So, yeah, I'm a bit of a newb to this whole forum thing, but I joined, because it has helped me a lot with my G37-related questions. Please pardon if you notice newbness in my post, lol. But I'm gonna be very detailed.

I have just recently installed the Fast Intentions Carbon Fiber Catback along with the High Flow Cats. Absolutely love it!

But, continuing to my issue: When the exhaust is on a colder start--like the beginning of the day or what not--and when my RPMs are just around the 1.7k - 2k range after a down-shift (the 5 A/T drivers will know exactly what I mean), just right when the exhaust sounds very beefy, it vibrates my interior; and that is essentially my issue. What gets me is the fact that when it vibrates around the range, my rear-view mirror and sunglass holder start rattling and making noise. As soon as it gets passed 2k, it all goes away. It just gets annoying slightly having to twist my mirror or open/close the holder for it to go away when I'm in the city.

My concern: Is this normal? Are any of you guys getting same/similar issues? When the exhaust gets hotter, or the temp outside is warmer, the issues go away and it doesn't vibrate the interior in the low RPMs. I just want to know if it's a common thing with the CBE + HFCs, or whether I need to do something to get rid of it. I've had the install done by Infiniti dealer here where I live, and everything looked solid, so I don't believe it's anything of their fault. Please help!

 

Welcome to the joys of HFCs. Realize that you have set yourself up with one of the loudest exhaust systems for this car, so some degree of noisiness is unfortunately to be expected. I think what you are experiencing is normal for the Fast Intentions catback. I personally have the SS Oval canisters, which are much quieter, but I still get a sympathetic vibration around 1.7k while the engine is bogging due to a high gear selection. It does vibrate my interior, and cause CD cases to rattle, that sort of thing.

The thing with HFCs is they tend to increase an exhaust's potential for drone at certain engine speeds. This is especially pronounced in an automatic car because you have less control over the engine's RPM. This is personally why I don't have them.

 

yes, i have the FI CF catback and HFC's... I agree with droogie here, + the fact that there aren't any rubber dampeners like those used in the stock setup. Mine vibrates too at low speeds just like droogie explained it.

 

^ i think thats pretty cool!

 

Droogie and Borfoo, thank you, guys! That was the exact explanation I was looking for. I really don't mind the drone, to be honest. Even the fact of increased drone with the HFCs. Somehow, I'm just in love with how it sounds. But now that I know I'm not the only one with the interior vibe, I'm alright with it. Because I'm a newb to this whole exhaust thing, I wanted to be sure that the vibes aren't caused by something malfunctioning or what not.

Nonetheless, I love this set-up! Currently drooling over some other stuff I want to get.

By the way, Borfoo--in your opinion--do you feel any increased power gains from the Stillen CAI within low RPMs? Low as in from idle to 3k. I just noticed that you have the exact set-up which I'm aiming for. Any feel-able power during acceleration under 3k RPMs?

 

Can you put rubber dampeners in if you wanted to reduce drone? How would you do this?

 

I love this exhaust. I have the Carbon Fiber new X pipe with 18" resonator. I have the same slight thing except I don't feel it from my mirror, or cup holder. Its around the 1-2K RPM when on the gas. It vibrates or sounds like a loose part or something by the right Door area of the Coupe or underneath that area? Sounds like a sub-woofer hitting a metal sheet instead or paper. I have to go back to the mechanic to install the Heat Wrap that FI is sending me. I wonder whats causing this vibration on that side only and goes away once I pass the 2K RPM. Awkward thing is that I didn't have to cut the Heat Shield on the rear of the passenger to clear the canister. The canister clear with no cutting involved. It has like a 3/4 inch space clearance between the canister and the heat shield, I wonder if thats the cause of the vibration?? Because the instructions say Cut the heat shield to clear canister? The mechanic just removed the EVAP canister Cover and all good to go. Lets see and hopefully I can find out whats the cause of the vibration.

 

Hey all. I have the FI CBE and don't get the shaking mirror. Maybe bc I have a sedan? Def get the worst drone around 1.5-2k rpms.

Im considering getting rhfc and my question is will the rhfcs make the drone worse/louder? Also, does it make the exhaust sound louder or only deeper?

 

No, there are rubber dampers already in the car for reducing vibration causes by the catback hitting something, but that's about it. The drone is just something you have to live with or learn to love. It's a symptom of your setup, not something you can fix.

 

You don't need to go to the mechanic to install that heat wrap. It takes a few minutes and some zipties.

It's possible that is causing your vibration, however, there is a documented rattle that comes from the passenger door. I think it has something to do with the latching mechanism.

 

HFCs will make the drone more prominent, resonating will mitigate that somewhat. It'll still be more prone to drone than a stock setup. Yes, the sedans have a different design to their canisters. HFC's will make the sound louder and give the tone a fuller body, if that makes sense.

 

^^ With the Stock OEM exhaust, I never had that loose/vibration, or sound of a sub woofer touching a metal of sheet, specifically in that area?? With the exhaust from FI Carbon Fiber wouldn't it be on both sides? Where can I find the documented rattle of the door? BTW its not the noise of cracking popping of the windshield

 

Thanks. Dont know how I feel about the drone getting louder with rhfcs. I was hoping the sound would just get deeper. I have read about the hiss but don't think that will be too bothersome. I'm undecided. Guess ill have to wait and see what tax season brings.

 

^^ help!

 

a bit of an aside comment, but I was getting a weird rattle from the frequency of my HFC and catback. A towel in the sunglasses holder resolved the issue.