Porsche's PDK transmission is one of the more frustrating pieces of technology introduced in recent years. It makes for a brilliant marriage of engine and gearbox, producing fast, jerk-free gearshifts that make an old-style manu-matic or conventional automatic seem crude.
But its manual gear selection leaves a lot to be desired. Some think it was a simply case of Porsche not wanting to copy the accepted "left for down, right for up" arrangement used by all its competitors. Whatever the reason, the result is counter-intuitive and confusing. If you have to think about how to operate something in a moment of stress, it's too late. So if the F1-style steering wheel was the only modification to the way SpeedArt's SRS 420 drives, it'd be a major improvement all by itself.
A long-standing debate among paddle-shift advocates is whether or not the paddles should be fixed to the steering column or move with the wheel. There's a strong case for both designs. SpeedArt's paddles, fixed to the steering wheel, allow you to operate them without moving your hands from the nine-three o'clock position providing you don't have too much steering lock going on.
The other piece of good news is that SpeedArt's 340mm F1 steering wheel is not only manna from heaven for the latest PDK-equipped cars, but also the Tiptronic-equipped Boxster, Cayman, or first generation 997s. A wheel will soon be available for keen Cayenne drivers as well, and no doubt a Panamera version will not be far behind.
Out of the box, the 385 hp and 295 lb-ft of torque from the all-new 3.8-liter second-generation 997 Carrera S motor gives the car a sharpness in response and beefiness in delivery that is hard to better for the money. Its lighter internals and direct injection deliver a crisper edge than before and improving this fine motor would seem to be a pretty tall order. But that's exactly what SpeedArt has done with its Power Kit II for the facelifted 997.
The conversion includes a sport air filter, equal-length headers, 200-cell metal catalysts, a stainless steel sport exhaust, and an ECU remap. If your car is fitted with the factory Sport Chrono package, you can also have the exhaust system with an electronically controlled bypass flap that activates when the throttle is depressed beyond a certain point.
Excessive exhaust backpressure is the bane of gas flow in any engine, especially a force-aspirated one, but you still need a certain amount of backpressure to keep the gases moving properly. Porsche has its standard exhaust systems flowing so well that it's very hard for an aftermarket exhaust specialist to improve the sound without actually losing power at the same time. More than that, with the high precision of the ECU programming required for current emissions laws, it's also clear that the intake and exhaust systems are now optimized along with the fuel and ignition maps. So for any meaningful gains to be had, intake and exhaust upgrades and ECU re-mapping must be done together as a package.
With all these modifications carried out, SpeedArt's Power Kit II delivers 420 hp, 35 more than standard, along with 325 lb-ft of torque. That's the same horsepower as the 996 Turbo from a street-legal, naturally aspirated 3.8 liter flat-six, albeit with 89 lb-ft less torque. How things have moved on.
Porsche's PASM active damping system has some leeway for different spring rates, and SpeedArt takes advantage of this using shorter, uprated springs made to specification by H&R.
Porsche's bespoke Brembo brakes have a good reputation for staying power. They also have reasonable headroom built in, so coping with a few more horses will not push them over the edge. Because of this, SpeedArt does not insist that you upgrade the brakes with the 420-hp conversion, but they do substitute the rubber brake hoses for braided stainless steel ones that resist flex and thus giving better pedal feel. But if you're a trackday junkie, SpeedArt will happily fit an uprated road or race brake system to your car.
SpeedArt boss Bjorn Striening is particularly proud of his new 20-inch three-piece forged alloy wheels. They are around nine pounds lighter per corner than cast alloy wheels of the same size, and help to keep unsprung weight low. Available in three sizes-8.5-, 11.0-, and 12.0x20 inch-the wheels look even larger than they are thanks to an optical trick with the design and coloring of the spokes. Because the spokes overlap the outer rim, they're as long as they would be on a 22-inch wheel. In addition, their centers are slightly concave, which makes them look deeper and help to give the car its purposeful stance.
While the spokes look normal dark metallic gray from a distance, close-up you see that they actually have a rough finish like the old black crackle on classic Ferrari rocker covers. This kind of originality and attention to detail shows Striening's personal interest and involvement in his company's products goes far beyond the norm. "It's easy to make a wheel design, commission a few hundred sets from a wheel manufacturer, and then just sell lots of boxes all over the world," he says. "But I'm still an enthusiast always looking for ways to make things better and more appealing to my clients."
