E85 Demystified...

[Boostwerks.com]

First of all, there is nothing "wrong" with E85 and we even plan to tune our Turbocharged rig with it here soon. I just keep reading some very opinion based responses so I figured I'd share a good article from those who know best.

Injector Dynamics was nice enough to put together this article which is not only fun to read but you might just learn something.

http://www.injectordynamics.com/AlcoholArticle.html

Enjoi.
Bryson

 

[O-Gauge Steamer]

Why would anyone think there is something "wrong" with E85? I am tinkering with a map in my F/IC so as to be able to run it. I just need to get the O2 Sensor control figured out so I can fool the factor PCM. It will want a 14.7 AFR and the E85 needs to be, what, 9.7ish depending on the mix?

Let us know how it goes as I believe that you can run much more boost with the E85 for all of the reasons it is a good fuel.

BTW, a good starter article that...

 

[Talyn]

I just need to get the O2 Sensor control figured out so I can fool the factor PCM.

I tried every which way I and AEM could think of to get it to work with no success. If it was a factory wide band it would be easy.

 

[gradon]

I was able to offset the o2 on the 96 obd2 setup enough to get down into the 11s in CL with the F/IC(was just fooling around in Neutral). I used values of -.25V to -.5V. I have both o2s--header and post cat--connected so I assume it offsets both o2s at the same time(probably only need the front one connected, unless you have a system that uses two upstream sensors like the 00-01s).

 

[O-Gauge Steamer]

Talyn, yours is the experience that I am most familiar with and have not heard of any great success stories.

Maybe the thing would be to use an O2 Emulator and rely entirely on the AEM to keep things balanced. Would hate to do that as the Heep's PCM makes a great fine tuner...

I'll call AEM and ask the question. It could be yet another Chryco thing.

 

[Boostwerks.com]

I dont see any reason why the O2 offset table wouldnt work. As long as you make a corresponding change in the fuel map the it should be able to target a lower lambda value without the ecu trying to change it back. To do it effectively would certainly require dyno time however. But like i said we havnt tried this yet either so who knows.

 

[Milford Cubicle II]

Why would anyone think there is something "wrong" with E85?

Because it's hygroscopic and less energy dense than gasoline. Other downsides aren't ethanol's fault however, such as the way they screw with the gasoline content - per the article. The article was excellent btw :thumbup:

I need some clarification though, how does one actually know the octane rating of e-85? From the article it sounds like it could vary wildly, which of course would make it very hard to run it with any confidence if you've tuned to a particular octane. I saw the baby bottle method, and that makes sense. But it doesn't tell you the octane of the gasoline in the mix.

 

[gradon]

I'm still of the opinion that if you have a highly modified engine or forced induction, you should force the PCM into constant OL and tune the whole map. I know you can do that by disco-ing the cts@t-stat, but maybe you can add a resistor to fool the pcm to think that it is colder than what it truly is. Maybe there is another sensor you can tweak to force it into OL. 96 and unders still use the ds rear head-mounted cts to feed the dash gauge, but you 97+s would read low temps on the dash if you did this(as well as a CEL for the CTS). How do O-gauge and Bryson deal with part throttle boost afrs w/o the pcm pushing it's 14.7:1 agenda? The AEM will do it if tuned correctly using the offset o2 maps, which is why I ditched the home-brew map adjuster, the Split Second PSC-1, and Unichip(only cause I couldn't do it myself). Right now, my AEM is in circuit, but is not changing anything(I know, I know, ~$500 spent w/ the patch harness not being used to its potential). I need a tank full of gas and one of my brothers w/ the laptop in the passenger seat or else pony up $300-500 to get it load tuned on the dyno(which I feel they still wouldn't attempt to use the offset o2 map).

 

[tbburg]

First of all, there is nothing "wrong" with E85 and we even plan to tune our Turbocharged rig with it here soon. I just keep reading some very opinion based responses so I figured I'd share a good article from those who know best.

The only thing "wrong" with E-85 is that it's even available. The whole point of ethanol as motor fuel is as a replacement for petroleum based fuels(gasoline and diesel) The problem is, it takes about a half gallon of diesel to produce a gallon of ethanol. As diesel has about a third higher energy density then alcohol, you don't end up replacing much fuel so much as burning more of it overall.

As far as Alcohol as a motor fuel,.. drag racers have been using it for years. All it ever required was timing adjustment and replacing the fuel delivery system.
The "problems" everyone has with alcohol(straight, E-85, or any other blend) is trying to make it work in systems that aren't designed to run it. It's the equivalent of taking a well running small V-8 with a 600CFM carb, and trying to mod the engine to run on alky without changing any major parts. You have to double the fuel delivery, and that's not a minor jet change or "tweek".

I've been loosely following some of the supercharger threads(Belt- Turbo- etc) mainly out of mild curiosity(no personal plans along those lines).

My question here is: Why? Why bother? When tuning for that last little gain in HP, you give up fuel flexibility(no more 87 octane, etc)We have to use (and pay for) premium blend fuels,.. 93-, 95 octane or higher. If you're pushing that hard, why not just say screw it and run 98%("pure" alcohol, as the article says.) And if you're not pushing for that last little bit, why bother with the blends? :dunno: