AUDIFAN008

Anyone tried 100oct gas on RS4 ?

larryV

reluctantly because it was $7 a gallon and it was long drive out of the track for decent 93 octane gas.

Honestly, it didn't feel any different. Car didn't feel any faster and in the session I went out with the car, it didn't go any faster on the straights before the braking zone. I hit about 115 mph on the front straight in previous runs on 93 octane and it was about the same with 100 octane. Even my lap times were same.

RS4JAG

I wonder if the ECU could be modified to map for it?

123Thumperer®

i think unless the ECU is expecting higher octane, it doesn't know what to do with it.

AUDIFAN008

to around 94 oct on my other cars and was quite a different on feeling, I guess i will do the same then.........

Bob W.

ouch.

AUDIFAN008

if someone can come up something like a map switch for RS4, it will be perfect =P

JDBlueAudiS4

is less knock (if your logging) and better A/F ratios becasue the ecu will correct a small ammount (up to about 96 octane the ECU will do corrections). This will allow the car to run at its peak performance and not have any hiccups while doing it. Our standard pump gas is not as good as whats found in certain european countries, race fuel (GT100) is made using a different process then standard 91 or 93 so I would believe you will see like under correction by the engine for "bad gas" as it where. I know the S4 used to love race fuel, plus you have to remember it smells-so-good.

AUDIFAN008

the ratio to 96oct?
I got this 100oct from 76 gas station.

I ran pure 100 on 540, STI and CLK500 before, it was fine but like you said 540 and clk500 gets least difference on performance.

JDBlueAudiS4

the ECU adjusts from around 91 to over 94, since 94 octane gas in the US is less then optimal, pure race gas will far exceed 94 in every shape and form and your ECU will adjust a little over 94 but the bigger thing is that the car will not exceed the limits of the gas (something that can happen in 91, 93 or 94. Thats what I am trying to say.