Dangler {/KAWF} BUMP

Last night dkirk and I went to fill up w/ 104 Sunoco ($4.50 per gallon, just down the road from 55 gal drums). We started going back and forth about his APR chip w/ the race program and my new GIAC chip I installed last night after I put in the gas (and cleared codes, etc w/ VAG Tool).

Anyways, he says that his car will take the fullest advantage of 104 octane when he switches to 'race' mode b/c it actually has a different program. I thought that If I reset my ECU (just unplug it for a few minutes then reset it up) it would do the same - recognize the high octane and do its thing.

2 questions: One, is this true that an ECU that is reset\rebooted will perform as well w/ 104 octane as the 'race' program from APR. Two, what exactly is this 'thing' the ECU does? (retard detonation???)

Thanks, I'm a bit confused

S4MadMan

Oh Frrrrraaaaaaannnnk...here's a question for ya. =)

frank

but the advantage is that he doesn't have to pull the ECU or wait for it to learn

that 100+ octane is in the tank


so it depends on how long the giac or any "non-APR race mode" chip,

has had to adapt


so far as I know...nobody has measured if

the same car with 100 octane


is REALLY any faster with APR Race vs another chip reset and adapted for 100 octane

just because APR maps, SHOULD be better

doesn't mean they are

esfor

It made about a 3 tenths difference in the quarter mile for me with the MTM StageI/II chip. I basically emptied the tank then put in Sunoco GT+ and reset the ECU by way of battery disconnect.

Basically, it was explained to me like this (and feel free to correct me).

Octane is resistance to predetonation (knock). With turbo engines running higher boost (chipped) there is more chance of knock, esp in warmer temps. When the ECU detects knock it will retard the timing. If you have higher octane, no knock, no retarding...

Beyond the actual timeslips, I noticed the engine was a LOT smoother through the whole RPM band even in 90+ air temps. There was no hesitation which I seemed to get occaisionally with the chip and high engine/air temps.

-Alex

Pat-SoCal

The only way it will recognize good gas is by the lack of knock in the motor.

Octane is simply a means to an end. The end, or goal is an efficient fuel burn in the cylinder (5v head design already is efficient enough), and a byproduct of that is a lack of detonation and knock.

Why is the lack of detonation good? You are allowed to push more air through the motor (higher manifold pressure (boost)), therefore, it is possible to make more power on higher octane fuel. Will a stock S4 see a big diff. between premium, and race gas? Probably not. Can you run an APR race program on premium? Sure, as long as you don't run the motor into too much timing (romping on the gas at too low an rpm).

Anyway, there's a ton more to write about this, but I'm done for now.

frank

but it will recognize a lack of knock..and stick with the aggressive maps

Shredster

Call the toll-free Unocal (Union 76) number and ask for the number to speak to their resident racing fuel, technical specialist. He is available to the consumer... wish I still had his number. I've spoken with this guy/fuel chemist and gas is his life. Even if you don't have Union 76 gas in your neck of the woods, the phone knows no boundaries. Although someone here might be able to answer your specific ?'s, there is not a person on this board that couldn't learn something from this guy. He was blowing me away with his knowledge... wish I could regurgitate it for you.

frank

the benefit of higher octane, is Ign. advance or lack of retard...not more boost

The R

I had 105 in my car and reset the ECU. It didn't run as good as it did on the race program. What does that tell us? Probably nothing.....I seriously doubt that reseting the ECU will make as much power as a program dedicated for Race Gas.

I know you're not into hype Mr. Frank, but my car behaves like another animal on the race program compared to the regular chipped program.

Maybe one day we'll have proof weither it makes a difference or not.......

Ferris TMK

Only thing is the map has an finite number of degrees it can retard or advance..