impreza_GC8
06-16-2009, 09:26 AM
To make a long story short. My 5MT 4.11 Outback turns higher RPM on the highway than my 5MT 4.11 2.5RS does. Any of you who are familiar with my Outback know that it is a hodgepodge of parts. For his reason I thought that the car had been changed over to a 4.44 drivetrain, which would explain the higher RPM. I finally got a chance, with a little research help from some fellow STLsubaru members to run the transmission code on my car.
I learned something very interesting. The trans code was TY752VACCA. I checked the number on a chart supplied in this thread but also available on North Ursalia's website: http://www.stlsubaru.com/forums/showthread.php?t=12986
It came back as a 1997 Legacy Outback 5MT 4.11 transmission w/ open rear diff. I compared it to my 2.5RS transmission and found that the ratios were identical for 1-2-3-4 gears but the 1997 Outback had a 5th gear ratio of 0.871 and the 2.5RS has a 5th gear ratio of 0.780. Couple that 5th gear ratio with the WRX wheels and tires (shorter diameter than the 70 series tires Outbacks normally come with and that explains why I'm turning such high rpm in 5th on the highway.
So basically, 5MT Outbacks have a more aggressive 5th gear than any other USDM 5MT which explains why my car pulls just as hard in 5th (if not harder) than it does in 4th and why I turn 3k RPM at 65mph. I'd rather have the longer gear of the 2.5RS so that my already thirsty car didn't guzzle as much gas on roadtrips.
Anyway, interesting tidbit for you. If any of you roadracers are looking for a more aggressive 5th, just swap over to a crusty old Outback 5th gear.
I learned something very interesting. The trans code was TY752VACCA. I checked the number on a chart supplied in this thread but also available on North Ursalia's website: http://www.stlsubaru.com/forums/showthread.php?t=12986
It came back as a 1997 Legacy Outback 5MT 4.11 transmission w/ open rear diff. I compared it to my 2.5RS transmission and found that the ratios were identical for 1-2-3-4 gears but the 1997 Outback had a 5th gear ratio of 0.871 and the 2.5RS has a 5th gear ratio of 0.780. Couple that 5th gear ratio with the WRX wheels and tires (shorter diameter than the 70 series tires Outbacks normally come with and that explains why I'm turning such high rpm in 5th on the highway.
So basically, 5MT Outbacks have a more aggressive 5th gear than any other USDM 5MT which explains why my car pulls just as hard in 5th (if not harder) than it does in 4th and why I turn 3k RPM at 65mph. I'd rather have the longer gear of the 2.5RS so that my already thirsty car didn't guzzle as much gas on roadtrips.
Anyway, interesting tidbit for you. If any of you roadracers are looking for a more aggressive 5th, just swap over to a crusty old Outback 5th gear.