The mechanical build also sets the DSC Sport Active damper apart from all other class competitors. Offering the finest guide seal, piston, and shim stack arrangement on the market (.01mm guide clearance), the DDA valve incorporated damper withstands heavy load changes with no signs of hysteresis or stiction. Each design is tested on a shock dyno at 17 million cycles and must hold 85% of its damping performance to be approved for production. The result is the world’s most versatile suspension system that provides a previously unheard of combination of race-winning performance on the track and daily driver comfort on the street.

Porsche’s Cayman GT4 is a wonderful car that is an absolute joy to drive. And that’s just it – it’s meant to be driven. There’s so much to love from a true driver’s perspective. Mid-engine platform, manual gearbox, its 3.8L NA flat-six engine that pushes 385hp from the crank. It really is one of our favorite Porsches. However, it does have a few shortcomings as you begin to push its limits on the track.

It’s been well documented, by elite race/test driver Randy Pobst and others, that the GT4 suffers from a case of understeer from the factory (see here, here, or here). Pobst also mentions that, on track, the Cayman GT4 feels “slightly underdamped,” particularly over bumps. As long time friends, TPC Racing owner Mike Levitas has discussed these characteristics at length with Pobst, exchanging notes and feedback on the GT4’s handling on track. Using a combination of data gathered at the race track and notes provided by Pobst, Mike has spent the better half of the last year sorting out the balance of the GT4 for track use.

Understeer

The TPC Racing Stage 2 GT4 Suspension includes a DSC Sport controller with a GT4-specific calibration table, rear toe links designed specifically for the GT4, and TPC Racing proprietary sway bar settings and alignment specs. Together, the components of the package work together to reduce understeer and improve damping for a better handling and perfectly balanced Cayman GT4.

Masking the understeer issue is pretty easy to do. In fact, Randy already shared his trackside quick fix in his second Motortrend review of the GT4:

I got so frustrated that I crawled under its gorgeous body and adjusted the anti-roll bars myself: full soft front, full hard rear, textbook to reduce understeer. It certainly helped, but the overriding feel remained a numbing push, hurting the response through the middle of the corners.

However, as his experience suggests, adjusting the sway bars doesn’t fully solve the issue with understeer the car has coming out of the factory. The other inexpensive – and vital – step in reducing the GT4’s understeer is a proper alignment, which Randy also addresses in the same article. It’s something the TPC Racing team does very, very well.

Identifying the Problem

However, Mike Levitas adjusted the sway bars and aligned the car. And aligned it again. And aligned it a few more times. However, regardless of what he did, he continued to walk a fine line between that numbing understeer and dangerous snap oversteer. So he looked at the data. Based on the data from multiple outings at Virginia International Raceway and Summit Point Motorsports Park, Mike determined that the rear toe curve was the culprit. One can set the static toe settings exactly where they should be, but as the suspension travels the toe curve produces some less than ideal characteristics.

Finding the Toe Curve

After multiple progressions of track days, street testing, and parts development, Mike developed an improved toe link specifically for the rear of the GT4 that reduces the toe deviation. The package, paired with the proprietary TPC Racing specs, allows for optimal toe settings, both statically and when subjected to suspension travel in high load applications. What this means is even at the highest of g loads the toe settings are still optimal for grip. In fact, it made such a vast improvement we were able to soften the rear dampers using the DSC Sport controller for even more grip on both corner entry and exit.

Paired with a DSC Sport controller to improve damping, the TPC Racing GT4 Toe Link Kit transforms the GT4 into what it always should have been from the factory: a perfectly-balanced mid-engined, normally-aspirated, manual transmission drivers’ car that is just at home on the track as it is on the street.

While TPC Racing already offers a toe link package for the 981 and 718 that fits the GT4, it is the proprietary offset bushing design that sets this package apart from any other GT4-compatible toe link package on the market. This is the only toe link package on the market designed to optimize the toe curve on the rear Macpherson strut design of the Porsche Cayman GT4.