Unless they develop a car's suspension closely with one tire manufacturer for optimum results, most car manufacturers use three or four suppliers. The same is not true for aftermarket tuners, who tend to work with specific companies for all their parts. SpeedArt uses Michelin and Continental tires depending on each client's application and driving style.
"We offer customers a choice of Michelin Pilot Sport 2 or Continental ContiSportContact3 tires," Striening explains. "The Michelin is a slightly better steer on track and on a dry road, while the Continental is superior in the wet."
The SRS-II aero kit adds a lower valance and a splitter to the factory front bumper. "We retain the factory front bumper with its LED daytime running lights to keep costs down," Striening says. "Together with the GT3 moustache air outlet, the face of the car is significantly changed without the added expense of a complete new molding."
SpeedArt's signature sculpted side skirts visually join the lower front spoiler to the rear bumper. Here, SpeedArt removes the lower rear section of the factory bumper and adds its own diffuser. This is flanked by the four 90mm exhaust outlets, whose tips can be ordered with either a matte black or polished finish. The aero kit's finishing touch is a rear wing with ram-air inlets flanking its support structure. The wing is inclined at a five-degree positive angle of attack, and the combined effect of the new front and rear aero is a 55-pound reduction in lift.
Inside, the only Speed additions to the cabin are the paddle shift steering wheel and the brushed alloy door kick plates.
I first drove this car in August 2008, when SpeedArt had only just fitted its older style 10-spoke wheels, front spoiler, moustache, side skirts, and a modestly sized fixed rear wing. The engine was stock, and the steering wheel, diffuser, and larger rear wing were still in the works. Now completely transformed, the SRS 420 demo car promises to be a different animal altogether, and as I drive it on local country roads to the nearby Malmsheim test track, I'm eager to see by just how much.
I select PDK's Manual mode and drive on the paddles without having to think about which way is up or down. Because of this, I instantly feel at one with the car. Around town, the shorter springs make the ride a lot firmer than standard, even here in Germany. They move the secondary ride to a point between the normal car's Comfort and Sport modes; I'm not convinced that this setup would be tolerable on badly maintained UK roads. That said, the car had just returned from a group test at Hockenheim with a German magazine and was still set lower and stiffer than a customer car would normally be.
Moving faster on the open road, the primary ride turns out to be just fine, and at high speeds, the SRS 420 exhibits rock-solid body control both on turn-in and through high-speed bends. It maintains that feeling of agility through tighter bends, inspiring the confidence you need to really lean on the mechanical grip and the ability to throttle steer the car once you've learned what it can do.
The other thing I took an instant liking to was the engine. As I said before, the new direct-injection engine has a spunkiness to it that was not present previously. The better breathing, more aggressive ignition advance at low rpm, and snappier e-gas throttle response provide noticeably better punch and make this conversion feel like money well spent.
At Malmsheim, I have the chance to run the car out to the redline in the intermediate gears, and I'm impressed with the way it seamlessly delivers its power ratio after ratio. It feels more aggressive and more incisive than standard when you open the taps fully, yet is just as docile as the standard car for everyday town driving.
Over the years, I've become rather blasé about some minor upgrades that simply involve air filter, exhaust, and ECU re-map, as the results are sometimes no more than 10 hp with more decibels behind my head. In this case, the extra 35 hp and 30 lb-ft of torque can really be felt, and they're delivered cleanly with a crisper throttle response.
As a modestly priced, naturally aspirated 997 conversion, SpeedArt's SRS 420 does what it says on the tin. And even if you don't want to go faster or look more extroverted, that paddle-shift steering wheel at last fulfils the inherent promise of the PDK gearbox.
3.8-liter flat six, dohc, 24-valve. Sport air filter, equal-length headers, 200-cell metal catalysts, sport exhaust, ECU remap
Seven-speed PDK automated manual
Speedart/H&R sport springs
Wheels and Tires
SpeedArt alloys, 8.5x20 (f), 12x20(r) Continental ContiSportContact 3, 245/35 (f), 305/30 (r)
SpeedArt SRS-II aero kit
SpeedArt paddle-shift steering wheel, brushed aluminum sill plates
Peak Power: 420 hp
Peak Torque: 325 lb-ft