Tech: 2015 Mustang Halfshaft Install

2015 Mustang Halfshaft Install Featured

10-Second Effort

Boost Works adds heavy-duty halfshafts and clicks off a low-10-second pass in its blown S550

By Steve Turner
Photos courtesy of Boost Works

With any luck you caught our story on Boost Works’ installation of a Kenne Bell Mammoth supercharger on a 2015 Mustang GT. It was the first application of the big Kenne Bell Twin Screw on the latest Coyote Mustang, and it made great power. However, the Boost Works team realized that applying that power at the racetrack might result in breakage.

Before heading to Royal Purple Raceway in Houston, Texas, to drag test its Kenne Bell 3.6LC-supercharged 2015 Mustang, Boost Works decided to upgrade the stock halfshafts with the DriveShaft Shop’s 1,400hp-capable replacements.
Before heading to Royal Purple Raceway in Houston, Texas, to drag test its Kenne Bell 3.6LC-supercharged 2015 Mustang, Boost Works decided to upgrade the stock halfshafts with the DriveShaft Shop’s 1,400-hp-capable replacements.

“Seeing the stock-axle carnage on the American Muscle car, we decided to give Frank a call over at The DriveShaft Shop. After discussing our long-term goals for the car, he suggested that we install a set of their 1,400-horsepower axles,” Travis Burelle of Boost Works explained. “Two days later, we had a set of axles at our doorstep. I can’t say enough about how helpful the folks at D.S.S. have been.”

With the independent rear suspension bolstered for battle, it was finally time to put the Kenne Bell-boosted 2015 Mustang to the test. The Boost Works crew towed the black beauty up to Royal Purple Raceway in Houston, Texas, to see what kind of times the car was capable of running.

One look and you can see the DriveShaft Shop halfshafts (top) are more robust than the stockers. They feature 108mm CV joints with 300m billet chrome-moly cages, while the center bars are hewn from Ovaco 300M alloy steel and the splines are cold-rolled. Suffice it to say they are far stronger than the stock shafts, which will last about 10-20 passes with more-than-stock power and sticky tires.
One look and you can see the DriveShaft Shop halfshaft (top) is more robust than the stocker (bottom). The D.S.S. shafts feature 108mm CV joints with 300m billet chrome-moly cages, while the center bars are hewn from Ovaco 300M alloy steel and the splines are cold-rolled. Suffice it to say they are far stronger than the stock shafts, which might last about 10-20 passes with more-than-stock power and sticky tires.

“Once our axles were installed, we set off for the drag strip. Having a McLeod twin-disc, and 655 rear-wheel horsepower worth of grunt under the hood, we felt confident in our ability to crack the 9-second barrier for the first time,” Travis said. “This is a full-weight street car that could be daily driven on a set of drag radials. We tip the scales at 3800 pounds with a 250-pound driver (I’ve been told I need some weight reduction), and around 110 pounds worth of blower, heat exchanger, pump, lines, and fluids.”

Remove the upper spindle bolts and the axle nut, before prying out the stock halfshaft, which is retained by a C-clip. Unlike the clips on the old-school 8.8 rears, these clips will compress as you pry out the stock shaft.
Remove the upper spindle bolts and the axle nut, before prying out the stock halfshaft, which is retained by a C-clip. Unlike the clips on the old-school 8.8 rears, these clips will compress as you pry out the stock shaft.
 You can slide the stock halfshaft past the hanging spindle and brake. The fluid is filled right up to axle level, so you shouldn’t lose enough to require refilling the diff.
You can slide the stock halfshaft past the hanging spindle and brake. The fluid is filled right up to axle level, so you shouldn’t lose enough to require refilling the diff.
The C-clips compress, like a piston ring, when the D.S.S. shaft is installed and expand once they are inside the differential to lock the shaft in place.
The C-clips compress, like a piston ring, when the D.S.S. shaft is installed and expand once they are inside the differential to lock the shaft in place.

 

The powerful Mustang definitely put the stronger axles and the new independent rear suspension to the test. Once it was official that the 2015 Mustang would sport an IRS, we were definitely skeptical of its potential drag strip prowess. However, the S550 has proven quite competent on the 1,320.

With the stock shaft out of the way, you can reverse the process by sliding in the D.S.S. halftshaft and bolting everything back up.
With the stock shaft out of the way, you can reverse the process by sliding in the D.S.S. halftshaft and bolting everything back up.
Mate the new halfshaft to the brake rotor and pre-tighten the axle nut.
Mate the new halfshaft to the hub and pre-tighten the axle nut.
With the halfshaft installed you can reinstall the upper spindle bolts.
With the halfshaft installed you can reinstall the upper spindle bolts.

 

“Out of the hole, the D.S.S. axles performed flawlessly, as did the McLeod clutch. Pass after torturous pass, we clicked off 1.4- to 1.5-second 60-foot times,” Travis elaborated. “The noise inside the car was that of a small explosion at each 5,000-rpm clutch drop, but the new parts performed flawlessly. The IRS never flinched, and we are quite impressed at just how well this car performs on otherwise stock suspension! Ford definitely did its homework.”

However, the testing was not without disappointment. The Boost Works crew had hoped to be the first to break into the 9-second zone with a supercharged Mustang. It just wasn’t to be, but they were able to claim the spot as the quickest supercharged Mustang of the moment with a 10.22 and 126.77 mph hit, which you can watch right here:

You may first tighten the axle nut with an impact gun, but be sure to properly torque it to 125 lb-ft with a torque wrench. Before doing so, be sure the parking brake is engaged.
You may first tighten the axle nut with an impact gun, but be sure to properly torque it to 125 lb-ft with a torque wrench. Before doing so, be sure the parking brake is engaged.
While Boost Works hoped to break the 9-second barrier with its supercharged S550, you have to be impressed with a full-weight street ’Stang ripping off a 10.22 at 126.77.
While Boost Works hoped to break the 9-second barrier with its supercharged S550, you have to be impressed with a full-weight street ’Stang ripping off a 10.22 at 126.77.

“Like the S197, it appears the S550 has an issue with the clutch pedal being sucked down to the floor at high rpm. This made the Fourth to Fifth gear shift a bit dicey. So, after the 1,000-foot mark, we ended up losing mph with a partially engaged/slipping clutch. We’re currently investigating and going over the parts/data with McLeod to come up with a solution. This is all part of R&D, and these things happen,” Travis confessed.

So, they haven’t reached the 9-second zone yet, but the car is poised to do so as soon as they work through the combination. That said, you have to be impressed by a car that can rip off a low-10-second pass and still retain street-worthiness.

“While we could have gutted the car out, and stripped it down to bare bones, we really wanted to show people what the new GT is capable of in daily driver trim,” he said. “This setup is easy to repeat, and can be done with a daily driven car. Running 10.20s at nearly 3,800 pounds is impressive, and we think the car has nines in it just as it sits.”

Next up, the Boost Works team plans to add a built short-block, an automatic trans, and crank up the boost. With those mods, they will surely be running much quicker e.t.’s.

With the new D.S.S. halfshafts in place, the Boost Works 2015 Mustang was track-ready.
With the new D.S.S. halfshafts in place, the Boost Works 2015 Mustang was track-ready.
Pleased with its 10-second performance—but not satisfied—Travis Burelle and Curt Howell of Boost Works are busy building up this 2015 Mustang for its next drag-strip assault.
Pleased with its 10-second performance—but not satisfied—Curt Howell and Travis Burelle of Boost Works are busy building up this 2015 Mustang for its next drag-strip assault.

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