I believe the newest version of the Crawford HFC doesn't have the mounting points for the bracket in the photo anymore (which goes to the transmission)

 

i had this piece installed by the people that initially did it - rattle is still there, it seems to be coming from my stock exhaust.....


that problem will go away soon though




catch my drift? =P

 

There is a REAL long thread about the FI cats doing the same thing, regardless of the material (ceramic or metal)

 

not sure if this is related, but i had a same problem long time ago when i installed the crawford HFC with an aftermarket exhaust. i called the crawford, and they said the heatshield around the cat is touching the frame, and i need to make a minor modification to it. even my mechanic said the same, the engine is moving side to side under acceleration, and the gap between the heatshied of cat and the frame is too close to each other. i squeezed down the heatshield metal on the cats, and i didn't have the rattle noise anymore. i have a stock exhaust now, but still no rattles.

 

it has to have something to do with the heat shield. i went under my car and put heat tape on the cats and shield. still there. when it is cold its worse. i am going to go under my car and wrap the whole cats with a towel and see if it still does it. does anyone have any up to date info on this???

 

Guys,

In a few weeks, I'll be wrapping the top part of my cat-back system (cats to the H-pipe) with thermal exhaust wrap to see if that quiets it down.

If you'll read my previous thread about this issue, G35 member Ballisticus said thermal wrap (as well as two sets of resonators) quieted that rattle down considerably for him. I've already welded in one set of 14" resonators (no room for a second set on my Stillen cat-back system), and have 100' of 2" wide thermal wrap that I'll be using to cover as much of the exhaust piping as I can - my goal is for a damping effect to neutralize some of the exhaust pulse (rattle). Check out this thread:

https://g35driver.com/forums/intake-exhaust/133182-new-resonators.html

This problem seems to be pretty prevalent with high-flow cats or test pipes. Not sure if FI is a culprit but I'll let you guys know how my exhaust sounds after the wrap job. For what it's worth, the G accelerates like a rocket!

-B

 

I had the shop that installed mine pound the crap out of the heat shield with a rubber mallet, to provide enough space between it and the cats.

It definitely helped. I actually need them to do it a little more.

I can rev my engine in park with no issues. Car sounds great.

I can hear the rattle after I put the car in drive and accelerate quickly.

 

Ok, so i went under my car and wraped the whole cats and a portion of the y pipe with a thick towel and the rattle is still there.. upon closer observation it sounds like its coming from the glass pack in the mid pipe. does anyone know what will happen if i just took out the resinator and replaced it with a straight pipe? maybe it will perform and sound better...

 

i had some annoying rattle after i installed a ypipe, i took off the heat shield and it still rattled i was taking off hte hfc and the wierdest thing one of the nuts on the cats came off so the bolt was just rattling. you guys make srue everything is tight?

 

sweet thanks for the advice, i put some heat wrap and some clamps on my flex portion of my fuji y pipe and it quieted it down alot... hardly even noticable now... i guess what was happening was, since the crawford cats dont have as good of a hold as the stock cats did w/about 3 bolts holding them on to the car and the crwfrds that have a jimmy rigged exhaust clamp holding them on it was vibrating more causing the flex pipe to vibrate... uuuuuuu i hate vibrating sounds on my luxury sports car.

 

The heat shield is touching the HFC which is causing the the metal to metal sound. Easy way to solve this problem gently bang the heat shield with krowbar Problem solved.

 

Hey G&Z,

Glad to hear the thermal wrap helped out. I hope to wrap mine tomorrow. The temp outside is supposed to be in the upper thirties tomorrow and I don't have a garage to work in, so I'll have to wait and see if I feel like braving the cold.

More to come...

-B

 

Hey all,

I finally installed the thermal wrap and the results are outstanding. Check out my other thread for all the details:

https://g35driver.com/forums/showthr...68#post1836168


-B