your welcome

 

it actually does do SOMETHING, although not much. A friend of mine as a wrx that we tuned here. he's in cali for the summer and has to add 3 cans of octane booster to avoid knock on the 91 per tank. Retuning for **** water cali fuel will be necessary, but enough octane boost will do something. That said you are better off adding toululene to your tank.

 

The octane booster in a bottle you can get at Pep boys or Autozone are worthless (IMO). They will raise the octane from 93 to maybe 93.1.



If you want a good octane boost, mix some race gas with your regular gas. Or you can go to your local paint shop and get some Toulene or Xylene.



Here is a link that talks about mixing toulene into a tank of gas. However I wouldn't do this type of thing often in you FD. A 5 gallon can of Toulene cost me about $35-40 at my nearby paint shop. If you really wanted to you could also get a 50 gallon drum for about $250-$400 (depending on where you are at).



http://elektro.cmhnet.org/~charlie/photos/...di/toluene.html



Q: How much toluene should I use per tank of gas?



A: Octane ratings can be very easily calculated by simple averaging. For example, the tank of an Audi A4 1.8TQ is 15.6 gallons. Filling it with 14.6 gallons of 92 octane and 1 gallon of toluene (114 octane) will yield a fuel mix of:



(14.6 * 92) + (1 * 114) / 15.6 = 93.4



HTH