I have a catback exhaust system and have been using a silencer on it since I had it put on. Today a friend of mine asked me if they descreasd HP. Up until today I never really gave it much though. I'd always assumed that since it came with it that it wouldn't but after taking it off and looking at it I'm starting to think it would. Does anyone know? The reason I've been using it is because I used to get tickets all the time on my old one and paying $150 to $300a month really got old quick for an exhaust.

 

depends on the size
i would keep it on becasue you might gain a hp or 2 on the high end, but you do lose a lot of low end. we tried the test on my friends supra and he got 1 hp on the high end with it off, but his power curve was wayyy better with it on

 

I have a glasspack on my srt custom exhaust and Ive never lost any hp it actually helps with not losing back pressure like I would if I had my srt exhaust without one .

 

You cant really compare what helps or hurts performance on a Supra to what helps or hurts performance on a Neon...but thats just my opnion.