Tom-Guy

No. In fact, the knock limit of 87 vs 89 vs 91 vs 93 varies depending on brand, etc. Hell, one week 93 at one station is good and the next tanker truck they get in the ---- sucks, even at stations/brands that advertise "no ethanol". My engine is a little volatile below 2000 rpms, and really I'm a dumbass for not putting in a cam w/ some overlap to help it out. But, that's beside the point.

As long as you aren't pressing knock limit, normal 200-250 whp HMT setup, I don't think 87 would hurt anything. Right up to the point you run out of octane on 87 the power and timing should be in line with what you get on 93.

sewell94

i can agree with that but earlier you stated

I dont want the guy thinking that his "e10" 87 is more knock resistant than 93, for the past year or two if the stations use 10% ethanol to bump the rating of the cheap stuff, they also used it to bump the better stuff to 93.

its all about the "edgimication"

Tom-Guy

Hrm, you are correct. Would you rather I clarified my statement like this?

"E10" 87 is going to have a lower knock limit than 93 octane fuel, so it will safely support less power. However, when operated within it's safe range, the addition of a significant portion of ethanol to 87 octane gasoline slows the burn rate of the fuel which has the effect of "retarding" the burn, as if timing had been taken out of the ignition maps. In the specific set case of my high CR undercammed D16 this provides an additional amount of thermal safety that, in my specific example, prevents pinging and detonation. Conclusions can be draw that, when within the safe operating limits of "E10" 87 octane, that the lower octane ethanol-laden fuel is more detonation resistant than pure 93 octane gasoline.


On second thought I prefer to resort to my HMT roots and tell you to ---- yourself, Tom. Cars are not simple constructs, and regardless of how much you clarify and spoon feed, people like Stalin simply aren't capable of ever understanding. Why bother? You understood what I meant. Let everyone else participate, scrabble for the intellectual scraps, or wallow in their own ignorance like they have since the dawn of time.

sewell94

---- you too, go put on your rogaine that i supposedly scammed you out of, then read up on ethanol, reapply rogaine, then get back to me.

Who is Stalin?

I'm all about letting everyone else participate.

turbo4life

thanks for the input i took it out for a little ripper on that gas on 6-7 pounds but didnt rev it up all the way didnt hear no knock or anything ill just pull a few degress and take it out for some rippers on fresh 87 arco..



and jd more on the e10 they dont have that here in my town i did see my first gas station here and they got e85!! so that is 85% ethanol and 15% petrol?

Tom-Guy

E10 is slang, not how the gas is labelled.

t_cel_t

more then likely they do not call it e10, here in WI you cant even buy strait gasoline any more. very few stations will still have strait 93 but all 87 and 91 is 10% ethanol

Oscar

So "e10" 93 is better than straight 93, or at least more knock resistant? I'd have to retune(add a few more degrees?) for the "e10" to compensate for the slower burn rate?

BigBird

Hmm interesting read, but for how often I drive my car I'll just have it tuned on chevron 94.

Smith-02

i had learned timing and knock correction set for 93, my dad borrowed my car because i borrowed his truck a while back and filled it up with 87(did not tell me he did). apparently he did not hit any amounts of boost because the first pull i did it sounded like someone threw a truckload of screamers (1990's movie reference) into my cylinders

after that, it seemed to do okay