4:14 pm

Heiko (who posts on here occasionally) seems to have some experience with turboing the cloned singles as evidenced in the link below from Rafael's site. Perhaps he could be persuaded to comment. Of some concern regarding the turbo application shown is the apparent lack of accumulator/plenum.

Ron

http://dieselkrad.info/forum/index.php? ... bo#msg_994
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Re: Turbo's on singles - effective or not?

Post by BoxerOtto » Tue Jul 06, 2010 5:41 am

i'm having good success with the installation of the turbo on my clone so far , here are some pics of what i got going on. of course the chamber that looks like an air filter housing is really only holding a set of reed valves the rest is open plenum chamber about 1500cc. i believe at low rpm (no boost) they do the job of holding the overlap pulse. once it starts to boost they just flow open. boost gauge is actually suprisingly smooth. 1/4 to 1/2 throttle 5lbs easy, wide open gives up to 9lbs.another very important mod was to make a pressure relief valve for the oil pump. having a 140 lb gauge being run off the end was no good for the turbo feed. the clone has a pee hole on the inside cover of the oil pump which dumps off excess volume of oil but does not regulate pressure as the hole size does not change ,and as the oil warms up pressure drops off. ok on an engine destined to run at constant higher rpm, not so good at idle.so off the gauge port i plumbed in a gauge ,the tubro feed, and pressure relief which dumps back to crankcase. this way at idle i still have 50lbs and wide open about 70. i also blocked off said pee hole as it no longer needed.i have about 500 to 600 km on it so far , all off road km because the rest of the bike is still not road legal. i'm not running off my main tank yet because i need to make a petcock with injector return line yet so i have a 200ml plastic grass trimmer tank i'm running off of. it's not as fast as the 66 t bird ,but it's not to far off the 66 tiger 500. back to work! http://yfrog.com/msdsc02452j http://yfrog.com/msdsc02451j http://yfrog.com/0mdsc02152rj http://yfrog.com/16dsc02151mdj http://yfrog.com/0mdsc02150hvj http://yfrog.com/0gdsc02145gkj http://yfrog.com/mudsc02144j http://yfrog.com/mudsc02143bj http://yfrog.com/mudsc02456bj http://yfrog.com/75dsc02113tj http://yfrog.com/msdsc02112nj http://yfrog.com/0kdsc02111yj http://yfrog.com/0gdsc02114iwj http://yfrog.com/htdsc02110tj

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Re: Turbo's on singles - effective or not?

Post by Sphere » Wed Jul 07, 2010 6:15 pm

I got rid of the static, someone else can download ´em and start attaching them 3 at a time to save them for all eternity :mrgreen:

Very nice setup indeed.

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Re: Turbo's on singles - effective or not?

Post by BoxerOtto » Wed Jul 07, 2010 7:52 pm

thanks man. im just not very computer friendly, i like the diesel better. what not all the pictures.

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Re: Turbo's on singles - effective or not?

Post by Sphere » Wed Jul 07, 2010 8:03 pm

Alright then I will edit the post tomorrrow I was mainly interested in the turbo setup.
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Re: Turbo's on singles - effective or not?

Post by BoxerOtto » Wed Jul 07, 2010 8:49 pm

just kidding , you don t have to if you don t wanna. bye the way any updates on your build. have you ridden it much yet.

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Re: Turbo's on singles - effective or not?

Post by albertaphil » Thu Jul 08, 2010 5:03 am

I'm extremely interested to see the reliability of well tuned, well looked after small diesels with turbos. Frankly, 9psi sounds like an awful lot of boost for an engine that wasn't designed to have any. My 1996 VW golf TD only runs 8.5psi. My chev 6.5 TD pickup goes into limp mode when boost exceeds 12 psi for more than a few seconds (I built a mechanical wastegate controller to bypass the messed up electronic one).

However, with the yanclone singles, I haven't heard of any particular weak spots, which would be accentuated by increased power output, so you're entering some uncharted territory. That being the case, if you were to put a pyrometer on the bike such that you don't overheat your exhaust (and piston and cylinder head and valves), I'm expecting good results.

