E85 - Anyone else getting great results?

[kir_kenix]

I grew up in central Nebraska and we have a pretty decent e85 availibility here. Some vehicles drink the stuff up, and even with the loss of mileage you can more than break even. Other vehicles seem to hate the stuff. Most EFI vehicles run e10-e20 just fine, with a small drop in FE. With the cost differential every vehicle I have more then breaks even.

If you tune for power, E85 can be your friend. Cheap, high octane, and available virtually everywhere in the midwest. You'll find alot of guys tuning for it around here.

[comptiger5000]

Fortunately, if the price spread is large enough for it to be worth trying, I should be safe to give E85 a shot in the Jeep. Fuel rails are steel (not stainless), and AFAIK, there's no aluminum anywhere in the system, and the gaskets should all be ethanol compatible (and E10 certainly hasn't been an issue). Not sure how it would do for mpg without more compression though, as it's only 9.1:1, and the timing is already pretty cranked (needs 91 octane minimum).

[Big Dave]

The late, great John Lingenfelter did some work on high performance Chevy engines running on both straight ethanol (actually denatured alcohol) and E85.

He took a LS7 engine (7.0 liters 505 HP from GM) and modified it for alcohol. Obviously he jacked the compression up to 14:1 and advanced the ignition timing a bunch, but he also addressed the power loss by installing bigger fuel lines, pumps, and injectors. Result: 800 HP and he claimed the thing was more fuel efficient on a HP/MMBtu heat input basis. I’m sure he had no corrosion issues.

I would believe the increased efficiency at a very high compression ratio.

John Lingenfelter is dead, but his company still modifies Chevy engines. They might (for a price) work up an alky engine for you.

Maybe the best approach for a high-MPG alky engine is a very small engine with insane compression and/or turbo boost, but to keep the driving characteristics good, you gotta have a bigger injection system.

To burn alky efficiently, you have to sacrifice the dual-fuel capability. I’d also recommend a big fuel tank because you don’t know where the next E85 pump is.

[comptiger5000]

Agreed on needing to give up dual fuel capability to get good mileage on E85. The only way to avoid that would be instead of high comp NA, go mid-comp turbo with advanced timing, and cut the boost way back on E0 or E10. Unfortunately, I can't build the Jeep for E85 only, as it's not available at home.

[abogart]

Originally Posted by abogart

I will be making the 180 mile trip across the state again today, and I should have some results of how the E30 performs.

The results are in: 33.5 MPG on E30 up from 33.2 MPG on E20 . Note that I did increase tire pressure 40 to 45 PSI during this time and the weather has been warmer. I did have to adjust the SG fuel% up a few more points again, thinking this might affect trip MPG readings.

Knock retard kicks in at about 26" MAP. at 2500 RPM and 24" at 1500 RPM TC locked. Fuel trim ran +4 at cruise and up to +6 city. Mid-range horsepower is diminished under normal load, but still manageable for reasonably good acceleration without tripping the knock sensor, however low-end torque is even better than on E20. I actually found it difficult to cruise above the 12.4" MAP where the TC unlocks, cruise control just pulses between locked and unlocked. Cruise throttle is only 8% relative TPS, so some VERY fine footwork is required to maintain steady-state cruise.

I just put an E40 blend in the tank last night. I could immediately tell that mid-range power is reduced even more during acceleration between 2000 and 2600 RPM. Low-end torque seems even better than before. I was able to run up to 29" MAP (100% load) without tripping the knock sensor . Still not sure if BSFC is better in this range though. Fuel trim ran +7 city, I haven't seen it go higher than that yet, hopefully this is just because the AFR is right and not because it can't adjust any higher.

One thing that I have noticed is that I can cruise at idle for quite a ways with the trans. in D now. I'm wondering if this has anything to do with the fact that I just cleaned out the EGR passage in the intake. Another theory that I have been tossing around is that the extra vapors from the ethanol in the tank are being collected in the EVAP canister and released during deceleration. This might explain why fuel trim drops to -4 or even less during deceleration in-gear, most likely signifying EVAP purge operation.

I have also noticed that the car starts and runs a lot smoother on higher ethanol blends than on regular gasoline. I will post when I get the results from the E40 tank. Not sure if straight E85 is going to work in this car, but these blends have some seriously promising results.

[notanarborist]

Originally Posted by Frank Lee

I googled it once upon a time and IIRC several reputable sources said by '88 all U.S. cars had ethanol resistant fuel systems.

Cars sold, or made in the US? I know for a fact that my 92 Eclipse and Talon had aluminum rails. I believe they continued it into the 2nd generation cars in late 90's as well.
Could it cause corrosion in the intake and cylinder heads as well? What about aluminum pistons?

[Frank Lee]

Never heard of problems aft of the fuel system.

[abogart]

Got results from the E40 tank. Fuel trim running +3 at cruise, up to +10 city. I can run up to 29.9" MAP at 2500 RPM and 27" at 1500 RPM, although 22" is still the sweet spot. MPG is the same or better than on regular fuel. SG fuel% was dead-on this time, didn't need to adjust.

Had to refill with midgrade 89 E10 because I cut the return trip a little too close with this tank. This brings the tank E% to 24%. Strangely enough, the return trip reported worse MPG with a tailwind. Not sure if this is just because SG has been calibrated to the increasing E% in the fuel, but I did notice higher MAP required to maintain cruising speed on E24 than on E40. Interesting...

[Allch Chcar]

Originally Posted by notanarborist

Cars sold, or made in the US? I know for a fact that my 92 Eclipse and Talon had aluminum rails. I believe they continued it into the 2nd generation cars in late 90's as well.
Could it cause corrosion in the intake and cylinder heads as well? What about aluminum pistons?

If they used bare aluminum than Mitsu/Chrysler would have been fools. Aluminum needs to be coated with zinc to protect against corrosion.
Stainless steel is better than steel but it gives up strength for corrosion resistance. Plastic is better IMHO than metal for the fuel system but it has to be a certain range of polymers like viton not nylon.

There have been recalls on vehicles for not being E10 compliant. The only ones I remember for newer cars were VW and Lexus. I've heard a rumor that Ford changed over the entire fuel system to be compatible with higher Ethanol blends in '94.

Originally Posted by Frank Lee

Never heard of problems aft of the fuel system.

I've heard of people saying that engine parts would fail but I think it would have to be an old engine with lead era valveseats.

And @ everyone just to clarify all alcohols are corrosive. Ethanol is less corrosive than Methanol. They both have oxygen which is corrosive but it also helps improves power and efficiency (which is not the same as MPG that is directly related to energy density).

The Compression ratio doesn't need to be higher for alcohol to be efficient. That is just a rumor. Ethanol can run efficiently at higher compression ratios than Gasoline but it is not necessary to be more % efficient. If you want dual fuel ability I'd keep the engine as stock as possible and get a tuner for it with several tunes for different blends.

And be careful adding Ethanol or too much too fast, I'd hate to hear you blew your engine because your engine leaned out and broke something . Adequate fuel is a big concern when you're decreasing energy density that much.