24VSC

Still wet from its recent birth, VW enthusiasts have already set out on the quest for more power from the 24-valve VR6 engine. One of the easiest methods to achieve that goal is the addition of a supercharger, a technology the crew at VF Engineering have been perfecting for nearly a decade.

I was a fan of Nik Saran's work back when he was utilizing the Z Engineering centrifugal supercharger. I like him even more now that he is using the Vortech supercharger, a locally grown unit with a reputation for bulletproof reliability.

"VF-Engineering designed this kit from the ground up using the tough Vortech Engineering V9 supercharger unit," said Saran. "The key to the design of this supercharger kit is the simplicity with which it can be bolted on. The kit is supplied with every part needed to get your car up and running supercharged on the same day. The kit is set up in three stages to give you an increasing amount of horsepower and torque. Each stage is a bolt-on kit and can be added on to the previous stage."

Performance, reliability and factory correctness were major factors during the R&D carried out over a period of 2 years in California. Custom, proprietary GIAC software is supplied with this kit to safely realign all fueling and engine management parameters. The materials and manufacturing processes used were selected to match the OEM components as closely as possible. The VF kit includes a Vortech V9 centrifugal supercharger, a proprietary billet mounting bracket system, a replacement OEM serpentine belt, GIAC software with the rpm limiter increased to 7000 rpm and soft rev limiters completely removed, Bosch pressure relief bypass system, and polished ceramic aluminum-coated pipework. The kit features a 1-year unlimited-mileage warranty on major parts or an optional 2-year warranty extension to 3 years total for $150.

We tested Robert Wang's 2002 GTI VR6, a nicely done car with a Dietrich RS4 aerodynamic package, Bilstein PSS coilovers, Autotech swaybars and 330mm AP Racing brakes with Performance Cafe big brakes out back. Wang used ECS hard bushings throughout the suspension with D-TEK S-2 running gear sized at 7.5x18 and shod with Pirelli P Zeros. Set up in Stage I trim, Wang's car was running a modest 6 psi with a Milltek cat-back exhaust, which bumped up the output to 229.6 hp and twist to 201 lb-ft at 3400 rpm.

The power comes on fairly smoothly once revs are up (about 3500 rpm) and pulls decently to six grand. It's also pretty darn quiet, a result of Vortech's new bearing design. It's a good first step. We'd really like to see more boost, however, and Saran is developing a Stage II kit comprised of bigger injectors, modified pulleys and new software. The 24V engine can certainly handle the extra load.

Saran has done his homework here--the entire system is nicely engineered from solid stock. The VF supercharger should provide many miles of trouble-free performance, if you can remain under the authorities' radar.

24V Normally aspirated performance

Volkswagen's most recent VR6 engine, residing within the GTI, is a marked improvement over its 12V predecessor. How Volkswagen managed to stuff 24 valves in so small a space is something of a miracle. Its engineering brains not only doubled the number of valves, they also optimized the valvetrain (volumetrically efficient inlet and outlet passages, independently adjust-able camshafts, roller- bearing surfaces) to run with far less restriction. The result is an engine that pulls to redline with surreal smoothness and makes significantly more power while doing so.

In preparation for the 2003 One Lap of America race, a group of hardcore VW fans prepped a 2002 GTI VR6 to tackle the 5,000 miles of the event. Raffi Kazanjian of Eurosport, Mike Potter of Virtual World Parts and Paul Grimes put their noggins together and built a car they thought would be competitive and yet was also civil enough to drive across the country. Judging by the few hours I spent behind its wheel, they managed to do both, and do them very well.

As they were competing with cars making three times as much horsepower, there was no way the team could ever hope to match the firepower. They did, however, optimize what was there and made sure all of it got to the ground. The engine was augmented with several bolt-on components, including Eurosport's Cold Air Intake, its stainless-steel exhaust and VW Motorsport mounts and bushings. The software gurus at GIAC optimized the ECU, revising fuel and timing curves and raised the rev limit a few hundred rpm. Although the gains were fairly modest (187 whp at 6400 rpm), the car was equipped with a Kraftswerks' close-ratio gearbox and Quaife limited-slip differential that left the car with decidedly pronounced accelerative properties.

This thing rips through gears like a formula car, the first three punctuated by tire-chirping upshifts. Nitrous Express provided a 50-hp-shot nitrous oxide kit for instant power, on the straights anyway. Use it anywhere else, and the GTI will launch into the abyss.

While VW has made forward strides with its suspension settings, they remain far too soft to be considered a true sports suspension. The team chose H&R RSS coilovers as replacements, and they deliver ride quality the factory should emulate, eliminating the GTI's tendency to wallow through the corners and dive during hard braking. SPC's adjustable upper strut bushings helped the team set up the car's handling for specific track conditions, and a Neuspeed 25mm rear swaybar was fitted to dial out the car's tendency to understeer. Eurosport's front and rear stress bars kept the suspension geometry in line throughout the brutal event.

For the big Stoptech front brakes, the team used aggressive Hawk HP pads. The rear binders were based on VW's 337 model Golf. Needing running gear that was both competitive and rugged, the team chose super-light 18-in. SSR Competition wheels and agreed that Michelin Pilot Sport rubber (235/40ZR-18) would deliver the needed grip .

The body was modified with European bumpers, black rub-strips, black side moldings, 337 side skirts, smoked Euro headlights, a Hella Micro DE wireless foglight kit, MHW smoked fender markers, European GTI taillights, Kamei rear bumper carbon-look protector, 4Motion front/rear valance, Hella rear upper spoiler, Euro Aero front wipers and a Skoda rear wiper blade. The car was also equipped with VW's factory roof rack and bike carrier so the crew could get around the various tracks more easily.

Despite the increased spring rates (800 lb. front/400 lb. rear), the car behaved very well during my test drive, providing good high-speed stability and great control through tight corners. Braking was well balanced, and if those Stoptechs had limits, I could not find them. But it was the GTI's Kraftwerk transmission that really made this car fly--the aggressive gearing was well suited to the canyon road we drove and made the most of the car's powerband.

There's something wonderfully utilitarian about a VW Golf, and to use it on the track seems a natural progression in its progress from factory to dismantler. Raffi and those like him keep the VW flame alive by such conversions and do a lot toward converting others to the VW cause. Well done. --LB