Octane Booster

Leaving out all the childish remarks (and god knows how YAMABEN felt when he posted the first 450 cam mod post) can anyone with any real knowledge of octane boosters or additives chuck their two pence worth in please. Constructive (hopefully) evidence would be helpful.

Anyone up for discussing the pro’s and cons of using these. All I have is a group of peers who race and use it, and swear by it and our dyno results.

I under stand it oxygenates the fuel, creating a faster more powerful burn – but the results we’ve had back off the dyno are inconceivable. Our increase on a 2 year old Supermoto YZ426 was 12 – 14hp. The bike ran fine (well bloody well actually) all race meeting (this weekend gone) despite comments about holed pistons….

If this so good then there must be others who use it too – I cannot believe that in such a widely read forum no-one has….? Fast forward is US manufactured, and imported to the UK under licence. Its not NOS as some have posted.

Technicians and educated opinions more than welcome & I’m sure this web site wasn’t built on sarky childish comments like some indicate.

It's not childish to say Bull $hit.

There are a couple of manufactures that sell legitimate tetraethyl lead concentrate. I believe torq racing fuels sells one and there is something called 'lead supreme 130' which is easy to get from batterysandstuff.com.

There are tons of threads on the web discussing 'mix your own solutions.

The simplest is 1 gallon of tolene from sherwin williams ~5$ and 3 gallons of pump gas. This will give you something with about 98 octane.

you can boost octane easily by adding toluene to the gas. It is one of the main ingredients in most gas sold to raise octane. I mix around 25% toluene with premium amoco or texaco gas.

I have been running it in our yz250fs for more than a year. The bikes make better power with the blended gas than with straight gas.

I have run it in the 450 since I got it last month, but since I havent compared it to straight gas I dont know if it makes any significant difference in power.

This is a complex subject. Basically, the thing is that there are a number of different things that can raise the octane number of a fuel. Some of these agents will also add power for chemical reasons that do not relate directly to the octane number itself.

Raising the octane number of a fuel beyond the level needed to control knocking and detonation will NOT add a single horsepower by itself. Some agents, like tetraethyl lead, are nearly inert as a fuel, but they raise octane. Other chemicals that raise octane also add more thermal energy to the gasoline, so it gets to be a sort of definite maybe.

Tolulene may or may not boost a fuel's octane, depending on what it already is. Running it up to 25%, however, will usually add power for other reasons.

Straight Methanol, on the other hand, is an opposite example. It's "octane" number, or knock resistance is so high when run as a fuel by itself that we used to run our ESO speedway bike at 15.5 to 1 compression. There is so little thermal energy in alcohol fuels, however, that it is necessary to nearly double the jet sizes versus gasoline in order to get it rich enough to run right. The gain in power comes more as a result of the increased efficiency of high compression.

If you want a very detailed tech sheet on this subject that is not really that hard to digest, check the work of another Limey, Bruce Hamilton, at:


Go to part three for the discussion of Octane. There's at table of contents in part one.

Let's think about this for a minute. The NEWEST YZ426 is 3 years old. Do you really wanna throw fuel like that at it? Get ready for a grenade :cry:

are you sure?

toluene runs fine in both of my 04 yz250f's, and my 05 450. It runs fine in everyones cars trucks and boats too. :cry:

Just curious........has anyone ever thought of trying the Nitro mix that you buy for the RC cars??? :cry: I'm not knowledgeable on the mix but they have 20%.......is that 20% oil, and 80% Nitro??? I'm just wondering.... :cry:


ive thought about it but have never done it. i dont know much about the stuff but the higher the % the more nitro is in it. last time i bought a gallon of 20% i think i paid 18 bucks. ive got a little bit left maybe i should put it in something.

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