Project Black Dog Part 2: Autotech 280mm brake upgrade

In initial performance testing, this 1996 Jetta, "Project Black Dog," required 167 ft to stop from 60 mph. That was a record: We had never tested a car that approached that distance. Right after the ability to turn, I desperately needed to help this car stop. The Corrado G60's 280mm front disc brakes are among the largest ever installed on a compact platform. They are a natural upgrade for any Volkswagen with lesser brakes from the factory, and are also the basis for aftermarket upgrades for many other marques.

Autotech Sport Tuning provides brake upgrade conversion kits for virtually any watercooled Volkswagen, using all-new parts exclusively from O.E. suppliers to ensure the highest quality. Autotech's options range from vented-rotor conversions for MkIs to a 334mm upgrade for MkIVs. For Project Black Dog, we used Autotech's MkIII kit that upgrades four-cylinder models to Corrado-spec front brakes. It includes 280mm vented rotors, calipers, carriers and Mintex pads. I chose Autotech's SportTuned cross-drilled rotor option, as well as Autotech's braided stainless-steel brake lines, which further improve pedal feel and the driver's ability to modulate effort. The lines were a simple addition and little extra work was required once the system was opened and bleeding was made necessary.

Autotech's 280mm upgrade kit requires the use of at least 15-in. wheels that are compatible with a Corrado G60. Black Dog's 16-in. Kosei K1s provided more than enough clearance. The Jetta came equipped with rear drum brakes. They are far from ideal and easily swapped out for the factory disc setup, but I focused on the front brakes, which do most of the work, for the first round of improvements.

Installation was completely straightforward, consisting simply of removing the stock parts and reinstalling different stock Volkswagen parts. Be sure the fasteners you use meet Volkswagen's standards, and consult the Bentley manual for procedures and torque specs. The braided stainless-steel brake lines were the only part of the job that was not transparent, with a slightly different form on the inboard ends in front. No problem resulted. (I have never seen an aftermarket braided stainless brake line that exactly matched the factory line it was meant to replace.) The rears were more challenging, and the driver's side rear would have required the removal of so many parts to access it that I decided to leave the stock line in place.

After bleeding the system and torquing the wheel lug bolts, I bedded in the new pads according to Mintex's instructions before returning the vehicle to its owner. With the significant increase in braking ability, it was soon determined that the Kumho Ecsta Supra 712 tires were insufficient. The owner complained of locking up the fronts. I drove the car, and agreed that though braking effort was easy to modulate, the tires simply ran out of grip at a moderate level of effort. This echoed past experiences with the tires; one example is a Miata keeping up with a Porsche fitted with Supra 712s on a mountain road.

Pirelli P Zero Nero tires were chosen in the same 205/45-16 size. An in-depth write-up of the P Zero Nero can be found online at www.europeancarweb.com/tech/0207ec_nero/. To summarize, the Nero is Pirelli's entry in the purely aftermarket replacement realm of ultra-high-performance tires. It has styling designed to appeal to a younger enthusiast, and its level of performance is made more affordable by doing away with some of the compromises necessary for a tire to be fitted as O.E. The tires completely transformed Project Black Dog, giving more grip everywhere. They provide acceptable ride quality and are not noticeably loud on the freeway. As a side note, don't let the tire monkeys use an impact gun to tighten the lug bolts.

The Jetta's new brakes were torture-tested at California Speedway in Fontana, with eight back-to-back stops from 80 mph. Because it had been some time since the brakes were installed on the car, the system was fully flushed and bled with Castrol GTLMA DOT4 fluid immediately before the test. Ambient temperature was approximately 95*F. Stops were done toward a radar gun and rotor temperature measured with a contact thermocouple probe after each stop. A "backside stop" was not used, meaning the car was slowed gently on the outbound, turnaround portion of each loop. This allowed the brakes more time to cool between stops.

The 80-to-0-mph distances and rotor temperatures are presented in an accompanying table. Using the procedure described, rotor temperatures bounced around in the mid-800*F range. There was one spike to 941*F, but the next stop was back down to 853*F. It is difficult to pick an upward trend in temperature or stopping distance out of the run-to-run variation, but the variation itself provides a clue to what was really happening. The brakes were able to recover enough on each run that the first portion of the run was consistent, and similar to the first run. However, by about 50 mph, the pedal would get spongy and effort became difficult to modulate. By the end of the run, there was not enough friction to lock the tires. The Mintex standard replacement "red box" pads were not up to this test. Autotech told us the Mintex C-Tech pads are much more capable, good to 450*C, or about 840*F, right in the range experienced in this test.

The table does not include 60-to-0-mph figures, because all stops were from 80 mph, and more heat was put into the system than if they had been from 60 mph. The shortest 60-to-0-mph distance extracted from the data is 142 ft, a full 25 ft better than the best 60-to-0-mph test with stock brakes and tires. It is likely an even shorter distance would have been achieved in plain 60-to-0-mph tests, as the pads would have been operating more effectively for most of the stop.

It's been some time since there was any news on Project Black Dog. It has been making regular visits to obedience school, though, and has been thoroughly retrained. Simple bolt-ons led to about a 10% power increase. The H&R Cup Kit suspension and anti-roll bars (the first set of H&R bars for the MkIII in North America) dramatically improved the Jetta's handling. With the 22mm front bar and adjustable 25mm rear bar set to full stiff, the handling balance is just right for an entry-level street car, basically neutral with a slight tightening of the line when the throttle is lifted. Slalom speed increased from 60.5 mph to 66.7 mph, and the skidpad performance skyrocketed from 0.77g to 0.88g. Stay tuned to www.europeancarweb.com for details.