2003-04 Mach 1 Registry Owners Club - View Single Post

GaPonyFarm · 01-07-2005, 01:51 PM

All of the above answers are excellant and provided the information that was asked for. There is also another explanation that is easier to wrap you head around. Our drivetrains are geared in such a way that the driveline is in a 1:1 ratio in 4th (manual) or 3rd (auto) and thats the numbers the dyno uses to do its math. When you change the gears from 3.55 to 4.10 (or 3.90, 4.30, etc.) you are unable to get to that 1:1 ratio... thus the "discount" of horsepower. The lower the gear (numerically higher) the greater the loss of horsepower... according to the dyno.

Some, not all, dyno packages are able to compensate for the gear change, but the operator won't know to make changes unless the owner of the car provides that information.

Just remember the dyno numbers in and of themselves don't mean anything. They are only valuable in that they, first, provide a baseline number that is used to measure relative gains/losses achieved by making modifications to the car.

The only accurate measurement of horsepower is by going to the track and running the 1/4 mile. By having the racing weight, ET, and mph, you can compute the REAL horsepower.

01-07-2005, 01:51 PM	#14
GaPonyFarm Loose Nut Behind Wheel Join Date: Oct 2003 Location: Columbus, Georgia Posts: 2,259	Re: Do gears affect Dyno Numbers? All of the above answers are excellant and provided the information that was asked for. There is also another explanation that is easier to wrap you head around. Our drivetrains are geared in such a way that the driveline is in a 1:1 ratio in 4th (manual) or 3rd (auto) and thats the numbers the dyno uses to do its math. When you change the gears from 3.55 to 4.10 (or 3.90, 4.30, etc.) you are unable to get to that 1:1 ratio... thus the "discount" of horsepower. The lower the gear (numerically higher) the greater the loss of horsepower... according to the dyno. Some, not all, dyno packages are able to compensate for the gear change, but the operator won't know to make changes unless the owner of the car provides that information. Just remember the dyno numbers in and of themselves don't mean anything. They are only valuable in that they, first, provide a baseline number that is used to measure relative gains/losses achieved by making modifications to the car. The only accurate measurement of horsepower is by going to the track and running the 1/4 mile. By having the racing weight, ET, and mph, you can compute the REAL horsepower.