RPM TECHNIK CAYMAN CSR
Well chosen mods from RPM Technik turn the Cayman 981 into a mid-engined masterpiece
Much has been written about the inflated values of Cayman GT4S and the yawning gap between this highly evolved halo model and the rest of the range. One could sit and rage about the injustice of this, muttering darkly about dealer allocations and flippers cashing in on yet another over-hyped, limitedsupply Porsche.
Or, like Buckinghamshire-based RPM Technik, you could take a more positive, proactive view and instead consider it an opportunity. Because in Man Maths terms the c. £40,000 gap between the respective used values of a 981 Cayman S and the starting price of a lowmileage GT4 at your local Porsche Centre gives you a big ballpark for playing with some upgrades to make the former into something akin to the latter. Or possibly even better.
The fiscally prudent would probably point out at the end of it you’ll never make your money back on mods whereas the GT4 will always be a GT4 and maintain its value accordingly. But we’ll leave that to those with the liquidity to pay £80,000-plus upfront or spend more time obsessing over residuals than behind the wheel. Because as a pure driving machine this new Cayman CSR is one wicked little car.
There’s a good chance you’re already aware of RPM’S CSR programme, the concept introduced with a 986 Boxster before spawning 996 and 997 versions for 911 owners. All are subtly different but the basic premise has stayed the same, CSR branding the umbrella for a package of mechanical and styling modifications intended to make the cars faster, focused and – most of all – more fun for the discerning driver. So it’s less about big power, attention seeking aero or other unnecessary bling. And more about highquality suspension, improving the range and response of the engines and then making some sensible weight-saving on areas that matter to handling, like wheels, tyres and brakes. The goal is a more focused Porsche you can enjoy both on the road and track without being overly compromised on either.
The modifications can be bought piecemeal according to taste, need and
budget. Or they can be added as a complete package to a base car to qualify as a full CSR model, subtly branded and liveried up accordingly. And that’s what we have here, courtesy of one generous RPM customer and his fully kitted out Cayman CSR. “
The devil in a makeover like this lies in the detail. Starting with the engine it gets Kline headers, high-flow air filters and a Cobb Accessport re-map with a handy dash-mounted interface for getting a sense of what it’s doing. RPM technical director and all-round engine guru Ollie Preston admits there is still work to do perfecting the map but the gains are already significant, a rough conversion of the at-hub dyno readings translating to around 350ps [345bhp] and a fraction under 300lb ft, up from the stock figures of 325ps [321bhp] and 273lb ft.
While the improved breathing obviously helps, the bulk of the improvement comes from the mapping, Ollie shocked to find the factory map doesn’t necessarily translate foot to the floor on the pedal to full throttle at the engine. Porsche will have its reasons for this, the stock set-up seeking to iron out flat spots and deliver its power smoothly rather than go all-out for maximum performance. Suffice to say on the CSR when you demand full throttle that’s exactly what you get.
A lightweight clutch and flywheel are fitted to improve response but the real killer feature is the reduced final drive courtesy of a new crown wheel and pinion, this dropping from the 3.89:1 of the standard set-up to a racier 4.125:1. Meanwhile a Wavetrac torque-sensing differential – as developed for previous CSR conversions – puts it all to the road.
Chassis work is extensive, the key points being Ohlins Road & Track coilovers, multiposition GT4 anti-roll bars and a heavily upgraded braking system based around sixpot ARP front calipers and touring car spec floating rotors. These are housed within lightweight 19-inch HRE wheels running Michelin Pilot Sport Cup 2 tyres, the combination of parts saving at least a kilo per corner.
Visual modifications are subtle but significant, the most noticeable change
When you demand full throttle, that’s exactly what you get
beyond the new wheels being the switch to a GT4 front bumper with its increased breathing and bigger splitter. There’s also a GT4 diffuser and a small rear wing fixed into its raised position, these all factory parts adapted by RPM and combining to give the CSR an understated but purposeful stance all of its own. In the cabin there are some neat touches, plastic trim parts colour coded to the exterior paint a nod to the GT4 while this particular car is also fitted with full Schroth harnesses in addition to the existing inertia reel belts. Incorporating them actually proved a significant challenge, RPM using GT4 harness mounts on the bulkhead but fabricating steel plates to adapt existing seat fixings to take the waist and crotch belts. Ollie takes particular pride in this being achieved without the need to drill the chassis or make any irreversible modifications that would prevent the car being returned to stock if required.
