View Full Version : Going with a Ford 9"


BriGuy
03-19-2007, 09:05 PM
We are saving now for a 9" for the wife's car. I am not very familiar with the rears. Which would be better a spool or an auburn differential. It will be a 9" with some 3.90 gears, 31 spine, and 4 channel ABS. Any help with this would be greatly appreciated.

The car is a '00 Formula WS6 with the full compliments of bolt-ons with a TRex and stock heads.

Yes I know that the 3.90 gears aren't the 'ideal' gears for the TRex, but she wants to start off with those first to see how it drives.

DuronClocker
03-19-2007, 09:06 PM
Go with a TrueTrac :) Better than the Auburn posi (nothing to wear out in a TrueTrac!), and perfectly streetable whereas a spool will be dragging a tire every turn.

Bandit LS1
03-19-2007, 09:17 PM
I second the TrueTrac

Jimmard
03-19-2007, 09:23 PM
I second the TrueTrac

I agree. I just ordered one from scott@drivelinesolutions. 4.11s trutrac, I even went with an aluminum center section to save quite a bit of weight (lighter than a 12 bolt now). I should get it by next week :drive:

NHRAMAN
03-19-2007, 09:23 PM
I second the TrueTrac
I third it. :judge:

BriGuy
03-19-2007, 09:32 PM
I should also mention that the car will be used more at the track. She will be points racing. Once the rear goes in the car will be used more at the track, with the occassional egged on race on the street. (No matter how the car sounds someone is always willing to race a female on the street just to see if she knows what she's doing.)

DuronClocker
03-19-2007, 09:47 PM
I agree. I just ordered one from scott@drivelinesolutions. 4.11s trutrac, I even went with an aluminum center section to save quite a bit of weight (lighter than a 12 bolt now). I should get it by next week :drive:

You're going to love it. I just assembled mine tonight (need to install the axles tomorrow after I get the bearings pressed on). Ordered on a Thursday, received the center section from him by Tuesday, and the rest of the stuff from Moser on Thursday. One week after ordering, it was all at my doorstep :)

I weighed everything separate and added together...got 181.1lbs not including the center section nuts or the torque arm mount bolts. Not terribly heavy at all. That didn't include the 13.5lb backing plates or rest of braking though.

Jimmard
03-19-2007, 10:24 PM
You're going to love it. I just assembled mine tonight (need to install the axles tomorrow after I get the bearings pressed on). Ordered on a Thursday, received the center section from him by Tuesday, and the rest of the stuff from Moser on Thursday. One week after ordering, it was all at my doorstep :)

I weighed everything separate and added together...got 181.1lbs not including the center section nuts or the torque arm mount bolts. Not terribly heavy at all. That didn't include the 13.5lb backing plates or rest of braking though.

I think the thing that is exciting me the most is being able to finally do some high rpm clutch dumps on slicks. I'm interested how much of a difference it will make on my otherwise stock car. It will have aftermarket torque arm, driveshaft, clutch, bellhousing etc by that time though. I'm soo excited, I cant wait much longer :drive:

Jimmard
03-19-2007, 10:26 PM
I should also mention that the car will be used more at the track. She will be points racing. Once the rear goes in the car will be used more at the track, with the occassional egged on race on the street. (No matter how the car sounds someone is always willing to race a female on the street just to see if she knows what she's doing.)

If that's the case, I would definitely consider 4.11s or more unless you plan on spraying. Good thing about the 9" is that gear swaps are easy, just get a new center section and bolt it in :drive:

DuronClocker
03-19-2007, 10:30 PM
I went 3.89s because 4.10s would put me past my 6800rpm limit at the track on 26" tires on spray :doh:

xpndbl3
03-20-2007, 03:11 AM
duronclocker, if you want to hook it up go with 28" slicks for more contact patch, no reason to run 26" tires if you want to be consistent and make hooking up easier.

oange ss
03-20-2007, 07:02 AM
if it's an M6 i would definitley consider the 4.11 and another vote for the Tru Trac, that's what i have in mine

BriGuy
03-20-2007, 12:58 PM
If the 3.90's don't do what she wants then she is looking at 4.56's. The main reason that she wants the 3.90's is for the 190 mile trip that the car will have to make to go from our house to the track. Although we do have a house to leave the car at once the race season starts.

35th SS
03-21-2007, 12:42 AM
she will want more like the 4.56 and 28inch slicks.

EPP
03-21-2007, 05:16 AM
I agree, go with 28" tall tires. They provide a larger contact patch ( o - O ) on the ground, and the taller sidewall doesn't shock the tread surface as hard, allowing more traction.
A nine inch with a spool is what I would go with for your application.
http://www.exoticperformanceplus.com/performance_parts/index.html?item=148 Bob