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Porsche Cayman GT4 Clubsport Build Overview

(2020 718 GT4 Clubsport โ€“ Track Day Edition)

If youโ€™ve followed Racer on Rails for a while, you already know our philosophy: take great cars, make them better, and then drive the hell out of them. This 2020 Porsche Cayman GT4 Clubsport Track Day Edition is the perfect example โ€” a factory-built Porsche Motorsports car with real pedigree and a second life that spans endurance racing, time attack, and driver development.

Before we go deeper, itโ€™s important to understand which Clubsport variant this is, because Porsche built several versions:


718 Cayman GT4 Clubsport Variants

Track Day Edition (This Car)

  • Designed for private owners and track day use
  • Same 425 hp 3.8L flat-six as Comp version
  • Lighter-duty fuel system
  • No air-jack system (but provisions exist)
  • Not homologated for GT4 racing

Competition Version (Not This Car)

  • Fully homologated for GT4 racing
  • Air-jack system included
  • Larger motorsport fuel cell
  • Endurance switches & safety electronics
  • Homologation restricts power/aero changes
  • Carbon and natural fiber material body panels

Newer 718 Cayman GT4 RS Clubsport

  • 4.0L RS-based platform
  • More power, higher RPM ceiling
  • Improved aero and suspension
  • The current model used in IMSA/SRO GT4
  • Much closer to a โ€œmini Cup Carโ€

Our car โ€” the Track Day Edition โ€” gives us the freedom to pursue more aero, more setup range, and more developmental headroom than the rules-restricted Competition version.


Where This GT4 Clubsport Came From

Photos of the car from its Ann Doherty era after arriving at RoR.

This GT4 Clubsport began its life with Ann Doherty, who ran it competitively in SCCA T1 and GT2 before upgrading to a 991.2 GT3 Cup Car.

Because the car came from Ann, we gained two major benefits:

  1. It had been maintained at a true professional standard.
  2. It had already proven itself at a national competition level.

When she moved to the Cup Car, we took ownership of the GT4 and immediately put it to work.


What We Used It For

1. Endurance Racing (2024)

Bombing down Turn 5 at Road America with World Racing League

The first chapter of this carโ€™s life with us was national-level endurance racing:

  • WRL Road America โ€” April 2024
    Our first outing. Strong pace, great aero learning, and flawless reliability.
  • ICSCC Cascade 8 Hours of Portland โ€” October 2024
    A full-day grind that gave us massive data on tire wear, pit strategy, and aero balance.

The car was consistent, predictable, and incredibly reliable โ€” exactly what you want in an endurance platform.


2. OnGrid Time Attack (2025)

With the Dundon Valkyrie aero package installed, the car moved into OnGrid GT+ and instantly became a serious contender.

Huge downforce. Big mid-corner speed. Better braking stability. It was a transformation.

Check out one of the flying laps from this past summer – matching 992 and 991.2 GT3 Cup car lap times!

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3. Driver Development & Testing Tool

This GT4 became one of our strongest tools for:

  • Advanced driver coaching
  • Back-to-back setup testing
  • Tire comparisons
  • Driver development beyond Spec E46, T3, and regional touring classes

Turnkey speed. Zero drama. Endless data.


Factory Specs โ€” 2020 Porsche Cayman GT4 Clubsport (Track Day Edition)

PHOTO SUGGESTION: Interior cockpit photo or engine bay shot.

Engine & Drivetrain

  • 3.8L naturally aspirated flat-six
  • 425 hp @ 7,500 RPM
  • 7-speed PDK w/ motorsport tuning
  • Motorsport cooling system
  • Mechanical LSD

Chassis & Safety

  • FIA welded cage
  • Motorsport wiring harness
  • Composite doors
  • Fire system
  • Air-jack provisions (air jack system not currently installed)
  • Recaro race seat + 6-point harness

Suspension & Brakes

  • 3-way MCS motorsport dampers (upgrade)
  • Fully adjustable alignment
  • Porsche Motorsport ABS
  • Motorsport stability control

Aero

  • GT4-spec splitter but currently running the full Dundon Motorsports Valkyrie Aero package (front splitter, canards, rear wing)
  • Adjustable rear wing
  • Factory Flat floor
  • Factory cooling and airflow optimization

Our Modifications & Upgrades

Dundon Motorsports Valkyrie Aero Package

  • Full-length carbon splitter
  • Functional multi-channel front diffuser
  • Canards
  • Swan-neck rear wing
  • High-efficiency rear diffuser

This fundamentally changes the carโ€™s downforce ceiling and high-speed stability.

