Independent Enhancements

The Driveshaft Shop and Lethal Performance team up to offer 2015 Mustang IRS upgrades

By Steve Turner
Photos courtesy of The Driveshaft Shop and Lethal Performance

The drivetrain experts at The Driveshaft Shop have gotten their hands on a complete Independent Rear Suspension assembly from a 2015 Mustang. They are currently developing a host of upgrades for the car, and these parts will be available from Lethal Performance.

In order to bring the Mustang to the world, Ford believed it needed an Independent Rear Suspension, and this our first look at the assembly out of the car. It wonâ€™t be easy for drag fans to swap in a solid-axle, so making this setup work and survive with big power will be the challenge.

Fortunately this gives us a chance to take a closer look at the real IRS assembly. This is what every wine-and-cheese car scribe has pined for in the Mustang. Itâ€™s going to be great to see how it really impacts the carâ€™s handling. However, we know that the street/strip and drag guys will have to find a way to make it work with beyond-stock power levels.

Thatâ€™s whyÂ The Driveshaft Shop is on the case. They are in the process of developing one-piece driveshaftsâ€”in aluminum and carbon fiberâ€”to replace the two-piece stocker. Clearly these will be more durable and lighter, but the company does say the S550 two-piece is lighter than its S197 predecessor.

That halfshaft does look a little spindly. Fortunately DSS is building robust, direct-replacement halfshafts for the stock differential.

Naturally, The Driveshaft Shop is creating a set of stout halfshafts for those looking to upgrade the stock diff assembly with stouter sticks. The big news, however, is the company will also offer a 9-inch differential upgrade for the S550 IRS. This could be the game changer that keeps the mega-power 2015s together, as moving to a solid axle is only a convenient option for race cars with fuel cells.

Stay tuned. This is just the beginning. Once the new Mustangs hit the streets the aftermarket will boil over with upgrades, and weâ€™ll be here to tell you about them.

Will these CV joints be a weakness for straight-line enthusiasts?

Though the differential still uses an 8.8-inch gear set, Ford says that dimensional and metallurgical torque-density improvements equate the strength of this unit to a 9.75-inch differential. The diff carrier is iron on manual cars and aluminum on automatic cars. If the so-called Super 8.8 seen here still isnâ€™t enough, The Driveshaft Shop will offer a true 9-inch upgrade.

Wonder why the new Mustang is a little heavier? Well there is a lot to an IRS, including a bulky subframe.

The S550 two-piece driveshaft is a bit lighter than the outgoing S197 two-piece. It only uses one CV joint, and itâ€™s not the same joint as the S197 shaft.

The S550 driveshaft weighs 30.55 pounds.

This is the IRS assembly on the assembly line.

Comments

comments

6 thoughts on “News: 2015 Mustang IRS Upgrades”

SID297

September 5, 2014 at 2:24 pm

Great info Steve. Thanks to the guys at Lethal for sharing the pics.
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black99lightnin

September 5, 2014 at 2:54 pm

how do the stock 15 shafts compare with 03/04 cobra’s?
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SID297

September 5, 2014 at 3:28 pm

Hard to tell. I have seen a couple different versions of the half-shafts (some noticeably beefier than others). I’m guessing powertrain choice determines which the car is equipped with.
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black03

September 5, 2014 at 7:04 pm

2015 MUSTANG DRIVESHAFT WEIGHING IN @ 30.55lbs!

Mad Props to our friends at The Driveshaft Shop (www.driveshaftshop.com).
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black03

September 8, 2014 at 4:00 pm

Great write-up Steve!! So glad to have you as part of our family here at SVTP!!!!
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EditorTurner

September 8, 2014 at 4:31 pm

Thanks Jared. I am happy to be here!
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