If you've ever seen a Porsche Supercup race, you've probably wondered how you'd fare in the Porsche's GT3-based spec series. And if you haven't, then you must have thought about what it would be like to drive one of these cars on the street...
In fact, you can get a fairly good idea of what a Cup car is like if you've been fortunate enough to drive the 911 GT3 RS, because it's actually the basis for the GT3 Cup cars used in the Supercup series. The biggest difference between the Cup car and GT3 RS are the transmissions (sequential for the racecar) and about 400 lb in weight (2646 lb race vs 3020lb road).
I'm sure most of us would be happy with a stock GT3 RS - one of the most focused and least compromising production cars you can buy. But some people, like John Mendoza, don't want to settle for second best. They want to know exactly what it would be like to drive a Cup car, so he did something about it...
His quest to build his own GT3 Cup car started when he loaded his 2007 997.1 GT3 on a trailer bound for Tennessee, signing the title over to the new owner. And in a classic case of not knowing what you've got until it's gone, it didn't take long for him to start longing for another one.
He went one step further, though, and put his name on the list at his local Porsche dealership for the yet-to-be-unveiled 991 GT3. But once he discovered the new car would only be available with Porsche's dual-clutch PDK transmission, he cancelled his order, preferring the connection and control of a manual shift more than the automated one.
Back on the hunt, he started looking for a 997.2 GT3 RS, eventually finding the right example in Florida. It was in Carrera white with red decals and had the lightweight halogen headlights rather than the heavier HIDs.
Once in his possession, Mendoza stripped off the vinyl, bringing it closer to the GT3 Cup car. He then added a Cup front splitter, which extends 15mm lower than the stock part to increase downforce. After that, he swapped the reclining carbon fiber seats, which weigh 39 lb each, for a pair of European-spec GT3 Clubsport seats (the same as fitted in the Carrera GT). Apparently, they cost a mind-blowing $20k, or what we call a down payment on a house!
The next swap was from the stock rear spoiler to the Cup wing. It sits considerably higher, measuring 66.9" to the road car's 57.5". It certainly makes a statement and both the splitter and wing came directly from Porsche Motorsport, costing about $5300.
A few weeks later, he got his hands on a titanium Akrapovic Cup exhaust from Aleks Doba at Alekshop in Fremont, CA. The $7k system was good for an extra 8hp at 3970rpm and, because it does away with the OEM side mufflers, weighed 46.3 lb less than the stock - further improving the performance.
Shaving weight was important because he'd add some with the FIA-approved, European Club Sport, six-point rollcage from Carnewal in Belgium. Installed by Mike Tolle at Tolle Fab in Rancho Cordova, CA, the $10k cage would add 84 lb, but the increased rigidity and safety was Mendoza's main concern with his intention to use the finished car on the track.
The next step was swapping the stock steering wheel for a lighter OMP part from Porsche Motorsport, attached to a Works Bell short hub and Rapfix II quick release.
Then came a CAE shifter from Germany. At first glance it looks like a sequential shifter but actually retains the H-pattern of the stock transmission. The lever is taller, placed closer to the steering wheel for quicker access and Mendoza said the action was "like a rifle bolt."
Wheels are vital to any project build and John was able to purchase the same BBS Motorsport wheels as used on the GT3 Cup car. They help shed some unsprung weight, tipping the scales at 22.2/23.4 lb front/rear versus 23.5/28 lb for the stock rims.
The wheels were purchased through our friend Eric Nareshni at Supreme Power Parts in Placentia, CA, costing about $1600 per corner. He also provided the tires, which are 245/40 and 335/30 Michelin PPS2 on the street. The car runs a second set of 18s at the track, fitted with 245/40 and 305/35 Nitto NT01 rubber.
To date, the suspension remains stock, the GT3 RS set up stiff enough for its intended use, although John plans to upgrade to RSS control arms in the near future.
As a production engine with one of the highest horsepower-per-liter figures in the world, the 450hp 3.8-liter RS motor didn't have much headroom for improvement but John took it to Sharkwerks in Fremont, CA nonetheless. They fitted the EVOMSit software that was reportedly good for another 16whp and 13 lb-ft on 91-octane gas with the stock exhaust. Throw in the Akrapovic system and the engine should be good for an extra 25-30hp to the crank.
As a final flourish, Mendoza revisited his choice of seats, deciding to remove the pricey Carrera GT items in favor of ultra-lightweight Recaro Pro Racer seats. Manufactured in carbon/kevlar and supplied by Griffin Motorwerke, they weigh a scant 10 lb each, counteracting the inclusion of the rollcage.
Some $43k later, John now has a faster, stiffer and more stable 911 GT3 RS, highlighted with genuine Cup parts and a selection of topnotch components. While that's a heavy budget, he can claim that he now knows what it's like to drive a GT3 Cup car on the road.
2011 Porsche GT3 RS
3.8-liter, flat-six-cylinder 24v with Sharkwerks/EVOMSit software, titanium Akrapovic Sports Cup exhaust
six-speed manual transmission with CAE short-shifter
Wheels & Tires
18x9" f, 18x12" r BBS Motorsport wheels, 245/40 R18 f, 335/30 R18 r Michelin Pilot Sports 2 tires (street) or 245/40 R18 f, 305/35 R18 r Nitto NT01 tires (track)
911 GT3 Cup front splitter and rear wing
Recaro Pro Racer seats, Porsche Clubsport six-point rollcage, Porsche Motorsport OMP steering wheel