VW Sport Tuning

Magnaflow’s Tech Center...        read full caption Magnaflow’s Tech Center has both a Dynojet dynamometer and a Mustang dynamometer (One known to provide pretty accurate absolute numbers.—MAX), and we would have liked to have performed the dyno tests on both dynos. Unfortunately, the Mustang dyno was down when we were performing these upgrades. Baseline peak numbers were established at 139.2 hp at 5,450 rpms and 160.3 lb-ft of torque at 3,320 rpms.

After establishing the baseline...        read full caption After establishing the baseline numbers at Magnaflow’s Tech Center, we drove the 15 minutes to Autotech for the first round of mods. The chip and the filter were the first parts to be installed. Chris, Autotech’s R&D specialist, was the install wizard while Dana is the electronics guru that does all of Autotech’s chip programming and installation. K&N’s panel filter is what Autotech recommends for use with their chip and exhaust. To install it, first you must gain access to the stock filter and remove it. To do so, simply remove the screws that hold the top of the airbox to the bottom of it and pull the filter.

K&N’s filter is pre-oiled...        read full caption K&N’s filter is pre-oiled from the factory. The filter not only flows better than the stock one, but can also be reused after being cleaned and re-oiled.

The filter includes a rubber...        read full caption The filter includes a rubber gasket with an adhesive back that must be applied to the top portion of the airbox. K&N also includes gasket lube to be used on the surface that contacts the filter. Apply the lube liberally to the gasket, and reinstall the top of the airbox with the screws that connect it to the bottom.

Autotech “optimizes fuel,...        read full caption Autotech “optimizes fuel, timing, and boost maps for performance-oriented driving when using the stock turbocharger and premium 92-octane fuel.” Max boost is regulated to 1 bar, or 14.7 psi.

Dana uses the VAG computer...        read full caption Dana uses the VAG computer tool to make sure that everything’s synched, and the system is reset before sending us back to Magnaflow for test numbers.

Though we were only able to...        read full caption Though we were only able to play with the chip and filter mods for a total of about 30 minutes of seat time, the difference was immediately apparent. We couldn’t wait for the exhaust and didn’t really have to. Because VW installs the exhaust before the suspension, it is necessary to cut the exhaust at the rear torsion beam/axle in order to replace it.

After completely removing...        read full caption After completely removing the OE exhaust from the car, the slip clamp that is used to connect the catalytic converter to the rest of exhaust is transferred to the new resonator, as is the exhaust support at the middle of the vehicle. Autotech’s exhaust is a three-piece unit that uses slip-fittings and clamps for installation. After installing the resonator, pass the midpipe over the torsion beam, and connect it to the resonator pipe using one of the included clamps.

Back on the dyno with chip...        read full caption Back on the dyno with chip and intake, the car proceeded to make some awesome runs, but we were surprised at the dip that starts to take place on the torque curve at 5,100 rpms. The engine had had plenty of time to cool before each run, so we knew that the engine wasn’t getting a hot charge from the intercooler. Our new baseline numbers were 161.2 hp and 188.6 lb-ft, which translates into a gain of 22 hp and 28.3 lb-ft. Depending on the drivetrain loss percentage that you prefer use, you can determine that with the widely accepted 12.5- percent loss that flywheel power is at 184.2 hp, or, using our conversion factor, 173.7 hp.

All the horsepower runs. The...        read full caption All the horsepower runs. The chip/filter run follows the stock run for about the first 400 rpms, at which point it surpasses the stock plot and continues to build. The power difference with the addition of the exhaust is very apparent. The chip/filter/exhaust run starts off stronger than both the stock and the chip/filter run, and ends up stronger as well. It’s easily visible where the stock exhaust hampered performance. The maximum gain, with the addition of the exhaust to the chip and filter, occurred at 5,380, where there is a 35hp difference.

To fit the muffler in place,...        read full caption To fit the muffler in place, put the remaining clamp on the muffler pipe and slip the pipe onto the midpipe. Push the muffler’s hanger onto the chassis’ rubber support. The attitude of the muffler suggests it is truly a performance piece, as does the tone. We noticed that, if you wanted to, you could bend the hanger so that the tip pointed more downward and less to the side. Once the car has been driven for a while, the tip takes on the awesome gold, blue, and purple hues that tell the trained eye the tip is polished stainless steel.

The final pull. Torque peaks...        read full caption The final pull. Torque peaks at 3,100 rpms and begins to drop slightly at 3,500 to a plateau that lasts from 3,800 rpms to 5,250 rpms. Horsepower keeps building to its max at 5,180 rpms, at which point it plateaus and drops to a slightly lower plateau that is maintained to redline.

