Get the most out of your GT3 car

Porsche’s GT Department specials have come to dominate the trackday scene, both in the UK and around the world. There can be no greater confirmation of Porsche’s excellence in this arena than to walk down a pit lane at any given circuit past rows of GT3s, GT3 RSs, GT4s and the like. They have become the de facto choice and with good reason. Not only do they clearly offer the expected levels of performance, driver interaction and reward, but they’re also famously hardy, able to soak up punishment on the day and don’t require lengthy and expensive maintenance after every outing.
 
Then again, every working machine needs to be taken care of and circuit driving places an incredible strain on a car. Every mile you drive on a circuit equates to many multiples of road miles for wear and tear on components. Even something as fit-for-purpose as a GT3 needs an understanding approach. Consider too that if you were to move up to a purpose-built track car such as the Cayman GT4 Sprint or a 911 Carrera Cup, you’d automatically be into maintenance by hours, which can get very expensive when it comes to an engine strip-down and rebuild. Having a manufacturer’s fixed servicing schedule doesn’t miraculously exonerate you from good practice.
 
To find out more, we went along to RPM Technik in Hertfordshire. As specialists in this area – and technical advisors to the Club on GT cars – they’re well placed to know all the ins and outs of maintenance, trackday prep and appropriate modifications. With a rather menacing-looking black 992 GT3 RS in the workshop as our guinea pig, we decided to go through each area of the car in turn to find out what needs checking or replacement.



GET PLUGGED IN
The first thing to know is that Porsche recommends a different service schedule if you intend to use your GT car heavily on track. RPM’s Technical Director Ollie Preston grabs the PIWIS tablet, the official Porsche diagnostic tool, and explains: “We start by plugging in and taking a VAL [Vehicle Analysis Log]. It’s hooked up to Porsche, so they can see what we’re doing, and it also shows any warranty or recall info and gives us full details on the car.
 
“There’s actually a separate track servicing schedule that Porsche publishes, with an engine oil change at every 3,000 miles and an oil and filter change every 6,000 miles, but there’s also attention to things like the centre lock wheel nuts, hubs and replacing wheel bearings on the rear axle. Every 12,000 miles, it’s the turn of the drive shafts and front wheel bearing housing. As you can see, there’s more maintenance required than people think.”
 
It’s important to remember that this is 12,000 track miles in the case of components such as the driveshafts, not road miles. That’s why Ollie recommends keeping a detailed log of all the trackdays you do and the corresponding mileages. Such bookkeeping isn’t vanity; it’s a crucial aspect of maximising the performance of your car and ensuring your own safety.

 
“The basic stuff you do when a car comes in, particularly after a trackday, is to check bearings and suspension components for play and look for any debris in the vents – you don’t want to restrict those, particularly on these later cars. Check the splitter at the front, making sure nothing is hanging off. Tyre wear is important, so we look for even wear – you don’t want to be scrubbing tyres either.”
 
As we speak, senior technician Ricky Nash has the car up in the air and is checking the surprisingly complex underside, which is dominated by an almost completely flat floor but also features various plastic ducts, slats and fins, directing air for cooling and aerodynamic purposes. Run the car too low in its setup and you risk damaging important parts. Specific things to look out for vary from model to model. One such example is the air intakes on 991 RS models, which can easily fill up with pieces of gravel and especially if the car has had an ‘off’. This becomes readily apparent if the car is having an air filter change.
 
Another obvious check is brake pads, but Ollie cautions about just giving them a casual glance. “Because the pads are so big, quite a lot of people look at the top and think there’s loads left on them. But, in reality, because you’re pressing so hard on the pedal on trackdays, you tend to wear them at the bottom of the pad like a wedge. There can be excessive wear at the bottom of the pad on the leading edge and that can go through to the back and damage the disc. As the brake pad wears down, the heat transfer to the caliper becomes quicker and then you cook the fluid a lot quicker. The first half of the pad wears a lot slower than the second half.”

 
As many readers will be aware, damaging one of Porsche’s giant carbon ceramic discs is a painful prospect. Expect to pay nearly £40,000 for a complete set. Gulp. Ollie says the jury is still out on whether to actually use the factory carbon discs if you’re a dedicated trackday goer. When the carbon ceramic discs first started appearing on Porsche GT cars, taking them off and replacing them with conventional iron discs was a popular modification. Today, with the progression of technology, such an approach isn’t automatically necessary.
 
“Some people put them in a box, others see how they get on with them on the car,” he says. “If you regularly keep an eye on them, they don’t just suddenly fail overnight. You can see when they’re starting to wear and that’s sometimes the point people look for an alternative so they can put the originals away and maintain the value of the car.”
 
The RPM Technik workshop has a special digital tool for checking their integrity. Once, it was necessary to weigh them, but now a reading that confirms their density can be taken in an instant. And therein lies one of the strange conundrums of buying a GT car: “Everybody always wants one of these original when they buy one [second-hand] and not one that’s been tracked,” Ollie notes. “Usually, that’s before tracking the car themselves…”

 
STRAIGHT TO THE POINT
One of the absolutely crucial aspects to get right with any Porsche, and particularly a GT car where you’re going to be driving it close to the limit, is the geometry settings of the suspension. GT cars are designed to be completely adjustable, unlike more regular Porsche models, and by this we mean that the precise angle and position of the wheels relative to the body can be set. As anyone with even a smattering of car knowledge will know, the values of such things as toe in or out, camber and so on all have a huge effect on how a car can drive. They can mean the difference between a car that’s verging on being downright dangerous to one that feels perfectly in tune with the driver.
 
