Autotech R32 brake conversion

As part of the background research for a VW MkIII/MkIV brake buyer's guide, we contacted Autotech Sport Tuning to see what they had cooking in high-performance brakes. A few years ago, we looked at the company's Audi-based big brake kit for MkIIIs, and we wanted to see how the market had changed. With 75k miles rapidly approaching on our subject car's odometer, it became time to address the brake system, due both to everyday wear and tear and the fact that the extended warranty would soon expire, thus raising the possibility of performance modifications and the need for additional braking. Most fortuitously, our inquiry came close on the heels of the company's introduction of a VW R32-based brake kit, so we decided to put it to the test. At the time we began, Autotech had secured the entire supply of replacement R32 brake parts. For those who have been stranded on a deserted island for the past year or so, the R32 is Volkswagen's ueber-Golf, with 241 bhp, 236 lb-ft of torque, and 4Motion all-wheel drive. Tipping the scales well past 3,000 lb, the R32 has serious braking needs.

The Specs
R32 front rotors are 334x32mm, much larger than a New Beetle 's 280- or 288mm diameter (2.0L and 1.8T). Audi TT Quattro brakes measure 312x25mm. Round back, the R32 has 256x22mm vented rotors compared to the regular 232x9mm solid discs of the MkIV 2.0 and 1.8T cars. Unlike a racing-bred brake kit, the R32 uses a two-piston, floating caliper similar in design to ordinary Golf parts. The calipers are painted blue to evoke memories of high-performance Audi and Volkswagens past. The front rotors are directionally vented to enhance air cooling. An arrow cast into the hub shows the direction of travel. The rotor is cast in two pieces--a lightweight aluminum center with radial spokes attaching it to the heavier cast iron rotor. In addition to making the large part lighter, it just looks cool.

Installation
It can be tricky to fit monster brakes behind some road wheels, but the R32's two-piston sliding calipers lack the outward protrusion of a four-piston caliper and gave no problems with the 18-in.O.Z. Racing Superleggera wheels (european car, 12/02.) Autotech recommends 18-in. wheels but has found some 17-in. setups to fit. In the case of a front puncture, the spare goes on the rear, and the rear tire moves forward until the next stop. Step-by-step installation instructions for the Autotech R32 brake conversion can be found online at www.europeancarweb.com/tech. Below are some basic tips. Front: The front brakes are easily swapped. The carriers and calipers are asymmetrical and packaged separately, so make sure the bleeder screws are pointing up. The parts fit exactly in the same manner as stock. Consult a shop manual, such as those published by Robert Bentley, for torque specs and diagrams. Rear: Autotech offers the rear brakes in two different configurations. One option is to use special rear brake backing plates that require removing the hub (necessitating wheel bearing replacement); the other, less expensive and easier route is to simply trim the backing plate to clear the wider, vented rotor. Again, bleed screws go up. Autotech offers the rear calipers in blue. The carriers are available only in silver, but because everything is apart, it's not difficult to paint the carriers yourself.

Testing
We headed out to California Motor Speedway's mini dragstrip to do some heavy-footed 80-to-0-mph and 60-to-0-mph braking tests, first with the stock setup, then with the Autotech R32 conversion. Autotech sent along its technician to swap parts at the track, but through no fault of his, installation complications meant we were able to test only the front that day. The front does most of the work in braking, and we saw excellent results. We expect they would be even better with the complete system. Before and after testing was done on the same car, the same day, the same surface and with consistent weather. A Stalker radar unit was used to measure stopping distances. A contact thermocouple probe was used to gather rotor temperatures after each stop. Infrared pyrometers can develop significant errors as radiant heat loss increases at higher temperatures (when the rotors begin to glow).

We enlisted Sport Compact Car's Josh Jacquot as a driver, using the same stopping point, same speed, same time between runs and same return-trip stop. SCC's Dave Coleman operated the radar, and european car engineering editor Dan Barnes took rotor temperatures.

Analysis
Thoroughly thrashing the stock brakes wasn't very hard to do. After the first 60-mph stop, the brakes began to fade and the temperature began to rise. The second stop was 11 ft further, followed by 15 ft more for the third. After five stops, the stock brakes were done. Any additional stops would only set the pads afire. The rear brakes were doing less work than the fronts, and were thus cooler.

The Beetle was driven slowly around the parking lot to both cool the car and brakes safely.

Armed with parts, tools and a liter of ATE Super Blue brake fluid, Autotech's head wrench swapped over to the larger R32 front brakes. There are a number of different schools of thought on brake bedding techniques. The common themes are increasing speed slowly and steadily, being firm with each successive stop, and allowing the brakes to cool as you go. This method seems to work well. Given a choice, I would have driven a day or so before doing any testing just to make sure.

The first stop with R32 brakes was 7 ft longer than the first stop with stock brakes.The second stop was 8 ft shorter than stock, and the temperature 44*F cooler. As the R32 brakes warmed up, they continued to improve until the sixth run at, at which point the stopping distance leveled off with a string of mid 120s.

Dave Coleman summed up the experience, writing, "Stock fell steeply and caught on fire. R32 changed so little run to run that I'd call it a flat line. Got bored after nine stops when we realized it wasn't changing." Clearly, the R32 brakes performed admirably under a brutal regimen of repetitive stops and would have been able to keep at it for far longer. These weren't the sort of conditions one would experience in day-to-day driving, but it's nice to know the capabilities are there. Anyone who has driven in the Rockies, Sierras or Alps can appreciate the added margin of safety imparted by oversized binders. We've now driven close to 1,500 miles in mostly urban environs and are happy to report the kit has been more than satisfactory.

Bottom Line
Autotech's R32 big brake conversion is a welcome addition to the Volkswagen tuning marketplace. With a price point between $300 and $1,000 less than an aftermarket racing-type brake setup, it's a solid option. With the Volkswagen R32 coming to America, there will be a supply of replacement and repair parts into the foreseeable future.

The decision to go with the rear brake conversion is entirely up to you. We elected to use R32 parts all around for the sake of balance and correctness. Because the front end of a car does the lion's share of braking duties, the additional braking capabilities in the rear probably won't be noticed much, but they certainly don't hurt. If one elects to do the rear, the decision to go the full route with the special backing plates is largely determined by having access to a stout puller to remove the hub. Autotech can provide the parts, whichever setup you choose.