. . .Playing by the Rules
SWC racecars are supposed to look like they came right off a showroom floor. Don't believe the hypein the first of two parts, Jeff Glenn goes inside Doug Rippie Motorsports to see the extras SCCA doesn't talk about.
Photos by DRM.
Building an SCCA SPEED World Challenge machine ought to be easy. This is a series for production-based cars with sealed engines and strict controls over modification. They look like something you'd find in your driveway, only with gutted interiors, more stickers, no ride height, and big wheels. Get a car, get a MIG welder, and you're ready to hit the track, right?
Not exactly. And here's why: Because racing is all about rules. Not speed. Not glory. Not bravery. Not technology. Rules.
Which makes sense, really. Without rules, every race for the last 30 years would've been won by a Saturn V rocket. The object isn't really to go fast as you can, but to go fast as you can under a precisely circumscribed set of conditions. At the most fundamental level, it's in the meeting, probing, rethinking, and sometimes flouting of the rules that all races are won or lost. If it weren't, the guy with the NASA patches would just win every time.
Now narrow that idea down to the realm of Corvette racingthe SCCA SPEED World Challenge, in particular. This series, which fits somewhere between amateur club racing and GM's assault on Le Mans, grew out of Showroom Stock of the '70s and '80s. The latter is remembered today as yet one more once-popular series that proved cheap racing never remains that way. In its latest SWC incarnation, the series doesn't even pretend to be cheap. Instead, the rulebook lays out a season of 50-minute sprint races with enough TV coverage and car-to-car equalization to tempt dozens of high-rolling race teams to take their favorite brands to the track. Corvettes compete in the GT category against a wide range of coupes and sedans sporting anywhere from 425 to 550 horsepower. The SCCA would love you to think these are quite like the cars you and I drive, but that is a big, fat lie.
Just ask amateur racedriver Ed Braswell. Braswell worked his way up from club racing and is ready to take on the World Challenge. When he isn't driving Ed runs a successful construction company out of the Florida Keys, so funding is not a huge problem. Last year he sampled a C5-era Z06 in the series, but after carefully reading the rulesyou see a theme coming herehe came to believe that a C6-based entry was smarter. Under SWC rules the Z06's aluminum frame is illegal, and even a regular C6 has to weigh 50-odd pounds more than a C5. On the other hand, it gets to run more displacement, the transaxle sits farther back, andif clad in light carbon-fiber bodyworkthe extra mass can be placed very close to the ground.
Ed contacted Doug Rippie Motorsports, with whom he'd already built several street and track cars, with his goals and his budget; Braswell figured his "production" Corvette racecar would set him back about 150 grand. For one-sixth that he could've gone faster in a secondhand Formula Mazda, but that was beside the point. Different series. Different rules. Apples and oranges.
Doug Rippie cut his teeth on Corvettes. The man grabbed a '72 regional championship in SCCA with one and built his own '84 GT1 version to win a Central and National Championship. He co-drove winning Showroom Stock C4s and earned big Corvette credibility with a star-studded driver lineup for '88 and a dominant four-car team in '89. Then came a '92 World Challenge title, a '95 Le Mans entry, simultaneous high-output street programs.... You get the idea: DRM had been through this drill before. They knew how to read rulebooks and knew how to come up with competitive racecars. They even knew Ed Braswell and knew that he'd see it through. The only thing different this time around was that Rippie would be letting us ride into the storm with him along the way. And what we found out in the process surprised us.
For one thing, you'd think it would all start with a shiny new C6, or at least with a shiny new C6 chassis. Au contraire. Why spend a pile of money on something shiny when the ugly but perfectly usable equivalent can be had on eBay for 750 bucks?
The chassis arrived in October, considerably burnt around the edges having just come through a summertime LA County firestorm. DRM knew they could treat the charred chassis exactly the same as they would a brand-new onepine-tree fires don't get hot enough to damage steel, they just make it look pretty darn awful.
After stripping away all the glues and coatings and cutting out the burnt cinders of flooring and gas tank, DRM hauled the frame to a local commercial stripper. There it was bathed for the better part of two weeks in a heated, electrolysis-inducing solution charged with five volts of electricity.
After its refreshing vacation at the chassis spa, the frame came back to DRM a little easier on the eyes and a lot easier on the welding gear. In no time at all it was flipped upside-down and the original jacking points were removed, reinforced with tubing and steel plate, and reinstalled. "The stock points on the frame tend to get crushed with all the jacking a racecar endures," Rippie says. "Plus, since the car will end up too light [by SWC rules] at the end of the build anyway, it's a nice place to add a little weight way down low." Provisions for holding the new fuel cells were fabricated at the same time.