Of course, Porsche sets all its cars up at the factory before delivery, but this doesn’t automatically mean you can simply forget about such matters – even on a brand-new car. For starters, the values that Porsche dial in will inevitably be a compromise between road driving and circuit work and will also be set to keep most drivers happy most of the time. Personal usage, driver ability and preference profiles will mean a setup can be dialled in to an individual’s taste.
 
Notwithstanding this, a new car also takes time to settle onto its suspension and, as Ricky shows once he’s hooked this barely run-in 992 GT3 RS to his flat floor base and lasers, it has moved – it’s not perfect. “We tend to suggest alignment is done once a year,” Ricky says, “but, if you’re a heavy track user and running over the kerbs a lot, maybe try twice a year. If you’ve had a spin, we’ll check afterwards anyway.”



HOW LOW CAN YOU GO?
Another area of adjustment is with the car’s ride height. “If you’re doing more circuit work, you may want to try and bring the centre of gravity a little further down,” Ricky notes. “But you don’t want to go too low, because you’ve got a lot of aero on these cars pushing them down and lots of underbody parts, and you don’t want to be having an impact under a serious compression. On the other hand, if it’s a road car, you want the ability to go over speed bumps and still be usable.”
 
There are subtleties between the different models too. For example, on this 992 RS, with its significant aerodynamic performance, Ricky is mindful of not introducing too much camber given that the tyres are already being pushed down hard into the road’s surface. He also says they’re actually softening off the front end’s response because many find the ‘double wishbone’ cars too sensitive to changes in direction, especially at high speed.

 
THE SAME OLD STORY
Of course, the GT car lineage stretches back over a quarter of a century now and what might have once been routine maintenance for a 996 GT3 or a 997 RS is now something entirely different. Naturally, there are still owners of the older cars who want to track their cars and track them hard. Given their capabilities and the purer, more analogue experience they offer where the driver is arguably even more important, why wouldn’t you? However, the majority of trackday goers want the latest, fastest, most capable Porsche their budget allows, so the market for the older models is now dominated by collectors. That’s a very different set of priorities.
 
“We’ve got one coming in early next week,” Ollie notes, as we congregate around a 996.1 GT3 in his projects workshop. “That one’s a Club Sport and it’s got the Cup car low ratio crown and pinion, the brakes from the Mk2 with the six pots [brake calipers], various solid links – a lot of Cup car bits on it. But the owner has all the original parts and it’s coming in to have everything put back to original, because I think that’s the way they’re going now.” As ever, the real value is in originality.
 
If you are preparing an early car for a trackday, the inspection starts with reassuring familiarity for anyone with a 996-generation 911: checking for debris in the radiators. As ever, this generation of 911s is prone to getting all manner of stuff collecting down in the corners of the openings which, if left, can trap moisture and then corrode the air conditioning and coolant radiators nestled deep in the nose.

 
From there, it’s a check of all those usual suspension arms, and specifically their bushes, for wear and play – like you would for any 996, really, although they are a bit tougher. As Ollie says, the cars tend to do fewer miles too. Nevertheless, if you’re in the market for an early car, it’s worth bearing in mind that a lack of underseal and the car’s age can mean corrosion is a very distinct possibility. Make sure you get a good look at the underside.
 
As for springs and dampers, Ollie keeps it simple. “There are lots of options, but the best two are to either take the dampers off and send them back to Bilstein for an overhaul, which is really sensibly priced and only has a short turnaround time, and then to re-fit with a new set of springs (either Porsche or Eibach) of the same rate, just keeping it all the same.

But, of course, there’s a lot of good suspension companies out there that do parts for these and we’ve always gone back to the KW setup on them. They just work really well for track use and for road use. They’re stainless steel, so they last well, can be rebuilt for not-crazy money and last a long time.”


 
BRAKE WITH THE PAST
One known weak spot of the early cars was the brakes and these were upgraded to six-pot calipers on the second-generation cars.
 
“We’ve done a lot of those upgrades over the years,” Ollie says. “They do need them if they’re going to be driven hard on a track. We’ve seen corroded brake lines, particularly where the lines push into the plastic clips. You get dirt in there and then it will hold the moisture in that against the brake pipe and rot it while it’s in the clip. The flexi lines can be 25-year-old rubber now, so they can collapse in on themselves – it’s sensible to put a set of braided lines on. The plates in the differential on these were always known for wearing out, especially the standard road ones. We used to put the motorsport diff packs in them, because otherwise [when worn] they act like an open diff.”
 
Of course, the good old Mezger engine needs the correct maintenance but, as anyone who knows these cars will attest, an appropriately hard-worked Mezger flat six is a happy flat six and big mileages are entirely possible.

 
Whether young or old, the GT3’s reputation is built on its ability to soak up punishment on a track and, if nothing else, this article proves that there is no glaring weakness that owners need to be concerned about. Instead, it’s all entirely sensible stuff: take the prep of the car and running it seriously; don’t equate track miles to going on a Sunday morning coffee run; and give the car what it needs when it needs it. In return, it should provide many happy seasons of blissful track action.

This feature was written by Adam Towler and first appeared in the June2025 issue of our monthly Club magazine, Porsche Post. Join today to receive your copy, as well as enjoying a host of exclusive member benefits and savings.