In the words of Randy Pobst himself, “I marveled at the balance and control of the TPC-tuned Porsche GT4 I drove at Summit Point. TPC Racing makes this great car better to drive.”

The mechanical build also sets the DSC Sport Active damper apart from all other class competitors. Offering the finest guide seal, piston, and shim stack arrangement on the market (.01mm guide clearance), the DDA valve incorporated damper withstands heavy load changes with no signs of hysteresis or stiction. Each design is tested on a shock dyno at 17 million cycles and must hold 85% of its damping performance to be approved for production. The result is the world’s most versatile suspension system that provides a previously unheard of combination of race-winning performance on the track and daily driver comfort on the street.

I have just spent a few days driving various other “sports” cars in day to day street driving meaning real roads, cambers, crappy surfaces nice surfaces etc etc.

I got back into my 7GT2 this morning and I simply cannot believe how resolved and sophisticated the chassis is. My car wears full solid bushings pretty much everywhere, Cup 2 tyres with 245 at the front and the full DSC Sport shocks/Swift spring/DSC Sport Controller.
The car is incredible, the most amazing thing to drive in everyday street driving it soaks up bumps, the steering is scalpel sharp, the power goes down well as the softer initial springing delivers more grip than one would imagine…. today I’ve been driving in 3 degC dryish conditions on Cup 2s and the car is a pussycat sure it is a lively pussycat but an absolute delight for anyone who actually enjoys driving…
Of course the party trick of the set up is when one goes fast, really fast, everything tightens up and the car is a ballistic go kart – frikkin unreal.

Just thought I’d do some flag waving here as I have always been (and will continue to be no doubt) a major sceptic on any “revolutionary” new product and I held off buying this for way too long. If you have a 7GT2/3 and you actually use it on the road then this will be the best thing you ever bought for it, as for its track credentials well the TPC team seem to do pretty well using this setup on their race car. Yes it’s quite expensive but it is high quality and will doubtlessly retain its value if you decide to sell your car – all GT2/3 guys without this kit should be having major FOMO – get your credit cards out and live it — tb993tt, Rennlist

Tractive has developed the most advanced and FASTEST responding electronic actuating valves in the market to control and manage electronic dampening systems. Countless calculations have been performed before the first prototype of the Tractive DDA valve was put to the test. The aim was high, the fastest moving and most stable bi-directional, internal proportional, damping valve with the upmost linear adjustment behavior possible. A valve that wouldn’t be impressed by working temperatures below -30 C or above 140 C. These DDA valves, which are patented, also are widely used in the BMW/KTM motorcycle industry ESPECIALLY BMW as well as other automotive manufactures. If you are familiar with WP Suspension, the owners made Tractive in order to advance themselves into the automotive industry with their vast amount of expertise and engineering experience to provide the highest quality dampers possible on the market for automobiles. Tractive kept in mind during the design process the location of where the DDA valve was to be located and carefully chose for the added benefits in regards to any environment for the fastest moving parts with respect to cooling, lubrication, and corrosive and environmental influences.

The DDA valves curve is controlled by the DSC controller which allows for the fastest reaction times based from LIVE CAN various inputs from the vehicle which allows reaction time within 6 milliseconds! The DSC Sport controller is a MUST with the Tractive RT damper package. The seals to the Tractive dampers are a proprietary design that offer the lowest stiction in the industry. Guide clearance and sizing as well as the tightest in the industry. The DSC Sport Controller allows for NO MORE TOOLS NEEDED! This added benefit is great in itself, you won’t have to ever worry about getting the car up in the air or pulling out a screwdriver to adjust your compression and rebound, this can all be adjust via DSC Sport controller! You get a TRUE active working suspension thanks to DSC Sports controller algorithm and the LIVE CAN data it sees from the vehicle the DSC Sport controller managing the Tractive RT (or other brands) package gets input from Acceleration, G-force, Velocity, Steering, Brakes, Speed, and more incorporated into the most advanced algorithm (with over a decade in experience handling CAN data, algorithms, and calibration file tuning on our own product) to give you the best and most affordable bolt on product out for main stream manufactures being the DSC Sport controller.