[thekurgan]

I found a thread using the search, but the poor guys question was not answered, so here it is:

Is it safe or recommended to use octane booster substances in the 335i?

[BK]

From http://www.nsxprime.com/FAQ/Miscella...lAdditives.htm - who knows how accurate it is, but other Google searches gave similar results. The net - octane boosters help for 87 octane gas, but don't "boost" 91 or 93 octane gas by very much at all.

Octane boosters offer little help in the quest for higher octane. Most popular street-legal octane boosters claim increases in octane ratings up to five points, and those boosters intended for off-road use only claim up to seven points. That's a lot of octane to hope for simply by pouring an additive in a tank. Sunoco told us that before they launched their GT-100 Unleaded retail pilot program, they wanted to be sure that a 100 (R+M) / 2 octane street legal fuel would be of value, and that enthusiasts would not be able to get the same (or better) results using an octane booster. Nine of the most popular retail octane boosters were put through a series of tests to determine where the consumer could get the most bang for the buck. The test results were verified by an independent testing facility, using several brands of regular unleaded and premium gasolines, just to make sure everything was legit.

According to Mark Borosky, Vehicle Test Engineer for Sunoco,"Of the nine octane boosters tested, none showed a significant increase, and one actually lowered the octane number of the test gasolines."Testing repeatedly showed a maximum increase in octane of 3.5 points by only two of the six street legal octane boosters when the recommended treatment rate was blended with lower base 87 octane gasoline. The best the remaining four products could muster was less than a one point increase. "While clearly no one would actually use an octane booster in a low base octane fuel, we wanted to give the manufacturers the benefit of the doubt relative to their claims of five-to-seven point increases," explained Borosky.

When tests were performed using 93 and 94 octane fuel, even the two best products from the previous tests produced a disappointing 1.5 to 2 point maximum increase. The remaining four street-legal octane boosters showed less than a .5 point increase. Those products designated for offroad use only didn't fare any better than the street-legal products. Subsequent tests where the dosage of octane booster was doubled, tripled, and even quadrupled produced only minimal improvements in octane, regardless of the base octane number of the test gas. In fact, quadrupling the treatment rate of the most powerful additive produced only a 3.5 point increase in octane when added to 93 premium, resulting in a cost of $3.25 a gallon.

[thekurgan]

Thanks for the response, in my area, 91 is the max, but I've seen 93 and 94 on the east coast, always wondered why the west coast doesn't have the same ratings or levels. I googled, but was overwhelmed by the responses!

[Shift_Fast]

I put in Cheveron 91 octane....with Torco Fuel Additive, to blend it to 93/94 octane....just what I run

[sonic03inSC]

Torco is good stuff. It will turn the plugs a little orange.