News of Chris Carr's record busting last week (367.382mph) caused me to wonder just how far this art can be refined. One of the biggest restricting factors in the battle for two wheeled LSR domination is the very tight space the power unit has to fit in - 28x18 inches by the rules. Power is what's needed, if you reckon on power requirements climbing at the cube of the speed increase sought you won't be far off. So for a 10% increase in speed we need a 33% (1.1 cubed = 1.33) increase in power - this rather crude formula assumes "all other things remaining equal", well of course they don't, developing more power will no doubt require a heavier motor, stronger frame etc etc and a few too many pancakes for breakfast could ruin things. In '56 a streamliner 650 managed a staggering 214mph with an estimated 80bhp on tap (another dirt track rider). Chris's speed last week is near as damn it 71.53% faster than Johnny Allen's 214.17mph - so: 1.7153 cubed X 80 bhp = 403.75 bhp. BUB racing have managed to get 500 horsepower out of this tiny compartment. It is considered desirable to run a "big bang" motor and take advantage of the power pulses, I guess traction is a massive issue given the single tyre footprint and the loose surface. I couldn't resist the photos (robbed from BUB Racing's website). 3000cc, turbocharged, four cam, 16 valve, methanol-gulping V4 producing 500bhp @ 8500rpm - AND - 400ft/lb of torque !
Some how the tidy shot of the component parts makes the engineering look very clinical and lifeless in contrast to the shot of the beast assembled and plumbed in - imagine the racket. MORE SALT !
News of Chris Carr's record busting last week (367.382mph) caused me to wonder just how far this art can be refined. One of the biggest restricting factors in the battle for two wheeled LSR domination is the very tight space the power unit has to fit in - 28x18 inches by the rules. Power is what's needed, if you reckon on power requirements climbing at the cube of the speed increase sought you won't be far off. So for a 10% increase in speed we need a 33% (1.1 cubed = 1.33) increase in power - this rather crude formula assumes "all other things remaining equal", well of course they don't, developing more power will no doubt require a heavier motor, stronger frame etc etc and a few too many pancakes for breakfast could ruin things. In '56 a streamliner 650 managed a staggering 214mph with an estimated 80bhp on tap (another dirt track rider). Chris's speed last week is near as damn it 71.53% faster than Johnny Allen's 214.17mph - so: 1.7153 cubed X 80 bhp = 403.75 bhp. BUB racing have managed to get 500 horsepower out of this tiny compartment. It is considered desirable to run a "big bang" motor and take advantage of the power pulses, I guess traction is a massive issue given the single tyre footprint and the loose surface. I couldn't resist the photos (robbed from BUB Racing's website). 3000cc, turbocharged, four cam, 16 valve, methanol-gulping V4 producing 500bhp @ 8500rpm - AND - 400ft/lb of torque ! 
Some how the tidy shot of the component parts makes the engineering look very clinical and lifeless in contrast to the shot of the beast assembled and plumbed in - imagine the racket. MORE SALT !
3 comments:
I didn't know they used Rolls Royce radiators grilles.
Don't think I could cope with 500 bhp so close to the old tackle myself. One thrown rod and that's your lot of a Saturday night.
Great post Diplo. I've always wanted to go to Bonneville. From down here in Sussex we have John Renwick attempting to take the sidecar LSR with a Vincent powered outfit (failed) and a few years ago Jim Tiller took his antedeluvian Allard over for some very quick runs. Vincent-wise, Max Lambky an American keeps trying year after year with his twin engined streamliner which is a frightening device but is always plagued with mechanical problems.
Thanks too for your extremely easy-to-understand rules of going faster - excellent!
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