I am, unfortunately, a VW tragic. My 2010 Volkswagen Golf GTI has seen 50,000 miles of hard use under my stewardship and has only just survived my gauntlet. I’ve tracked it dozens of times and have learned dozens of lessons along the way. This, in my opinion, is how to set up a GTI for the track.
To be clear, the insight in this post applies mostly to the most recent of GTIs, from the 2006 Mk5 GTI to the latest Mk8 stuff. The Mk5 and Mk6 share identical suspension platforms, while the Mk7 and Mk8 are MQB. However, the principles, physics, and engineering ideologies across them all are fairly similar. That’s to say every one of them reacts similarly to similar modifications. Let’s hit the major points.
The great weakness of most turbocharged cars is cooling capacity. Turbos add a lot more heat in terms of underhood temperatures, oil, and coolant temperatures. Overheating arrives a lot more quickly, and it is much harder to cool a turbo car down from a critical temperature than a naturally aspirated car. In normal driving, this would never be an issue, but on the track, GTIs get hot extremely quickly.
For Mk6 owners like me, all I can do is add an external oil cooler because there are no true upgrades available for the radiator. Mk5 and Mk7 folks get options from CSF, a California-based company that makes some of the finest radiators in the aftermarket. CSF uses proprietary cooling tech like B-shaped cooling tubes to maximize radiator performance. Every other aftermarket option I’ve seen has been incredibly expensive, has no increase in cooling capacity, or both.
The stock EA113 and EA888 cooling systems tie an oil cooler into the coolant circuit, meaning that the radiator also shoulders the job of shaving off the extra heat from hot oil. The upgraded CSF radiator claims to keep temperatures stable at 260 degrees Fahrenheit for oil and 212 degrees Fahrenheit for coolant under track conditions, even with a stock oil cooler. I’d love to test those claims if I get a newer GTI, but this seems to be the best choice in the aftermarket for now at $600.
In my own track testing with the stock Mk6 cooling system, overheating arrived quickly and then skyrocketed. Coolant temps would climb steadily to 230 degrees Fahrenheit, then spiral quickly beyond 230. I also found a 40 to 60-degree difference in oil temperature to coolant temperature on the stock oil cooler, meaning that 230-degree coolant meant 270-degree oil or higher, which is unacceptably high. Even CSF’s claimed 260-degree number is a bit warmer than I’d like, so I think an external oil cooler should be on the list.
A company based in Ottawa, Canada called iABED makes the required plate that makes an external oil cooler a seamless install for the early Mk5’s EA113 FSI engine, the late Mk5 and Mk6 EA888 Gen 1 engine, and the Mk7’s EA888 Gen 3. The Mk8 likely has similar fitment to the Mk7, but there is no real confirmation yet. This plate will delete the factory water-to-oil cooler and replace it with provisions for AN (Army-Navy) fittings to plumb an oil cooler. I did it to my car, and it worked extremely well, but it does require a reasonably large cooler to achieve truly bombproof cooling. With the cost of braided AN lines, fittings, a thermostat, and the cooler core itself, budget around $500 to finish the job, including time to mock up and install the part. It requires the intake manifold and water pump to come off, and the tight engine bay of these cars makes running the lines a pain.
It helped a lot with cooling in my case. Coolant temps took a lot longer to genuinely overheat and oil temps would cap out at 260 degrees on track days with a low ambient temp like 60 degrees. Unfortunately, the lack of radiator upgrade made warmer 80-degree-plus track days still a tough proposition. The next step would be hood venting and a larger oil cooler, but I never tested that.
Suspension and Tires
Once your GTI is properly quenched, the suspension is the next big step to take. Remember, reliability is always first, especially before increasing performance. Supporting mods make sure everything works better. In the case of modern GTI suspension, it is quite a curiously engineered setup that takes some trial and error to get right but the first thing to do is get good tires and wheels. The stock wheels are heavy and a 17-inch wheel removes quite a bit of weight. At the very least, get some grippy tires designed for track use. My personal choice is the Falken Azenis RT660.
I run a staggered tire setup. The difference on my car is that I staggered compounds instead of width. I’ll explain how it came about in another post, but it was the result of harebrained experimentation that works and kills understeer. I run an RT660 on the front and Michelin Pilot Sport A/S 4s on the rear. Believe me, it doesn’t oversteer everywhere. That’s how understeer-prone these cars are.
Getting 80% there with suspension takes a triad of mods: camber, caster, and a rear sway bar. For Mk5 and Mk6 owners, go with the Whiteline anti-lift kit or Powerflex adjustable caster bushings. These go a long way in waking up the frankly dead steering feel of those early VW electric power steering racks and add some much-needed on-center weight. For the Mk7 and MQB folks, the Whiteline caster bushings do much of the same job.
Camber can only be handled with camber plates thanks to the clamp-type design of the VW steering knuckles. Another caveat is most camber plate designs require the strut top to be unbolted for camber adjustment thanks to a strut tower cup restricting access to the center of the strut from the top. Owners have cut the cup with no ill consequences as it has no real structural purpose, but it’s just annoying to have to do it.
Ground Control sells camber plates that are adjustable from the top, making alignments easy. They are also well-designed and up to the task, whereas many of the cheaper options might not be able to do the job. Adjusting to-1.5 to -2 degrees of camber goes an incredibly long way with these cars to adding grip, reducing understeer, and even wearing the tires more evenly on the track. I’ve found that my tires last an extra track day or two with some camber and they no longer cord the insides.
The final piece of the essential suspension puzzle is a rear sway bar. In my experience with the Mk6, these cars respond dramatically to changes in sway bar stiffness and my car runs a matched set of 24-mm Whiteline sway bars. If I had to do it again, I would go straight to 034 Motorsport and get their 25.4-mm rear sway bar, designed to work with the stock front sway bar. This is excellent because the stock front sway bar requires a finicky front subframe removal to replace.
Then some final tricks for Mk5 and Mk6 folks include my highly recommended combination of Passat/CC aluminum front uprights and control arms that lighten the front suspension, add rigidity, and change the effective steering ratio. This makes the car turn in more eagerly and helps it dance better, at least for my hands. And some brake pads and fluid should be on the list too. No need for larger brakes as these GTIs have adequate braking power and heat capacity, but a big brake kit could help pedal feel.
This is just the beginning for any GTI owner looking to make their jack of all trades just a bit better on racing tarmac. Like modifying anything else, the rabbit hole is deep and is also influenced strongly by personal preference and setup. My goal for this is to get some GTI people started on a journey, and these parts should afford anyone a bit more driving satisfaction. Even on a backroad. Just make sure to lift-off oversteer for me.