Hello,


This is a follow-up topic after having asked for your help here.

I solved my issue with a MotorDyne XYZ-pipe with its resonator module, while keeping the GT-Haus midpipe and muffler.

But, when I ordered the XYZ-pipe (through Z1 MotorSports, I also purchased Fast Intentions' Resonated High-Flow Cats (RHFC) because, "why not". I thought that extra resonators on the cats would help too...

Silly me !

I had the RHFC installed yesterday and the sound is now a LOT louder. The volume is insane (in a bad way) in the 3-4K RPM range and it has become slightly raspy again. It is louder than when I had the GT-Haus Y-pipe (but less raspy).

It is a surprise, because on their site, Fast Intentions says this :
I had also checked out user reviews and people seemed to say that the tone was a bit deeper but the overall volume was identical or had barely increased.

But then again, the GT-Haus muffler is what it is, and might be the culprit here. It produces a beautiful note but also seems to amplify the volume to extreme levels.

So the questions are : is this due to the cats being new, will the sound volume go down to something close to what I had with OEM cats ? Or is it normal and here to stay (unless I put the OEM cats back, which I will probably do in this case) ?


Once again, thanks in advance

 

^^ Funny I had FI's RHFC on my 09 and also and thought they were louder than the Z1's I previously had installed. I went back to Z1's and sold the FI RHFC's. They'll get louder as they break in :/

I have Z1's again on my Q50.

 

Bump, does anyone have a clue about what might be wrong ? I suspect something from the install that the local garage might have missed and I would need directions for them.

Even highway-cruising speed is completely unbearable and I am quite sure that this should NOT be the case.

Please help me !

 

Certainly doesn't seem like anything is wrong unless you have an exhaust leak but I doubt that's the case. RHFC is the quietest option when replacing OEM cats so if you really don't like it then you should probably put the stock ones back on. I don't really see the point in replacing them unless you actually plan on having the car tuned. I would argue that most exhausts sound better with stock cats but that's just my opinion. If you do decide to remove them let me know they're the last thing I want before I get my car tuned.