I have an OBX exhaust and replaced the muffler with a Megan dual fireball canister muffler with silencers. The OBX muffler was loud and hung too low for my driveway and the Powertech pt1012 I had after that was too loud. Well, any way had car dynoed and to my suprise when removing the silencers I lost about 20 hp and about 20 tq. and when I put them back in I gained it all back and got about 5-7 up top. What gives? do we need back pressure to make power? Here is linke to dyno http://www.hpphoto.com/servlet/LinkP...613d69a8&size=

 

CAn you possibly post your dynos. This is extremely interesting.

 

from my understanding canister mufflers work better in small displacement forced
induction cars
You dont see GTP's/ Mustangs with anything but a
chambered muffler

 

I have dyno sheet, but not sure on how to post the dyno results on sight??

 

20 hp is a huge amount to lose through a change in your exhaust setup. The dynos you had done were on the same kind of dyno, correct?

 

yes, same dyno

 

Backpressure has nothing to do with it...backpressure is for 2 stroke engines, not ANY 4 stroke. What you're thinking of is gas velocity...that's what we need.

 

I don't see how there can be 20hp and tq difference by taking out the silencer. A friend of mine has a 99 SE with a silencer in his muffler and his car is considerably quicker with the silencer out of the muffler... Dyno sheets would be extremely helpful..

 

would replacing the Megan muffler with stock muffler & keeping b pipe increase exhaust velocity?