How do gears affect dyno numbers?
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How do gears affect dyno numbers?
From what I understand, the higher the rear end gear ratio, the lower the #'s will be on the dyno. Is this correct, and can anyone explain why it is so? Thanks,
-Marc
-Marc
#5
It's my understanding that the HP numbers will read slightly less, but the torque will be higher. Auto cars with a higher stall tend to lose a few ponies to the rear wheels, but the torque increases due to the torque multiplication produced by the higher stall. So in essence, it would make sense that a higher numerical gear ratio increases torque multiplication to the rear wheels. As far as the a slight HP loss, I do not know the technical answer. A friend with a 2002 Z28 went from 3.42 to 3.73. He gained 10 RWTQ and lost like 3 RWHP on average.
#6
your gears (or final drive ratio) should be figured into before you do your run. if i remember right, the operator should input that into the dyno. overall though, if you dont factor in the ratio, the higher the ratio, the more torque you should read, since the mechanical advantage is "higher". anyone know for sure?
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#8
There is parasitic loss running a deeper (numerically higher) gear ratio. Typically you'll see 8-10RWHP loss going from 3.42 to 4.10 in a 10 bolt. With a swap from a 10 bolt with 3.42s to a 12 bolt with 4.10s and heavy DS you'll see slightly more.
9 inch rears are the worst due to offset pinion location. 9 inch rears are the strongest though.
To help offset the loss you can run gun drilled axles, alum gears etc. Most just live with the slight loss for greatly increased strength.
9 inch rears are the worst due to offset pinion location. 9 inch rears are the strongest though.
To help offset the loss you can run gun drilled axles, alum gears etc. Most just live with the slight loss for greatly increased strength.
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So overall, you do, lose some but it could be minor. Then again, it could be inputed into the computer when the dyno is set up, resulting in a more corrected number. Uhhh...right?
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Originally Posted by Marc '99T/A
So overall, you do, lose some but it could be minor. Then again, it could be inputed into the computer when the dyno is set up, resulting in a more corrected number. Uhhh...right?