bcstang

hey guys, i tried using the search to find some threads on gears but my search keeps freezin up on me, so ill just ask a question that im sure has been asked before. i have an 05 gt, and im putting 20" foose nitrous' on it and i know im gonna have to get gears to keep some pull in my ride. i want to find out what rpms ppl out there with similar setups are at when on the freeway,maybe 60 to 70 mph?preferably with 3.73's and 4.10's, but if someone out there has the 4.30's thats cool too, thanks.

99flhr

Determine what ratio you currently have, lets say 3.55, the difference to 4.10 is 15.5%. Observe your tach at 70, increase that reading by 15.5% and thats what you`ll have with 4.10`s @ 70
Difference between 3.23 and 4.30 is 33%, you get the idea.

Earlier post showed all revs at various speeds in all the gears, auto & stick. Can`t find it, as search is pretty lame. This will give you the starting point to make your hypothetical calculations

grampa_stang

I'll attach a spreadsheet where you plug in the tire size295/35/20 or whatever and you also
plug in the gear ratio. It's setup for autos and manuals. Just save the fileand rename it to a .xls
I'll throw in the other spreadsheet too. These are both courtesy of other forum members.
Do the same thing...save as a .xls

PROMETHEUS PRIME

At 80 with 4.10's and 20's I'm right around 2900 rpms

onederful100

i got stock rims 17", 4.10's and at 70 in 5th i'm at 2500 rpm's.

99flhr

Great spreadsheets! Thanks Grampa Stang!

grampa_stang

No prob. They're kind of fun to play around withthe different tire sizes
and gears.

bcstang

thx for the help guys. 2900 with 20's and 4.10s sounds fine to me, i just didnt want to lose all of my gas mileage for road trips in the summer time, looks like ill be pickin up some 4.10's

Thurman

90mph 18" wheels 3000 rpm's 4.10's

RED121572

2400 rpms @ 60mph. 3.73's. 18" Wheels.