2006 Volkswagen GTI - And The Winner Is...

Two weeks prior to SEMA '06, we worked alongside VW of America to host the GTI Tuner Challenge (et 1/07). Four elite tuners were invited to build an '06 GTI, and compete for an industry award plus a prime spot in VW's SEMA booth. Although et's scoring meant APR's project placed second (by one point), it won the overall award based on the scores of our sister magazines Sport Compact Car and European Car, as well as taking VWoA's own award.

The highlight for APR at the challenge included fastest lap at our Streets of Willow track day, as well as the highest numbers at the dyno: 356hp and 389 lb/ft of torque. After a minor software adjustment the tuner made a second dyno run, demonstrating its potential with an impressive 387hp and 405 lb/ft or torque.

With all this coming at the end of '06, it was just the icing on the cake for APR. There was history and future plans behind the project, so we sat down with the project's coordinator, Chris George, and uncovered the exclusive inside story. "Early last year we heard rumblings about the possibility of a collaboration between us and VWoA to build a project similar to the previous R GT cars at SEMA '05," he explained. "So we traveled to their headquarters and showed them what we've done with the 1.8T. We also demonstrated our capabilities with the 2.0T - mainly our K04 kit - and VW wanted to see more. Eventually, we were chosen as one of four tuners to compete in the GTI Challenge."

With the success of becoming part of VW's SEMA presentation, APR started to build a bigger turbo kit, with plans to make it available to the public. When VW heard about this, they explored the possibility of incorporating the kit into the official SEMA concept car, the new R GTI (et 12/06). VW wanted to produce a car the public could replicate more easily, rather than a complete one-off concept like the '05 SEMA cars. So when VW designers were preparing the tuning program for the R GTI, they consulted with APR.

Turbo Tuning
APR's stage 3 turbo upgrade for the 2.0T is expected to be available in spring '07. The engineering team had developed the kit using only its in-house expertise and equipment. "Even before we were selected for the Challenge, we planned to produce a turbo kit for the 2.0T," Chris elaborated. "The SEMA opportunity gave us a kick in the pants because the project had to be completed sooner than we'd ever done in the past. It was the quickest turnaround on a turbo kit in the history of our company."

Although development was carried out at an astonishingly fast pace, reliability and drivability remained APR's top priorities. The existing APR K04 kit for the 2.0T gave the engineers an excellent starting point, but essentially none of the hardware was carried over. What they learned most was the need to increase fuel flow. "By seeing what we were able to produce with the K04 (300hp, 323 lb/ft), it gave us an indication of what we knew we could get from a big turbo," Chris explained. "What it came down to was how to manipulate the fuel. The FSI motor wasn't like anything in the industry and was one of the biggest hurdles to overcome. FSI cars have a tremendous amount of fuel pressure, making them very sensitive and resulting in problems if the changes were incorrect. Fixing the fuel problem was the key to gaining power."

Once APR identified the obstacle, the engineers made haste to rectify it. "We had to find specific injectors," Chris admitted, "but there weren't any available in the time frame we had. Basically, we took the stock injectors and reworked them. It was a lengthy process."

Injectors were one part of the problem but APR also had to deal with the fuel pump. "For the 2.0T FSI, a mechanical pump on the head controls the amount of fuel that reaches the injectors," Chris explained. "Hitachi-made the fuel pump but didn't have any upgrade options at the time. We contacted them several times, but they had nothing that would work."