I ate my wafer...

3/28/2006

I did a couple of wildly irrational and stupid things last weekend. The milder of them involved the purchase and consumption of 10 gallons of ethanol, which, one has to admit, usually does lead to stupidity.

So, what happened? Wild drunken debauchery? No, I just filled up my car with straight e-85 ethanol. Believe it or not, I wanted to proove a point about the drop in fuel economy that non-high compression engines suffer on ethanol due to the lower energy content. DO NOT try this at home with a car not designed for ethanol. There are all sorts of potential problems, ranging from corrosion to excessive lean conditions that fry exhaust valves and melt pistons. As of today, I have 80 miles on the e-85, and at least from what my trusty WinALDL program is telling me, I'm not likely to fry any mechanical parts. However, driveability, when cold, is horrid. I'm extremely glad that I waited until spring to try this experiment, since my wet-intake TBI system seems to suffer from poor evaporation with ethanol.

Warmed up, driveability is OK, and the BLM/INT values show that the ECM is adjusting the fuel mixture to compensate for the alcohol. I'll compute mileage in about a week.

8 Comments:

  • Bob...Just saw yer blog. Enquiring minds want to know: What make of vehicle? I'm assuming a "Flex-Fuel", of course...How badly does it run when cold? I'm aware that that is one of the inherent probs with ethanol, which is why it's limited to 85%. Even so, what vehicle runs great when it's 20 below? (Celsius or Farenheit, take yer pick) A year ago I used to own an old, old
    Toy PU and just for fun, I threw in a gal of denatured alcohol into a nearly empty tank. I was actually shocked by how much better it ran. Shocked, I tell you. (it was carburated, btw) However, when I went to get it smogged (in California, they 'dyno' test it) it failed. The HC's and CO's were quite low but alas, the Nox was over the limit. Unfortunately, I had to get rid of it because I was moving out of town but to this day I don't know if it failed because the fuel mixture was wrong (to lean?) or because the catylytic converter was faulty.

    By Anonymous rogrrr, at 5:15 PM  

  • 1987 GMC Jimmy. 2.8L TBI engine, 700R4 transmission, 3.73 Axle.

    No, its not a Flex Fuel (FFV), which is one of the reasons that the cold drivability was horrid. The other reason is that it uses a nonheated single wire O2 sensor, so it takes a while before it gets into closed loop feedback operation.

    I could burn a PROM that would enrich the fuel trims when cold, which is one of the changes made in a FFV. Also, I could run a heated O2 sensor. However, this was just an experiment, not a long term plan:

    E-85=2.50/gal,
    Unleaded 87 Octane=$2.55

    The truck only got 16mpg on the e-85, compared to 20-21 on 87 octane, so you can see that it is a loosing proposition.

    To get decent mileage out of E-85, you need to run it in a high compression engine that takes advatage of its 100+ octane rating. That is, despite the ~15% lower energy content of e-85, you can get decent mileage out of a, say 11:1 engine since the engines overall efficency improves with increased compression.

    Obviously, the downside is that an engine designed to totally take advatage of e-85's octane rating couldn't run on normal gasoline. (Well, you could run it on 110LL avgas...but that would toast O2 sensors...)

    By Blogger Bob, at 5:46 PM  

  • Wow, I've got no clue what any of those acronyms mean.

    By Blogger Tom, at 2:24 AM  

  • Fucking shit bob, if I knew anything about cars I would have a raging boner by now.

    By Blogger The Gringo Himself, at 1:41 PM  

  • Crap, I don't know what they mean either, Tom...as for the raging boner guy...what's a raging boner? Can I get one of those online?

    "burn a PROM that would enrich the fuel trims when cold"- What are you talking about here, Bob? As for the mileage, when gasoline costs $5 per gal in a few years, E-85 will seem like such a bargain...if you can get it.

    By Anonymous rogrrr, at 5:16 AM  

  • IMHO, biodiesel, perhaps from algae is likely to be a better long term proposition than ethanol. Biodiesel from the right source oils doesnt require the massive energy expenditure needed to distill ethanol.

    The truck I used has a relatively simple fuel injection system that uses simple computer chips call PROMS to regulate how much fuel to inject, and when to inject it (as well as control other engine operations like spark timing and advance). It wouldn't be a big deal to make a PROM that would fix most of teh diveability problems with ethanol, although the mileage is pretty much set in stone.

    Good links for fuel injection info for GM OBD-1 engines:
    http://kenhiester.tripod.com/

    http://winaldl.joby.se/

    http://www.cruzers.com/~ludis/c3xref.html

    http://www.fuelinjection.com/portinj.html

    I LOVE winaldl, and use it pretty often when driving. I also have access to a PROM burner, so I could make chips to adjust the car's computer to run smoother on ethanol, though I would have to swap chips to run regular gas.

    By Blogger Bob, at 10:11 PM  

  • Forgive me Bob, I'm no techie (hey, I can change plugs 'n stuff) so what do you mean when you say "LOVE winaldl, and use it pretty often when driving" ? I looked at the site, which apparently only applies to older GM's (last time I owned a GM- an '85 S-15 with a prehistoric pushrod 4 banger- I swore I'd never buy another one and I've kept that promise- tho I might change my tune if Toyota doesn't go FFV) So, How do you "use it pretty often"?
    You may be right about biodiesel- which would be sigh of relief since the the global commercial transportation sector (and thereby, we mortals) runs on diesel- Ships, trains, planes, trucks...

    By Anonymous rogrrr, at 7:54 PM  

  • Ehh, I can agree that if you were driving a carburetor 1980's truck it probably was extremely worthless.

    The fuel injected trucks are a big improvement, and the nice thing about winaldl is that basically all GM products prior to 1996 can use it, and it costs nothing (well ~5-20) for a cable.

    There are eqivalent products for most fuel injected cars from other manufacturers, and in general, google is your friend if you're interested.

    By Blogger Bob, at 11:17 PM  

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