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crank torque and horsepower???

1.2K views 13 replies 5 participants last post by  Krispy  
#1 ·
how much torque and horsepower at the crank do the 01 and 03 gsxr1000's have? and is it under rated ??
 
#3 ·
BusaGeek@work said:

Who gives a flying F%$k. Are you going to drive on your crank any time soon? What we need is the rear wheel HP of the others, not the crank HP of the gixxer. Crank HP is a number that marketing people really like, that's why you see it in pre-release materials before a bike comes out.
i must give a f#%k or i wouldn't be asking? i already know rear wheel hp. in the future donkey if you don't know the answer don't bother to reply!!!! nice screen name geek!!!!
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i hate people that reply with smart a$$ answers.............
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#7 ·
Not that I want to get in the middle of this pissing match, but crank HP could be needed to determine drive train % loss.

Or to simply compare the R1 HP #'s to Suzuki #'s. But then again we'd need to pressurize the air box as well.

I still think Yamaha is attempting to blow smoke up a lot of girls dress'.

I personally would like to know fi there is any HP difference from going from a 530 chain to a 520 chain. Is there a rotational mass calculation for using less unspring weight (ie chain conversion or aftermarket wheels) Or does this not have any effect on the HP #?


Krispy
 
#8 ·
Krispy said:

I personally would like to know fi there is any HP difference from going from a 530 chain to a 520 chain. Is there a rotational mass calculation for using less unspring weight (ie chain conversion or aftermarket wheels) Or does this not have any effect on the HP #?
it depends on how you measure the horsepower. on an inertia dyno where power is calculated from acceleration, things like rotating mass matter. on an eddy current brake dyno where the measurement is done under a constant load, it doesn't matter.

if you had two bikes that were identical except that one had wheels that weighed 200 pounds each, the bike with the heavy wheels would show less horsepower on an inertia dyno than the other bike. but on an eddy current dyno, both bikes would dyno the same.
 
#9 ·
Exactly the info I was looking for.

So, I guess my next question is, does a good dyno operator include this info, or not? Does he have access to proper adjustments factors (ie:HP# X 0.95 for a 520 conversion, or HP# X 0.91 for aftermarket wheels) to accurately measure HP for a heavily modded bike on an inertia dyno.

Thanks
Krispy
P.s. sorry for the thread hijack. (don't want to be called a Dick pussy ass moron)

:p
 
#10 ·
Krispy said:
So, I guess my next question is, does a good dyno operator include this info, or not? Does he have access to proper adjustments factors (ie:HP# X 0.95 for a 520 conversion, or HP# X 0.91 for aftermarket wheels) to accurately measure HP for a heavily modded bike on an inertia dyno.
well, one could say that you don't need such a correction, because the change in horsepower readings is a quantitative measure of how changes to rotating mass affect acceleration, and this is also reflected in the real world.

that bike with the 200 pound wheels accelerates the inertia dyno's drum slower than the bike with regular wheels. this carries over in the real world - that bike with the heavy wheels would accelerate much slower, not just because the bike weighs much more, but also because of that additional rotating mass. even if you could get the two bike weights exactly the same by removing mass from somewhere else other than the drivetrain, the bike with the 200 pound wheels would still accelerate slower.

on the other hand, if you listen to factory pro's propaganda, they like to blast dynojet dynos for exactly the same reasons. they claim that dynojet dynos don't measure 'true' horsepower the way their own eddy current brake dynos do.
 
#11 ·
I'm pretty sure FactoryPro dynos have a process for doing a load controlled run and several inertial (or partially loaded) runs to determine the inertia of the rotating mass and deal with it.

A heavier chain doesn't really take away horsepower. The HP is there, but it is being used to spin the chain instead of propel the bike. If you add 50 pounds to the frame, does the bike have less horsepower? It goes the same for a heavier chain. To complicate matters, the weight of the chain has more of an effect in higher gears and/or with larger front sprockets.



P.S. ........
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