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E-10 injector size factor?

Posted: Tue Jan 19, 2010 6:33 am
by Hoghead
All we can buy here is Thailand is 95 octane Average of RON + MON in either E-10 and soon to be E-20
Normal petrol 95 is only at Shell and not at all outlets

I am piecing together a MS system for my air cooled 2332 Beetle and read the manual re injector sizing relating to HP, but do not see a factor for gasohol.

HP is unknown as there are no rolling roads near here but I guesstimate 120 - 150 HP. This would suggest either a 18 or 22 Lb injector.
30 Lb injectors would put me in range decrementing 20% for duty cycle and 10% for E-10 - is this an reasonable assumption

How about E-20 injector sizing?

Re: E-10 injector size factor?

Posted: Tue Jan 19, 2010 12:18 pm
by Matt Cramer
I'd probably add around 10% to the injector size for E20, based on our rule of thumb of 50% for E85. It isn't a huge difference compared to gasoline.

Re: E-10 injector size factor?

Posted: Tue Jan 19, 2010 4:48 pm
by Hoghead
E-85 is coming and I am thinking of flex fuel using the MS

Do you think I can get a one size fits all injector that can run E-10-85 and not be too large at idle? Or thinking another way, will a 40% oversized injector be too large at idle on a street driven car.
One would think so as the factory can do it

If so then I need 20 x 1.5 = 30# or 36# at 80% duty cycle

Re: E-10 injector size factor?

Posted: Wed Jan 20, 2010 5:40 am
by Matt Cramer
Sure, you can get away with some surprisingly large injectors with MS2.

Re: E-10 injector size factor?

Posted: Thu Jan 21, 2010 12:13 pm
by devastator
Hoghead wrote:Do you think I can get a one size fits all injector that can run E-10-85 and not be too large at idle?
E-10 will not require a different injector(s). 10% Ethanol is usually comprised of 5% alcohol and 95% gas as there is gas added to ethanol to make it undrinkable by humans. E85 is another consideration entirely.
Hoghead wrote:Or thinking another way, will a 40% oversized injector be too large at idle on a street driven car.
That'll work fine. Remember that you can also increase the fuel flow needed for E85 by adjusting the FPR a few lbs higher.