I noticed today after a high spirited run down my favorite desserted straitaway my exhaust changed its tone.....kind of sounds a litte deeper now....it doesnt sound like anything is leaking and the sound is coming from the tail pipes....could I have blown something loose in the muffler, I observed my A/F at wot and it looks ok about 11.5, I cant hear anything wrong up front either. has anyone known of any problems the nismo exhausts have?.....what is a good replacement or will nismo honor the warranty? Could it be my Rt cats?

 

I notice that after i run my car a little harder than usual, my exhaust note gets a bit louder and deeper like you just described. It could possibly be the heat??

 

Duflaci, remember those posts when the cores of the RT cats were blowing out? I wonder if you are having similar problems.

 

How long have you had your exaust? it might just be breaking in.

 

Did you notice any drop off in performance ? Is so...I would say your cats are collapsing . I had the same problem . Noticed a different sound from the exhaust and the car didnt perform as well .I was at the track and had just done my best run 13.2@105 . On the way back to the pits....the car sounded different...I only did 13.9 @97 on the next run . Knew something was wrong. Them RT's are crap on this car .Only way to find out is to take one off . I would start with the driver side . Seem thats the one that goes bad first . Both mine were bad but drivers side was totally collapsed....good luck....Bill

 

The exhaust has been on there over a year......I think it may be the cats but I didnt notice any drop in performance if any I think it got better....and the raspiness is gone and it sounds deeper ....how much if any? would either affect my A/F mix

 

HUH....I just thought I had an exhaust leak....Damn I will have to keep my ears and eyes open a little more....I was to check it out when I change the oil

 

More than likely , Sooner or later , they will collapse down over the top of the part that pushed thru . Wish I would have taken a pic of it .The middle of the of the cat material pushes out , and the sides collapse over the middle , closing off the exhaust . HOpe its not the promblem . But the rasp going away sure sounds like it...good luck

 

gonna order some crawford cats monday.....

 

Thats what I did...

 

Wow, I've had my RT cats for almost 6 months, they seem to still be ok. Could it possibly that I'm using them with the stock exhaust as opposed to an aftermarket?

 

I think the 10 lbs of boost might have helped it....LOL