gear help...4.30s or 4.56s
Im torn between which gears to get either the 4.30s or the 4.56s
I recently went to the track and my setup right now is 12 bolt w/ 4.10s and 28" DR
spinning 1.67s and going 10.9s @ 128.8 going through the traps at 6300
my car peaks at 6k and holds power to 6800 when we stopped the dyno pull
on the mustang dyno it did 465/415
race weight is 3190 w/ me in the car
hooking and in good weather i feel the car will be trapping in the 131 range
thanks
brandon
edit
on 28" 275DR and 4.56s Ive been 130s I didn't notice the shiftlight (under 7) so should be perfect. I'd guess its about 200 rpms more with no growth then 3055S ETdrags normally do
Last edited by studderin; May 18, 2013 at 10:04 AM.
the 12 bolt has been very good to me multiple 1.49s and low 1.5s back when i had the old suspension, still trying to dial in new sus and get seat time w/ new engine setup as well
Your peak is 6,000, how many rpm above peak are wanting to run?
On of my current mentors told me to run 200 to 300 rpm over peak.
http://dragracingonline.com/raceresu...irebird-5.html
A rule of thumb that was told to me was: For every 20 teeth added or subtracted, you gain or loose 250 to 300 rpm.
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I know they are available for a 9", because I am dialing in my car. Currently I have 4.22, 4.30, 4.33, 4.40, and 4.44
My peak is 5800 and I am wanting 6000 to 6100.
4.22 would be my suggestion.
Last edited by Heyfred; May 18, 2013 at 12:20 PM. Reason: My screw up
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The improvement from 4.10s to 4.56s is getting the car moving, big help in the short times then down track. The cars only traveling what, 0-40mph is 1st gear. thats not getting down the track quickly with the timer counting away. tim tosto said a few years ago, how the t56 gearing is not great for drag racing, get the car out of 1st gear as fast as you can. I keep finding how true that is, the more I, and talk to others that race a t56. The far side of this would be run some crazy rear end gears so the car 60' better with the stock t56 gears, and buzz the motor more. A clutch/suspension tech guy will like that, but the valvetrain/engine guy will not.
Big example ALL the fast mustang NMRA/NMCA dont run a t56 (in t56 cars) and run a weaker t5. Not only because its a lot smaller and lighter, but the ratios. One of the reasons they run some much faster at the same weight and power as we do. single disc clutch, on 26' slicks 1.35 60 is bad.
But sorry OP I don't have any info to help. Hope it gets all figured out, but a side note those are damn good numbers to a slow guy like me haha (12.9 @109)



