Hi G Owners,

I have a 03 G35 Coupe with basic modifications such as intake, plenum spacer, Osiris Engine Management, with a tune. My exhaust is completely stock and today I had HFC installed and it has this horrible exhaust smell that I noticed. It had the entire garage smelling that I had to let the garage door stay up to air out the smell. Is this a normal problem with getting HFC and will it go away or am I stuck with this problem. Any help would be welcome.

 

Is it a sulfer/rotten egg smell? If so your cats are bad. Hopefully you have a warranty.

 

Shea exhaust smell is perfectly normal when installing HFC's. Don't listen to this fool^^, I think he missed the part you don't have stock cats any more.

Luv ya mean it Scraggle.............

 

If it's simple exhaust smell then yeah, but the way he's describing how "horrible" it is I'm just thinking it's something else. Bad cats do infact smell like sulfer.

 

I grew up with leaded gasoline and converters didn't exist, the inside of our exhaust tips ran white (led) we enjoyed the smell of our exhaust! Today's exhaust smells far worse with HFCs or ART pipes...leave the garage door open whenever your G is running!
Gary

 

Thanks for the help regarding this issue. I thought something was wrong because I didn't know that it would have the exhaust smell. I only knew about the rasp issue from installing HFC.

 

It's good thing the smell caused you to open the garage door. You know what carbon monoxide poisoning is, right?

 

Now about why, but do you understand why installing HFC causes rasp? Nissan designed our exhaust systems for a specific flow rate/volume, replacing those very restrictive OE cats over whelms the system. Looking at factory cats one has to wonder how anything gets thru there. Adding HFCs is like putting 3# of dog crap in a 1# can, there's a visual!
Gary

 

Rasp is mainly caused by the diameter difference in piping, specifically a larger diameter meeting a smaller diameter tube (there's other causes, but this is the #1 offender). A 2.5" HFC butting up against a 2" stock y-pipe is going to not sound that great.

To the OP, please research mods more before installing something. A HFC works by having larger holes in the catalyst material, so more exhaust "fumes" make it into the atmosphere. It's a normal side-effect of this mod. I'm curious what brand HFC you installed that smells so strongly. Mine smell a little, but nothing crazy, and I went with HFC over test pipes specifically due to smells (and I still care a little bit about the atmosphere).

 

Maybe OP bought a used HFC where the filters inside are already fried? or is that even possible?

What brand?