09 viper acr

viper acr roll bar

We were requested to build a roll bar for our good friend's brand new Viper ACR. This is the car Dodge built to break the records recently set by the Corvette ZR1 and the Nissan GTR at Germany's famous Nurburgring Nordscheife track. Dodge took two box stock ACR's to Germany and, with just a few shock and air pressure adjustments, set the lap record of 7:22.1 (besting the old record by over 4 seconds). So, this car has plenty of potential for speed. Our buddy attends several track events throughout the year with the Viper club and other organizations. He was concerned, understandably, for his safety at these events (the car accelerates to over 150mph at the roval at Cal Speedway!).

Most track day organizers will let you run your vehicle in the slower run groups without anything more than a helmet. Depending on the organization or race organization (NASA, SCCA, NHRA, VCA etc.) the requirements are different according to the class you wish to run. We advise to check with your particular organization for their specifications.

The parameters for this project were decided over several evenings sitting in the car looking at every possibility for the construction of the roll bar. The main concerns were: safety, rearward vision and aesthetics. Safety was, of course, our #1 concern. We briefly discussed the idea of a bolt in roll bar in case he wanted to remove it at a later date. That idea was quickly scrapped because there was no way to design anything that would be safe and bolt in. So, we set out to design something that would enhance the value of the car by adding safety and performance (chassis stiffness).

Once we had the car apart, we looked at the factory decklid support bar. There has been some discussion on the Viper forums about this bar providing rollover protection. Unfortunately, this bar is basically a bracket to hold the decklid hinges to the composite body. Rollover protection is minimal because of a lack of rear diagonal bracing and bolted construction to the factory bulkhead.

It was decided to fabricate a complete roll bar to tie in the rear bulkhead to the frame and rear shock mounts. We noticed a couple of areas that would need to be reinforced. The area where most aftermarket roll hoop rear diagonals are mounted is NOT an actual structural part of the shock mount (see picture below left) and the bolt is basically threaded into 14 ga. sheet metal(!). We fabricated brackets (1/8" steel) to box in the mount and reinforce the top plate. We also custom machined two parts; one below threaded to recieve a 7/16" bolt and another above welded to the rear diagonal. We then welded the lower assembly together strengthening the upper shock mount and providing a solid anchor point to attach the rear diagonals.

The next area that needed attention was at the lower frame rail where we were to tie in the main hoop. We decided to reinforce with 1/8" plate to box the end of the frame rail and to solidly tie the hoop to the frame and bulkhead. The rear bulkhead also needed to be slotted for the tube to pass through and the factory sealant and paint removed.

Now that we had everything reinforced, it was time to bend the chromoly tubing to fabricate the actual bar and rear braces. We added diagonal tube braces to the rear reinforced with plate for extra strength. We designed the main hoop to be as tight against the headliner as possible for unobstructed rearward vision and custom appearance. Gussets were also fabricated on the interior to tie the bar into the side frame rails and bulkhead.

After the final fit, we had the roll bar powdercoated and painted a custom red stripe to match the exterior of the car. The bar was then welded and fully gusseted to the chassis and finally sealed with factory urethane for corrosion resistance. The interior was then re-installed with only two small notches necessary in the side panels to clear the bar. Our buddy was VERY happy with the results (so were we). We have all of the patterns to duplicate the roll bar you see here. If you would like one of our roll bars installed in your Gen 3-4 Viper, call or email for an appointment.

Viper onboard fire suppression system