Rubrignitz

I'mplanning a good bit of suspension work on my car in the near future and decided to also upgrade my 3.55 rear to 4.10's along with this differential.

http://store.summitracing.com/partde...p;autoview=sku

I've heard that they're not intended for track (drag racing) use and are somewhat less durable due to the cast iron case. I don't plan on flogging my car on the dragstrip, maybe a 1/4 mile blast every once in a while on street tires. Has anyone had any bad experiences with the Torsen diff (damage etc)?

Gene K

Why? When you can buy the Eaton Detroit TruTrac (Which is parallel axis helix gear insted of worm gear) which is very strong
and works very well on the street, roadcourse, strip, etc for less from the same place?

PS the Torsen came factory stock in some year Camaros and they usually replace them with TruTracs when they blow them up.

Rubrignitz

Just knew I wanted a torque-sensing/geardrivenas opposed to posi/locker diff. Haven't looked at the TrueTrac hard but I will. I have a Richmond Powertrax in my truck and it's great in the truck (will pull a stump out the ground) but I knew I didn't want anything like that in my car.

And the road racing guys love the Torsen. I'll definetely give the trutrac a look though. Thanks!

Gene K

The TruTrac is a Torque Sensitive Helical LSDthat has a very high bias ratio of around 3.5 (Double the factory unit).

However it does fit into that category instead of the (Worm) Geared Torque-Sensitive Differential like a Torsen or Quaife ATB.

Most of the Road Racing Guys I know use Quaife ATB (Not Cheap) but last I heard they dont make a 31 spline only 28

Rubrignitz

You're right Gene. The TruTrac is a 3 pinion as opposed to the 2 pinion torsen unit and stronger gear design. Otherwise they are similar in operation. I think I just may have to go with the Detroit .

marcuskeeler

This may be a dumb question, but if you don't want to wail on it at the strip, why would you even want the increased RPM/reduced cruise speed/bad fuel mileage you're going to get from 4.10's ??

Rubrignitz

I'm running 20's and liked the way my car accelerated with the factory 17's. 4.10's should get me back there. I'm also contemplating 3.90's dunno yet. I keep hearing such great things about the torque sensing diff's I decided I want one. The gears are a second thought actually. I may just go with the 3.90's...

drbobvs

+1 for the TruTrac!

Rubrignitz

I think all that talk aboutbad mileage, high increaserpms w/4.10 is overrated. I had 3.23 gearsin my truck. I went to a 20' rim/tire and it was a DOG after the taller tire change. Installed 4.56 gears and was worried about the increased rpm, fuel mileage, etc. I actually gained about 1-2mpg around town (probably lost 1-2 on highway). My 70mph (cruising) rpm changed by about 700 rpm (2k-2.7k) which was negligible to me in a truck and my torque was back to like it was before the tire change. I'm really happy with the 4.56'sin my truck other than it gets really loud at up to around 85-90mph (the flowmaster 40's have more to do with that) and I don't really ever go that fast in it.

I wouldn't want that much gear in my car though, I think I'd be happy with 4.10's. I'll have to do some more research though. I'd like to stay <2500rpm at 70mph in the car.

alloutt

can't you change to 31 spline also?
It shows this on there site, Mustang 8.8 28T IRS (Cobra SVT)