I must say, the concept of a single cylinder engine that costs $400 brand new from Princess Auto (plus a $300 turbo) that can reliably move a 400lb bike at highway speeds is pretty exciting.

Cheers,
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Re: Turbo's on singles - effective or not?

Post by BoxerOtto » Thu Jul 08, 2010 6:03 pm

i am mounting a pyro gauge on it. as far as 9 lbs being a lot of boost ,just because it can do it doesn t mean you have to have it there all the time it seems to have a nice sweet spot from 3 to 6 lbs. i have to start some where and if it s going to be that fragile i don t want it. i m running the hell out of it off road to see what breaks and i will fix any weak areas. it should be bullit proof by the time it gets out on the pavement. i have seen normal engines right out of the box never make 600kms before so i m feeling pretty confident with this one. i ll keep posting as i go.

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Re: Turbo's on singles - effective or not?

Post by coachgeo » Tue Feb 19, 2013 6:18 pm

andrewaust wrote:Last week I came across a small IHI clone turbo ... Maybe a small blower is more effective? That I'll leave for someone else to tinker with :) ;)
Update please

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Re: Turbo's on singles - effective or not?

Post by Sphere » Tue Feb 19, 2013 6:30 pm

Maybe it slipped your mind but andrewaust is no longer among us...
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Re: Turbo's on singles - effective or not?

Post by coachgeo » Tue Feb 19, 2013 7:09 pm

My bad........ and I even looked at the Andrew McGarity thread to verify and still got it wrong.... assumed they were different Andrew's for stupid reason's.

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Re: Turbo's on singles - effective or not?

Post by dieseltech » Thu Jan 02, 2014 8:45 pm

andrewaust wrote:I've always been curious if a turbo would work on a single diesel as many have no form of throttle valve
There is no throttle valve because it does nothing useful in a diesel. In fact it only does harm by increasing the intake pressure loss. Mercedes-Benz used a throttle plate in some W124 diesels to increase EGR "effectiveness" at idle, but as EGR is also extremely harmful to the engine, the throttle plate did A LOT more harm than usual.

A throttle plate also does no good for any turbo - turbo gassers need a blow-off valve setup in some form to prevent compressor stall (EXTREMELY harmful to the turbo, can rapidly snap the turbo shaft) from occuring when the throttle is closed. Also again it only causes heavy losses in any case.
andrewaust wrote:Diesel engines have a torque curve around 2200 rpm for smaller engines, truck engines etc can be much lower! So what has this got to do with a turbo on a single? To get good power, torque and efficiency from a diesel, boost should start at its torque curve or it will lag, being a real slug.
You are seriously misunderstanding how a diesel engine produces torque (and thus power).
An NA diesel has a nearly flat torque/RPM characteristic - there is still a torque "peak", but the "peak" torque is only 5-15% greater than low- and high-end torque (various losses at low and high RPMs decrease the available output torque slightly). An idealized (nonexistent) NA diesel has a perfectly flat torque characteristic all the way from idle to the redline due to the absence of these losses.

A diesel engine is a heat engine - it converts heat energy to mechanical energy (used to drive the bike). The cylinder can only hold so much air, and you can only burn so much fuel in that air before it will refuse to burn completely and belch tons of black soot like... well, like a smoky diesel.
In any case the output torque is approximately proportional to the amount of fuel burned per engine cycle. And power = torque * RPM.
Because the amount of air available per cycle is nearly independent of RPMs, the max amount of fuel that can be burned is also nearly constant, and thus the available torque is also nearly independent of RPMs.

We can't really increase the max RPMs much - the heavy internal parts of a diesel engine don't take well to overspeeding, and there are other issues pertaining to the injection system which make this even more infeasible.
So how do we increase the available power? By increasing the available torque. And to do that you need to burn more fuel per cycle.

But to burn more fuel you also need more air. Since the cylinder displacement can't really be changed, you need to increase the density of the intake air. The only practical way to do that is by pressurizing it.
However, compressing air in such quantities takes a tremendous amount of power. That power has to come from somewhere.

