4.30's, 4.56's or 4.88's?

[Finaltheorem47]

Hey guys, working on my Viper T-56 swap and trying to tie the last loose ends up by deciding on what gear I want to run in the rear end.

I did some plugging and chugging into an online calculator and my main goals are to:

1) have fun, I could care less about my time or mph, I'm looking for it to be fun to drive and I rarely/never take it to the drag strip.
2) have a great highway rpm for economy/long trips/wear and tear.

This isn't my daily driver.

The calculator suggests that I'll be around 2200 rpms with 4.88's at 70mph so that is great and just what I'm looking for, but from reading other posts on the forums, I've seen several other people comment about even 4.10's being too short of a gear for their T-56, so I would just like some input of what your opinion is before I bite the bullet and get them installed.

Ford Mustang: Mustang Tech: Calculators & Decoders: RPM Calculator
http://en.wikipedia.org/wiki/Borg-Warner_T-56_transmission

 

[Darkc0bra]

I would do 4.10's because that is what I am about to do with mine. I have driven and rode it our cars with T45 and T56 and they feel amazing with the 4.10's. You would have too much fun with them installed. I know I would and I am ready to get mine and put mine it today. They are decent for Highway driving too. 4.10 FTW Since you are looking 4.30's and up I would do 4.30's

 

[kxt]

beware of info for the 03 or 00R geared t-56, the viper gearset is WAY different. I have 4.30s and a viper geared t56 and love it. At a minimum go 4.30s and do not look back. I'd go 4.56s if/when I redo this rear end. the viper has such a high first gear i can take it till about 40mph then the 2-4th are close ratios, when you hit that .5:1 OD all the revs drop away and you're back to just sipping gas on the Interstate.

 

[WhiTriCobra]

If you're N/A and staying that way, I would get 4.30's if it was me. Does your T56 have the .80 5th and .63 6th gear? If so, then yes to 4.30's. If it's the .74 5th and .50 6th gear, viper specs, i would go with 4.56's.

 

[Finaltheorem47]

It was pulled from a Dodge Viper and I have tested 6th gear by spinning it and it is indeed a 0.50 unit.

 

[Bob Cosby]

4.56s. You'll be hard pressed to get a set of 4.88s to be quiet for a long period of time (been there, done that).

Given the 2.66 low gear (need all the help you can get) and the .50 6th gear (great cruising rpm for steeper gears), I wouldn't even consider 4.11s, and would sail right past 4.30s.

 

[WhiTriCobra]

Then 4.56's FTW. Beast in 1st gear and tamed in 6th gear.

 

[kxt]

^+1

 

[97desertCobra]

I also support 4.56's with the Viper spec T-56. If you plan to stay n/a then this is a no brainer. I have the Cobra spec T-56, 3.73's and boosted. I wish I would have went with 4.10's.

 

[tmhutch]

Since you have a .50 6th that will allow you to comfortably run just about any gear available I would think of this in terms of first gear.

Alot of guys like a really aggressive first gear so they can launch hard at the strip with tires that dont spin and a chassis/suspension combo that dead hooks. A 3650 1st (3.38) combined with a 4.56 rear gives a 1st gear multiplication of 15.41!

While this is great for drag racing it's not so comfortable for around town driving when 1st gear is the equivalent of granny low in an old farm truck. Nice thing about the 2.66 1st in the T-56 is that allows you to run an aggressive gear like 4.56 with a 1st gear that is equivalent to a 3650 with 3.55's (like the stock Mach 1). Think of your current first gear only slightly more aggressive. I think it is perfect for all kinds of driving and works very well for most guys that like to hit the strip once in awhile.

If you wanted an even more aggressive 1st you could go 4.88's but I'd heed Bob's advice about the noise issue. You could go 4.30's but 1st gear torque multiplication is a bit less than the stock TR3650/3.27 combo.

The perfect gear in my opinion is the 4.56.

 

[Bmeagher]

Best calc!
MFactory Competition Products - Forged Transmission Components

 

[Finaltheorem47]

If you wanted an even more aggressive 1st you could go 4.88's but I'd heed Bob's advice about the noise issue.

You'll be hard pressed to get a set of 4.88s to be quiet for a long period of time (been there, done that).

Could both of you go into more detail about this? 4.56 is good but 4.88 seems great to me and depending on noise (like worse than a loud fuel pump?) maybe I could deal with it.

 

[Bob Cosby]

Rear gear whining - even if its not too loud - gets real annoying after a while, and there is NOTHING you can do about it except try another set of gears (once they start whining, I've never seen someone be able to make them stop by adjusting the setup).

Perhaps someone has had a set of quiet 4.88s, and/or you know someone that can install as set that will be quiet. If so, cool. However, my experience keeps suggesting that you're better off not trying it.

While I'm at it....even 4.56s can be loud if they are not setup correctly. Of course that goes for any gear, but the numerically-higher gears are more susceptable to making noise.

Good luck with whatever you chose.
Bob

 

[01cobravortech]

4.56s on my old 01 Cobra and TR3650 were lots of fun! They did whine like a mother though when I was in 5th and climbing past 70mph. Also had 4.10s in the past. You're going to love 4.56s with the T56.

 

[mpe331lx]

430's bare minimum. I'd go with 4.56.