View Full Version : What's a good gear size?


hotrodth
06-25-2012, 03:29 PM
Running 233/239 cam stage 2.5 5.3 heads. Currently have 3.73s this is with t56 and 27" tire. Wondering if a 4.56 is too much?

Bob@BruteSpeed
06-26-2012, 06:09 AM
You need to figure out what rpm you want to be going through the traps at. Bob

hotrodth
06-26-2012, 07:19 AM
Not sure. I know with the 3.73 I am hitting 6k in 3rd about 20-30 yards before finish line. No time to hit 4th to make a diff. I'm hitting 100mph in 3rd at 6000. My limited has been raised to 6800 since cam install

hotrodth
06-26-2012, 07:20 AM
My 60 ft SUX at a 2.2

hotrodth
06-26-2012, 07:23 AM
Also cruising on highway in 6th at 70-75 My rpm is at 1700.

Ethan[ws6]
06-26-2012, 09:43 AM
I have 4.56's with a tire that is ~25.66" and 4th gear maxes out right around 115mph for me. With the taller tire you would get some more MPH to play with than that. Do you daily drive the car?

hotrodth
06-26-2012, 09:55 AM
No not a dd but its my only vehicle.I drive company truck every day. I don't want to lose all my top end. But I only have like two choices for a Toyota 8.4" rear. 4.10s or 4.56. Id like some 4.30s but can't find any.

Ethan[ws6]
06-27-2012, 09:05 AM
You won't lose any top end really. Even with a 4.56 6th gear would be good for over 200mph, assuming you had enough power to hit that mark.

When setting up gearing, you want to look at your trap speed. You want to try and make it so that as you are crossing the finish line you are just passing peak power in your 1:1 gear. So, if power is starting to fall off at 6500 (just for example), you would want to set gearing so that you are crossing the line at ~6600 in 4th gear. That will be the absolute best setup for track use.

L84ARACE
06-27-2012, 11:07 PM
I have 4.56's and love em ! 65 mph @ 2000 rpms

hotrodth
06-28-2012, 04:38 AM
I have 4.56's and love em ! 65 mph @ 2000 rpms

What tire size?

Ethan[ws6]
06-28-2012, 06:46 AM
He's probably running around the same tire size I am. My 65MPH is right around that RPM as well. I'm running a ~25.66 tall tire. 275/40/17

hotrodth
06-28-2012, 07:07 AM
This is in 6th correct

Ethan[ws6]
07-01-2012, 01:25 AM
Yes..