at 3000rpm, in 5th gear, my speedometer says 71mph.

this is a painfully stock '84 GSL-SE.

the car does *feel* slower than what the speedo says, but i'm not sure how much.

i guess my question is, how fast should my car be going at 3k in 5th?

 

Your speedo only tells you how fast your driveshaft is going, so unless you've changed gears in the tranny, the speedo and tach read just like it left Mazda. If you're going a different speed, it's most likely your rolling diameter that's different on your wheels - less likely your rearend has been changed.

 

use a stopwatch and time the mile markers or a measured mile.

 

That sounds about right. Unless you've got undersize tires, 71mph is what you'll get from 3000rpm in 5th. (GSL-SE) That's what I see on mine, also stock.

 

hmm. i did 60 in *just under* 3k in my '83. it just feels slower than what it says. when i get on the freeway, i do about "80" just to keep up w/ traffic.

i guess this weeeknd, i'll just have a friend pace me.

 

The speedometor gets the signal from the driveshaft, and so does the odometer, right? So get on the highway and see if one mile from the odometer matches one mile between two mile marks.

 

I have a stock '84 GSL-SE.

At 60 mph in 5th, my tach reads just under 3000 rpm.
I wish it read that at 70 mph!

 

BTW, SE has a different ratio on the 5th gear than non-SE.