Can someone help me out? My speedometer is broken and I am participating in a track event as a novice which limits me to 95 MPH. I'm on 205/60R/13 tires. The drivetrain is an 83 GSL tranny and diff. So can someone either do the math for me (or tell me how to figure it out with tire diameter, final drive, and RPM), or someone with the same tire size go out on the highway and tell me what RPM in 5th 95 MPH is? I don't want to get in trouble at the track.

 

All I can say is at 82mph I am doing 4000. Car is out of gas or else I would do it for ya.

 

Thanks Stu, this is for the PDX at ZF haha. That does help though.

 

Third gear: 7879 RPM
Fourth gear: 5502 RPM
Fifth gear: 4539 RPM

This is assuming the gear ratio charts on Mazdatrix are accurate (there are two diff ratios listed for '83; I used 3.909).

 

Sorry to make you do that work, and thanks PercentSevenC, but I just installed a 2nd gen cable I had laying around (I assumed it wouldn't work cause the car has 236K miles and I figured the original tranny wasn't spinning the cable, but it works! IT bounces a little bit give or take 3MPH, but it's probably enough to drive the track.