For our application, Maximum...
For our application, Maximum Motorsports recommended its standard torque arm for the Fox-body Mustang (MMTA-1), which retails for $449.
While many enthusiasts believe that late-model Mustangs are only good for drag racing, there is a strong opposition to that claim and one that regularly pushes our beloved ponycar around vigorous road courses in the pursuit of faster lap times. It's all about going fast in the end.
If you haven't followed MM&FF's project Stolen Goods, let us bring you up to date on our subject vehicle. Having come across a fantastic deal on a '93 Cobra, we set about rebuilding it, literally from the ground up, and started with a Maximum Motorsports Road and Track package for its suspension. For the rear suspension, we planned to use MM's Panhard bar/torque arm arrangement, but we wanted to get a comparison with and without the torque arm, and to do that, we had to complete the long build process and get the car up and running before we could flog it for testing purposes. Having put some 4,000 miles on the Snake, not to mention numerous track tests, we were ready to install the torque arm and convert the factory triangulated four-link to a three-link/Panhard bar design.
We began the installation...
We began the installation by fitting the torque arm to the rear axle housing. Bolts were left loose so we could move the arm around while we were installing the crossmember.
"The Mustang four-link came from the '78 Fairmont, and its design was fairly compromised to begin with," says Maximum Motorsports' Chuck Schwynock. "It doesn't do anything exceptionally well. In fact, body roll should be controlled by the springs and sway bars, not the control arms as is the case with this setup. The four-link has a tendency to bind up, and when it breaks loose the results can be unpredictable. The popularity of the Mustang showcases all of its deficiencies due to its old engineering."
The team at Maximum Motorsports set out to design a more current suspension setup for the Fox, and they ended up with a Panhard bar/torque arm setup in their shop car. Maximum actually has several torque arm options depending on your car's horsepower, subframe connectors, and the rear axle gear ratio.
After assembling the front...
After assembling the front bush mount, we installed it on the torque arm and inserted it into the crossmember. We were then ready to position the crossmember so we could locate its mounting tab locations on the subframe connectors. You want to measure to make sure the crossmember is centered in the chassis before you make permanent modifications.
To install the torque arm, we visited HP Performance in Orange Park, Florida, as it had the experience to perform such an installation, as well as a drive-on lift to facilitate it. Special tools like a MIG welder and angle finder are used, but many of you have these at home, so it is possible to do the job on a set of jackstands. The torque arm was installed in a few short hours and the results were immediately apparent. Straight-line traction, especially on our street tires, was much improved, which is quite helpful given our 430 hp powerplant's propensity for lighting up the rear tires. We did notice a slight increase in vibration through the floor, but that has either subsided or we have just gotten used to it because it doesn't seem to be present anymore.
We had previously run Stolen Goods at our local autocross without the torque arm, and one of the major issues we had was extreme brake dive and the subsequent rear lockup. With the torque arm installed, brake dive was reduced, which gave the rear tires more traction to perform braking duties with. We never had to change the brake bias as the reduced brake dive solved the issue.
During our post-install track session, we noticed that the rear tires were rubbing the inner fenders during hard cornering. After consulting Maximum Motorsports, we'll have to look into getting a better fitting wheel/tire setup out back. Now that the rear suspension is no longer binding, the body is rolling over more freely. While Maximum offers an increased spring rate to both compensate for that and the increased rear traction, it still allows for the body to move freely. The 10-inch wide rims and 275mm-wide tire combination just isn't going to cut it, but we see it as a good problem to have. We'll look to go back to a nine-inch wide wheel and a slightly smaller width tire and get back to the track to power out of the corners with confidence.
The mounting tabs are then...
The mounting tabs are then welded on. Maximum Motorsports offers tabs for both rectangular and round subframe connectors. We recommend using its full-length ones like we did.
After the tabs cooled down,...
After the tabs cooled down, we bolted the crossmember in and gave the area a quick coat of paint.
In utilizing the torque arm...
In utilizing the torque arm and Panhard bar suspension, we were able to chuck these factory upper control arms. It's amazing to think that the factory gave these cheap stamped steel units, not one, but two jobs to do.
As per the instructions, it...
As per the instructions, it is important to make sure that the bushing is fully inserted flush in the crossmember like so. It may help to leave the crossmember unbolted, and then in a side-to-side, push-pull motion, rock the crossmember until the bushing is in.
The torque arm setup frees...
The torque arm setup frees up the axle from its previous binding situation with the stock four-link arrangement, so Maximum recommends that you step up the rear spring rate. We did just that and noticed no difference in ride quality, which was great.
Since the torque arm limits...
Since the torque arm limits axle windup much more than the stock suspension does, Maximum has you set the pinion angle to match the transmission output shaft angle. Use an angle finder on the driveshaft flange and the exposed, machined surface on the bellhousing. Then adjust the torque arm with the provided shims. Thankfully ours was within one-half of a degree, and we called it good.
The torque arm bolts were...
The torque arm bolts were then tightened up.
How To Determine Which MM Torque-Arm Is Best Suited For Your Application
1. Find your car's differential gear ratio in the Engine Torque Table.
2. On the same row as the gear ratio listing are the ratings for the maximum engine torque, and the maximum rear wheel torque, for the Standard Torque-arm.
3. If your car exceeds these ratings, then look at the next column for the maximum torque ratings for the Heavy Duty Torque-arm.
|Engine Torque Table|
| ||Standard TA||Heavy Duty TA|
| Max. |
Though the late model F-body...
Though the late model F-body guys were lucky to have a torque arm/Panhard bar setup from the factory, their stamped steel piece wasn't nearly as beefy or good looking as the Maximum Motorsports unit is.
Maximum Motorsports points...
Maximum Motorsports points out that not all exhaust systems will work and you may need to make some modifications. Project Stolen Goods uses a complete Dynomax exhaust system, and we had no interference issues. The guys at MM have a good idea what fits and what doesn't, so give them a call. We think its time we painted the subframe connectors already.
There seems to be a lot going...
There seems to be a lot going on under the car these days, but that's the difference in going the extra mile to make sure things work properly and aren't compromised like with the bargain factory arrangement.
Most people are concerned...
Most people are concerned with ground clearance when it comes to torque arms. As you can see here, the mufflers, control arms, and sway bar all rest as low or lower than the torque arm. Having put about a thousand miles on the car since the install, we can tell you ground clearance has never been an issue.
One of the benefits of the...
One of the benefits of the torque is reduced brake dive. We noticed a huge difference in this, as you can see in this photo. The majority of the rear wheelwell gap has more to do with the way we had the spring height set than it does with brake dive. Less brake dive also means you can use more rear brake bias, and any time you can use more of your brakes and traction, the better off you'll be.
We've certainly noticed that...
We've certainly noticed that the axle rotates side to side more freely, even after adding the stiffer springs. Where we thought we had plenty of clearance between the tire and the inner fender, we noticed that the increased body roll closed the gap and forced contact between the two, resulting in a bit of smoke in the turns. While you can bump up the spring rate to compensate, we were perfectly happy with the ride quality and handling, and are looking into a better fitting rear wheel/tire setup.