Levers are simple machines that increase torque by trading required force for greater distance. Finger tightening a nut is hard, tightening a wing nut is easier, tightening a nut with a wrench—piece of cake; the longer the lever arm, the less force is required. But the force has to be applied over a greater distance. Gears are essentially pinwheels of spinning levers. The radius of a gear is the length of the lever arm, and by varying the size of paired meshed gears, you can have multiple ratios running on the same input and output shafts—we call it a transmission. Some of us, apparently fewer and fewer every day, enjoy selecting those gears on our own. Alex Ross of Sharkwerks is a gear-changing enthusiast, so it makes sense that his company, which is known for making fast Porsches faster, would turn its attention to one of the best examples of Stuttgart's shiftable masterpieces, the Cayman GT4.
The Cayman GT4 transmission has six gear ratios—and reverse, but we'll just ignore that. The lowest gear, First, uses the biggest moment arm for maximum leverage or torque to get the car rolling. To review, your mechanical advantage comes from exerting force over a greater distance, in this case that distance is rpm. This is why the lower the gear, the greater the torque applied to the road, but the lower the speed of the vehicle. A Cayman GT4, for instance, does roughly 47 mph at its 7,600-rpm redline in First. The engine itself develops the same amount of torque in any gear, but it's the transmission that is converting that force over the distance.
The initial drives of the Cayman GT4 left both customers and journalists blown away by the car's handling, driver involvement, and power delivery. The actual shifter mechanics in the car might be in the top five ever produced; off the top of my head, I can't think of another car that shifts better. One of the very few laments from both reviewers and owners with the car is that they simply don't get to shift enough. The Caymans: S, GTS, and GT4 all share the same tall gearing better suited for high-speed European tracks and autobahns. As previously mentioned, these cars will all do 47 mph in First and will get you to an illegal-on-American-public-roads 81 mph in Second. You can get yourself thrown in jail by only using Third, which tops out at 111 mph. This continues on a predictable path until you get to the top of Sixth gear at 194 mph at redline. None of the aforementioned Caymans or Boxsters that share the same gearbox will do anywhere near 195 mph, but the lower rpm on the highway is better for fuel economy.
As already mentioned, Alex likes shifting, and with those really tall gears, he found himself sticking the car in Third gear and leaving it there for just about every canyon run imaginable. The GT4 makes its peak torque of 309 lb-ft from 4,750-6,000 rpm, which means in canyons, anywhere from 4,400 rpm to redline is pretty exhilarating.
The easy way out would have been to just change the final drive ratio, which is the gearing that turns the differential itself. This would have made even more sense, since Sharkwerks changed out the factory limited-slip differential for a more aggressive piece from Guard. The final drive, however, would have essentially changed every gear, and Alex was already satisfied with First and Second—and Sixth as well, but more on that later. Instead, new gears were built to order for Third through Sixth on this car. Alex recommends the factory Sixth gear for most applications, as you will hardly ever use it for anything other than highway cruising.
Sharkwerks is known for its larger displacement engine builds; however, this car is fitted with just bolt-ons. First, an air filter upgrade from BMC takes the place of the factory paper element. Then an IPD Plenum is used for more flow and uses a larger 82mm throttle body out of the Porsche parts bin. On the exhaust side, CarGraphic sport manifolds flow into the factory mufflers, but the very last section now consists of an X-Pipe, which culminates in two larger tips. Finally, the ECU was reflashed using EVOMSit software, which all adds up to a claimed 415 hp at the crank—and we can't mention the crank without also mentioning the Sharkwerks clutch and flywheel package, which saves 15 pounds compared to the factory equipment.
Since the car has more power, better gearing, and is quicker revving, you might be wondering what Sharkwerks has done to upgrade the suspension. The company dialed in the alignment. That's it; that's all that is needed. Like I mentioned, this is already one of the best cars of the 21st century in terms of handling. The first time I drove this car at Road Atlanta, my initial thought was it would be tough to make the GT4 any better without compromising driveability on the street. Apparently, Alex had that same thought and decided to leave well enough alone. From the factory, this car comes equipped with the front suspension setup from a 911 GT3, which is pretty much as good as it gets to begin with. The rear suspension is the standard MacPherson Strut units of all the other Caymans and Boxsters out there, supplemented with a few stiffer bushings and adjustability thrown in. It is also very good, but like all MacStrut setups, it doesn't like being over-lowered. It throws off the geometry, lowering the roll center and increasing the roll couple. I know Porsche gave it adjustable height coilovers from the factory, but avoid the temptation—lower isn't always better.
For a tire, you can't get any better than the stock Michelin Pilot SportCup 2, and the factory size is pretty much all you're getting under the car. He did, however, add a set of Fifteen52 wheels from the Urban Outlaw Collection.
There are a few other aesthetic mods, including longer uprights for the rear wing, which keep it out of the driver's view and increase downforce. On the front, canards (or "dive planes") stick out of either side of the front bumper. Are they effective? Well, they really make the car look a whole lot faster.
