Ethanol, for the uninformed

[Nasty Dream]

We don't have E85 here (yet, at least), but ever since they started putting 5%, and then 10% (and supposedly 15% ethanol is on the way), I've been concerned about the future of a car that requires premium fuel and about the effect it would have on the amount of boost I could run. Because they simultaneously began reducing the octane of premium fuel to 91.

I figured they were diluting it with filler to make up for the crazy situation with supply/demand/cost of gasoline.

I didn't really know anything about ethanol other than it must be closely related to alcohol.

I immediately reduced the amount of boost I was running to 14psi from 16 - just to be safe.


Now, from what I'm reading here (and I've read everything I can find), this is some great stuff for turbo vehicles.

>So I don't need to reduce boost with 10% ethanol - and in fact I could theoretically increase boost? (I don't have the mods to support it yet) What kind of psi difference would 10% make? Not even 1, I guess.

>Is it going to leave gunk on my injectors?

>Final question: do I have to drain my tank to switch to other fuels, or is that only when going to or from e85 to straight gasoline?

Anything else an uniformed customer should know? Please don't re-invent the wheel on my behalf. Much information is already here and here.

 

[architechnik]

Be aware that if they are dropping the octane rating, then it is NOT a good idea to increase boost pressures. The octane rating is the final note that will indicate propensity for early detonation (knock).

If they increase the ethanol and decrease the octane, they just aren't treating the other 90% of fuel as much as they should. In other words, they use crappier fuel to mix with the higher octane rating that ethanol has - around 99.

If you have no tuning abilities and supporting mods, I would not suggest using anything higher than 10% ethanol without eventual consequences. You do not have to drain the gasoline completely if you have the ability to tune.

Some people I know actually have three tunes that they store - one for e85, one for 91 octane, and one for a 50-50 mix. Pretty easy to load each one when you carry a laptop around and helps out when going on road trips where you don't know what will be available.

Some ethanol will leave residues on injectors if they are old pintle-style injectors. They were never really designed for that fuel and it can cause excessive build-up if not tuned properly. Continued over-fueling is usually the major cause of that build-up and these turbo cars often end up in that area.

I hope all this answers some of your Q's.

 

[Boostnvegas]

I live in Vegas and I just run 91 and have never had a problem. But I do know that the gas for a few months has more oxygen in it. It says so on the gas pumps.

 

[Nasty Dream]

Some people I know actually have three tunes that they store - one for e85, one for 91 octane, and one for a 50-50 mix. Pretty easy to load each one when you carry a laptop around and helps out when going on road trips where you don't know what will be available.

Ahh, I got it. I misunderstood what someone meant by 'draining'. It's not because you can't mix them, it's because he was tuned to use a certain fuel!

Some ethanol will leave residues on injectors if they are old pintle-style injectors. They were never really designed for that fuel and it can cause excessive build-up if not tuned properly.

I've got the stock 2g injectors. These are not pintle-style, are they?

Continued over-fueling is usually the major cause of that build-up and these turbo cars often end up in that area.

Over-fueling? You mean running E85 exclusively?

I hope all this answers some of your Q's.

It did, but it introduces new questions! Thanks, if you have the time.

 

[crusada]

Ive been thinking about all of this as well which is why when my rebuild is done I may just tune with link. I was going to have a chip burnt for my tune but now im undecided .

 

[architechnik]

Ahh, I got it. I misunderstood what someone meant by 'draining'. It's not because you can't mix them, it's because he was tuned to use a certain fuel!

That is most likely the case. Ethanol mixes pretty well, so there is no concern about having it separate with other fuel. It actually will allow a small amount of water to mix with gas and can clean out a system that has had trace amounts of water seep into the fuels system.

I've got the stock 2g injectors. These are not pintle-style, are they?

I believe the stock injectors are standard pintle-type, where if there is really high flow they can get clogged. The same situation with the disc-type injectors where the small holes get clogged. You need more flow with ethanol than with standard gasolines, as the volume required to create the same combustion is greater.

Over-fueling? You mean running E85 exclusively?

No, I mean providing more than needed fuel for stoichiometric combustion, where the exact ratio of fuel to air is used in combustion. Turbo-charged cars often require more because of the risks of predetonation (knock) under high combustion situations.

 

[Nasty Dream]

I believe the stock injectors are standard pintle-type, where if there is really high flow they can get clogged. The same situation with the disc-type injectors where the small holes get clogged. You need more flow with ethanol than with standard gasolines, as the volume required to create the same combustion is greater.

So whatever injector upgrade I need for my application, I should actually get slightly bigger ones and run richer?

I don't think that's what you meant. I don't quite follow. Any more detail?

No, I mean providing more than needed fuel for stoichiometric combustion, where the exact ratio of fuel to air is used in combustion. Turbo-charged cars often require more because of the risks of predetonation (knock) under high combustion situations.

Ah OK. So in any rich condition, ethanol is worse for injectors than gasoline.

Is fuel injector cleaner is a good or bad idea?

 

[95talongirl]

You need more flow with e85 because it is not as efficient as pump gas. You use 33.3% more ethanol then if you were to run pump gas; this is the reason for the larger injectors on E85. On the same token, you will also see a drop in fuel economy due to this.

 

[Nasty Dream]

You need more flow with e85 because it is not as efficient as pump gas. You use 33.3% more ethanol then if you were to run pump gas; this is the reason for the larger injectors on E85. On the same token, you will also see a drop in fuel economy due to this.

So if I was running in a rich condition due to an unregulated hp fuel pump, this would help me lean out?

 

[black_gst]

Nasty Dream I have a question for you, where did you get that sticker on your mirror in your avatar?

and about your question, E85 or any fuel for that fact is usless without a way to tune for it. Ethanol has been in fuels for years now and most cars can adjust themselves based on the ethanol content, I think out here in Cali we have 15% ethanol in our fuel.

personally I run my Talon on E85 and love the stuff!