PDA

View Full Version : what ratio to run with a T56?



scogin918
01-07-2005, 09:47 AM
i am ordering a floating 9" from www.musclemotorsports.com and i need to figure out what ratio would work best with a t56 tranny, 17" wheels, and between 500-600 hp. ANY SUGGESTIONS?

Matt
01-07-2005, 09:58 AM
what are you going to use it for?

Even with 4.10 you should still be below 2100 rpms in 6th at 80.

scogin918
01-07-2005, 10:07 AM
Some street, some road course, some ECTA events. Having a Nascar rear end i could buy different third members, but i want to start out with a good overall ratio.

Matt
01-07-2005, 10:16 AM
Personally I'd say 4.10, I don't know how tight your engine powerband is.

try this out
http://www.xse.com/leres/bin/gearratio?title=2000+F-Body+with+MM6+manual+and+4.10+gears&rpm=6000&mph=80&gear1=2.66&gear2=1.78&gear3=1.30&gear4=1.00&gear5=0.75&gear6=0.50&reverse=2.90&axle=4.10&tire=diameter&diameter=25.75&circumference=80.90

MuscleRodz
01-07-2005, 10:52 AM
You need to also consider tire diameter as well. If you are running 26" tires I would go 3.73. If you have a 28" tire I would consider 4.10. A good compromise would be a 3.90. Another consideration is what 6th gear ratio you have. Please be more specific so we can give a more specific answer.

Mike

scogin918
01-07-2005, 02:15 PM
27" tire with stock 6th gear ratio(.56). i like the 3.90 idea.

USAZR1
01-07-2005, 02:17 PM
Some street, some road course, some ECTA events. Having a Nascar rear end i could buy different third members, but i want to start out with a good overall ratio.

Gear the car like you would a five speed. You will never use sixth gear on the track.

ballistic69
01-07-2005, 06:17 PM
27" tire with stock 6th gear ratio(.56). i like the 3.90 idea.

Her was my thought process on gear selection:

Based on your cars weight and hp use a calculator to determine your trap speed in the quarter mile with the calculator. Select the rear end ratio that will put you in the trap speed range at the top of 4th gear at max rpm. Your 5 th gear will be for top speed and 6th for fuel economy (highway crusin). Base on 6500 rpm, 27" tire and 3200 lbs your trap speed is about 138 mph, there for a 3.73 ratio is what you should consider.

http://www.geocities.com/z_design_studio/transmission_z28_6.html
http://www.smokemup.com/auto_math/trapspeed_lbs_hp.php?sid=337bad6549d7d23d25c1fcebc 4615776