Originally Posted by chuck65
I agree, the automatic shouldn't get better milage than the stick because the stick is a direct drive system when it is cruising in 6th. gear. You can't get more efficient than that.
It has to be that the stick and automatic have different final drive ratio's. Does anyone have those numbers? It would be interesting to compare them.
The owners manual lists the stick in 6th. at 0.838 and the automatic in 5th. gear as 0.833.
I don't know what those numbers mean. I'm used to seeing rear end ratio like 4.11:1 and 3.80:1 etc. where the higher the number the higher the rpm will be at a given speed and the poorer the gas milage but it will give better acceleration performance.
What is the difference in RPM @ 60 MPH with the stick in 6th. , and @ 60MPH with the automatic in 5th? I think the automatic would be turning less RPM which would account for the higher mileage numbers.
What those ratios mean is the engine is spinning (arbitrarily) 2000RPM, in 5th gear multiply that by the trans ratio (.838) then multiply by the rear end ratio. That gives you the RPM of the differential.
With a 3.27 rear the math equates to 5480.42 RPM then take the tire size into account to find the mileage that you're traveling
Justin