Do you lose hp and/or tq if you put silencers on your exhaust? For example, let's say you have dynoed your exhaust and it gained 10 hp and 5 tq (just random numbers to make a point) with the silencers off, would it be lesser if you put the silencers on? I read something about losing a little bit of gains but just wanted to make sure. Thanks in advance.

 

I just installed my own custom exhaust for my G35 sedan and I used Injen SES mufflers. I drove home from the shop without the silencers in. The next day I installed them, because the system was a bit to loud for me. I plan on getting a dyno done and one of the things I wanted to do is, on my 3rd pull, pull out the silencers and see what happens to the numbers. I have no idea when I'll be able to get the dyno done however.