Kawi2strokes.com Forum

Easy, assuming you pick the right fuel
Last time I checked VP had a huge number of fuels for drag cars (with / without turbo, blower, NoS, high compression / low compression, painted purple / not painted purple, etc.). The the same amount of choices for left turn only cars on dirt and then more for asphalt. Same with bikes and applications.
There are some tuners that mix different types of VP for their own witches brew.
Our little ol' 10:00 drag car gets a mix of Sunnoco purple and pump gas as we saw no significant differences in the big money stuff and do tune by exhaust gas temp. Then again, we weren't looking at the last .001 second gain either.

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There are only two types of motor sport racing:
Nitro and everything else
(Sometimes referred to as fast and slow)

Interesting discussion guys - thanks. The stuff I was using (Street Blaze 100) has a Specific Gravity of .75 @ 60°F per their spec sheet at http://www.vpracingfuels.com/motorcycle ... on15560032. Wikipedia says that typical specific gravity of gasoline range from 0.71–0.77 so I wouldn't expect jetting to be off *that* much but it sure ran differently!

Bill, what do you usually use in your race bikes?

Frank, SG alone doesn't say much about required jetting. For example, the SG of ethanol is about 0.79, but as you know, jetting for ethanol is not even close to jetting for gasoline.

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If it surges, that's normal, upshift.

One of the most popular fuels for H2s is C-14, its very light, less than just about any pump fuel you will find. And sorry about mispelling Tertiary in my first post, perhaps its better to call it MTBE.

A funny story about fuels. There was a class in IDBA for exotic fuels, the only requirement is you had to fail the fuel test, which was just a specific gravity test, you drew out a small baby food jar of fuel before a run, they tested its weight and if you were within a specific range you were good.

Well, the Fuel class record was open so I bought some Klotz Coolinal which is nitro propane and very heavy. I took a gallon of C-14 up to tech before the race with the bottle of Klotz and I added an once per gallon until it flunked the fuel test....it took 15 ounces !!!! We reset the record with a few tenths to spare...ha.

Dayum Bill,
Another great insight on setting records.

Thought you guys might find this interesting about nitromethane from Wiki:
"Since an engine's cylinder can only contain a limited amount of air on each stroke, 8.7 times more nitromethane than gasoline can be burned in one stroke".

"In model aircraft and car glow fuel, the primary ingredient is generally methanol with some nitromethane (0% to 65%, but rarely over 30% since nitromethane is expensive compared to methanol) and 10–20% lubricants (usually castor oil and/or synthetic oil). Even moderate amounts of nitromethane tend to increase the power created by the engine (as the limiting factor is often the air intake), making the engine easier to tune (adjust for the proper air/fuel ratio)".

So let's say you've got an old beat up lawnmower (or minibike) that you don't mind wasting.
When I raced the Briggs and Stratton modified go-kart class we had to just about double the jetting with a stock carb with methanol. Where would one find a ball park jetting curve for say 25% nitro / 75% methanol?

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There are only two types of motor sport racing:
Nitro and everything else
(Sometimes referred to as fast and slow)

Jim, I know this doesn't answer your question, but I got a kick out of old time drag racer and hydroplane engine tuner Bob Bernardon telling me that as opposed to gasoline engines that need the jetting just right, with alcohol you use much bigger jets, and usually go a few sizes bigger than needed since it doesn't hurt power, and for nitromethane, some guys drill out the jets with large drills, and others simply take out the jets completely.

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If it surges, that's normal, upshift.

That must follow the old engineering principle that if more is good then too much is not enough!
The fule funny cars have raw fuel dumping out the zoomies in the staging lanes and that is before the driver turns the fuel pump way up. Found it interesting that Wiki says nitro is easy to tune.

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There are only two types of motor sport racing:
Nitro and everything else
(Sometimes referred to as fast and slow)

Newbie: "My H2 carbs don't seem right. I have low power at high throttle/rpm, and I hear pinging."
Mraxl: "If you remove all your jets and run 100% nitromethane, your problems will go away."

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If it surges, that's normal, upshift.

Nitro: the tuner's "snake oil."

I thaught nitro would burn a triple up