We know you've been sitting on the edge of your seat since last month when we tested every true CAI (cold-air intake) we could get our hands on for the Mk4 VR6. Well, as promised, this month we tested every exhaust we could find, and here are the results. For the exhaust test, we used the dyno facility at the Primedia offices in Anaheim, California. This is the same shop Sport Compact Car, European Car and a number of other magazines use for their testing. The facility houses a Dynojet 248C dynamometer and a full range of Craftsman tools for our greasy little hands. We tested the car over a period of two days and some of the results were surprising, even to us.
We feel a need to mention something we call a 3% error correction at this point. What this means to you is there's a 6% margin of error on any dyno test and the actual power could be either 3% higher or lower than dyno'd. So in the real world, a system that tests at 169hp could also test at either 168 or 170hp under the exact same conditions. There are actually a few systems in the test that prove this, so we wanted to ensure you are as informed as you possi-bly can be.
There were no restrictions on what exhausts could be entered into the compar-ison. So, in all fairness, it shouldn't be taken as a straight comparison. Some manufacturers only make 2.25" systems, while others make 2.5" setups, but we ran them all. We've noted the size of the systems for you, but keep in mind the 2.5" systems produced higher numbers in most cases -- possibly indicating that everybody should offer such a system for the VR6.
Generally the 2.25" systems dyno'd a few ponies less, but most were much quieter than their 2.5" counterparts. So all this should be taken into consideration when making your purchase.
The real question is: Are you willing to endure a louder car for those few extra ponies? Or would you prefer more refine-ment with slightly less power? The decision is yours.
Make sure you review the following pages and keep in mind we are positive your butt couldn't feel a 3hp increase. So will your decision be refinement or power? We know which we would choose.
We've included another of our exceed-ingly creative points scales. To keep it simple, we used a 1 to 10 scale, where the average score was 5. Anything below average received a lower score and anything higher was scored higher. Sounds simple enough, but here's our feeble attempt to confuse you: We scored the systems in four categories -- power, ease of fitting, finish and price. The 10-point system was applied to each category, with a possible 40 points up for grabs for each exhaust.
Power was judged on peak numbers alone, although we advise you to pay more attention to power under the curve. Ease of fitting was judged on just that -- how easily the systems went on and how much mess-ing around it took to get them to look right on the car. Finish involved how the welds looked, how pretty the unit was and so on. The final category was price since we knew this is important to all of us.
Please bear in mind this test is a guide and should be looked at subjectively. In the end, you know what will best suit you, and this article was designed to be one phase of your research. Armed with this, you have to decide which system has the right com-bination of power, price, prettiness and practicality for you. Good luck.