Anyone running E85?

[MalcolmV8]

I've been following a few posts on the Cobra forums and guys are reporting performance equivalent to 116 octane race fuel, some say better. Apparently its resistance to detonation and the amount of timing you can put in the motor is phenomenal. Also when spraying with nitrous it apparently works very well.

I was curious if any of you are playing around with it? I only have one E85 pump and it's about 25 miles from me in the exact opposite direction I ever drive in so it's not really feasible for me at this time.

Malcolm

[cgrey8]

E85's been discussed quite a bit on the tuning forums and I believe its actual octane equivalent is somewhere around 105, but because it is ethanol, which requires a much lower actual AFR, its cooling effect is much better than gasoline with the same octane. And yeah, the boosted guys talk about how much better the headroom is for increasing the spark with E85 vs Premium pump gas.

But there are some details about Widebands you'll want to be aware of when tuning for an alternative fuel. This article I wrote hopefully helps to clarify them:
Widebands, they don't really measure AFR.

[MalcolmV8]

Yeah I saw in my LC1 manual the different lambada settings for different fuels. To bad I don't have an E85 close by on a regular easy to get basis or I'd switch my car too after reading the success of the other guys. Especially with how much head room it gives them on these boosted motors.

On a regular non performance daily driver I don't really see the benefit because the lower cost does not out way the reduced mpg enough to make it cost effective.

[cgrey8]

On an unmodified naturally aspirated gasoline engine, the only way it makes sense to switch is if your drop in fuel economy isn't as much as the drop in cost for the fuel such that your mile/$ actually improves.

For a daily driver, the best way to take advantage of ethanol is to rebuild the engine to make the most use of E85 by building it for high compression. 12:1 naturally aspirated for ethanol is not unreasonable although it does completely remove the chance of running normal pump gas. So the best alternative is to build the engine for high 10s to 11:1 CR. That way, you still have the chance of running premium pump gas, even if you have to alter your spark tables to keep the premium from pinging the heads off. With a tuner, you can keep 2 different tunes loaded...one for E85, one for premium gas. Then you can flip between them depending on which fuel you fill up with. I've heard rumors that high compression recoups A LOT of the fuel economy losses normally associated with an E85 conversion. I just wish there was an E85 station near me. That would be incentive enough for me to start my 331 project even if my old house hasn't sold.

But for boosted engines, the benefits purely a performance related thing. The ethanol lets you run higher boost pressures and run more spark advance without doing damage. But I don't have any feel for just how much. Although if you were willing to sacrifice some boost (i.e. performance), you could run the engine higher compression and gain some of the fuel economy benefits even on a boosted machine. But I got no clue whether you abandon gasoline at that point or if it's just a matter of self control...when you are running pump gas, you don't run the engine into boost without the risk of damage.