Dundon Motorsports Valkyrie Aero front Bumpcer Canards in focus

Data & Electronics

  • AIM data integration
  • Radio/comms upgrades

Race Prep & Setup

  • Multiple alignment profiles
  • Corner balance for sprint, endurance, and time attack
  • Dundon headers/exhaust (optional configuration)
  • Tire mapping across A052, F200, and slicks

Deep Dive: Dundon Valkyrie Aero vs. Porsche Factory vs. Manthey Racing

Porsche Factory GT4 Aero

  • Designed to be predictable and safe
  • Built to meet strict GT4 regs
  • Limited splitter/wing/diffuser scope
  • Great for consistency but capped on downforce

Manthey Racing Aero

  • Refined airflow
  • Cleaner front-end efficiency
  • Slightly more downforce than OEM
  • Still constrained by GT4 rulebook

Dundon Valkyrie Aero

  • Not rule-limited
  • Significant downforce increase
  • Real front-end loading under trail braking
  • Balanced with a serious rear aero package
  • Center of pressure stability improves with speed

At The Ridge, the difference was dramatic: the car stopped washing out in the T3โ€“T4 transition and gained real front-end authority.


Real-World Lap Time Proof

This wasnโ€™t a pure A/B test โ€” different drivers, power levels, tires, and conditions โ€” but the result is hard to ignore.

June 2023 โ€” Homologated GT4 Aero @ Road America

  • Hoosier A7 (sprint tire)
  • Full GT4 power
  • Lap: 2:25.6

April 2024 โ€” Dundon Aero @ Road America

  • Yokohama A052 (endurance tire)
  • WRL power restrictions (ยพ intake blocked)
  • Full endurance fuel levels
  • Laps: Low 2:24s โ€” consistent

Less power.
Heavier car.
Slower tire.
Faster laps.

Conclusion:

The aero works. It transforms the platform. Check out this video comparison of the Dundon vs Manthay aero on the faster Cayman RS GT4.

YouTube player


What Types of Racing This Car Excels In

Endurance Racing (WRL, AER, ICSCC Enduros, ChampCar Pro)

  • Ultra-consistent
  • PDK-friendly
  • Great tire life
  • Zero drama across long stints

Time Attack (OnGrid, GTA, SCCA TT)

With Dundon aero?
Itโ€™s a legitimate GT+-class weapon.

Sprint Racing (SCCA ST, ICSCC ST/SPO, NASA ST1/ST2)

Great for drivers moving beyond grassroots or regional programs.

Driver Development

One of the best โ€œadvanced learningโ€ platforms weโ€™ve ever used.


Interested in Renting or Developing a GT4 Clubsport?

If youโ€™re curious what a Porsche Cayman GT4 Clubsport can do, weโ€™d love to help.

  • Want to rent this GT4 Clubsport for a race weekend or time attack?
    We offer full arrive-and-drive + coaching.
  • Already own a GT4 or Porsche race car?
    We can help you extract more from the car and yourself with setup, aero, maintenance, and coaching.

Reach out anytime. Letโ€™s build something fast together.

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Race Report 5 & 6: Portland International Raceways – Finally!

And we’re back from the winter 2022 trip with four race weekends under our belt, at new tracks for most of us and ready to come back to familiar ground where nothing would be easier but instead the challenges would be different.

This is post will cover two race weekends as we were at Portland International Raceways April 29 – May 1 for the ICSCC season opening race (Rose City Opener, hosted by Cascade Sports Car Club) and then back again two weeks later, for the SCCA Hoosier Super Tour stop, a part of the US Majors Tour.