For VW fanatics of years past, the GTI was the pinnacle of Volkswagen performance and technology. However, with mainstream integration of VW’s product, the original vision of the GTI has been lost, turning the GTI into little more than a trim package. Granted, VW does intend to remedy this in upcoming model years and reorient the focus of the GTI towards the performance side, but that still leaves owners of the current generation of the GTI wanting something a little sportier. Enter Autotech.

Autotech has been tuning watercooled Volkswagens (And only Volkswagens.—MAX) since deep into the last millennium and has developed a list of products for the GTI longer than a roll of toilet paper. The company’s “Sport Tuning” philosophy has existed since its 1983 inception, and simply stated is “to improve all parameters of the performance envelope of a vehicle.” When we found out that Autotech was going to sport-tune the hell out of a 2000 1.8T GTI, we began a thumb wrestling competition to see who would be the lucky staffer that would get to spend a week in beautiful San Juan Capistrano, California, at Autotech’s facility. The added bonus to cataloging the buildup was that the staffer would be able to drive this car for that week and play with it after each round of modifications. The down side, however, was that the car had to be given back to its owner after that week was up.

First up on the list of mods to be performed was adding power to the decidedly anemic 1.8L turbocharged engine. The beauty of this little dynamo is that it is extremely under-tuned from the factory, and getting a lot more power requires little more than reprogramming the engine-management software and alleviating some of the back pressure that the turbo has to deal with. With a reported 150 flywheel horsepower available, we began our first round at Magnaflow Performance Exhaust’s Tech Center in Rancho Santa Margarita. At the Tech Center, we established a baseline dyno plot to calculate how much additional power Autotech was able to produce.

Wheel horsepower, transferred to the ground through the stock wheels and tires, rang in at 139.2. Now, depending on whether you subscribe to the 12.5-percent drivetrain loss convention or prefer to determine the drivetrain loss by interpolating it from the factory-claimed flywheel horsepower and the actual dyno numbers makes all the difference. Therefore, we’re going to give you both. Performing the necessary math, we determine that the actual flywheel horsepower is 159.1 by using 12.5 percent as our conversion factor. If we compute the drivetrain loss using VW’s numbers and our own, we determine it to be 7.2 percent. Torque, however, is another story.

Dynojet dynamometers are great for determining horsepower and torque gains but may not provide you with absolute output numbers. What this means is that while our gains are real and accurate, we may not be putting out the exact numbers that the dyno sheet reads. This is especially apparent in the torque figures we obtained.

For the 2001 model year, VW rates the 1.8T in the GTI at 150 hp and 155 lb-ft. This, however, is a model year 2000 car, and Volkswagen introduced the 1.8T into the GTI halfway through that year. In the 2000 press kit provided by VW, the only transversely mounted 1.8T was available in the Beetle and made 150 hp and 162 lb-ft. What this means is one of three things: the dyno numbers over-estimate the output at the wheels; VW underrates the torque numbers for the 1.8T in the GTI severely; or the torque numbers are still underrated but are based on the Beetle’s 1.8T rather than that in the current GTI.

Whatever the case, gains are what we are interested in, and our baseline torque number was established at 160.3 lb-ft. After the first round of modifications, which included the replacement of the stock air filter with a K&N direct- replacement filter and the addition of Autotech’s Q-Chip, horsepower jumped 22 ponies to 161.2 hp, and torque went up by 28.3 lb-ft to 188.6. With the addition of Autotech’s exhaust, it was immediately apparent that the chip is tuned to work with the 2.5-inch diameter piping of Autotech’s exhaust. Where the chip with the OE exhaust had a drop in horsepower at about 5,100 rpms, the horsepower continues to build with Autotech’s exhaust. At 5,380 rpms there is a 35 hp gain with Autotech’s exhaust in place, but peak horsepower builds to 180.1 hp at 5,180 rpms. Torque also jumped up to 206.5 lb-ft with the 2.5-inch exhaust, relieving a lot of back pressure.

Once all the components were installed, it was time for a test drive. The turbo characteristics are amplified with the addition of the parts, but it is manageable if you can deal with the lag and the rush of power that occurs once the turbo has spooled at about 3,000 rpms. At cruising speeds on the local freeways (About 65 to 75 mph.—MAX), downshifting to pass was about as pointless as asking George Bush, Jr. the meaning of the word hypocrite. The car accelerates like a rocket, but there was one problem. The GTI’s stock suspension wasn’t up to the extra power and left the driver feeling extremely unsure about high-speed canyon runs and highway jaunts. That, however, was taken care the following day with the suspension mods Autotech performed. You’re going to have to wait until next month to get the inside look at Autotech’s reworking of the GTI’s suspension, but take a look at the installation of this month’s parts and dyno plots to get an idea of what you can expect from Autotech. See you next month for more Sport Tuning.