Lethal Performance bolsters its 2015 Mustang IRS for the drag strip
By Steve Turner
If you have been following along with our coverage of Lethal Performanceâ€™s 2015 Mustang GT build, you know that the company has taken an aggressive path with its mods. Eventually that path leads to the drag strip, so it was time to take a break from adding power and fortify the drivetrain to withstand drag launches.
From what we have learned, the stock halfshafts wonâ€™t last long when they are wedged between sticky tires and elevated horsepower levels. Anywhere from 10-20 hits, and you might snap a shaft. It could be even sooner if that hit packs the instant torque wallop induced by nitrous.
â€œThe next steps of our build will be to beef up the rearend with some Driveshaft Shop axles, a Driveshaft Shop driveshaft, a full American Racing Headers exhaust, and a big olâ€™ front-feed, 2.9-liter Whipple Supercharger kit,â€ Lethal Performanceâ€™s Jared Rosen told us after the nitrous install. â€œOf course all of the supporting mods such as a fuel system, injectors, clutch and flywheel will be part of the equation.â€
As such, Lethal selected a set of the companyâ€™s 2015 Mustang 800hp Direct-Fit Axles (PN RA8505X4 and RA8506X4; $1,199.98).
For those of you that have high-powered Terminators, you know the tale of weak halfshafts. The good news is the S550 shafts are sturdier from the jump. Of course, that doesnâ€™t mean that they canâ€™t be improved to support the kind of power that you plan to add to your new Mustang.
â€œFirst we started with both the inner and outer splines going into the hub and the differential. We have been working with Ovaco steel out of Sweden and they came up with a material called Ovaco 300 that has been used by D.S.S. in each and every IRS/CV driven world record breaking car to date,â€ the company explained. â€œSo each spline is now made from this amazing 300m material (on both the 800hp and the 1400hp versions). We then made 4340 billet CV mounts and are using our proven 108mm CV with full 300m billet chrome-moly cages and races (with the 1400hp axles using the larger 30-spline bars). This along with Neo HPCC1 grease and with a higher durometer Neoprene boot, it will handle just about anything you can put to it.â€
Besides the materials, the manufacturing process is designed to further improve the durability of the shafts.
â€œWe didnâ€™t stop there, the center bars we made are done with our CNC spline-rolling process, which most people â€˜in the knowâ€™ will tell you that a rolled spline is significantly stronger than one that was done with material cut away because it is actually forging the spline and compressing the micro structure to make it even stronger,â€ D.S.S. says. â€œSo what we have here is a proven design, and if thatâ€™s not enough so we also have taken the time to put end caps on the end of the CV housings in case they are ever taken apart (you guys pulling the diff will love this, as the six bolts come off and the diff will come out, try this with a stock axle) and the caps have blue RTV inside to ensure a perfect seal.â€
While the shafts are rated for up to 800 horsepower, thus far D.S.S. reports that they havenâ€™t found the limit of the shafts just yet. We are pretty sure that Lethal will try to find that edge with its car. With that in mind, we checked in at Power by the Hour in Boynton Beach, Florida, to document the installation of these shafts.