Home track advantage

Wait, aren’t most of the people who race at these events, also from the region? For the ICSCC race – absolutely. A little less for the Hoosier Super Tour but that’s not exactly what we mean here. One of the many challenges of each of the stops on the winter trip was that even though we spent countless hours on the simulator training for each track, and it made a massive impact – we were still driving the tracks either for the first time or the first time in the specific race car each of us were driving.

That’s not a BMW or Porsche?!?!? Gama taking the EK Honda Civic with a K24 swap out for it’s maiden race weekend at a known and comfortable space – Portland International Raceways. Photo credit: Doug Berger

That means that at minimum, some material amount of our mental capacity was still being allocated for learning the track. That also means less mental capacity to think about improving on a specific corner or to focus on race craft.

So what happens when you get to a track that you’ve driven hundreds, if not thousands of laps on in real life, simulator and in a variety of conditions and cars? All that occupied mental capacity (and some), comes back and becomes available to be used on another area of improvement. That could be anything from fine tuning a specific setup component for given conditions, exploring different lines/entry speeds into a corner or working on race craft.

It could be anything but the bottom line is that the ability to learn and improve is simply easier because there is one big important thing to think about much less.

So what happened? New Personal Bests All Around!

The ICSCC weekend was held using the non-chicane configuration which further simplifies the course and results in really only ~7 corners total.

Ann in the Porsche Cayman GT4 Clubsport – Finally!!!

Ann in the Porsche Cayman GT4 Clubsport had never driven PIR without a chicane but we had a sense of what her pace would have been from her lap times at Portland last August (2021) with a chicane.

This would also be Ann’s first time driving on Hoosier A7 tires. Results? Ann immediately jumped into the 1:13’s early in the weekend and while she was able to sustain that pace, it looked like there was more low hanging fruit.

One of these is not like the others. Ann Doherty in her Porsche Cayman GT4 Clubsport crashing the GT1 class party.

In the Group 4 race, where she was in the middle of GT1 class cars — You read that correctly, while she was competing in the GT2 class (there were only 2 cars in class that weekend), she was in the front half of the GT1 cars! She put her head down to defend and get as far up the grid as possible and she dropped into the 1:12’s with a scorching 1:12.842. In that race, she would have finished in P3 overall and P3 amongst the GT1 class cars.

And the prior days Group 1 race, when the race started in wet conditions and transitioned to somewhat dry conditions, she was P1 overall and lapped almost every single car except the EK Honda Civic (driven by Gama and more on that below)… twice!

Mega, mega, mega drive by Ann.

Cascade Sports Car Club – Rose City Opener XXX at Portland International Raceway | Ann (#4) and Gama (#309) lapping every single car in the field one time and lapped almost every car a second time before finishing P1 and P2 overall and in SPM class. Photo credit: Doug Berger

When we returned two weeks later for the Hoosier Super Tour event May 13 – 15, the goal was to build on the gains from the first PIR weekend to put it all to work against a stacked GT2 field featuring a Dodge Viper, TA2 Chevy Camaro, a few additional stock cars, nearly tube-frame chassis E46 M3 and even a Porsche 997 Carrera Cup car!

Results? Even more gains and finally, finally – Ann’s 1st SCCA Hoosier Super Tour podium (P2) came on Sunday afternoon’s final race in complete downpour conditions. In dry conditions? Ann improved her personal best lap time by 4.5 seconds from the prior August – incredible progress! In clear air, Ann was competitive for podium contention but in the race, the straight line advantage for the more powerful cars was simply too much for her to keep them behind her for the entire race distance.

So many close podiums in the first 4 races of the year but it finally all came together for Ann in Portland and in the rain.

Simon in the BMW 330ci Spec E46 running in SE46, Touring 3 and SPM

For Simon, we had done 8 Hour Enduro in his car last October and he had done mid-1:19’s here and there and average fast pace was in the high 1:19’s/1:20’s.

