Norton racing at Mid-Ohio

Ok, so since hp is torque X revs, & the tuned length inlet boosts torque [anyone recall those Mopar dualquad ram inlets?] what revs do you get that 70 odd hp figure from?

Torque =(hpx5252)÷rpm, not hp x rpm. If torque equalled hp x rpm then an engine that made 100 hp at 10,000 rpm would have twice the torque of an engine that made 100 hp at 5000 rpm. Its the other way round.
For a long long time I did not understand torque. I read some very long and complicated explanations of how torque is dffers from hp. Finally I saw the simple equation for torque and saw that is is just a function of hp and rpm. To have a high torque engine, make a lot of horsepower without having to go to a high rpm, like a Norton or a Vincent, not like a Honda, at least the ones I have owned!



Wow, I had no idea that my Commando would only dyno around 35 hp at the rear wheel, though I have heard that the dyno numbers are pretty low for a stocker.
When Phil Irving was asked why the Vincent twin feels so powerful with only 55 hp (Black Shadow) he replied that this is a BHP listing for actual Brake Horsepower whereas some of the numbers given out by other manufacturers such as Honda, represented "Brochure Horsepower"
It is also because the Vincent engine develops a lot of torque, or put another way, has good horsepower at a low rpm number.

Glen

Should not the color of the bike be baby blue? :wink:

Good Luck

Team FASTLIKEJUDY

Torque is force, & revs are the time factor as conversion to shaft horsepower;
http://kawtriple.com/mraxl/articles/197 ... bikes2.htm
I note this Commando [2S Combat?] did better than ~ 35 R.W.H.P.

My apologies , I read your initial post incorrectly, then provided an equation that was in violent agreement but positioned the other way round!

Glen

Thanks, Glen, - a case of the dreaded 180 degree reciprocal course..

Your Mid-Ohio report; Got two 1st places in EA Twins and two second places in GP750 to Ryan Ambrose on the dreaded Big D Cycles Triumph out of Texas. The Norton went well, only a few minor issues, had to weld up a cracked pipe Sunday morning, scrounge up a broken shift lever bolt Saturday and repair a broken throttle cable spacer Friday; the usual fussing around. Turnout for the weekend was a little light but the weather was great. Kenny didn't make it out but I will be seeing him this weekend at this vintage race documentary filming which is being done at a race track up here in Canada called Calabogie. Should be some interesting bikes there including Jamie Waters exact Monocoque Norton racer replica- it will be fun to see that out on the race track. Race video from Mid-Ohio to come soon...

Well done ! Must be a really good Triumph if it can beat a Norton. I raced a 500cc Featherbed Triumph for 12 years in the late sixties early seventies. It was a 650 motor with a billet crank of 63mm stroke. I only ever persevered with it because it was so strong in the bottom end. It still had the long rods, and the barrels were shortened 12mm. It was a nasty piece of shit. I used a CR box with a high first gear. On the tight corners on most circuits you couldn't ride fast enough to keep it in the power band. If it dropped out the bottom, and you slipped the clutch, the bike would immediately snap sideways. I put a two into one exhaust on it, dropped 1500 revs off the top - only revved to 9000rpm, and finally got decent lap times after getting a bit more torque. It was a really strange bike. I rode it at Phillip Island a couple of times, and on the big circuit, it would just keep going faster - it was all top end power.

From the gospel according to Irving ['Tuning for speed' 1965 P.173];
'The distance from valve seats to the outer end of the air-intake valve of the carburetter has a large influence on this [volumetric efficiency], & on most racing machines is of the order, 10-13 inches'