About 6 months ago, I got tired of being deafened by the noise of my Spec V's Vibrant Street Power muffler that has had all of its packing blown out long ago. I thought the perfect solution would be a variable muffler like the VT, and in theory, it was. However, the theory didn't quite live up to reality. First of all, the flapper valve rattles on overrun, which I decided to live with. Worse, the exhaust note was pretty choked sounding under most conditions. And then a couple of weeks ago I noticed a pretty severe loss of mid-range power and an obvious increase in turbo lag. Couldn't figure out what was up with it.
Until Sunday, at a local autocross in Palm Bay, when the car was acting like its old self again; that is to say, enough power to spin the front tires in second gear all the way down the first straight. Then on Monday morning, on my way to work, all the mid-range was back and the turbo was spinning freely. When I got out of the car, I immediately noticed that the exhaust sounded deeper, throatier, and a little louder than usual. I determined that the flapper valve in the muffler had been stuck closed and was now jammed all the way open. The car has been feeling and sounding great all week.
When I bought the VT, I was discussing it with a friend when the subject of the valve bearings came up. We both wondered how they were able to make bearings like that live through the heat and moisture inherent in the exhaust stream. I figured that they must have something designed for the conditions, but apparently my original concerns were justified. The bearings have failed after six months of service. Fortunately, I actually like it better now - the exhaust note sounds great and the car is as responsive as before the switch. My conclusion is that I probably should have saved a little money and just bought a regular turbo muffler.
