race gas

[heath_jones01]

i just started racing tt last year, and it seems i am the only one that races a stock 400 engine... does race gas help a stock engine with only a k&n filter and slip on pipe?

no if everything is stock you will end up frying your piston rings. Dont quote me on it but i'm pretty sure thats what will happen

[Wheelie]

FoxHondaRider--You have no idea what you're talking about.


Heath--Running race gas in an internally stock 400ex won't hurt anything. It also won't help either--if by some chance you do notice better performance, it won't be enough to justify the cost. A stock 400 doesn't have high enough compression to warrant race fuel.

[GPracer2500]

Originally posted by FoxHondaRider
no if everything is stock you will end up frying your piston rings. Dont quote me on it but i'm pretty sure thats what will happen

As wheelie pointed out, that's not true at all.

[GPracer2500]

The gains from running a power-adding oxygenated fuel are well documented (VP's U4 is popular). A couple to maybe up to a 5% power increase should be expected with such a fuel. This holds true even on stock compression engines. There are even oxy fuels designed specifically for low compression engines.

A traditional leaded racing fuel (something like VP's C12) may not gain much power-wise. You might get a smidgen of extra performance but I doubt it'd be anything you'd notice. Maybe the biggest advantage in a stock engine would be the consistency of the fuel and the resulting consistency in a/f tuning (i.e. jetting). And the more desirable distillation curves of a good racing fuel might add some snap and/or help keep engine temps in check.

Whatever you do, switching fuels will require careful carb tuning. Different fuels require different jetting. You can't just swap fuels around without making any jetting changes (or at least confirming the jetting) and expect any benefit. If you're going to the trouble of running an expensive, high performance fuel then go to the trouble of having your engine tuned on a dyno equipped with an air/fuel meter.

Personally, I'd save the money you would spend on a racing fuel and upgrade some hard parts in your engine. Even a simple cam swap will get you more profound and easier to come by gains.

Mostly, I agree with wheelie. Careful fuel choice and careful tuning could get you some benefit but it's not worth doing when you could spend the money on other things.

[AutoRoc]

You can definately make more power with the right fuel. VP has more than a few fuel with BIG oxygen content that will make more power. Dump it in and jet it up a few sizes to start. Careful plug reading and jet swapping will get you the power.

With low compression, I would try U4.2, MS101, MS103, or even CMP. Goodluck!

[trx400EXtreme]

i run 110 at the dunes on a stock fo hundy motor. if anything it will eliminate a little carbon build up.