dirtydeedsinc

Since I've seen more posts on them, I'm thinking of getting 4.10s again instead of 3.73s. For those of yall that have them, do you have any problems or delays getting it up to 140 MPH or so? A lot of the racing I've done lately has been on open highways with no traffic and sometimes I only start to pull away when I hit 100. Plus my wife likes it when I take it up that fast. I have seen that the theoretical top speed at 6250 RPM is around 160 or so.

Timmay!!!

I still have yet to max out my car but she pulls strongly through 120-130.

moosestang

I'm more interested in what my rpms will be at 75mph in 5th gear. What's the calculation to figure that out again? I'd like to know with the stock 27.2 inch tire diameter and 28 inch because I might go with a 28 in the rear.

dirtydeedsinc

I found a spreadsheet someone did on here a while back that gives all that info and more. I keep a copy on my USB drive if you want it.

The formula for RPM is ((Speed * 1056)/Tire circumference)*Rear ratio*Trans gear ratio

With a manual, it's about 2588 @ 75MPH, auto 2854 @ 75MPH.

dseid2

Check out the gear ration calculatorat
http://www.et-studios.com/motorsports/gears/gears.html
Plug in your tranny ratios, rear end ratio, engine red lineand tire diameter and it calculates rpms and speed for each gear in increments of 1000 rpm's

The ratios for a 5sp manual are 3.37, 1.99, 1.33, 1.00, .68. I think the overdrive on the auto is .72 (saw it somewhere). The stock tires on my car are 238/50/18's which equates to a tire diameter of 27.25, redline is 6000 rpm's and I am running a set of FRPP 4.10's. at 80 mph I'mturning about 2750 rpm's, at a hypothetical 145 I would be turning 5000 rpm's

northy_polk

i looked at the calculator. i've got 20s with 265/35s so that puts me at about 27.3 inches in diameter. . . but wheres fifth gear on the chart? it's missing, right? that's what i was interested in [mostly]. thanks for that calculator though!

GT Bob

Just skip 4th gear and put 5th gears ratio into its spot.

dseid2

Or plug 2ond through 5th in.