Written By Steve Baur
Photography by the FSC Staff, Jeff Wilson, and Courtesy of Moser Engineering
With Chevrolet and Ford offering body-in-white programs to racers, there’s a need for a rear suspension for these vehicles that can handle the rigors of a racing application. When the body-in-white Camaro came out, the independent rear suspensions used in the production 5th-generation F-body were hard to find, more expensive, and not the ideal choice for racing enthusiasts. Moser Engineering sought to change that with its Live-Axle Conversion option for 5th Generation Camaros.
“We do a live axle conversion for C5 Corvette and that sells really well. The Camaro seemed like the next step,” said Moser Engineering’s Tim Irwin. And it wasn’t necessarily about the COPO Camaro, but wanting to provide something for guys who just want to run a Camaro.
“There was no suspension adjustability with the IRS. You can buy a better center section and half shafts—the weak point is the hubs,” notes Irwin. “It’s [the IRS] simply not geared towards drag racing.”
With Stock Eliminator racers in mind, the live-axle conversion was first designed with Moser’s 12-bolt rearend. Knowing that there are classes with more powerful drivetrains that can benefit from the live-axle conversion, Moser also engineered a version that uses the company’s M9 fabricated 9-inch-style rear axle assembly.
Suspending the live axle is a three-link torque arm system that employs a panhard bar for lateral location, and a drag-racing-style, adjustable anti-roll bar is also built into the design. With the exception of the fixed lower control arms on the 12-bolt (An NHRA S/E requirement), everything is adjustable with the live-axle conversion, so there won’t be any problem dialing in your suspension.
Included as standard equipment with the 12-bolt version are 35-spline custom alloy axles, a lightweight Moser spool with Pro/Comp ring and pinion gears, 1350 series Chromoly pinion yoke, bearings and studs, and all hardware needed to install the assembly. From there, you can upgrade to a Wavetrac differential, choose from optional gear ratios, and pick from several axle shaft options. Powdercoating is also available for an added cost and there are about a dozen finishes to choose from. Moser also offers optional rear disc brake kit if you prefer to use their products and/or source everything from one company. The M9 version of the live axle conversion features similar standard components, though a center section for the housing is not included.
The M9 axle assembly does offer a number of advantages over the 12-bolt.
“The gear options that you have with the stock carrier is limited,” Irwin tells us. “The options are just about unlimited with our 9-inch version. The 9-inch also features an inner pinion support—the 12-bolt doesn’t have that. If you’re using an automatic and not making big power, the 12-bolt will work fine. If you use a transbrake or make tons of power, the 9-inch is recommended.”
Another benefit to the 9-inch is the option to run larger axle shafts. “You can put 40-spline axles in the 9-inch—we’ve seen some big horsepower supercharged cars bend 35-spline axles at half track.”
Moser’s live-axle upgrade will work in a street application, but there are quite a few racing-type of mods that need to be made to be able to use this system. Removal of the factory fuel tank and charcoal canister is part of the installation, so a fuel cell is required. Likewise the stock fuel lines must go as well as some of the chassis metal that supports the factory cradle. With a little bit of welding needed, the live-axle conversion is mostly a bolt-in project. Lastly, you’ll need to reprogram the ECU to turn the ABS light off.
“GM uses a bearing with an integrated magnetic strip for the ABS,” Irwin notes. “We were going to use that bearing and use a different housing end, but the bearing didn’t offer enough options for high-performance axles.”
We asked Moser if any of their dealers had one of these systems going in a car so we could get up close and personal with live-axle conversion. They ended up putting us in touch with Jesse Wilson, husband to LME 5th Gen Camaro Challenge competitor, Jenna Pierce-Wilson. The Wilsons’ Camaro started life as a six-cylinder F-body, and with Moser less than an hour from their home, it made sense for Jesse to call Moser to find out if they had a live-axle solution for their new race car.
Live Axle In Live Action
Jenna Pierce-Wilson’s 2010 Camaro may have started off running in NMCA in MagnaFuel Open Comp, but it was built to run the 5th–Gen Camaro Challenge class at the Chevrolet Performance LSX Challenge.
Power comes from a 430ci, LSX block-based engine with C5R cylinder heads, a Mast Motorsports cast aluminum four-barrel-style intake and Holley HP EFI. Purchased from Real Street competitor Rodney Massengale. The Camaro has run a best of 9.78 at 140 mph, and yet they’re leaving about 2,000 rpm of the engine’s upper powerband on the table. “It should be able to run the 9.50 index once we rev up the engine.”
At the time of the call, they didn’t, but they were interested in offering one and thus the Wilson’s Camaro became the prototype for the conversion. The engineering took about seven months, which included several changes to the torque arm design to get it just right.
Changing the entire rear suspension design necessitated a new rear shock for the combination. Moser sold both Afco and Penske shocks at the time, but didn’t have an option for Wilson. Moser gave Wilson some baselines and he took it from there. Looking to his circle track roots, Wilson called Advanced Racing Suspension, which built a set of double adjustable rear shocks for the application.
“We run a stacked spring instead of a single,” Wilson told us. “We tried to keep a soft, single spring initially, but we were going into coil bind. We stiffened it up and we were still close to binding, so we went to the double spring setup and run a 350lb, 4-inch spring on top and a 200lb, 8-inch spring on the bottom.” By going to the double spring setup, Wilson got a much needed extra inch of travel while being able to keep a relatively soft spring rate.
Having had a few events with the live-axle under the car, Wilson has learned what the car liked and what it needs to be better. The Camaro has been a best of 1.39 seconds to the 60-ft clock, and it goes 1.40 consistently with either foot brake or transbrake launches.
“I’ve talked to guys that have the IRS and what they’ve had to do to make it work,” says Wilson. “I think the potential is there to out 60-foot the IRS cars. It should be in the mid-to-low 1.3s. That should put us on par with the factory COPO cars. The torque arm is very forgiving. When everyone was slipping on the hot greasy track at LS Fest, we drove right through it. We can get down marginal tracks very well.”
One issue with the combination is that the engine doesn’t accelerate fast enough to carry the front end once it picks up. Wilson plans to solve this by altering the front suspension to allow for more travel. The COPO front cradle has this built into it, but it wasn’t available when the Wilsons built this car. While the car, weighing in at just over 3,400lbs, maintains a 50/50 balance, it needs more travel to transfer more weight to plant the back end plant and then it will carry the front end out.
For those building a dedicated drag car, Moser’s live-axle conversion is a great option that brings adjustability and rock-solid reliability to the rear suspension. With a wider range of axle and gear ration options, it also provides a way for racers to optimize the rearend for just about any engine combination.