100 oct on a stock ecu

[sheefo2k]

do our computers have a way of learning the level of octane in the tank thus change the timing for more power or am i dreaming?

[Activ3]

Not sure about non-m's, but the M3 gets a noticeable gain when running high octane gas, so I'd say it's possible that our computers can change the timing... thats what VANOS is for right?

[MSpired]

I don't know about non M's, but M's can read up to 96 octane and advance timign accordingly.

[turboaddiction]

I don't know the stock DME that well but when someone knows how to tune it by reverse engineering so they can control all the maps and everything like it is a mega standalone...then I don't see why not. I say this since I have much experience with standalones. As far as unleaded that only matters with O2 sensors and cats. More cats actually cause they get destroyed quickly by leaded fuel. 100 is unleaded so I don't see why not. If you tune for it then you should be able to make much more power.

[sheefo2k]

I used to run 100 on weekends down at the track and I ve noticed a nice pull all across each gear. It felt as if the car kept pulling and pulling and pulling. I didn't know if it was my mind play tricks on me or did the car really adjust the timing.

[Saintly]

I used to run 100 on weekends down at the track and I ve noticed a nice pull all across each gear. It felt as if the car kept pulling and pulling and pulling. I didn't know if it was my mind play tricks on me or did the car really adjust the timing.

I have done many runs on the dyno and when ever we have added better octane fuel the power curve just keeps going up to a point. No other changes other adding fuel.:thumbsup:

[turboaddiction]

I have done many runs on the dyno and when ever we have added better octane fuel the power curve just keeps going up to a point. No other changes other adding fuel.:thumbsup:
Nice! So the answer to the original question is yes.

So what is this point? Please post dyno sheets of before and after. How high on octane did you go?

[clean-m-tech330]

I only run 100... 91 is :censor: do it / end thread-

[Mike Benvo]

I wouldn't run 100 in your cars often. You run the risk of burning out the cats. The car will adjust timing accordingly, but only to a certain point. It's definitely not worth the price for everyday use, but a nice addition to a track day.

[steelgrey330ci]

were do you guys get the 100 octane from, or just buy a bottle of octane boost and put it in the tank.

[ST06M3]

I wouldn't run 100 in your cars often. You run the risk of burning out the cats. The car will adjust timing accordingly, but only to a certain point. It's definitely not worth the price for everyday use, but a nice addition to a track day.

Besides running rich, which leaves fuel deposits in the exhaust downstream and then burns up the cats, is there is another reason?

I thought if the A/Fs are good and the car is neither rich nor lean, the 100 unleaded should not burn up cats.

[MSpired]

Besides running rich, which leaves fuel deposits in the exhaust downstream and then burns up the cats, is there is another reason?

I thought if the A/Fs are good and the car is neither rich nor lean, the 100 unleaded should not burn up cats.

What he said...Unless your running leaded

[NickG]

I wouldn't run 100 in your cars often. You run the risk of burning out the cats.

How do you figure? What does 100 octane unleaded fuel have (or not have) in it that will cause the cats to burn out?

(I guess another way of saying what you said is, if you run 93 octane in a car designed for 87, you'll risk burning out the cats. Am I right?)

[Mike Benvo]

How do you figure? What does 100 octane unleaded fuel have (or not have) in it that will cause the cats to burn out?

(I guess another way of saying what you said is, if you run 93 octane in a car designed for 87, you'll risk burning out the cats. Am I right?)

I was referring to leaded gas. If you run 100 octane unleaded, it will just skew the AFR's for 5 or 6 runs until it the car learns the properties of the new gas.

You can see in the dyno attached the car learning the higher octane gas with successive runs.

[NickG]

I was referring to leaded gas. If you run 100 octane unleaded, it will just skew the AFR's for 5 or 6 runs until it the car learns the properties of the new gas.

You can see in the dyno attached the car learning the higher octane gas with successive runs.

OK, so you were referring to leaded fuel. In that case, I agree.

In general, the different octane rating should not affect the AFR of the runs. I don't know what the setup was for the dyno you posted, but I'd bet something else is going on.