I picked up my V35 Coupe 6MT about three weeks ago, and noticed when giving it the beans it has what I thought was a heat shield rattle. However, when I was getting new tires put on (my friend works at the shop) I was in the bay looking underneath my car and discovered that it has BERK cats installed. I knew it already had a Borla exhaust on there but the HFCs was news to me. The PO also had an X-Pipe welded in where I think the stock Y-Pipe used to live.

After a bit of reading, it appears that it isn't a rattle after all (Pretty sure the OEM heat shielding had been removed completely as well) but rather from the BERK cats.

Is there anything I can do? It's really annoying during hard acceleration to hear that rattle/raspy noise.

 

Motordyneengieering.com

 

And what exactly am I looking for?

 

ART pipes.

Berk HFC's have a bad rep on here for prematurely failing. The ceramic substrate material in the cats will break apart, reducing efficiency and causing all kinds of noise issues one of which is a rattling sound. Also the OEM cats had the heat shields on them and when they were removed you no longer had any shielding down there.......

 

Ok thanks. As for heat shielding, I meant for the entire exhaust not just the stock cats.

 

With the Borla exhaust (sucks) the y-pipe should be long gone, the x-pipe is blending the volume from each bank! The previous owner was trying to get rid of the rasp with the x-pipe. I suggest you get your G back on the rack, with see if your exhaust is touching anywhere. Berk HFC are what caused my rattle, most obvious at idle! Happened to me after 8 months, called Berks told them about the rattle got no answers! A few months later I called again and my warranty had run out, was told I was SOL! Replace with Fast Intention HFCs, that's what I've been running since or Motordynes ART pipes either one might eliminate the dreaded rattle/rasp!
Gary

 

Hi guys, new to this site and trying to join the family, my question is should I be having any bogging down during high speeds? I hit the freeway after they were installed and the car bogged down around *************
idk it was wierd almost like if I was running out of gas or something lol
help?
Thanks G family

 

Bad cats will choke the engine off at higher rpm.

 

But it started doing it once I began running test pipes, my old cats had a bad heat shields

 

Did you reset the ECU? Or it could be something else that coincidently popped up after adding the test pipes.

The cat substrate acts like a resonator and kills the rasp. Remove them and instant rasp. Common on Honda V6 engines too. The pre-cat deletes make similar power gains to test pipes on the G, and also make the exhaust raspy. The solution is to add an additional resonator.

 

So bad heat shield can be the culprit to raspy/tin can sound coming from high acceleration??? Bad CATs?? Sounds like bad rice burner/Exhaust on my 2008 G35x. I can' stand the sound but also dont want to spend money where not needed. Thanks G fam!