Possibly the most important exterior modification is the affixation of the #PDKREXIT sticker on the right-wing side plate. Alex is an Englishman and during the whole Brexit fiasco, he coined this term to describe his feelings for Porsche favoring the dual-clutch transmissions. This car embodies that feeling, not only toward PDK, but also the naturally aspirated engine, the lack of rear-wheel steering, the lack of a torque-vectoring differentials—all the things that make current Porsches so fast, but to guys like Alex, less involving.
I can argue back and forth all day about the merits of technology and its place in the car world. I appreciate both sides of the argument. In the end, what matters most to me is the driving experience. That's why we took the car up to one of California's finest roads to get an idea of how this modified GT4 works in the real world.
First and foremost, what you should know about the experience of this car is nothing has been done to take away from the fact that it is a Cayman GT4. Not only is it a GT4, but it is still a GT4 designed to be enjoyed primarily on the road with occasional track days. It hasn't been turned into a race car. It hasn't been turned into a mid-engine GT3RS. This is a re-geared and slightly personalized GT4.
My first experience with the car is with Alex sitting shotgun. He walks me through some of the features on the car, a little bit about the ratios, and a lot about why he thinks most people are doing too much to these, quite often before the owner has any real experience in the car.
Initially, the car doesn't feel that much different from my recollection of the last GT4 I drove on the road. On the track, with factory road alignment settings, the car understeers to the apex and then wants to step out at exit. With a track alignment, which I suspect the cars had the first time I drove them, it is much more balanced but still leans a little bit toward understeer—generally a good thing. With a passenger in the car, I didn't get anywhere near the limits.
Pushing a little harder allowed me to get the car up into Third gear, and the shift wasn't a huge step like I remembered. I wasn't shifting anywhere near redline, which means the shorter Third gear was even more appreciated. The shifter action is still mechanical bliss. I can't really say I noticed the lighter flywheel.
The car sounds just right, especially having driven the new 718 just a few weeks prior to getting into this car. It isn't a loud car, which is a good thing when you're on a road routinely monitored by Highway Patrol and Rangers. All they have to do is sit at the bottom with their windows down to see if it's worth heading up the mountain to hand out a ticket.
After a few hours of photos, I jumped in the car unsupervised. There is one particular section of the road that is very tight and technical. My favorite cars through it are still the Lotus Exige and the Mini Cooper S, if that gives you a feeling for scale. It is still very quick, the turns are cambered, the sightlines are good, but with stonewalls on one side and a double yellow on the other, it doesn't suffer mistakes kindly. This Cayman, with its surgically precise steering, predictable throttle response, and responsive PCCB brakes is a pleasure to thread through here, unlike a 911, which has outgrown this section of road.
Keeping the car around 5,000 rpm going back and forth from Third to Fourth reminds me why I like manuals. I kept the car in Normal Mode, as opposed to Sport, so I could do the rev-matching myself. In Sport, the car auto-blips for you to rev-match on downshifts; one step closer to PDK. This is where, I think at least, I noticed the lightweight flywheel. I was curious if making the car rev faster would confuse the auto-blip. I tried; it didn't.
On some of the faster sections of the road, I found myself stretching out the gears a little more. Shifting from Second to Third at redline resulted in a 1,400-rpm drop. Running up to 7,200 rpm in Third and then dropping the shifter back to Fourth results in just a 1,200-rpm drop on the tachometer. If you are really pushing hard, you need to shift again, and quick.
I continued slashing around, following the contours of the mountain, mostly staying in Third and Fourth, but a little lower in the rpm range. The shifting in this car is so natural, it becomes a dance. I normally want my shifting to disappear into the background; I only care about getting corner to corner; what happens in between is irrelevant. With this GT4, everything is happening in one mechanical string of movements. I find myself thinking about #PDKBRXIT T-shirts and license plate frames.
I will be honest, in this canyon, I couldn't tell the difference with the new limited-slip differential. If there would have been a stock car to compare to, maybe; I think the real difference would probably come on a racetrack, trying to get out of lower speed corners.
So the question is: If I owned a GT4, would I do this to my car? Re-gearing Third, Fourth, and Fifth will set you back about $5,400 with labor. The lightweight flywheel and sport clutch is an additional $2,400 and the Guard Differential is $2,900, so we are talking about $10,700 for all three. The thing is, if you're doing the gearing, you may as well do the diff and clutch since you're paying for the labor anyway. I would have trouble laying out that kind of cash if it weren't time to replace the clutch. If it were clutch time, then sure.
I am still of the opinion that the best thing you can do for a GT4 is a good alignment, driving instruction, and money set aside for tires. If you must play around with the car, then this is the best thing I've tried yet. It is possible to make the car better with just a little more mechanical advantage. Remember what Archimedes said, "Give me a long enough lever and a place to stand, and I'll move the world."