Thread: E85 Tuning Discussion

what software are you using?

matt werent you and I debating over this tuning method and you were saying the exact opposite? and E85 is not economical at all around here with the drought. E85 is up to 3.30 a gallon here and premium is like 3.80. How are you guys getting over 20 mpg? Ive been calculating it off of how many gallons used vs miles traveled and i can not get over 20, even going 65 on a highway the whole way. I upped my cruise timing to over 40* and lowered my part throttle shift speeds and TC lockup speeds, and even put the stock pulley size on.

The quickest way to tune it is IFR's, but i cant seem to get my fuel trims dialed in (not that i ever could before)

Originally Posted by JoRoW99

matt werent you and I debating over this tuning method and you were saying the exact opposite? and E85 is not economical at all around here with the drought. E85 is up to 3.30 a gallon here and premium is like 3.80. How are you guys getting over 20 mpg? Ive been calculating it off of how many gallons used vs miles traveled and i can not get over 20, even going 65 on a highway the whole way. I upped my cruise timing to over 40* and lowered my part throttle shift speeds and TC lockup speeds, and even put the stock pulley size on.

The quickest way to tune it is IFR's, but i cant seem to get my fuel trims dialed in (not that i ever could before)

Open loop.

I was seeing 29mpg @ 75 with cruise held down on E28 blend running high 30's timing.. same tune more or less ran 31.5mpg @ 75 on E0 93 -- Figure a 7-8mpg drop from E0 to E85 and low-mid 20's mpg highway is a real possibility with the right tuning scheme.

You should be comparing E85 to race gas, a full size intercooler, meth setup, not 91/93 gas. It's a MINIMUM of 105 octane and gets to be about 109 full blend but has the characteristics to be very competitive with C16 when used wisely. E85 can replace a full size intercooler but comes with some drawbacks and that is it needs a bigger fuel system, gas mileage is reduced. Anyone who is running E85 and overly concerned with gas mileage shouldn't be running it all the time.

Without the 10-20% ethanol blend in regular/some premium gas the price of that fuel would go up 40-60 cents. It's used as an octane adder which would normally be toluene, trimeth and a few others. The problem is that those additives are very expensive, ethanol is less.

The main problem with ethanol is the misinformation.

Originally Posted by FoSHO99

You should be comparing E85 to race gas, a full size intercooler, meth setup, not 91/93 gas. It's a MINIMUM of 105 octane and gets to be about 109 full blend but has the characteristics to be very competitive with C16 when used wisely. E85 can replace a full size intercooler but comes with some drawbacks and that is it needs a bigger fuel system, gas mileage is reduced. Anyone who is running E85 and overly concerned with gas mileage shouldn't be running it all the time.

Without the 10-20% ethanol blend in regular/some premium gas the price of that fuel would go up 40-60 cents. It's used as an octane adder which would normally be toluene, trimeth and a few others. The problem is that those additives are very expensive, ethanol is less.

The main problem with ethanol is the misinformation.

105 when it's E79 or higher.

E70 (E68) is less though.

Ok, the actual octane rating of e85 (assuming it is actual 85% ethanol) is only about 96 AKI (its 105 octane in the RON scale).... which is the scale that the US and Canada use for their octane rating (RONxMON/2)...

the reason it seems like a higher octane is because it burns a lot cooler than regular gasoline..

In regards to the mpg (or mpd in this case) you have to consider your driving habits more than anything. first off, with e85, you should really be tuning in open loop if you can. This will save you some highway (and city for that matter) mpgs. I get about 23-24 (91 premium was 28-29) mpg on the highway running 50* of timing with an average afr (gas afr that is) of ~16/1. Around town I get just under 20mpgs (91 premium was ~21) with about a 15.5/1 afr. So as long as your % mpg loss isn more than the % difference in the price of premium youre still going to be saving money but each person will have different results pending.

But in the end you dont get e85 for the economical factor anyway... and if you do most of your driving around town youre not gonna lose that much mpg anyway... just the biggest hits on the highway...