[Rez90]

Looks like a nice piece. I'm wondering if anyone has any real world experience. I'm mostly curious how it sounds with the valves closed. if it was like stock or quieter it would be a winner for me as for DDing the TH i'm not looking for anything louder than stock. But of course i'd love the option to hit a button a straight pipe it from time to time.

http://www.quicktimeperformance.com/427218B/

Thanks.

 

[Car-Guy]

I had something like this on a couple of my Vettes that came straight from the factory. (NPP option) If I recall correctly they work by vacuum control. A few seconds after the car started up a valve would close and the exhaust was super quite. And it would stay that way until you hit a certain RPM (3500 rpm's I think) then they would open up, supposedly giving you another 10 to 12 hp.... There was an after market option (called mild to wild) that would allow you to press a button and open the value anytime and at any rpm... It was cool but to be honest, it was to loud for me at lower speeds.

 

[GraniteHawk]

I ran QTP products on my old GSX & Evos for year & loved them. I've seen a couple TH owners post on IG having issues with the QTP valves. The plate inside the valve breaks off & get stuck in the muffler/exhaust tip. Hard to say what is causing it, maybe quality issue on that valve? Extra vibration from the TH?

 

[dobtruckers]

Well these have butterfly valves just 6-8 inches from the tips. So the heat there is a lot less than upstream and if they were to break loose it shouldn't be a big issue - other than maybe one side being a lot louder