[roadtalontsi]

110 shouldn't hurt anything but is way over kill. id go for 100 if you really feel the need to run race gas. since you dont have a tune for it the need for 110 isn't there. Since your going to need alot more fuel running 110 you may throw an adaptation code for your fuel trims being way to rich, because it will take more fuel to get the target a/f. definately if you have cats use unleaded. but honesty anything 93-95 is your best bet. Defenitely reset your ecu and let it learn a little. Anything higher wont be necessary because you ecu wont advance the timing enough to take advantage it.

[gosu]

Originally Posted by jays05

Because racing fuel has a different specific gravity... It needs to be leaned out to make power.

And leaning it out adds to the effect of "its going to be more rich" ??

0.739 -Vehicle gasoline

0.722 - 110 Octane

very small difference

My bad I did not read the whole thread. I just glanced and kept seeing 91, 93, 94 octane, not the original topic of 110

[roadtalontsi]

yes leaning out makes it rich. sounds stupid but in the ecu's logic. Try to follow this. Since its going to take more fuel (110) to equal what it is used (93) to, this causes the engine to run slightly lean at first. It identifies that the engine is running lean so it compensates and adds fuel. It does this temporarily called short term fuel trim. once it maxes that out it will starting adding to the long term fuel trim. The long term fuel trim is slower to respond and is memorized. This is what must be "learned" when the ecu is reset. Also it is going to remember the maximum timing it can run before knocking. this is another advantage of the reseting of ecu when changing octane, so it can pickup the timing where it may have knocked before. ecu logic is not easy to understand but in the end it does make sense.

[gosu]

Indeed I understand. But after it learns, adds timing, its all good, its fast. I have reset before and IAM took me 1 min to get to 1.0 factor. STFT goes fast so I guess were all right? Who puts 100 or 110 and runs like a grandma. And as I said on my last post I though it was a transition between 91 and 94, bad me for not reading the whole thread

[Bishop]

Originally Posted by importfanatic17

Do you have an AP? If not, once you flash Stage 1, you should notice a pretty nice difference.

Originally Posted by Fletch07STI

Flash stage 1 FTW!
91 octane..
thats one downside to living in cali

but oh so many upsides!

I didnt read past page 1, but i agree w/ these guys.... the tune for 07 08 are pretty choppy and lean... i had an accessport on my 03 wrx and loved it, just picked up my accessport for the 07 STi on friday and WOW did it smooth everything out... and boost comes on alot sooner..... You will probably hate it at first, but its because the car has to learn the new mapping from the accessport.... after a few days it will run like a champ... After just probably ~6 hours worth of driving between installing it yesterday and driving around, and driving around today, its smooth as hell, but there isn't alot of throttle response.... no worries though

[vovik05]

Originally Posted by Bishop

but there isn't alot of throttle response.... no worries though

WAT! not a lot of throttle response? i'm worried

[Bishop]

Originally Posted by vovik05

WAT! not a lot of throttle response? i'm worried

It comes and goes... but the power delivery is SO smooth and the transition between shifts is awesome as well....
Im pretty confident its just the ECU adjusting as it learns.....
When i installed the AP the RPMs dropped pretty bad between shifts and it felt like i was bogging the car between shifts.... that has since past and it shifts like butta
OEM map had boost coming on late, and i was surprised how quick it came and how much better the car pulls w/out any boost (not alot of throttle)
I haven't romped on it, i filled the tank about an hour and maybe 20 miles after installing the accessport, so im seeing what kinda gas mileage i get....

Because the throttle response is sometimes there and sometimes its a little sluggish (gotta put the pedal in a ways) im pretty confident that its just the ECU learning....
If i remember to keep watching this thread, i'll definitely let you know if the throttle response increases.... but like everyone has to say with the accessport, you need to allow some time to let the computer learn the new settings

[WRX4ME LE 482]

Ive heard many people say that they just reset their ECU every now and again and it makes their car feel more powerful. They truly believe the system somehow "learns" their wimpy driving style, and somehow becomes aggressive when reset.

To my knowledge, there's no system like this in place. What I know may happen, however, is if they run the piss out their car at some point, make it knock like hell, and have the IAM reduce, sometimes it may take a while (if ever) for the IAM to go back up to the full 1.0. Resetting the system starts you at .5, and it pretty quickly goes up to 1 from there.

If your car has either reduced its IAM, or just plain learned out a lot of timing, resetting it will do you good, especially since race gas of sufficient octane will keep you running strong for that duration.

Course there is the whole lead will kill your cat thing, but I dont think I would do any kind of serious racing without high octane due to the high temps.