First impression heading out of RPM’S Buckinghamshire base is how smooth and quiet the engine is. This is deliberate, the owner sticking with the standard system so as to keep within track day noise limits. It’s an interesting contrast with the aggressive set-up of the chassis, the bumpy local Broads revealing a degree of agitation to the ride and sensitivity to cambers you don’t get in a standard S.
It’s not unduly harsh though, the trademark Ohlins flow giving a pillowy sense of plushness even with the stiffer springs and reduced wheel travel and
nothing like as brittle as the passive Sport chassis option offered by Porsche on regular Caymans. As much as anything this particular set-up again reflects the tastes of the owner, who Ollie describes as a dedicated track day driver willing to accept a little more harshness in return for improved circuit performance. Harshness that can easily be dialled out on the Ohlins adjusters if you want a more roadbiased set-up.
Joy of joys there’s real incentive to use all of the available gears too, the short-shift mechanism improving the already positive movement of the stubby shifter. With its reduced inertia, improved breathing and beefier power delivery the engine has the needle on the rev counter fair whipping its way round the dial, the off-cam lethargy you get in the standard car negated by both the increased torque and the lower gearing. As such throttle response is far sharper, the engine happy to pull from 3000–4000rpm in any gear but happier still in the upper reaches of the range. That noticeable step-change in tone and ferocity now lies beyond 6000rpm, which could be frustrating and peaky on the road were it not for the expanded mid-range and improved response.
On twisty B-roads this more often than not means you’re slotting to and fro between third and fourth, which is a much faster and more pleasant motion than going cross-gate between second and third as you would be in the conventionally geared car. Or, indeed, a GT4. Even fifth and sixth have the flexibility for making more relaxed progress, the lower final drive meaning the shift indicator is constantly nagging you to shift up, even at a relaxed motorway cruise and showing just 3000rpm or so. Where a long-geared standard car might need a downshift to squirt into a gap or even deal with a slight gradient you now have response to leave it in gear.
The opposite is true when you’re making more spirited progress on a back road but with a drivetrain as responsive as this it’s hardly a chore, the combination of the shifter’s short throw, the lack of inertia in the engine and the snappy response of the clutch encouraging fast, precise shifts and rewarding accurate rev-matching and fancy footwork. Shifts that would be redundant with the standard gearing now become an indulgence you can enjoy purely for the
Joy of joys there’s a real incentive to use all of the available gears
sake of it. Which is exactly what an enthusiast’s car should deliver.
On the road this all adds up to a richly interactive and immersive driving experience. Compared with a GT4 the CSR maintains the standard Cayman’s sense of agility and compact size, the sense of flow arguably more entertaining in this environment than the more serious and locked-down feel of the factory special. At the same time it unlocks some of that ability realised by the GT4 and proves how the standard Cayman S is, if anything, a little constrained by its factory settings.
Can the CSR match a GT4 on the track though? Our venue is Longcross proving ground rather than a dedicated race circuit, the short but challenging ‘Snake’ section actually more like a B-road. One with the advantage of being able to use all the available width with no fear of anything coming the other way!
A greasy, wintry surface and Cup 2 tyres focus the attention somewhat, the slightly fatter sidewalls on the 19-inch wheels more visually appealing than rubber band tyres on the 20s worn by many stock 981s. Cups can be a little alarming on standing water but in these conditions they’re balanced and predictable, the limits low but easily read and the car giving you options galore on how to take the corners.
In this set-up there’s still a degree of front-end push if you barrel into the corners too quickly and no amount of power can overcome it. Trailed brakes to keep the nose tight or a lift to tuck it in are all you need though and, once settled, you can get hard on the throttle and fully exploit the more muscular power delivery the revised gearing and extra grunt provide. There’s no need to wait for it to come on cam, the increased mid-range urge meaning the Wavetrac diff can assert itself and rotate the car into the turn on the throttle.
It does so more softly than the plated differential used by the GT4 and the CSR is definitely less spiky in its on-limit behaviour. But such is the natural balance of the Cayman you’re confident playing with cornering lines and sliding it around, safe in the knowledge it’s not going to bite you or do anything too unexpected. Ollie admits they have experimented with a plated diff