fuel mixture question

Tried 8% nitromethane and 102 octane gasoline on a two stroke engine
( 70 cc ) It seems like it slowed a litle down, but
gained more low rpm torque.

It is possible too mix in some methanol , but how mutch? 10 % ?

The engine is currently running on 4% racing two stroke oil.

 

Don't be a sissy, use a lot more methanol than that, cut down on the
gasoline, use methanol as your main power base instead of gasoline, and
then "tweak" the fuel mix with as much nitromethane as you dare to
use...

Methanol was once available at the gas station down the street from
where I lived. It was made available as an alternative fuel, not
because it's used in Indy car racing. It was 108 octane fuel and I
wondered about using it to boost the octane in my streetbikes. But the
pump was out of service...

A local racing club once allowed methanol and nitromethane fuels to be
used in Formula USA racing, where any modification possible was
allowed, but nobody was interested in fuel blending, they all used high
octane race gas. I guess none of them were ever into go karts...

I got this info from a national go kart champion...

The rule of thumb for carb rejetting is 1% richer for every 1% alcohol
added to the fuel mix...

But you'll need to increase your jet sizes by 50% and you may find that
the idle mixture passages in your carburetor are just too small and you
might have to abandon a street oriented gasoline carburetor like a
motorcycle uses in favor of some trick race carburetor (like a pumper)
to get enough low speed fuel/air mixture...

Or maybe you'll just abandon the notion of having your engine idle at
all, since you're going for the big power of alcohol and
nitromethane...

Nitromethane, (CH3N02) is what is called a "thermalcharger" fuel. It's
50% oxygen by weight, heat releases the oxygen, chemically
"thermalcharging" the engine. But nitromethane is corrosive, over a
period of time, engine destruction is inevitable...

Flush out your engine with a liter of gasoline after you run it on
nitromethane. These fuel blends are going to destroy seals, gaskets,
plastics, and maybe the floats in your carburetors. Deal with it, be
ready to replace whatever gets destroyed...

About 15% nitromethane is the maximum recommended. Nitro is slower
burning than methanol. It burns with a luminous flame, so you can see
the fire. Methanol has an invisible flame, water cools the flame and
that's why you see the pit crew at Indy car races throwing buckets of
water on fires there...

Nitromethane and methanol won't hurt your skin, but you should wear
googles and fireproof clothing when you're mixing these fuels...

Gawd only knows what a lot of methanol will do to a synthetic oil used
in premix, and whether the methanol will wash the lubricating film off
of the cylinder walls. Model airplane engines still use methanol and
nitromethane fuel mixed with a lot of castor oil, they don't use
synthetic oil in the mix...

Castor oil flows toward hot spots in the engine, instead of away from
the heat. That's good. The downside of castor oil is that it turns to
gum and makes the piston rings stick when the engine cools. Real racers
strip their engine down after every race meet anyway, and clean all the
gum and deposits out of the engine...

Fuel blends:

Mild blend: Methanol 70%, Benzol 10%, Gasoline 10%, Racing Castor 10%

Medium Blend: Methanol 70%, Acetone 5%, Gasoline 5%, Benzol 10%, Racing
Castor 10%

Hot Blend: Methanol 55%, Nitromethane 15%, Acetone 5%, Gasoline 5%,
Benzol 10%. Racing Castor 10%

Other blends:

A. Methanol 75%, Ether 10%, Water 5%, Racing Castor 10%

B. Methanol 25%, Acetone 35%, Ethyl Acetate 5%, Gasoline 35%, Racing
Castor 10:1

C. Methanol 25%, Methyl Ethyl Ketone 35%, Ethyl Acetate 5%, Gasoline
35%, Racing Castor 10:1

D. Methanol 15%, Diethyl Ketone 35%, Ethyl Acetate 5%, Gasoline 35%,
Racing Castor 10:1

Benzol (108 octane) will auto-ignite without a spark. It's used as a
coolant in fuel mixes...

Ether can be used as a starter fraction...

Gasoline is used as a starter fraction...

Acetone is used as an igniter to boost top end RPM and acceleration.
It's a strong solvent that will eat up plastics. It's used as a blend
stabilizer and it helps to tolerate water in the fuel mix. 1 to 3%
distilled water are sometimes added to the fuel mixture...

Fuel mixtures can be stored, and they do absorb water from humidity in
the air. This water is not necessarily a bad thing, the water turns to
steam when the fuel is burning, and this reduces pinging...

Pinging is a strange engine phenomenon. Pinging takes place when you
have to close the throttle a little bit, it doesn't happen at full
throttle. If you never had to slow down, your engine wouldn't ping when
you opened the throttle again. Steam from water in the fuel mix raise
cylinder pressure and keeps the spark plug from igniting the mixture
prematurely...

 

Dang! If you had told the drag racing boys that 50 years ago, they
could have saved all that bother...

And we wouldn't have the spectacle at the christmas tree, with flames
shooting out the exhaust pipes and the eye-stinging fumes and the
wonderful smells of methanol and nitro-burning top fuel dragsters...

The atavistic avatar is iconic...