Similar to Ann, Simon was immediately on the pace, consistently in the 1:19’s, along with a few other Spec E46 cars but by the end of the weekend, Simon was one of only two Spec E46’s to drop into the 1:18’s and separating himself from the pack of Spec E46’s and closing the gap to Chris Hart, who is an incredibly fast, consistent and national caliber driver. Chris placed P3 in the 2021 SCCA Runoffs in Touring 3 class, past PRO3 champion and spent many years driving stock cars professionally – this guy can wheel!

Simon in the hunt, looking for a way around a turbocharged Subaru WRX STI in the Group 1, SPM race. Photo credit: Doug Berger

During the SCCA Hoosier Super Tour stop, Simon similarly built on his gains from the first weekend and was immediately doing 1:26 lap times – improving his past personal best but on Hoosier Tires versus Toyo Proxes prior. About mid-day on the test day, we did a lead follow session with Simon and I (Gama) with first Simon leading and Gama following – doing mid to low 1:26 lap times and then we switched. Simon was able to follow closely and we both consistently did mid to high 1:25’s – BOOM! New personal bests and now having done lap times that are at the very pointy edge of the Touring 3 and Spec E46 field.

Saturday, Simon qualified on pole for his first Hoosier Super Tour pole position and in wet conditions! During the race, we had dry conditions so at the start Gama got in front of Simon and Chris Hart. About 4-5 laps into the race, Chris had an overheating issue and DNF’ed while Chris, Gama and Simon were running almost nose to tail.

After Chris pulled off track, Simon stuck to the rear of Gama’s bumper and finished P2 for another Hoosier Super Tour podium finish!

Simon’s 4th podium of the year and currently leading the Hoosier Super Tour points standing in Touring 3 (with Dave in 2nd place)

Unfortunately a failing lower ball joint was found in Simon’s car post-race and due to not having press tools at the track, that ended his weekend.

Simon leading a pack of ground pounders through Turn 12 at Portland International Raceways. Photo credit: Doug Berger

Dave skipped the first ICSCC Portland race and drove at Pacific Raceways during our second stop at PIR.

But wait – there were a lot more cars in the Racer on Rails Paddock(s)!

Now that we’re in the thick of the PNW racing season, the SCCA US Majors and Hoosier Super Tour races start to die down (races are still held but mostly out of our region) and we start to dial up the races from our local sanctioning body, the International Conference of Sports Car Clubs (ICSCC).

For the Rose City Opener, we had our group of PRO3 drivers out for their first race of the year and I (Gama) brought out a personal passion project for it’s second race weekend but it’s first with the current power plant – a JDM K24A swap with a JDM Honda Integra Type R transmission and a pretty heavy duty Limited Slip Differential from MFactory.

At a familiar place, the goal with the Honda was to simply get some race mileage on the new chassis, make sure it was running properly, figure out what likes to shake loose and see if we could put down some consistent competitive laps at 80-90% effort. And boy did the Honda deliver!

That little K24A Honda Civic, leading the pack (aside from Ann who had checked out in her Porsche Cayman) to Turn 1 at the start of the SPM Sunday afternoon race. Photo credit: Doug Berger

We worked through some gremlins but with absolutely zero focus on speed, the Honda was consistently doing extremely fast Spec E46 lap times and on Yokohama A052 tires (a really sticky street tire but nothing like a Hoosier tire). There is some serious potential in this car and we’re excited to further develop it over the season. It will be mid June before we see the Honda out again and it should have some new upgrades that will help with reliability and maybe a bit more speed.

Across the rest of the team, every driver improved their personal best lap times with no Chicane at Portland in a 20+ car field and pushing towards the front in PRO3 and a 10+ car field in Spec E46.

What better way to end this race report than with some in-car video of what a very angry Honda 4 cylinder engine based Civic sounds like, bombing around Portland International Raceways at the same speeds that a front running Spec E46 does?

Turn those headphones down a tiny bit and enjoy!

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Gama in the #309 K24A Honda Civic Hatchback doing a low 1:18 lap time during Sunday AM qualifying.