Suspension/Drivetrain - Spring 2007

Spring of 2007 found my car sitting in my garage up on jack stands. I started out planning to just rebuild the axle assembly. So I ended up doing a couple of other things:
1. Install an 8.8 rear axle assemble out of an 03 Mustang GT.
2. Replace the stock clutch/flywheel with Spec pieces.
3. Replace the stock LCAs with MMS tube arms.
4. Install a DTS rear differential girdle.
5. Replace the driveshaft with an aluminum driveshaft.
6. Rear brakes and HR wheel spacers.

PROJECT SUMMARY - The 8.8 Mustang GT rear was a great addition to the drive train. Power accelerations are very predicable and I like the fact I no longer have a one wheel wonder. The Spec clutch and pressure plate grab nice, but after putting over 10k miles on it I still have clutch shatter I must deal with. If and when I ever change to a different clutch I will probably not go with Spec again for this reason. The aluminum flywheel does make the engine seem to rev quicker, but I did notice a decrease in highway fuel ecomony. This it probably due to less rotational inertia to keep the car moving at a steady speed. The aluminum driveshaft might have been a purchase I could have done without. The LCAs were a good decision. They definately help with lateral body placement in the turns and I have not had noticable wheelhop since. Overall, despite the added NVH I have since I've replaced these parts, the car has gained noticable preformance increases. Here are some weight comparisons:

                   OLD                                                                        NEW
Steel Flywheel                  25.25lbs.               Spec AL Flywheel  13.5lbs.
Original Clutch Disc              6.2lbs.                  Spec Clutch Disc  4.5lbs.
Original Pressure Plate  20.25lbs.            Spec Pressure Plate  18lbs.

Axle Assembly
Initially I was going to rebuild /upgrade the 7.5 assembly, but after I priced out everything, I would have had $1300 into it. I found an 8.8 assembly for $650.

This is how the car looked during the 2007 spring. While I had the rear out I desided to replace the stock clutch with a more suitable piece. The last time I had the car on the dyno I could smell the stock clutch giving way.

Pulled out the gear case first, and then the bellhouse without much difficulty. I replaced the stock cast flywheel with a Spec aluminum flywheel. I replaced the stock clutch and pressure plate with the Spec Stage 2+ 10.5" GT pieces.

Ugly, old, and rusty on the top. Shiny, new, and pretty on the bottom. The Spec aluminum flywheel comes with both 11" and 10.5" diameter pp (pressure plate) mounting holes. The stock v6 clutch/pp is 11" in diameter. Once again, the idea behind going with the smaller diameter clutch/pp is to lighten up the rotational mass on the engine. Lighter rotational mass means quicker engine accelerations. But that also means less inertia to assist the engine in overcoming forces wanting to slow the engine down (drag).

The Spec aluminum flywheel bolted to the crank. Hmmm shiny.:) The 2002 v6 engine is internally balanced. This requires the removal of a steel counter weight that's held on to the flywheel by three taper-headed allen bolts. Not removing this weight will cause the engine to vibrate noticably.

The Maximum Motorsport LCAs offer more resistance to lateral axle movement. The urothane (front) spherical (rear) bearings make a noticable difference in the way the car's rear feels during cornering. I do feel more vibrations in the car, but they are tolerable.

The DTS 8.8 aluminum differential cover is quite a stout piece. I torqued the main cap support studs to 3-5 ftlbs. With the filler port above the axle centerline you're able to put in 2 quarts of 75w140 lube instead of the 1.8 quarts that normally fills it.

I also replaced the stock steel driveshaft with a Ford Racing aluminum driveshaft. The stock driveshaft weighed ~25.25 lbs. The aluminum driveshaft weighed ~13.5 lbs. The idea behind using a light driveshaft is to reduce the rotational mass the engine has to overcome during acceleration. The more you can reduce the energy used to turn the drivetrain componances, the more that's left to put to the road, so the theory goes.

I also redid the rear brakes with new pads and rotors. While I was at it, I painted the rear calipers and added a pair of 25mm H&R wheel spacers to bring the edge of the tire out a little. I'm not big on appearance mods. :P

Page 1: In the beginning - Fall 2003
Page 2: Let the modding begin - Fall/Spring 2004
Page 3: Deer hit damage - Summer 2005
Page 4: M112 Blower Install - Spring/Summer 2006
Page 5: Suspension/Drivetrain - Winter/Spring 2007 (you are here)
Page 6: Eaton M112 Porting Project - Winter/Spring 2008

Page 8: Modification List