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Originally Posted by jeff88
Oh, cool that makes total sense, didn't think about that. Thanks! Do you think that if one were to use ethanol (along with any supporting mods) with a VVT engine, one could increase torque to increase city MPG?
I assume by maxing out your injectors you mean the fuel pressure needed? Could you upgrade your fuel pump/injectors to allow for the higher pressure?
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Definitely, but you will never get better fuel economy numbers with E85 over gasoline. But cost per mile is another thing. In the same vehicles you burn 20-25% more fuel using E85. Your Air fuel ratio with gasoline is about 14.7:1 while E85 is more like 10:1. That is why fuel system upgrades are required sometimes to run it. Usually larger injectors will get you by but a upgraded pump could be needed. Alot of variables come into play, mainly how good your stock set up is.
Quote:
Originally Posted by betasniper
They probably run a higher CR in their racing engines due to the higher octane rating of E85 which would improve torque and efficiency. Problem with flexfuel type cars for ordinary customers is that they can't bump the CR too much due to having to run also be able to run on Regular (or possibly Premium) gas.
Edit: It says that they do run a higher COMPRESSION (They said combustion) Ratio in the racecars and it does mention that the high CRs have to run E30+ exclusively.
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My knowledge is with high horsepower street cars making 500-1000 horsepower. In this instance vehicles that benefit the most from E85 are supercharged or turbo charged. These are not high compression engines but have highly volatile combustion. E85 is more detonation resistant so they run higher boost and/or increased timing with E85 vs 93 octane. E85 also has a cooling effect on the intake charge which is helpful for both forced induction and naturally aspirated engines. Because of that cooling benefit the general rule of thumb is that E85 is only worth running in a N/A street car in warm weather.