detailed TECHNICAL info on engine (ETHANOL) modifications

[bioethanol100]

Hi,

I'm Mike from Belgium and i would like to convert my car (AUDI 80 1800S) to run on ETANOL (100% ethanol is my goal otherwise, 85% would be enough.

I tried to find informations on what the main differences between the engine of a FFV and that of a normal benzin vehicle are. It's not difficult to find information on ethanol fuel, but detailed TECHNICAL informations on engine modifications/ differences are what I can't find. Could someone give me some ideas/where to look/hints ...?

Many thanks,

Mike

 

[Azmio]

yes, we have done many of that with several engines programs for many different cars.

Take x engine speed when you plot it and compare it with 0.5x. There is a difference in the achieved torque. The reason why there is a difference is that the amount of air inducted in each cycle depends on the engine speed.

So, i will stick with my point in my previous posting.

 

[patprimmer]

If you have a very small throttle bore, you will need full throttle. If you have a very large throttle bore you can get maximum torque or even maximum power at part throttle.



Regards

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[globi5]

Or you can drive up a hill at 2000 rpm in the highest gear and notice that the car accelerates about the same regardless whether you are at 50% or 100% throttle.

 

[GregLocock]

Exactly.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Azmio]

Pat

During engine development, we did try throttle bodie with different diameters. Between several throttle bodies, the horsepower increase by 1-3 ps at WOT

Considering the 4 bolts available at the intake plenum, i doubt if we can find throttle body big enough to enable maximum power to be achieved at part throttle.


Globi,

Without, proper datalogger, GPS, etc., I would agree with you. However, the equipment will tell different story, so I beg to be differ.

On test track, average human needs around 10-20 hp difference to notice the difference.

 

[patprimmer]

Hey guys we are off on a tangent from the OP.

Azmio You seem to be talking of a specific engine where others are talking general principals.

If you now have say a 50 mm throttle plate, I am sure what you say is correct, however consider a typical American drag race engine With a hat and tunnel ram. A hat has 3 butterflys that are about 80 or 90 mm dia each. These have sufficient airflow at half throttle to have negligible increase in airflow on a 6 litre engine at 4000 rpm

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Azmio]

oh, I thought we are discussing about the Audi that Mike is thinking about running it with ethanol.

Anyhow, the principle is still the same. Though majority of the engines that i have worked on were intended for production cars, I can recall the design and operation of F1, GP1 and superbike engines that we worked on.

If you have access to the 3D CAD data or drawings, you can see how we flushed the individual butterfly throttle body with the intake port. The intake port and the throttle body is perfectly matched to avoid any mismatch that may cause losses.

Now, the throttle plate area is more or less dictated by the intake port entrance shape. Therefore I doubt that you can add any bigger throttle at the end of the development stage prior to the next race.

Remember that the intake port entrance dictates the shape of the throttle plate. By using bigger than the most optimum shape, there will be mismatch to both the intake port and variable trumpet. Any mismatch will cause several hp losses for 900hp 10 cylinder engine. In this context, even with bigger throttle body resulting the flanges mismatch, regardless of part load or WOT opening, you wont be able to get the maximum horsepower that engine is capable of producing.

Well, I never worked with engine as big as 6 liters like yours, but I think the principles are applicable to the single and also individual throttle for production and race cars.

Oh by the way, we have so many throttle opening profiles from the telemetry. You may know who the drivers or riders are. I hardly found any evidence where they spent most of the time at part load for conditions requiring every single pony from the engine. Even if we beg them to go part throttle, they will still go for full throttle opening.

Anyhow, can we get back to the original question put up by Mike from Belgium. If we ask him not to go WOT, I think he wont go WOT.