Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB - View Single Post - Official BRZ MPG Numbers. Big Gear Ratio Differences?

aLiskov · 03-16-2012, 01:56 PM

I agree with you 100%, but manual or automatic, gear ratios is what dictates how the power is being put to the wheels. You can have a v6 300hp engine, behave like a 400hp V8, with the right kind of gearing. The engine isn't designed for that kind of behavior, but you can do it.

Typically you get the "gear ratio" of the car, by multiplying transmition gear ratio by final drive ratio(diff ratio). That is then used to calculate how much torque is being applied to each wheel.(Fast Car Physics)

And that was the point I was trying to drive, given that the final ratio is exactly the same(unless they use a different configuration of a Torsen, which wouldn't make any business sense), there must be a big difference in the transmission ratio.

Once the car is the last gear, at the same rpm's, the only difference between an auto and a manual is that gear ratio. Otherwise, you would get the same exact mpg.

03-16-2012, 01:56 PM	#3
aLiskov Junior Member Join Date: Mar 2012 Drives: Scion FR-S Location: United States Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Agreed but... I agree with you 100%, but manual or automatic, gear ratios is what dictates how the power is being put to the wheels. You can have a v6 300hp engine, behave like a 400hp V8, with the right kind of gearing. The engine isn't designed for that kind of behavior, but you can do it. Typically you get the "gear ratio" of the car, by multiplying transmition gear ratio by final drive ratio(diff ratio). That is then used to calculate how much torque is being applied to each wheel.(Fast Car Physics) And that was the point I was trying to drive, given that the final ratio is exactly the same(unless they use a different configuration of a Torsen, which wouldn't make any business sense), there must be a big difference in the transmission ratio. Once the car is the last gear, at the same rpm's, the only difference between an auto and a manual is that gear ratio. Otherwise, you would get the same exact mpg.