OT: GSpeed 1996 Viper GTS Build

[GSpeed]

As many of you are aware, GSpeed acquired Performance Speedtech in August of last year. Performance Speedtech was a well-established sports car shop in Cresson, TX at the Motorsport Ranch with a history of racing Vipers since the early 2000s. As part of that merger, we took over the build of the owner's 1996 GTS with the goal of making it the best Viper racecar we could. Some of you may laugh at the idea of making a Viper handle, but you'll see the crazy lengths we had to go to make it happen.

We know this isn't a BRZ or FR-S, but this build has been so crazy and so much fun, we figured you might enjoy reading about it.

First, a little backstory.



The car was purchased by its current owner in 2002, and immediately became a time trials car. It spent the next few years racing SCCA T1 around the Texas region, and in 2004 held the T1 track record at Hallett Motor Racing Circuit in Oklahoma.







In 2008, things started getting serious. Gone were any pretenses of being a street car, with a full cage, stripped interior, carbon dash, and a mean-looking flat black livery.



In 2009, the car got a Motec M800 ECU, as well as an ADL3 dash logger. A Quaife ATB differential was also installed. About a year later, the T56 was tossed and replaced with an Emco DV46.





In 2011, a Bosch M4 ABS system was installed in time for the 2012 season.



The car ran very strong, but finished its last race of the 2013 NARRA season (at Texas World Speedway) barely holding together. The ball joints were crashing, the crankshaft had started to crack and was breaking all sorts of other parts with nasty harmonics, and it was clear it was time for some serious upgrades if the car was to go any faster. The car was put under the knife to take a serious look at the suspension geometry.

Then GSpeed entered the picture.

After talking over options with the owner, we all agreed anything worth doing was worth doing right. We set out with the goal of making the best-handling 2nd generation Viper road racing car in existence, fully aware of the magnitude of what we were planning.

The first step was to figure out what we were working with. The car had been a road racing car for 15 years. Combining mid-90s Chrysler build quality with a hard life meant nothing could be considered straight or true. To do it right, we 3D scanned the entire chassis with a laser scanner, using a CMM probe for super-critical measurements.







At this point, we locked our engineers in their office, and a few hundred hours later, we had designed what amounted to a totally new racecar built on a Viper frame. Every pickup point and shock mount on the frame would be removed. Using the frame and bodywork as rough boundaries, every kinematic dimension of the suspension was analyzed as if it were a professionally raced GT car. The suspension is optimized for a 3" ride height at the front axle, and designed around the Michelin race slick in 30/65-18 and 31/71-18. Since it's a "real" racecar now, all bushing and ball joints have been replaced with aircraft-grade spherical bearings. The only rubber on this car is the tires.



Here's a shot of the in-process finite-element analysis we performed on all the critical parts to make sure they were up to the task, and not TOO heavy.



In order to make the control arms as long as possible, we had to work closely with a good wheel manufacturer. We worked with Finspeed to develop a custom offset for this car to give us as much room for the brakes as possible, and push the hub as far outboard as we could. Here's a shot of the F110s for their first test fit:



The owner was adamant about keeping the OEM frame rails as much as possible, so cutting off front and rear frames and replacing with tubular spaceframes was off the table. We didn't have a chassis table to put the car on in the new facility yet, so we had to build in place on the lift.

The welding fixtures were somewhat creative, but ultimately gave us what we needed. They contacted the frame at only 4 points, and allowed us to true up the suspension "boxes" (sets of pickup points) to each other, and to the frame. You can see the massive holes cut in the frame to clear the new pickup points.



The pickup points were then boxed into the surrounding frame, and heavily reinforced. The amount of hairline cracks we found around the factory welds was troubling. Not going to be a problem anymore!





We have a 3D printer we designed and built in-house, and one of the parts we had in mind was prototype uprights. Here's the plastic version, and the real version of the upright we designed for this car.



The first time we put the front wheels on with the new suspension, it was clear how significantly we'd altered the car. The front wheels, which used to tuck inside the front fenders, now stuck out substantially. Nothing a little carbon work can't fix!



Here's a shot of the new brakes. 29mm thick pads!





Here's the first time the car sat on it's own wheels since 2013:



Very significant event for us, and you can bet the shop emptied to come check it out and take pictures! Shortly thereafter, we dyno'd the car at 670whp and 690 lb-ft. The owner wants to keep the engine build specs a secret, but for an 8.6L motor, there's definitely more power left to find.

After a few test days, we took the car to Hallett for its first race since the rebuild. Despite a few off-track excursions, the car proved to be extremely durable!



[ame="https://www.youtube.com/watch?v=4qF__0RC1lk"]Viper SU90- Hallett NASA TX Summer Shootout Race 2 - YouTube[/ame]

The car qualified with a 1:18.6, and ran a 1:17.7 in the second race on Saturday! We weren't able to run the third and fourth races on Sunday, but we were extremely happy with the car's performance. Tire wear was amazingly even and smooth, and despite the rough track we didn't have any mechanical failures.

We've already got some more improvements on the way. The 1 5/8" headers have been replaced with 1 7/8" units, and we've got a new intake manifold being made. The goal is north of 800whp, which should be easily doable.

See you at the track!

Jake

[OkieSnuffBox]

Very nice and my home track!

Watch the the modified/whatever car in the 4/5 complex at the 5:00 minute mark, I'm convinced a car with aero, that is the proper turn-in for 5........no need to hang out wide all the way to "turn-in marker" of that tiny curb. Turn in midway, and and put the middle of the car over that curb for 5.

I'd be interested if he tested both lines and what the results were.

At least he was hugging the intro to 4 instead of staying out wide.

[solidONE]

Nice body kit on that BRZ! lol

[redlined600]

Thanks for sharing. Love the shock mount.

[Racecomp Engineering]

Goodness....very impressive work!