E85 - Anyone else getting great results?

[Frank Lee]

Yes, and it seems Tempos are my friends too. I can't help it! They find me and follow me home!

[snowfish]

Thanks Frank! I'm going to start the blend after it warms up a bit. I'm still in the process of cleaning up the 1ft+ snow that fell last night. Pretty high quality snowman snow! ugh!

[TestDrive]

Thanks, Frank. If ever E85 becomes an option here, I'll give different blends a try.

[shovel]

I run blends of E85 in my 01 Blazer 4.3, basically anything up to about E50 in ratio runs AWESOME, acceleration is notably smoother, enough that when my GF borrowed it while it was "drunk" on ethanol she said "your car is way faster than normal, did you do something to it?"

But the engine is unmodified - apart from a high-flow intake tract/filter which serve to increase the "problem" with running E85 in a non-flex-fuel vehicle - a/f ratio. I get about 15% worse fuel efficiency, MPG-wise on a 50/50 blend of E85/straight gas.

I keep wanting to get a FullFlex system but I just don't feel confident enough in that particular company's method - it seems an awful lot like a guess to me.

[Wonderboy]

I haven't come across any E85 around here, but sometimes I come across E10 while traveling. I've had noticeable increases in FE when using E10 gasoline (see fuel log); I think my record trip was using E10.

[snowfish]

Shovel, you're saying that you get better power, but less FE running the blend?

[shovel]

Originally Posted by snowfish

Shovel, you're saying that you get better power, but less FE running the blend?

Yep, precisely that and significantly enough that neither effect can be attributed to just being in my head.

Scangauge confirms the reduced fuel efficiency (both in measured FE and indicated fuel trim) and non-gearhead-girlfriend's "holy crap it's faster" confirms increased power

If I run more than about E50 (as in, top up on E85 while I've got a third of a tank of straight gas) the CEL illuminates because fuel trim goes out of range (+25%) - which is expected. As stated, this is on an unmodified vehicle. Vortec 4.3's use a unique "spider" injector setup so it's not so easy to just step up to higher flow injectors. I do think mine might need a good cleaning, however, as base fuel trim on straight gas is still +13ish on average.... with brand new o2 sensors.

[igo]

There are a few e85 pumps around here, but I never used them because I thought my car would run bad with it.

[snowfish]

It seems logical that with more power one should get better FE if my driving habits are adjusted accordingly. But, the scan gauge doesn't lie, I guess. I'm going to wait until I see sustained 50 degree temps to begin my experiment with E85. I'll keep you posted as how my 1996 4.0 Jeep likes the stuff. Thanks.

[shovel]

Originally Posted by snowfish

It seems logical that with more power one should get better FE .

Ethanol has far fewer BTU's per pound, which is why you have to burn more of it to accomplish the same work.

But ethanol also has a higher resistance to predetonation (octane) which allows more aggressive ignition timing, and provides smoother/more even burn - as well it brings a lot of its own oxygen to the party so it increases the volumetric efficiency of the engine.

As a side note, gasoline burns most completely at its stoich. ratio of around 14.7:1 at sea level. But it releases the most BTU's per pound at around 12:1 so on paper, you should be able to return better fuel efficiency when running rich than when running lean.