The chassis was then righted and all non-essential brackets were removed. Next on the schedule was supposed to be fitting the bodywork, DRM's plan calling for mocking up the new skin before beginning the welded-in rollcage. Fine idea, except that the body parts never showed up. To kill time the shop started fabricating the engine mounts, headers, and exhaust system instead, using an empty block as a template built out with correct cylinder heads and the right dry-sump pan.
"It's important not to forget the head gaskets when making this stuff," Rippie muses. "If you don't, suddenly everything no longer fits during assembly." Sounds like the voice of experience to us.
Two sets of headers were constructed, one boasting marginally longer primary tubes than the other. These will be interchanged as needed to set up the car for faster tracks like Road America or twistier ones like Infineon. Fabrication of the terminal outlet was made more complex by the use of a Boom Tube-type tip. This flat, wide dump system was originally dreamed up by aerospace engineer Boyd Butler and first used in NASCAR during the mid-1990s. By swirling the exhaust in a way that creates lower pressures than regular outlets, the Boom Tube puts out a higher-frequency sound with fewer decibels and a small but noticeable rise in volumetric efficiency. Adapting the system to the Corvette required cutting a slot through the chassis, reinforcing the frame all around the hole, and carefully reshaping the floors on the passenger's side to maintain ground clearance at roadracing ride heights. Rippie has had luck with these units in the past, but you never know: If it doesn't deliver for Braswell, they'll have to reshape the chassis to fit a conventional system.
Carefully reading the rulebook started the work under the hood as well. As determined by SWC officials, the engine in a GT entry can be balanced and blueprinted but can only use its original parts or pieces of equivalent size and weight. Once it's been checked for compliance, officials even seal up the engine to discourage creative tampering. Dry-sump oiling and engine-management software are open, while traction-control isn't allowed.
DRM ordered the parts for the engine in December. By the first week of February the six-liter, LS2-based short block was assembled and its cam timing had been set. The rules don't allow significant mods to the heads, only changing out valves and springs.
Just as they were prepping the motor for its first dyno session, DRM got a call from the SCCA looking to schedule its SWC GT inspection. "I figured they'd want to see all the paperwork on the parts, see the boxes, and then seal up the engine as soon as we bolted the heads on." Instead, once the inspector flew out he wanted to weigh the crankshaft and all the internals. That meant DRM had to disassemble the built-up block, let the inspector do his thing, then put everything back together a second time. All told, this ate up a week of the already tightening schedule.
The much-delayed bodywork showed up in the third week of January. Frustrating, but there wasn't much DRM could do about the delaythe way the rules were written, it could only be purchased from one supplier.
The new carbon skins were temporarily placed over the chassis, after which the stock B-pillar halo structure was removed to make way for the new cage. Between the low-volume, handmade composite parts and the one-off construction of the cage and brackets, fitting a new car's bodywork and substructure is always a time-consuming puzzle: Put a piece on, mark where it needs to be modified, take it back off, cut it, sand it, refit it, mark it again. The process repeats itself over and over until every piece relates perfectly to the rollcage, the chassis, and all of its external neighbors.
The rulebook allows a fair bit of modification to brake hardware, so a system was laid out with huge rotors, Brembo monobloc calipers, and air ducting right through the rails of the chassis. "We grab the air and put it into the frame rail, then direct it out near the wheel and attach a duct there; that way you're not fighting all that ducting stuffed in the suspension when you're trying to turn. We've done it that way since '92, and now several others are doing the same thing," Rippie says. The hardware was mocked into place pending the arrival of several key suspension components from Pratt & Miller, another SCCA-mandated supplier. It's legal to move the front-suspension pickup points by up to 25mm, but doing so isn't always successful. The geometry change demands careful calculation lest the effects come out unpredictably.
With the Corvette's debut scheduled for the first race of the season at Sebring on March 15thSWC will be an appetizer to the 12-hour ALMS season-openerDRM expects a busy month ahead. It's hard to predict the snags and traps they'll hit next, but when I ask if he figures they'll make it, Rippie pulls out his poker face. "Oh, it's too early to tell," he says. "We're waiting on some key pieces and there have been delays with several suppliers. We'll know pretty soon."
You have to assume it's a routine Rippie's gone with before; either way, CM intends to stick around and find out. Hopefully, the second half of this story will see Ed Braswell driving the car on its first laps at Sebring. In the next issue we'll know for sure.