Enter the turbo. A turbo is also a heat engine in its own right. It utilizes the waste heat contained in the exhaust gasses as a source of great power, and uses that power to smash a lot more air into the cylinder than would ordinarily fit. This allows much more fuel to be burned, and more power to be generated.

However, there is a catch. The turbo utilizes a centrifugal compressor and a centrifugal power turbine. Centrifugal turbomachinery is highly sensitive to the shaft RPMs - in fact, the actual performance varies with the third power of the shaft speed. So it needs to spin fast. Extremely fast. To the tune of 3000 revolutions per second. At such speeds the turbo itself is working at a power level of roughly a third as much HP as the diesel engine itself. That's tens of HP through a 5...7mm shaft.

To reach such RPMs the turbo needs a VERY high exhaust gas flow rate. Which is why it's extremely critical that the turbo size is properly matched to engine displacement. A turbo that is too small will start to develop max boost very early on, but at high engine RPMs, the airflow through the turbo inlet will approach the speed of sound, and no more air flow is physically possible - the engine is now being severely starved for air, and so the top end performance suffers enormously.

On the other hand, a turbo that is too big will never reach its optimal operating point, and so the performance will also suffer greatly - the max boost (and thus power gain) will be mediocre, also only being reached close to the redline, and there will be massive turbo lag.
andrewaust wrote:I set up the turbo today very crudely, nothing seemed to happen till I reached the high rpm limit of the engine, so results were not that impressive. At idle the turbine is hardly spinning that you
can actually see the vanes spinning around.

I'm not that really concerned if I cannot get it to work as this little turbo will be used on another multi cylinder project, before I commit to going further I'd like to see how others have gone.
At this point there is nothing for me to add. It is painfully clear that your turbo is hopelessly mismatched to the engine it's attached to.
andrewaust wrote:Maybe a small blower is more effective? That I'll leave for someone else to tinker with :).
You've hit the nail right on the head. The problem is, there is not really a "smaller blower". The smallest turbo commercially available - can't remember the designation offhand (I think it was a Garrett turbo though), but it has appeared at least once on this forum - is still so big that the 0.8L V-twin punsun is BARELY big enough to work acceptably well with that turbo.

I hate to burst your bubble, but there is just not a turbo available that would be an optimal match with these single cylinder diesels.

The highly pulsed nature of both the intake and exhaust flow in single cylinder engines also hurts performance a lot. Using exhaust and intake plenums would alleviate the issue somewhat, but then you are introducing excessive turbo lag into the system.

And finally, something that is really obvious yet many people fail to realize it - if you turbo a diesel you MUST increase the max fueling to actually gain any power. Really it's just a reiteration of what I've said above.
On passenger cars a special pneumatic actuator is used (generically referred to as an ALDA) on the injection pump which automatically increases the max fueling proportionally to boost pressure. On these single/twin cylinder engines you would need to homebrew such a setup yourself.

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Re: Turbo's on singles - effective or not?

Post by gilburton » Thu Jan 02, 2014 10:10 pm

No doubt your information is useful but you have obviously failed to notice the date of the posts and Andrew has since died :(

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Re: Turbo's on singles - effective or not?

Post by dieseltech » Thu Jan 02, 2014 11:11 pm

gilburton wrote:No doubt your information is useful but you have obviously failed to notice the date of the posts and Andrew has since died :(
Oh, that's very sad to hear. I wasn't aware of that since I'm quite new here.
I was directed to this thread by coachgeo:
coachgeo wrote:Here is a thread about turbo's on single engines. Maybe you can enlighten us more there?

viewtopic.php?f=32&t=962
And I did indeed fail to notice the date, since the above made me automatically assume that the issue at hand is still relevant.
Oh well, hopefully it may prove useful to others in the future.

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Re: Turbo's on singles - effective or not?

Post by Peter the blacksmith » Thu Apr 10, 2014 9:53 pm

It was useful, thanks a lot ! 8)
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Re: Turbo's on singles - effective or not?

