Motor Trend Project R28: Engine, transmission, turbo, and exhaust

Just as with myriad "make-over" primetime reality TV shows, our Project R28 has recently undergone quite a transformation as well. Visually it sports new Euro-spec R32 exterior bodywork accented by RH 18-inch alloy wheels wrapped in grippy Kumho Ecsta radials. Under the skin, the R28 has been fortified with KW Variant 2 adjustable coil-over suspension and custom alignment specs. Inside the cabin resides a custom-sewn Alcantara suede interior, lots of R32 interior bits (pedals, dead pedal, door sills, etc.), and some added stereo punch by way of a Bazooka subwoofer that looks like a Nitrous Express nitrous bottle.

Now comes the most important part of our makeover. On those makeover shows the final aspect to converting an ugly duckling into a swan involves a therapist who transforms a negative self-attitude into a positive one. However, our therapist (Marcel the mad scientist at HPA Motorsports) was intent on doing just the opposite: transform the mild mannered, politically correct Golf into a downright wicked, nasty, and angry individual. The plan: swap in a 425 horsepower VR6 engine that, like a duck destined for foie gras consumption, is continually force-fed. In this case, feeding comes by way of an HPA single turbocharger system that huffs through twin intercoolers. The final product is downright wicked when boost hits, yet retains smog legality and runs on 92-octane pump fuel. Here's a look at some of the install work.

From eBay Motors we scored a 2001 VW 2.8L VR6 engine that previously had a custom twin-turbo setup installed. The owner removed the turbo system but left some upgrade bits including a custom head spacer plate necessary for big-boost turbo use. The owner said that the VR6 only had about 5,600 miles on it, thus it was relatively new.	After some eBay scouting we came across a take-off HPA single turbocharger system replete with intake/exhaust manifolds, inlet piping, twin intercoolers, oversized fuel injectors, and various brackets/mounts/clamps.	The engine bay of our R28 has remained empty for many years (the previous owner removed the 600 hp twin-turbo V-6 for another project car) and it was now time to shoehorn-in some new muscle.
One nice bit that came with our eBay sourced VR6 was a Quaife heavy-duty 6-speed manual transmission that replaced the factory 5-speed cogbox. Before installing the engine we had a look at the clutch to make sure it was fine, and found out that installed was a Sachs Race Engineering heavy-duty clutch system with little wear. Perfect!	Also fit to the Quaife 6-speed gearbox was a HPA short-throw shifter kit that cuts shift throws by 20- to 40-percent (depending on the setting) and delivers more positive feel.	We started our turbo installation by bolting on the custom HPA cast-aluminum intake manifold replete with a special low mount inlet for the turbo's inlet piping. Simply align the new intake gasket, position the manifold, thread in the bolts and then torque them to spec. The turbo kit also came with RL "310" 30 lb/hr fuel injectors that will deliver the proper amount of fuel when big boost hits.
With the engine outside of the car, bolting on the custom HPA cast-iron exhaust manifold is a cinch. A new set of gaskets delivers a leak-free seal and a final bolt tightening with a torque wrench ensures proper clamping.	Before bolting the turbocharger to the exhaust manifold, we used some of our $2,500 worth of approved "sponsorship" funds to upgrade to a new Garrett "30R" ball-bearing center cartridge for the turbocharger. The 30R spools up quicker, offers improved reliability, and (most importantly) will let our R28 keep pulling hard above 7,000 rpm whereas the Garrett T3/T4 hybrid turbo would begin to fall off after 6,000 rpm.	We installed a new Bosch oxygen sensor in the turbo downpipe, then bolted the downpipe to the turbocharger's exhaust housing.
Before installing any of the turbo inlet pipes, we installed new platinum spark plugs and heavy-duty wires from Bosch.	To simplify engine/tranny installation, the Golf's front core support was removed. Although such removal looks difficult, in reality all it takes is the removal of a handful of bolts and the unit comes right off.	Darren Scharfenberg of HPA carefully rolls our turbocharged VR6 engine into the Golf's engine bay, then attaches the engine mounts.
The first of two intercoolers are bolted to the body structure of the Golf using existing holes in the Golf's body structure.	After the second intercooler is bolted into place, Darren installs the turbocharger pipework that connects the two front mounted intercoolers.	The oil inlet and drainback lines are installed along with the silicone inlet hoses that attach to the soon-to-be installed inlet pipes.
HPA specially designed and cast its own turbocharger housings that include (among many things) an integrated wastegate system. Not only is the HPA setup more compact (as opposed to having to run an external wastegate), but it also allows for easy boost level adjustments by way of an Allen wrench.	JThe inlet piping for the turbocharger is positioned and then bolted to the cylinder head. One end of pipe attaches to the turbo inlet while the other end attaches to a modified Golf airbox fit with a K&N high-flow air filter.	After the different metal inlet tubes are installed, the silicone connector hoses are attached. Here, one of the silicone hoses was touching an aluminum air conditioning line, so the A/C line was bent to provide proper clearance.
The RL high-volume fuel injectors are one aspect of the upgraded fuel system, while a Bosch high-volume electric fuel pump is the other important element. Here, the fuel pump and a new Bosch fuel filter are installed at the rear of the Golf.	With radically more air/fuel entering the VR6 engine, we needed an exhaust system to quickly vent the spent exhaust fumes. We used a take-off exhaust system from a new R32 (the R32 owner upgraded to a custom exhaust system and gave us the stock exhaust).	Here Darren installs the R32 exhaust system that bolts directly to existing mounting holes at the rear of the Golf. The R32 exhaust system was a perfect choice based on the following: 1. It offers great flow and an aggressive exhaust note; 2. It has dual exhaust tip outlets that are located in the exact spot that our R32 body kit has cutouts for (go figure!); and 3. It was free.
A re-flashed computer was installed and the remaining wiring was finished.	With over 400 horsepower on tap from our HPA single turbocharged VR6, we can take on most challengers. However, in the event that we need a little added advantage we installed a set of Nitrous Express halo rings that fog nitrous oxide over the top of the twin intercoolers. On a hot day with full boost, the NX sprayers will quickly chill the intercoolers thus providing a denser, more powerful air/fuel mixture for the engine. In actuality, none of the nitrous goes into the engine...it just sprays over the intercoolers.	Once the new turbocharged drivetrain was finished, the front of the Golf was reinstalled. Putting the front end back on may look difficult, but is quite easy.
Here's the final look at our turbocharged VR6 powerplant. The engine idles nicely, passes smog, delivers 25 mph fuel economy, and belts out a dyno-proven 427 horsepower. Go to www.motortrend.com to watch the R28 being 4-wheel chassis dyno tested as well as watch it run 12.10-second quarter-mile times at the test track.