i just purchased a pro circuit t-4 muffler to run on my 686 raptor and i would like some input just for comparison on what mains you are running.i had a chance to take it out last night briefly and make a few runs and with the same mains that i had in for my fmf(175-180) it seems to run good and strong from bottom to top with a good plug color so i may be real close now.i chose the pro circuit after seeing what they do in the real world out on the dunes on other quads and they seem to perform very well so we will see.on my first ride last night it feels like i probably gained at least a few horsepower as compared to the fmf-q that i have been using but that is of course just a seat of the pants guess.i will get a chance tommorow to run this set up at the dunes and i will do some racing so i can compare to my fmf but from what i could tell last night i should be quite a bit faster than i was.if anyone is using the t-4 on their raptor i would like to hear what you think about its performance and what you are jetted at.i purchased a quiet core insert just in case i get checked at the dunes but i dont plan using it unless i am forced to ,has anyone tried the quiet core on this muffler and if you have how much power loss did you experience?thanks for any responses.

 

Were did you find the core insert?? I need one before AMA starts regulating the exhaust noise at races in 2004...I also have the T-4, but my engine is stock and elevation is around 3000 ft. So i'm sure jetting would be different than Oregon....[img]i/expressions/face-icon-small-cool.gif[/img]

 

racerrob-i ordered the quiet core from the same place that i bought the pipe from and it will be here in a few days but you should be able to get the quiet core from just about any mail order company such as rmatv or dennis kirk.i am also sure the jetting would be way different where i ride but i would like to know what you think of the performance you got by installing the t-4 as compared to the stock system.

 

OH MAN....what can I say??....The difference is awesome. Snappy throttle response...great power increase bottom to top. I started racing after I bought the T-4...and after 1 race...the new law came out about noise limits. That totally p*ssed me off...[img]i/expressions/face-icon-small-mad.gif[/img]But if I can get the same power with the quiet core insert, I will be surprised. Gonna keep my fingers crossed....[img]i/expressions/face-icon-small-cool.gif[/img]