A little disapointed
#12
05-18-2009, 11:52 AM
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#13
05-18-2009, 12:18 PM
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Gearing will not change rwhp measured on a dyno (much). It will change the torque. The difference in HP probably comes from error. It will change the profile of the delivered HP, so the peak will come at a different rpm but will be very close to the same. A dyno is just measuring the amount of work done in a certain amount of time. The correlation between torque is non-linear so changes in torque will not necessarily change HP. I attached an example. It's a hellish gear change but notice what changes.
#14
05-18-2009, 12:46 PM
Where did it come from? That graph is either flat out wrong or incredibly misleading. If you have a 55% gain in torque then the only way you don't have a 55% gain in HP (which isn't on the graph) is to dramatically change the RPMs. The use of estimated speed instead of RPM makes it irrelevent.
#15
05-18-2009, 01:02 PM
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I realize I'm a noob here, new to bikes but I think I understand horsepower.
If you're messing with your gear ratio then you absolutely will affect your dyno. I don't see how you couldn't.
Ironically the first reply guy who doesn't make much sense had a point. Your torque number shouldn't change but going down a tooth should change your horsepower.
Horsepower is nothing but a fancy way of multiplying torque and engine speed. You went down a gear, and essentially moved your torque curve to the left. That has to move your horsepower to the left as well which is going to have an adverse affect on your peak number in a high reving 4 cylinder.
Posting both dyno numbers or a graph would help.
If you're messing with your gear ratio then you absolutely will affect your dyno. I don't see how you couldn't.
Ironically the first reply guy who doesn't make much sense had a point. Your torque number shouldn't change but going down a tooth should change your horsepower.
Horsepower is nothing but a fancy way of multiplying torque and engine speed. You went down a gear, and essentially moved your torque curve to the left. That has to move your horsepower to the left as well which is going to have an adverse affect on your peak number in a high reving 4 cylinder.
Posting both dyno numbers or a graph would help.
And +1 on the dyno being the biggest factor of this equasion. There's a couple local dynos near me that range in peak HP by 5-10%.
#16
05-18-2009, 01:30 PM
#17
05-18-2009, 02:30 PM
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Gearing will not change rwhp measured on a dyno (much). It will change the torque. The difference in HP probably comes from error. It will change the profile of the delivered HP, so the peak will come at a different rpm but will be very close to the same. A dyno is just measuring the amount of work done in a certain amount of time. The correlation between torque is non-linear so changes in torque will not necessarily change HP. I attached an example. It's a hellish gear change but notice what changes.
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