333pg333

^Simple. Just up the boost. That will increase your c/r

V2Rocket

not too low, perfect for adding more boost which = more power than cr will give

BC

I guess we will see. 10:1 compression on stock 928 pistons and 24psi from an SC coming up for me. I'll build another motor just in case.

David Floyd

Some of you dudes have been running E85 for several years now, I finally have a local E85 station, so doing my research on making the switch.

John J, Sid, Bruce, Rogue all have good things to say about E85, and at much less cost than race fuel, seems a no brainer.

I think an initial fuel change can be made by just using the race fuel map on chip board and increasing fuel pressure via Adjustable FPR and monitor the AFR gauge. I have an SMT6 but a dead laptop.

E85 users still happy ?

Rogue_Ant

Very happy - and my high CR motor just loves it!

333pg333

Not sure if your Race Maps will be right for that David. You have to add a fair bit more fuel when you switch to E85 so I wouldn't just top up your tank if you can't adj or monitor changes via your SMT6 and laptop.

Rogue_Ant

I agree with Patrick - E85 needs ~30% more fuel for the same amount of air. For timing, your race-maps will probably be fine, but you need a way besides the AFPR to add fuel. Assuming your running 3bar FP now, you would need to set your fuel pressure to ~5.3bar - that is getting pretty high (especially when you add boost pressure on top!).

David Floyd

Thanks guys

95ONE

I may not drive mine right now, but more and more conversions are going through my friends shop. Corvettes, Pontiacs, etc. are figuring out this "cheap" race fuel is fantastic. Cheap GM programming capabilities are facilitating its use also.

Bruce

333pg333

Just makes me wonder how long it will remain cheap. We have one bowser in our entire state. Luckily it's only a few miles away for when I want to use E85. We can also buy it from a Race fuel supplier but he charges a lot more for it. Our premier race series (V8 Supercars) have also switched to it this year...I guess to look like they're trying to be 'Greener'. Must mean they can run higher c/r and more timing I suppose?

Just buy a new cheap laptop David. Also if you are just going to use it to take some nice 'spirited' drives in the country at higher boost levels, you may want to carry a Jerry can of backup fuel as you will go through a tank much faster than you think.

fast951

David, Using a adjustable FPR is not the ideal solution. As Rogue stated, the base static fuel pressure will be too high to start with.

You want the DME software to handle the E85 for you. We do it via the V-FLEX E85. With the flip of a switch, you can run E85 or Pump gas.
I addition to adding more fuel to run E85, there are other things that must be handled differently in the DME.
E85 blend varies from one location to the next and between seasons. You can get E85 with 70% Ethanol, 85% Ethanol and in some areas as high as 90+% Ethanol. You need to be able to adjust the fueling for each. This can be done via the base software, or simply by adjusting the mixture via the PB. You will need a Wideband Lambda meter to get accurate AFRs to use as the target for the fueling.

Some run E85 by richening the mixture via the PB and not the base DME software. This is not a good approach as the load calculated by the DME is way off the actual load. IF you need to richen the mixture by 25-30%, then the load calculated by the DME wil be off by a similar percentage.
The AFRs can be close to what you want, but ignition will be off at Part Throttle..

blown 944

Still very happy.

I have done it a variety of ways, and IMO it is so forgiving that it is almost idiot proof.

I agree doing it via initial software with large injectors is best.

Lemming

I'll preface this by saying that I don't know squat about boost. Having said that, I'm moving ahead and putting a low boost SC on my 968 powered race car (kit from Carl at 928 Motorsports). Is there any benefit to running E85 in such an application? To start I will only be running 5 lbs of boost with an intercooler, CR of 11:1 on stock internals.

Rogue_Ant

YES! E85 will make a bit more power then gas, without changing boost. Plus, on E85, you have a huge margin of safety that you don't have on Gas.

Lemming

Can you speculate on the increase in fuel utilization. Let's say I get 6 mpg on track using 93, what would this be using E85? I ask because one potential downside is the increase weight I would have to carry to run a race.

And yes, I have a station within a few miles selling E85.