Tech: 2015 Mustang Driveshaft Upgrade

0 2015 Mustang Driveshaft Featured

Getting the ’Shaft

Lethal Performance gets its Mustang GT track ready with a D.S.S. driveshaft and a BMR safety loop

By Steve Turner
Photos by Steve Turner and courtesy of The DriveShaft Shop

We recently showed you how Lethal Performance upgraded its 2015 Mustang GT project car with a set of rugged halfshafts from The DriveShaft Shop. That was just the first phase in bolstering the car’s drivetrain in preparation for an assault on the quarter-mile. This time around we are documenting upgrades that will improve performance and safety.

The stock driveshaft (right) is built to deliver a balance of durability and acceptable levels of noise, vibration, and harshness. It is not only heavier than the one-piece D.S.S., but the Guibo at the transmission mount is designed to smooth vibrations, not deliver all the power to the rearend.
The stock driveshaft (right) is built to deliver a balance of durability and acceptable levels of noise, vibration, and harshness. It is not only heavier than the one-piece D.S.S., but the Guibo at the transmission mount is designed to smooth vibrations, not deliver all the power to the rearend. At 21 pounds, the D.S.S. unit comes in 12 pounds lighter than the stocker.

To drop some reciprocating weight and add strength, Lethal chose one of The Driveshaft Shop’s one-piece aluminum driveshaft for 2015 Mustang GT six-speed manuals (PN FDSH25-A; $854.99). The D.S.S. shaft itself is not just strong, but it features a more direct connection between the transmission and the shaft.

“What we have done is make a billet plate to eliminate the Guibo, then changed that end to a nice 1350 solid Spicer U-joint. The end is pulse-welded to the tube on the aluminum shaft and then a six-bolt CV just like the factory one,” says The DriveShaft Shop. “Why does D.S.S. use the CV and not a slider like from a 4×4? The reason is that D.S.S. high-speed balances their driveshafts and found out years ago that the CV is more stable and less likely to have Harmonic issues. Also the CV will have a much higher critical speed then a male/female slider.”

While performing the driveshaft swap, it was also a good opportunity to upgrade the car’s safety with a driveshaft safety loop (PN DSL017; $149.95) from BMR Suspension. Built from ¼-inch steel this loop is designed to meet NHRA standards. It comes with all the necessary Grade 8 hardware for installation, and it’s available in black hammertone or red powdercoat (pictured) finishes.
While performing the driveshaft swap, it was also a good opportunity to upgrade the car’s safety with a driveshaft safety loop (PN DSL017; $149.95) from BMR Suspension. Built from ¼-inch steel this loop is designed to meet NHRA standards. It comes with all the necessary Grade 8 hardware for installation, and it’s available in black hammertone or red powdercoat (pictured) finishes.

Since the new driveshaft is rated for 1,000 horsepower and tested to 9,500 rpm, Lethal doesn’t expect this unit to fail. However, it is not only better safe than sorry, but often necessary to run a driveshaft safety loop to make passes on an NHRA drag strip. As such, the Lethal camp chose one of BMR Suspension’s loops (PN DSL017; $149.95).

With that in mind, we pulled out our cameras at Power by the Hour in Boynton Beach, Florida, to document the installation of these upgrades.

Jake Long of Power by the Hour started the swap by removing the Lethal Performance Resonator Delete’s H-pipe crossover. Then he moved to the back and unbolted the stock ’shaft from the flange on the Super 8.8.
Jake Long of Power by the Hour started the swap by removing the Lethal Performance Resonator Delete’s H-pipe crossover. Then he moved to the back and unbolted the stock ’shaft from the flange on the Super 8.8.
He worked his way forward unbolting the two-piece stocker’s center support.
He worked his way forward unbolting the two-piece stocker’s center support.
The last step was removing the fasteners from the transmission flange.
The last step was removing the fasteners from the transmission flange.
With everything unbolted, Jake slides the stock shaft out.
With everything unbolted, Jake slides the stock shaft out.
This billet adapter replaces the factory Guibo, which is essentially a rubber damper which cuts down on driveline resonance. Of course, this setup leaves some slop in the driveline, so replacing it gives a more direct connection between the transmission and rearend.
This billet adapter replaces the factory Guibo, which is essentially a rubber damper that cuts down on driveline resonance. Of course, this setup leaves some slop in the driveline, so replacing it gives a more direct connection between the transmission and rearend.
Jake moved to the rear to install the D.S.S. spacer on the rearend flange. Be sure to clean the threads of the old thread locker and apply fresh thread locker to the new fasteners before you bolt things up.
Jake moved to the rear to install the companion flange on the rearend. Be sure to clean the threads of the old thread locker and apply fresh thread locker to the new fasteners before you bolt things up and torque the fasteners to factory specs in a crisscross pattern.
With the necessary adapters in place, you can then move the new D.S.S. driveshaft into place. If you are installing a safety loop as we are, now would be a good time to slide the loop over the shaft. You also might want a friend to help you hold the shaft as you install the fasteners.
With the necessary adapters in place, you can then move the new D.S.S. driveshaft into place. If you are installing a safety loop as we are, now would be a good time to slide the loop over the shaft. You also might want a friend to help you hold the shaft as you install the fasteners.
Jake wraps up the install by bolting up the new shaft and torqueing the fasteners.
Jake wraps up the install by bolting up the new shaft and torquing the fasteners.
Following up the driveshaft install, Jake moved to finalize the safety loop. He first supported the transmission with a jackstand. Then he removed the stock transmission crossmember.
Following up the driveshaft install, Jake moved to finalize the safety loop. He first supported the transmission with a jackstand. Then he removed the stock transmission crossmember.
Jake sets up the BMR Suspension safety loop atop the factory transmission crossmember.
Jake sets up the BMR Suspension safety loop atop the factory transmission crossmember.
Using the supplied Grade 8 hardware, he reattached the factory crossmember with the BMR loop mount between the mount and the chassis.
Using the supplied Grade 8 hardware, he reattached the factory crossmember with the BMR loop mount between the mount and the chassis.
He then slides the loop up the driveshaft and onto the mount.
He then slides the loop up the driveshaft and onto the mount.
The last step was to bolt the loop to its mount. Then the car was ready for a test drive. Everything checked out, so it was ready to roll.
The last step was to bolt the loop to its mount. Then the car was ready for a test drive. Everything checked out, so it was ready to roll.
Here’s the completed install. The aluminum construction of the one-piece shaft will accept a bit of torsional twist without snapping like a steel shaft. This twist is said to not only reduce harmonics but improve 60-foot times. If you notice that shiny, new Roush axle-back, we’ll show you how that goes on soon.
Here’s the completed install. The aluminum construction of the one-piece shaft will accept a bit of torsional twist without snapping like a steel shaft. This twist is said to not only reduce harmonics but improve 60-foot times. If you notice that shiny, new Roush axle-back, we’ll show you how that goes on soon.

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