I think if your read the label carefully you'll find ANY octane booster that is added in ounces will raise you Octane by a certain number of Points. Points are 1/10 of an Octane.
ie if the booster raises your octane by 4 "points" then your 93 octane is now 93.4.
There is no "additive" that added at 1oz per gallon will give any meaningful rise.
Toulene is added by the
oil companies to get the high octanes along with Xylene and MTBE (Methyl Teretiary Butyl Ether)
If the
oil companies have to use the above in fairly high percentages then there simply is no "magic bullet"...
I've been using toulene or xylene in both my Grand National (Turbo) and my Cobra that has 11.5 to 1 compression. It works very well at around 10 - 15% mix. I switched the GN to Alcohol injection and that also works great and is simpler.
I've given a lot of thought to buying a 55 gallon drum of racing fuel and simply mixing it but I hate to have that much gas in my shop. I guess I'll keep mixing the toulene/xylene for now.
By the way make sure if you do this that you premix it in a gas can first. Then put it into the tank "carefully". I don't use the mineral spirits or trans fluid that some people do as the mix is low and the 93 octane already has cleaning agents and lubricants. So I don't worry about it and have never had a problem.
Regards,