300 bhp Vincent!?
- Thread starter ericg
- Start date
I don't believe that is a typo, but it is not easy to guess the HP of a Nitro Methane fuel engine that is not run on a dyno. With cars, you can run the engine on an engine dyno and not ruin the tires or the running gear. With a bike, it is almost impossible to separate the engine from the chassis in a meaningful way and get a readout on the engine. You cannot run slicks on a dyno as they will be damaged beyond further use.
As a result, folks are left with general calculations that are rough estimates of the possible power per cubic inch. These numbers may give you an idea but they often just show the order of magnitude and can't be relied on for small changes. The estimate may have been made because the percentage change of the nitro went from 90% to 93%. The power goes up in a non-linear fashion, so it is hard to know exactly what this meant. I am guessing at the 90% number, but because I was there for the 93% mixture I am certain that was what was used at World of Speed. I suspect that the 5 hp per cubic inch number can vary quite a lot with the percentage of nitro, but I am not a "Pro Fuel" guy.
I would not call this a typo. I think it is just too rough to be of too much use. Alp is carrying around a bunch of fuel that would make that much HP. That doesn't mean that it is sensible to use it. Most of it goes out the exhaust making the bike run very rich. This is done to preserve the motor. The bike has run spectacularly well without any delicate tuning. The challenge now is to lean it out until the power is mind-blowing without it being engine-blowing.
Fortunately, this will take some more time, which means the bike will run again next season!
David
As a result, folks are left with general calculations that are rough estimates of the possible power per cubic inch. These numbers may give you an idea but they often just show the order of magnitude and can't be relied on for small changes. The estimate may have been made because the percentage change of the nitro went from 90% to 93%. The power goes up in a non-linear fashion, so it is hard to know exactly what this meant. I am guessing at the 90% number, but because I was there for the 93% mixture I am certain that was what was used at World of Speed. I suspect that the 5 hp per cubic inch number can vary quite a lot with the percentage of nitro, but I am not a "Pro Fuel" guy.
I would not call this a typo. I think it is just too rough to be of too much use. Alp is carrying around a bunch of fuel that would make that much HP. That doesn't mean that it is sensible to use it. Most of it goes out the exhaust making the bike run very rich. This is done to preserve the motor. The bike has run spectacularly well without any delicate tuning. The challenge now is to lean it out until the power is mind-blowing without it being engine-blowing.
Fortunately, this will take some more time, which means the bike will run again next season!
David
The only numbers that matter are on the timing sheet. The others are for bar room racing!