Here in CO the best gas I can find without driving 30 miles is Shell 91. Is the knock sensor in my 2001tt able to take out enough timing to COMPLETELY prevent detonation at WOT? If I drive the 30 miles and spend a small fortune on the Sunoco 100 octane will the computer recognize the change and prevent the knock sensor from messing with the timing, or is there a "learning process" involved. I ask this because I wonder if switching back and forth between 91 and 100 octane will "confuse" the system, or will I see an immediate difference in boost/performance?

 

is the car stock? at stock boost levels 91 to 93 it wont make much of a difference , if your car is tuned for higher octane then obvioulsy you will.

when you switch oct levels it ussulay takes about 15 min of driving for the ecu to adapt , or just un hook the battery for 20 min or so. you will not confuse the system.

 

The car is bone stock.The max boost I get from 91 is .8 bar. Do you have any info about the knock sensor at 91?

 

A little extra info/clarification: The owners manual recommends a minimum of 98 octane. So I imagine with 91 octane the ecu/knock sensor is retarding the timing to avoid detonation. I am curious to know what the "stock" boost is supposed to be with a car running the recommended fuel (or a little over like the Sunoco 100).

 

Congrats...I see you've moved up to a tt...nice

 

98 oct in europe is equvilant to us spec 91 and 100 oct to our 93 , they use different oct ratings.

these cars stock run .8 bar , regardless of 91 or 93,

 

Thanks UNVMY96. I knew there was a difference between how europe and the US display octane. I guess there is also the MON vs RON method here in the US. So to sum up what I understand you are saying is that our 91 octane on a STOCK 911tt will produce the performance numbers in the owners manual. The only reason to run the Sunoco 100 is if my car had a chip and tune that would take advantage of that higher octane.

 

sorry...typo unlvmy996

 

one more time....unvmy996

 

correct , when you start tuning the ecu then ,the higher the octane , the more timing and boost you can run .

 

Happy Holidays and thanks for saving me $100's at the track!