Stock horsepower: 162.79
Stock torque: 170.16
Autotech horsepower: 170.29
Autotech torque: 178.88
Diameter: 2.5"
Price: $699.95
Contact info: Autotech Sport Tuning, 949/240-4000, www.autotech.com
After getting our baseline numbers with the stock system, Autotech was first to be tested. The system is constructed from 16-gauge T-304 stainless steel and is CNC mandrel-bent tubing. It is beautiful in its construction, and while it isn't shiny all the way back, it has the marks of a high quality unit. All of the welds are TIG, which is stronger and better-looking than a wire-fed (MIG) unit can provide. The system also uses "shell-style" clamps as opposed to U-clamps to join the exhaust sections together. This type of clamp works really well to prevent exhaust leaks and is very similar to the OEM parts.
The system bolted up easily, and its three-piece design made installing the over-axle pipe a breeze. Autotech was the only system that had a turn-down tip, and with the sound reverberating off the pavement, it emitted an eerie grumble. The system wasn't excessively loud or raspy; it just had a solid grumble that turned into a roar at the top of the rpm range.
Power output was nothing to shake your head at either. The system made 170.29hp at peak -- an 8hp gain -- but under the curve there were 12-14hp gains over stock and a huge gain in torque on the bottom end. So Autotech wasn't as shiny as some other systems, but it finished with the third-highest power number, and did so without being too loud.
Stock horsepower: 162.79
Stock torque: 170.16
Euro Sport horsepower: 170.91
Euro Sport torque: 181.84
Diameter: 2.5"
Price: $619.95
Contact info: Euro Sport Accessories, 714/630-1555, www.eurosportacc.com
Euro Sport Accessories entered its 2.5" system. The company does make a 2.25" system as well, but we didn't get a chance to test it because of time constraints. The well-built system is made from 16-gauge T-304 stainless steel and is mandrel-bent. It uses "shell-style" clamps, which proved to be the easiest to install. Unlike U-clamps, the shell-style clamps lock down evenly and equalize the pressure across the joint, going a long way to prevent leaks or crushed piping. The system is a three-piece unit with a separate over-axle section, making it a snap to install. You can also adjust where the tips sit by twisting the over-axle pipe while it is still loose, ensuring it's properly aligned.
The trend with the three highest horse-power systems was the "unfinished look." We don't mean they're ratty looking, but they have a raw metal finish with no polished tubing, although the tips and mufflers are shiny.
The Euro Sport system performed really well on the dyno, making gobs of power both under the curve and at peak. Again, the 2.5" tubing lent itself to a vicious burble at idle that turned into a fierce scream under throttle. The downside of the system is that Euro Sport doesn't make one for the non-cutout rear-valance cars. This means you need to replace the lower valance with the newer version if you want to fit this system to a '01-or-older Mk4 Golf.
Stock horsepower: 162.79
Stock torque: 170.16
Electrodyne horsepower: 166.14
Electrodyne torque: 176.67
Diameter: 2.25"
Price: $470.25
Contact info: Electrodyne, 703/823-0202, www.electrodyne.cc
Electrodyne's Freedom Design exhaust is one that proves what we stated earlier when we talked about error correction on the dyno. It is a rebranded Sebring system, as is the Remus system. The exhausts are exactly the same, down to the part number on the muffler, and the difference in power was within the 3% error correction factor.
The piping is coated with black high-temp muffler paint and looks nice, although it generates a lot of smoke when the engine is started for the first time after the installation. The system fits well, and even though the over-axle pipe is one-piece, it slides into place painlessly. The tips are a clean twin-oval setup, which looks really good peering out from under the rear valance.
It seems the reason the Electrodyne's output didn't match Autotech's is quite simple; it's a 2.25" pipe diameter, as compared to the 2.5" setup. The VR6 likes to breathe deeply, and the bigger diameter made a significant difference on some of the systems. This wasn't always the case, however, so we can't definitively tell you the 2.5 is a hands-down better purchase. But on average it makes more power.
Stock horsepower: 162.79
Stock torque: 170.16
GHL horsepower: n/a
GHL torque: n/a
Diameter: 2.5"
Price: $689.00
Contact info: GHL Motorsports, 480/655-0935, www.ghlmotorsports.com
You may be wondering why we didn't print any dyno numbers for GHL, and that's because we received the wrong system. Turns out GHL's shipping department had accidentally sent us a 1.8T muffler. In the 1.8T, back pressure isn't a worry because the turbo provides plenty of it, so the muffler's internal design is different -- although it's almost identical from the outside. That's why the problem wasn't spotted until after we fit the system and ran it on the dyno. The system was slightly down on power from what we'd expected, and it was the loudest of the group. The piercing whooshing sound suggested the system was too free-flowing and didn't provide the backpressure a VR6 demands. Since the exhaust wasn't suitable for test, we decided to withdraw it from the comparison, with GHL's agreement.
The GHL system is constructed from T-304 and T-321 stainless steel, and all the piping is mandrel-bent to provide the best airflow possible. It's supplied in three pieces with a separate reducer, similar to the EvoMS piece. The TIG welds and polished finish were the prettiest of the bunch, and the multipiece design allows for easy installation and adjustment. The kit includes everything you'd need to assemble it in your driveway.
We'll be sure to get our hands on a proper VR6 system in the future to see what it's capable of.