Quote:
Originally Posted by Joshboody
For DI, the effective octane of E85 is something like 130. All fuels have a higher effective octane with DI, but the more energy needed to vaporize the larger the difference in "officially" measured octane (by a PI test engine) versus actual benefits of the fuel in DI. Methanol is better than ethanol, but its difficult for race gas to outperform unless it is oxygenated.
|
DI cars do have a cooling effect, but I haven't seen any evidence to suggest the effective octane is 130 with E85. I'm also not sure what % of E85 you're basing this on.
Quote:
Originally Posted by biz77
You are wasting your time on the semantics of octane rating. It doesn't matter. Leave the BMW World for a little bit and go do some exploring on platforms that have been using and tuning with E85 for more than just a year. Check out the EVO guys. Check out the Subaru Guys. Check out what the GTR and boosted Chevy LS guys are doing. There is so much info out there that proves E85 is equivalent to high test race gasoline across all these platforms. Quit hanging yourself up on the octane rating.
|
I spent about a half hour of my time on this. I wouldn't call it a waste.
My original intent was make an easy tool to show the estimated percentage of e85 mixed in the tank. I added octane as well for good measure. The entire thread explains the octane will not be exact, only approximate relative to the fuel itself, not the car.
As VNeBLOB42 said, it also helps others understand where in the ballpark their octane is as many believe E85 is 105 octane, or equivalent to 'race gas' (people often say this loosly). This isn't pure science, obviously nobody here is taking fuel samples and running it through a lab... we're just estimating based on facture fuel data and mix ratios.
I'm also very familiar with E85, I ran it on my 400whp Built STi for three years.
