Rear end gears on a dyno?
10-08-2007, 09:55 PM
#1
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Rear end gears on a dyno? Hi guys, I was just wondering if a rear end gear would change any results on a dyno? I'm changing from a 2.42 to a 3.73 and I'm going to document all the changes I make but not sure if I would need to make a "before" pull or not.
Thanks
Brian
Thanks
Brian
10-12-2007, 11:24 AM
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technically gear ratio does not affect HP. dyno's without proper inertia compensation will tend to be either high or low with a change in gear ratio.
the only change in hp will be due to the small drivetrain power loss or gain due to the pressure of one gear against the next and rpm.
with my DYNOmite which has the best inertia comp in the industry, i would typically make pulls in 3rd gear with an NA car and if the customer went from 2.42 to 3.75 i'd most likely jump up to 4th since the applied torque to the roll will be much higher and i wouldn't want tire slippage to affect the accuracy.
the only change in hp will be due to the small drivetrain power loss or gain due to the pressure of one gear against the next and rpm.
with my DYNOmite which has the best inertia comp in the industry, i would typically make pulls in 3rd gear with an NA car and if the customer went from 2.42 to 3.75 i'd most likely jump up to 4th since the applied torque to the roll will be much higher and i wouldn't want tire slippage to affect the accuracy.
10-12-2007, 01:54 PM
#5
gears will not affect the power that your motor makes, but rather the power lost through the drivetrain until it hits the wheels. as for 10hp, not sure about that but its not like it will make you slower just numbers will be lower with faster speeds
