luckythirteen13

every one is always asking what their rpms will be like when cruzing on the freeway but my question is about the track. if i went from 2.73 to 3.73 what is the top speed in 3rd (i have an auto)? will i run out of gear at the end of the run? what is the fastest quarter mile time you can get with 3.73 (assuming you had the power)?

Djs94stang

All you need to do is to calculate it. Take your engine speed at a particular mph in 3rd gear with the 2.73's. Take that rpm number and divide it by 2.73 and then multiply it by 3.73.

Example: If you are running 4000 rpm at 90mph in 3rd with 2.73's; then you'll be running (4000/2.73*3.73) 5500 rpm with the 3.73's.

roundman

with my 3.73 gear and 26" tall slicks, I got a best speed of 100.50 in the 1/4 mile with my AOD shifting it manually at about 5,300 rpm in first and second gear and if memory serves me right, the rpm at the finish line was about 5,000 rpm or so. you don't need to worry about running out of gear at the finish line IMO.

vfast

just need to worry if you have a big enough box to put all the broken parts in....

luckythirteen13

and what broken parts are these?

djs, ive thought of that but im not looking at my tac when im at wot, im looking at the road.

roundy, that sort of sounds like your running short on gear if your at 5900 in 3rd at the end of the run

roundman

with my AOD it ain't short of gear as I only have three forward gears now, no OD.

luckythirteen13

with your 4.56's what rpm are you at, at the end of the track?

roundman

with 26" slicks I was pulling 6,200 rpm but with the new 28" slicks I cross the line at about 5,700 rpm.

91hatchgt

Roundman, what do you have done to the car to allow it to spin that high in the RPM's?

86HOGT

I believe he's still on the stock motor.