Hey Guys,

I recently changed HFC from the Magnaflow to the Injen because I found that the heatshield on the Magnaflow rattles below 1500RPM. Unfortunately when I changed over to the Injen HFC, it produces a huge RASPY noise around 3000RPM when the car is cold. Once it's warmed up it goes away.

I also noticed that with my Magnaflow cats, even though they aren't broken and the 02 sensors were fine, my CEL would go off every 2-3weeks. With the Injen HFC, the CEL went off the night I got them installed.

Does anyone think they may have not been installed properly? or maybe the gaskets were put on wrong? I was looking around and I saw that some gaskets are meant to be put on a certain way and if they aren't, it will cause a leak.

Anywho let me know if anyone has heard of this.

 

Oh, and my 350z is an 07. As for my exhaust, I have a Fujitsubo Legalis with a Megan Racing Y pipe.

 

I've not heard of this.Who did your install?
HFC quality varies widely.I shopped around before I chose the ones I installed.
My Z1 Motorsport HFC's are perfect.I'm running a Nismo S tune catback which is
essentially the same exhaust you have.No rasp,CEL'S..perfect.
Besides a nice power boost and a great exhaust tone,the Z1 Motorsport HFC's
are priced well below the "name" brands.In addition,they install like a glove!

 

cel going off and rasp is common for hfc, something you have to deal with. Btw, i never knew injen, magnaflow, or z1 made hfc for the hr....

The hfc gasket is the same shape upright or upside down, unless the bolts weren't torqued all the way, then that might cause a leak

 

Yeah,I did'nt either(Z1 MOTORSPORT HFC).I had Berks on a previous car.
Also had Kinetix.I noted Z1 had HFC.Checked e'm out..great quality.The detail&construction is better than the Berk.Z1 designs their stuff in house.
They know Z's.Thats all they do.I'm running a Z1 spacer.Its been great.
Paid like $135!The HFC's did not disappoint.The car is a tad louder.At steady
hwy speeds,pretty damn quiet.No drone.
I highly recommend the Z1 Motorsport HFC's.
Cannot beat the price!

 

probably a leak..but in reality why didnt u just adjust or take off the heat shield that was rattling..would have made much more sense to me

 

I had my mechanic do it first, NRG automotive, then I went to prototech, and then a custom exhaust shop, can't rem the name lol.

The heatshield was welded onto the cat, I didn't want my mechanic to mess around with a perfectly good cat in case I wanted to put them back on.

Also I've gone to two different shops and had the HFC taken off as well as the Y pipe to verify that there were no leaks.

I heard that the flex pipe in the y pipe can rattle sumtimes so I even got a custom y pipe which was cheap and bolted that on but it still didn't fix the rasp.

All I've heard for a solution was to put more resonators on which I don't want to do because the exhaust note is already quiet as it is :S