PRI 2016: Porsche Cayman GT4 Turned Racecar By Bilt Racing Service


The GT4 Cayman project car sat at the CSF booth at PRI, and it looked menacingly ready for the track, albeit too clean for a racecar. The overwhelming desire to meet the team that built this Porsche GT4 Cayman lead us to Pawel Bulka, of Bilt Racing Service (BRS) in Illinois, and we soon found out why this Cayman looks so new-because it IS new.


This Porsche Cayman GT4 started out its life just like any other Porsche, sitting at a dealership in full street-car attire clad with a full interior and 6 speed transmission. With only a few miles on the odometer, its transformation began. Geoff Isringhausen from Isringhausen Motorsports, who is a huge import dealer who buys and sells racecars, bought the new Porsche Cayman GT4 and immediately had it shipped to Bilt Racing Service with the intent of building a competitive GT4 style car that can compete in PCA, SCCA, and NASA.


This will be a great new platform to start with, as Pawel told us that they ran the Clubsport version of the Cayman last year, but it wasn’t as developed as they though it would be from the factory. Last years Cayman came up short on several areas, including power, suspension adjustability and rear downforce-so BRS was hoping to fix all that with the new GT4.

Bulka told us that once they decided to do a GT3/GT4 type car out of it, “big aero, big splitter, big horsepower” is what they were after. Starting off with wind tunnel testing, BRS found that the factory rear wing was much too small, and wasn’t high enough. They remedied that by installing a 63-inch carbon fiber wing, placing it more toward the rear bumper and higher up near the roofline to help capture some of the cleaner air off the car. Once the rear wing was sorted out, a larger front splitter was required for improved front downforce and to help balance out the larger than factory rear wing.


When it came time for suspension, KW was their first choice. Pawel told us that KW had made them non-adjustable suspension which was used on their Clubsport from last year, but for the new GT4 they now have 3-way adjustable shocks which were the very first ones developed for this car. “We did a lot of testing with them [KW] five years ago at Daytona, so we already had a really good baseline shock. They made it in physical body for the GT4-So it was a nice bolt-on, an easy transition for us.”


We found out that one of the challenges for the car was the roll cage, which was completed in house. Since the car is mostly aluminum, finding acceptable mounting points were limited. However, because of their experience with the 981 platform from a few years ago, BRS had most of it figured out. “Luckily we were able to bolt the roll cage front and rear to the strut towers. and inside the car the rocker is steel, so we were able to weld the main supports to the rocker.” Bilt Racing Service is starting to work with T45 tubing, which is fairly standard over in Europe; most of their FIA homologated cars are made with T45. “So we’re importing that tubing which makes this car one of the first here.”


“A lot of vendors out here at PRI-we’re using their products” said Bulka, and that was heavily evident with even just a quick glance at the car. PFC Brakes are installed on the GT4, and they’re the new Clubsport version that were recently developed. To top that off, the lightweight and performance matching Forgeline Wheels create a proper appearance for the Porsche. “We are trying to shop with all the people that support us.”


Making a difference, but unseen, is the Cayman exhaust which has Headershield wrap on it. “We’ve been talking with PRI magazine and other people about it. Its a silica fleece with stainless shell on the outside-a lot better than header tape, a lot better than jet hot coating.” BRS  found about 50 percent reduction in radiant heat, and they picked up some horsepower as well. On this Cayman GT4, an extra three horsepower was found. Although that might seem like minimal gains, it can make a substantial difference when trying to extract every bit of power.


The Cayman GT4 is also running CSF’s new three piece radiator setup, and Pawel tells me that the center setup uses a much wider core than the factory piece and features B-tube technology. The tanks are welded versus fused plastic like the OE radiator-so they can take a hit when racing. “In road racing and other types of racing you’re bound to get out of shape with the car, come too close to someone else, and these things take a hit and keep going, as well as being much better at cooling. We’ve seen about a 10 degree temperature drop with their products.”


The BRS Cayman GT4 made 387 wheel horsepower, but they still have a little more dyno tuning to go and are exploring a few other options to elicit power where they can. “We’re really excited because we feel this is the car that will be a great GT4 contender … Globalization motorsports is happening, so we want to be on the leading edge,” which is why they’ve tried to pick and choose the vendors they have to achieve this build. Bulka told us that the future for the car is currently set for club racing and will see further tweaking once they start racing it.

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About the author

Charles Pages

With an ever growing passion for cars, trucks and things that go fast, Charles is always seeking new information and ways to increase vehicle performance and handling. With experience among diverse vehicles, Charles gives an enthusiastic "YES" to anything performance.
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