I installed the HFC's last night on my '11 G37X. Install wasnt too bad, biggest pain in the *** was just getting the bolts off and on by the header. Def made the car louder under acceleration but crusing is still as quiet as when it was just cat back only. There is slight rasp that can be heard in the car under load around 3-4k RPMs.

Only issue I am having now is when Im at a stop in gear I get a rattling/vibration in the floor of the vehicle. Its something I can feel and hear. If I put it in N or accelerate it goes away once the RPM's go up slightly.

I'm pretty sure its coming from the brace that connects to the HFC pipes. Anyone have any advice that has the HFC's to get rid of this before I go mess with it or end up taking it off?

Thanks!

Here is a quick vid from last night
2011 G37x - YouTube

R2C Intake
Berk HFC
Stillen Cat Back

 

Probably the heat shield, I'd imagine.

 

Thanks for the reply. Ill take a look when I get back under it. The only heat shields I recall were the ones on the old cats. Off the top of my head I cant remember any other ones.

 

Sounds pretty good!!

 

sounds sick dude! congrats

 

Sounds pretty nice! We're running the same exhaust, and like you I occasionally get very slight rasp around 4k RPMs. Good to hear that HFCs don't really impact rasp. Still I don't know if I want to get these cats, or get FI's RHFCs. Question, how long of an extension did you use to get those trouble bolts off?

 

Sounds pretty good, although I'm assuming it's so loud at WOT because you also have the stillen catback? I'm in the same boat and looking to get the HFCs but keep the stock catback.

No CELs right? Btw did you have a lift to do this on or just jacks? I imagine it'd be a hell of lot easier done on a lift.

 

Ugh, I just got mine done at a shop yesterday cause the demon bolt whupped my *** for 6 hours 2 weekends ago. I got raped for $350, they spent 5 hours on it. I still feel sick to my stomach. The only saving grace is my MPGs went through the roof afterwards and it does sound fantastic, guess I still came out ahead?

 

Really? How much of an increase did you see? I know the exhaust is certainly freer flowing without the restrictive stock cats but I wasn't sure how much of a noticeable increase there would be. Also do you have an X or the Rwd? Currently I only get about 22mpg but I drive 90% highway so it kinda sucks.

 

Sry havent been on in a bit, and thanks for the compliments... Also an update on the rattling while stopped and in drive, it went away the next day. Maybe a heat cycle and some bumps helped them settle? Idk but I'm just glad its gone.

It was just a few extensions, nothing crazy. Its only the only bolt you need to get from the engine bay. Putting the HFC's on went pretty quick, just getting the stock cats off from the headers was the hardest part. Total install time for me doing it with a friend was about 3-3.5 hrs I think. Also we used a lift. It will be very hard to do this install without a lift.

Yep no CEL's. Try and use a lift if you can. It will be hell having it on jack stands.