Post by klondikekid » Sat Aug 29, 2015 3:04 am

Garrett makes at gt12 that is their smallest turbo, I'm running that on my Kubota d950 3cyl. works very good. Tried a gt15 china clone off e bay. it was too big and it leaked oil and the boost wasn't as claimed, you get what you pay for.

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Turbo's on singles - effective or not?

Post by Stuart » Sat Aug 29, 2015 3:55 pm

Yes Klondikekid, you are right there. Buy cheap, by twice, as they say.
I've heard stories that many turbos that fail factory pressure tests are salvaged from bins and put out on eBay by unscrupulous people. Even saw that on a car show where they were up against the clock and this guy thought he'd scored a bargain. It failed & the mechanic put him straight.
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Re: Turbo's on singles - effective or not?

Post by UAofE » Sat Aug 29, 2015 11:10 pm

klondikekid wrote:Garrett makes at gt12 that is their smallest turbo
GT0632, actually.
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Re: Turbo's on singles - effective or not?

Post by coachgeo » Sat May 27, 2017 4:52 am

May Andrews work live on thru our Archive here.

Another has picked up his mantel of turboing singles and found success. See discussion at https://www.youtube.com/watch?v=81JiTssrTvg

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Re: Turbo's on singles - effective or not?

Post by coachgeo » Wed Jun 07, 2017 5:06 pm

Found some sound information on this topic. A 2014 research study that shows an "air Capacitor" is the key to turboing a Single cylinder engine. In the video above the fellow used an intercooler for same affect while at same time cooling the air charge.
MIT Research Paper Abstract wrote:...In order for the air capacitor to be practical, it needs to be sized large enough to maintain turbo pressure, cause minimal turbo lag and significantly increase the density of intake air. By creating multiple flow models of air through the turbocharged engine system, we found that the optimal size air capacitor is between four and five times the engine capacity. For a capacitor sized for a one-liter engine, the lag time was found to be approximately two seconds, which would be acceptable for slowly accelerating applications such as tractors, or steady state applications such as generators. The density increase that can be achieved in the capacitor, compared to air at standard ambient temperature and pressure, was found to vary between fifty percent for adiabatic compression and no heat transfer from the capacitor, to eighty percent for perfect heat transfer. These increases in density are proportional to, to first order, the anticipated power increases that could be realized with a turbocharger and air capacitor system applied to a single cylinder, four-stroke engine...
The red portion above confused me... but Im dumb..... what is the definition of "engine capacity" as used in this research paper compared to common "Engine Speak". Contacted the author of the study at MIT to clarify and he stated that yes it is normal engine speak.... Engine Capacity refers to the engine’s volume (bore X stroke)... AKA how many CC's your engine has.

deeper details in the study show they got in their experiment only 30% performance improvement. Think we would be plenty fine with that.

http://technology.mit.edu/technologies/ ... on-engines

https://dspace.mit.edu/openaccess-disse ... 21.1/98220 (PDF of Study)

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Re: Turbo's on singles - effective or not?

Post by coachgeo » Tue Jul 25, 2017 7:17 pm

Still little unclear... Does a Supercharger/Blower have same need for pressurized air charge storage? Would think not cause it does not wait on exhaust valve opening?

Same for the now available electric Turbo/supercharger/blowers.

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Re: Turbo's on singles - effective or not?

Post by mark_in_manchester » Thu Jul 27, 2017 3:03 pm

I don't know the correct terminology, but I guess it depends on the input impedance (ratio of pressure divided by volume flow) looking into the cylinder when the inlet valve opens.

If the input impedance is low (large flow) then all the pressure built up by the turbo / supercharger will collapse without pushing much air into the barrel. That's a bit like trying to turn over a starter motor with 8 AA cells in series - you have 12v, but the current requirement is so high, you don't have 12v for long!

A pumped-up reservoir is a charge-storage device - in electrical terms it has very low source impedance so it can pump a lot of air with not much loss of pressure. That means you need time to pump it back up, I guess, which you may have with a single.

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