E85 and Race gas talk?

[pilihp2]

So I feel like I haven't seen much talk about this. How come no talk of racegas or e85 tunes going around here? I'm sure there is power to be had from running a higher octane fuel like e85 or 100+ octane? e85 being ideal to me, seeing as it's actually reasonably priced.
So what say you? JHM? Do you guys do any e85 tunes for these cars? Any flexfuel sensor integration? Anybody seen anybody do any stuff like this?

Help me out here. I'm curious.

[MidwestB6]

It's been talked about a handful of times.

Race gas works well with a proper tune, there is an interesting thread on AR in the diy/tech/info section about homemade race gas, check that out.

Ethanol fuels are a bit more complicated on this platform, it would take quite a bit more to make it work. To my knowledge, nobody is running E85 on this engine. If anyone has gotten it to work, they most likely live at a gas station, they wouldn't be able to drive very far with fuel economy like that.

[EUROSWAGR]

E85 isn't gonna net you much of a gain NA, especially considering how much you would have to upgrade fueling.

[SprintBlueWorld]

The JHM tune adapts upwards in regards to octane levels, so the gains are built in. The tune does not adapt downwards, if ever you wanted to use 87, that would be a no go.

[rocket5979]

Like Euro said, there is virtually no point to running either racegas or E85 in a N/A vehicle. Some may see small gains, but that is offset drastically by the ratio between cost to benefit. In short, it just isn't worth the effort and cost unless you are running forced induction and actually need the extra knock control properties from the fuel.

[hutch959]

all true... (i have a 660hp, mitsubishi evolution tuned on E85)

the real advantage of E85 is that it doesnt detonate.
Therefore, you can run tons of timing and tons of boost (on a turbo car).

We actually tune E85 on turbo cars by turning up the timing and boost to the point we max out fuel or we see a reduction in power.
Not by the typical... "advance the timing till you see knock, then back it down 1 deg".

to do this we run massive fuel pumps and massive fuel injectors (i have 2150's on my evo).

I would guess that if you did all the fuel mods on a B7, and then tuned the car for E85, you would see somewhere in the 5% power increase.
just a guess.

just for comparison.. i saw a 25% increase in my evo.

[Brandywine050]

But don't go out of control with the timing, as with e85 its not the detonation or pre-igntion which will kill the engine, but the instantaneous in cylinder pressure spikes that occur which can crack cylinder walls, pistons, head gaskets, etc.

[hutch959]

true...

while tuning... its usually obvious.
1 deg advance moves usually will see 10 or 15 hp increases on the dyno up to the point it will fall off...
then you just back up one deg and done.

[pilihp2]

I know the advantages and requirements of e85 pretty well from first hand experience. My roommate runs e85 in his c4 S4 almost year round, my brother runs it in his c4 s4 24/7, I ran it in my 5ktq for a while when it was running. Those are all turbocharged cars. I was curious if anybody had any success with it in an N/A setting with these. I know the biggest advantage of e85 is cooler egts, no detonation, more timing, more boost. Obviously more boost won't help when it comes to N/A.

How big are the OEM injectors on the 4.2? How much of the injector is used when the car is modded on N/A power? When a supercharger is thrown onto them do the injectors need to be upgraded to bigger ones?

all big questions that I could probably search for. But where is the fun in that.

[hutch959]

i have no idea what the injector duty cycles on our cars modded..... but i would assume they are no where near good enough to run E85.

i would have to guess the 4.2 with a supercharger, big injectors, big fuel pump (and possibly moddified rails and line), on an E85 tune would be a NASTY...

it would smell good idling in the driveway also.
haha

[gaben2racin]

i've done 1/2 e85 and 1/2 91. idles way better and runs good. if you go with more e85 the s4 will bog a little when you floor it. if you want to go with full on e85 you will need an aftermarket fuel pressure regulator and most likely also the fuel pump. fuel pressure will need to be pumped up anywhere near or close to an extra 30psi to run correctly on full e85. depends on the car and what mods you got. anyone add on if they have tried 1/2 e85 and 1/2 91 or 93 on JHM tune curious if they have felt thier s4's running better or possibly worse?

[hutch959]

that "bogging" is because it is lean.
i wouldnt recommend this.

[gaben2racin]

Already ahead of you. As it will throw a lean engine code. Forgot to mention that. It will clear thou once you get the mixture right or just fill her up with 91 or higher. I have been mixing it for over 2 years no Issues.

[pilihp2]

I'm struggling to believe that a good way to fix lambda numbers being off from too much ethanol, is cranking up the fuel pressure...
No. Not good.

[hutch959]

first thing that has to be done if you put ANY E85 in your tank is to scale the injectors.

Stock injectors will not scale correctly with e85.

[QIKRNU]

Perhaps there's a reason JHM includes bigger injectors in their stage 1 SC kit.

[Brandywine050]

I'm struggling to believe that a good way to fix lambda numbers being off from too much ethanol, is cranking up the fuel pressure...
No. Not good.

Agreed, and running an additional 30psi overbase trying to bandage a fuel delivery issue is not a good idea as those injector were not flow tested at such pressures.BSFC of an N/A engine on gas it .45-.50 Lb/(hp-h) ethanol is ~ .65-.70 lb(hp-h) the whole fuel system needs to be replaced. pump, lines that are ethanol safe (braided with PTFE core is cheapest and less time consuming, regulator, injectors. ETC..

[pilihp2]

I know of MANY people who run e85 with stock tanks, lines, rails, regulators, and pumps for LONG periods of time. The ethanol safe thing is wayyyyyy over hyped IMO.

[dolphin B6 S4]

I've ran a couple gallons of 100 octane through the tank before, didn't make a notable difference. Smells good though.

[EUROSWAGR]

I know of MANY people who run e85 with stock tanks, lines, rails, regulators, and pumps for LONG periods of time. The ethanol safe thing is wayyyyyy over hyped IMO.

Yes on present day cars the hardware issue is hype...the fuel delivery aspect is not.

If people are screwing with E85 without being tuned for it or upgrading their injectors and pumps...they are playing with fire and will eventually get burned.

THIS is a stupid idea for those of you doing it or thinking of experimenting.

[hutch959]

^^^^Well said.