Just noticed that the minimum recommended octane is 93 (see label on gas lid). However, most premium unleaded fuel is 91. Is running a lower octane fuel reducing engine performance? Or worst, causing any engine damage?

 

not really the ecu will retard timing . almost always run race gas way more fun.. have giac race gas program and pump gas all and is well. get one you will love it

 

Can you feel the race program? I almost never run race gas, but I don't use my car for commutes. It's a cheap option once you pay for base program.

 

As stated by steve harris it's ok. On a TV car show the guy from LMC was given a TT to drive for a year (I think) and report on it. On one of the shows they dynoed the car on 92 oct. recorded the numbers. Then they drained all the fuel and put 87 oct. in it and re-dynoed the car. It was down about 15-17 hp but ran OK otherwise. BTW he really enjoyed the car.

 

Thanks for the verification! Mines is set for pump gas mainly for daily driving. I have yet to try the Race setting (humm). BTW, I'll pass on the 87 octane experiment.

 

Don't blame you, they were just testing the effects and if you can only get 87 it wouldn't be to bad. I run 93 all the time in mine.

 

I run 92 mostly and in my next state of tune, I will run 100 or a mix
of 92 and 100.

MK

 

You're going to be just fine on 91... The performance file you have is tuned "for" 91 octane so you're in good hands

 

But would 93 or 95 give more power on a 91 tuned car?

 

I have heard (or read) this debated a number of times and am confused myself. I think though that the higher octane may give better gas mileage (at least it does for me), but I don't think you trully get the power effects unless your program (and timing) can be adjusted to take advantage of the less volatile fuel.