Whether it's on the street or at the track, traction is immensely important. Spinning your tires will get you nowhere fast, and as high-horsepower Ponies become more and more popular, getting your power to the ground becomes more difficult.
In the past few months, we have stepped up the power output of our '11 AMSOIL Mustang GT. We've been cranking out high-10-second e.t.'s with relative ease, but a few issues have begun to decrease consistency and the quality of our launches at the track.
When we first began testing the car, we would hit the gas and the car would go. It was drama free, and we didn't have to work hard to keep the car straight. After some dyno time with Justin Starkey from VMP Tuning, power production jumped up, and the first 150 feet of every pass became a lot more exciting.
I use the word exciting because launching with more power is always, well, exciting. But also, the car reacted completely differently-bodyroll had become an issue. When we hit the gas before, the nose picked up slightly, the rear squatted a little, and before we knew it, we were crossing the stripe. Now the nose picks up much harder and the rear squats significantly more, but as power transfers through the drivetrain, it twists the body of the car as it rotates the tires.
Bodyroll equates to wasted motion. As the body rotates, it absorbs power being transferred to the rear.
To reduce this deflection of power, we turned to BRM Suspension. The Thonotosassa, Florida-based suspension company makes components for classic and late-model American muscle cars, and its line of products for the '05-and-up Mustang is a perfect fit for our AMSOIL GT.
To fortify the rear suspension and reduce bodyroll, BMR supplied us with its adjustable upper control arm and mount with multiple mounting locations, double-adjustable lower control arms, lower control-arm relocation brackets, and Xtreme antiroll bar kit. These parts are designed to strengthen the rear suspension and improve the suspension geometry for harder, more consistent launches.
Another problem was tire spin out of the hole. Up to this point, our dragstrip testing has been at Bradenton Motorsports Park (BMP), and the starting line was always prepped well. Now tire spin has become a near constant in our testing, so we tapped Mickey Thompson for a set of ET Drag slicks. Being that our tune and rear gearing is based around a 28-inch-tall tire, we ordered a set of 28x10.5-inch slicks to keep the gearing close.
After a trip to Weaver Tire in Brandon, Florida, to have the new slicks mounted and balanced, we headed back to BMP. During out last outing, we were able to crack off some passes in the mid-10.80 range, with a 1.75 and 1.69 60-foot time respectively. After heating the new slicks, we inched to the line and staged as shallow as possible. Leaving off idle, our AMSOIL GT hooked and went dead-straight out of the hole. The 60-foot time showed improvement, with a 1.57-second short time.
Unfortunately, mid-summer Florida air is not good for making power. We tripped the beams in 10.76 seconds at 126 mph, while our mid-10.80 passes from (much cooler) mid-May were done at over 130 mph.
Sadly, this was the quickest and fasted time of the night, but the 60-foot times were consistently 1.57. Imagine how quick we can go if we shed a few pounds and make a few more horsepower!
As power transfers through the drivetrain, it twists the body of the car as it rotates the tires.

The first parts we swapped...

The first parts we swapped were the upper control arm and mount. The BMR replacement bolts into the stock position using the stock hardware. The mount gives you two positions for the control arm. This allows you to change the position of the car’s instant center.

The first parts we swapped...

The first parts we swapped were the upper control arm and mount. The BMR replacement bolts into the stock position using the stock hardware. The mount gives you two positions for the control arm. This allows you to change the position of the car’s instant center.

1 After unbolting the control...

1 After unbolting the control arm from the rearend, two bolts on the backside of the mount and one large bolt under the rear seat hold the mount in place.

2 The control arm is adjustable...

2 The control arm is adjustable in length, and uses a polyurethane bushing on the body side and the stock bushing on the rearend side. The adjustable upper control arm allows you to set pinion angle.

3 With the new upper control...

3 With the new upper control arm set to the same length as the stock arm, we reinstalled the mount and control arm. Once everything was complete, we set the pinion angle to negative 2 degrees.

4 Next was BMR’s lower control...

4 Next was BMR’s lower control arm relocation brackets. BMR recently redesigned these brackets to be true bolt-in pieces. They use three existing mounting holes, and come with all of the necessary hardware. These brackets lower the rearend side of the lower control arm by as much as 4 inches below the stock mounting point. This allows you to shorten the instant center, which will drive the tire harder into the ground.

5 The lower control arm relocation...

5 The lower control arm relocation brackets slide into position relatively easily. We used a plastic hammer to tap them into position without hurting the powdercoat.

6 With the relocation brackets...

6 With the relocation brackets in place, we moved on to the lower control arms. These double-adjustable arms feature spherical rod ends on both ends to eliminate any deflection from the bushings. They are also available with polyurethane bushings if you want a softer setup. We set the arms to stock length and installed them.

7 BMR’s Xtreme antiroll bar...

7 BMR’s Xtreme antiroll bar is a two-piece design. The brace mounts to existing holes in the Mustang’s frame. Simply unbolt the rear exhaust hangers, and slide the mount between the hangers and the frame.

8 The antiroll bar then bolts...

8 The antiroll bar then bolts to the brace with supplied hardware.

9 The antiroll bar attaches...

9 The antiroll bar attaches to the rearend with supplied tabs, which need to be welded to the axle tubes.

9a BMR uses adjustable endlinks...

9a BMR uses adjustable endlinks with spherical rod ends. This gives you the ability to fine-tune the preload on the antiroll bar so the car launches straight.

10 The last piece of our...

10 The last piece of our suspension puzzle was new rubber. Mickey Thompson sent us a set of its ET Drag slicks. They measure 28x10.5, which we ordered to keep the gearing close to what it was with the old tires.

11 On our last trip to the...

11 On our last trip to the track, our AMSOIL GT launched hard, but inconsistent 60-foot times and tire spin became a factor for every run. Bodyroll was also an issue, as the body twisted to the point of lifting the left front about 8 inches off the ground, while stuffing the right rear into the wheelwell.

12 After installing BMR’s...

12 After installing BMR’s suspension and new Mickey Thompson slicks, the car leaves straight and consistent. It was much easier to control the car as it left the starting line, and little if any steering input was needed as the car accelerated.

13 Although the nasty Florida...

13 Although the nasty Florida air was a limiting factor, our 60-foot times were lower and very repeatable. We dropped the short times from mid-to-high-1.60 seconds to 1.57s, but lost about 6 mph since out last outing in the middle of May. Once we shed some unwanted pounds, these numbers should drop significantly!