KC_Prelude

I've read that toluene can boost the octane rating when added to gas and 1/2 -1 gallon in a tank can make a real difference in hp/gas mileage/ engine health, especially in turbo cars. Before I go ruin my car dumping a half gallon of something I know little about into my gas tank I would like to know if anyone has used it and what you thought about it?

zthang

I've also heard this before, but I don't know if it works. Only thing I do know about it is the structure of the molecule...a benzene ring with a methyl group attached. Very hydrophobic.

Ike

If you want a little octane boost it's good stuff, so is Xylene. Just don't get it on your paint :p


https://www.rx8club.com/showthread.p...hlight=Toluene

Velocity-8

I tried Xylene twice in my 8 and did not notice any difference.

Rotarian_SC

I thought I heard NA rotaries ran best on lower octane fuels, but I could understand the higher octane for turbo's so you could raise boost

wakeech

in this application it's less to do with the higher octane rating and more to do with the higher potential energy of the molecule.

w2aew

All else being equal - higher octane does NOT give you more power - period. Octane is a measure of the fuel's ability to withstand compression without combusting. The more compression you can get away with, the more power you can extract from the fuel. This is why high compression engines are more powerful and require higher octane fuel.

In modern engines with knock sensors, etc., you can end up with more power with higher octane - if and only if the engine management controls spark timing to eliminate detonation.

I have also read that the rate-of-burn of the fuel is dependent on octane. Lower octane burns "faster", and the higher octane burns "slower". This is why you can run more timing advance with higher octane fuels.

Bottom line, if the engine is optimized for a given octane, running a higher octane will not provide any power increase (unless you advance the timing, increase the compression, add boost, etc.)

wakeech

dude, i know all that. holy cow, there's a whole huge thread right above this one specifically on this issue. pure toluene or xylene has more potential energy in the same volume of liquid than your usual pump gas. this is not from my mouth but from the mouth of a scientist who's profession is inside a refinery.