Dyno and Sprockets
- Thread starter brad
- Start date
Johnnycheese
Registered
nope they would be different if done in same gear
JC...hey man hope everything is going well for ya....anyhow, can you give me some info.(Johnnycheese @ Sep. 28 2006,21:20)nope they would be different if done in same gear
Would I show a higher or lower HP/ Torque reading running a 17/42 setup, compared to stock 17/40? And depending on what gear, what sorta difference are we talking 1 or 2 HP? Given its the exact same weather conditions, air presure, etc...just a sprocket change.
Johnnycheese
Registered
I run bikes with 17/40 or 41 in 4th
anything lower in 5th
16-45 in 6th
for your setup anywhere from 2-4 hp differance (lower) but your torque would be alot lower
anything lower in 5th
16-45 in 6th
for your setup anywhere from 2-4 hp differance (lower) but your torque would be alot lower
reaper0995
Registered
it would be the same HP, but not the same torque. yeo, so most have seen the HP=(torque x rpms)/5252, and what this means for the gearing is that the gears will change the torque the dyno reads as well as the rpms it reads it at, and the two will be 'cancelled' per-say, and the results will be the same. NO dyno really reads the hp you make. it reads the torque you make and then the rpm it makes it at. then it computes it to get th end result of hp.
you see, you can have ANY amount of torque = any other amount of torque. also is true with any hp...you can have any hp equal to whatever torque you want, the catch is the rate at which that torque is aliviated at. so, if you have 1hp, and are reducing the gears significantly, you could make 10,000 ft pds of torque!! BUT, that would be at .5 rpms. see?
(.5rpms x 10,000)/5252 is about 1 hp. so, i would say that torque is actually an arbitrary number, and hp to be the actual useful number. torque is only useful in finding hp, or finding where your most efficient hp is made at. otherwise, the hp is what matters. though many may disagree, i would venture to say they DO agree, but not in the specific way i may have said it....at least for th ecommon man. and now i am rambling and you get the point.
you see, you can have ANY amount of torque = any other amount of torque. also is true with any hp...you can have any hp equal to whatever torque you want, the catch is the rate at which that torque is aliviated at. so, if you have 1hp, and are reducing the gears significantly, you could make 10,000 ft pds of torque!! BUT, that would be at .5 rpms. see?
(.5rpms x 10,000)/5252 is about 1 hp. so, i would say that torque is actually an arbitrary number, and hp to be the actual useful number. torque is only useful in finding hp, or finding where your most efficient hp is made at. otherwise, the hp is what matters. though many may disagree, i would venture to say they DO agree, but not in the specific way i may have said it....at least for th ecommon man. and now i am rambling and you get the point.
reaper0995
Registered
oh yeah, and any hp CANNOT equal any other hp. torque can by messing wit the lever arm. as it was said before:
"with a level long enough, I could lift the world"
BAM!! torque at work there
"with a level long enough, I could lift the world"
BAM!! torque at work there
Johnnycheese
Registered
HP does change on a dyno
and it doesn't matter what you think due to I have proved it in the real world
and it doesn't matter what you think due to I have proved it in the real world
Isn't HP based on the engine? I thought changing the sprocket would simply "slide" the dyno chart a bit. Kinda like a bike peaking at 10,000 rpm might peak at 11,000 rpm with shorter gearing, but the actual HP output would be the same.
I'm assuming this because Sport Rider went -1 in the rear of a Busa and acquired a lower ... yes LOWER ... top speed than with the stock rear sprocket. 4 MPH slower. Reason being since the Busa peaks at roughly 10,250, adding a taller gear "slid" the chart so it then peaked sooner. Doing so placed the Busa on the downside of the peak at the top RPMs and it wasn't able to benefit from it. In their words:
Because it revs just past its power peak in sixth gear at 190 mph (10,250 rpm), adding gearing drops revs off the downside of the horsepower curve, and the Hayabusa can't cope with the lowered rpm.
CLICK ME AND READ THE SECTION TITLED TOP SPEED
So how much does gearing affect HP and torque? Is it a formula like ~X +/- in the rear will cost you X +/- HP~?
I'm assuming this because Sport Rider went -1 in the rear of a Busa and acquired a lower ... yes LOWER ... top speed than with the stock rear sprocket. 4 MPH slower. Reason being since the Busa peaks at roughly 10,250, adding a taller gear "slid" the chart so it then peaked sooner. Doing so placed the Busa on the downside of the peak at the top RPMs and it wasn't able to benefit from it. In their words:
Because it revs just past its power peak in sixth gear at 190 mph (10,250 rpm), adding gearing drops revs off the downside of the horsepower curve, and the Hayabusa can't cope with the lowered rpm.
CLICK ME AND READ THE SECTION TITLED TOP SPEED
So how much does gearing affect HP and torque? Is it a formula like ~X +/- in the rear will cost you X +/- HP~?
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