I just got my 4.08 gears installed, driving around having some fun with the car when I here hissing noise sometimes when I accelerate other times when I let off the gas. It is kind of hard to describe, but it definetly does not sound right.

I have Crawford High Flow Cats on the car now, this is my second pair in 1 1/2. The first set, one of the cats cracked, bought a second pair, and I'm guessing the sound might be from the cats again.

If I have to replace the cats again, I'm done with the crawford setup. Can anyone tell me what cat or test pipe is a good product that will last and create HP. I'm not a big fan of the raspy noise the test pipes make, but if it will last more than a year then maybe i will consider it.

Thanks

 

I got my Berk cats installed a week ago with my Nismo (BTW, I absolutely love the sound) and I noticed a slight, and I mean a very slight hissing when I accelerate and then press the clutch in and then the I sometimes hear a "hiss" sound. Kind of like a quiet blow-off valve.

But you can only hear the hiss if you going through a tunnel or if you have a wall beside you so the sound can reflect. If no wall or tunnel, then I cannot even hear the hiss. Is this an exhaust leak or could this just be normal?

 

you have an exhaust leak


OP
IMO i would just do testpipes...

 

I heard good things about berks. Good price, good customer service.

TP: helix TP?, simple clean. Hope davidv won't post his same picture again..lol

 

If performance from a HFC is what you're looking for I would say Berk metallics.

One a similar note, can anyone recommend good ceramic cats for the HR?

 

how about can anyone recommend some TP for my invidia exhaust : )?

 

i dont know about that... i have a cracked cat and the sound is more of a quick "tap tap tap..." sound, not a hiss... i imagine an exhaust leak would sound similar..

 

My berks and nismo combo did the same thing. Normal for berks.

 

Glad to hear that it's normal!

I am going to double check this weekend when I do the oil change just for peace of mind. I can get paranoid if there is something wrong with the car lol.

 

Helix SS Test Pipes. 16,328 miles and still going strong (knock on wood).

 

^ lol

 

seems like everyone hf or tp crack whats up with that?

 

most people that have cracked test pipes or HFCs are usually setup with the Nismo Catback, they're known to crack test pipes and HFCs because the Nismo was designed to be used with the stock cats. If you compare the stock cats to any aftermarket HFCs or TPs you'll see that the stock cats are much more indestructable. The slight hissing that you're hearing doesn't necessary mean that you have a exhaust leak, that hiss could be caused by the TP/HFC rattling at around 2-3k RPM. When I had the stock exhaust with TPs, I'd hear that hiss/rattle all the time at around 2-3K RPM, but when I put the Nismo catback on, the rattle became really unnoticeble. It's still there, but it's just more quiet. When I had an actual exhaust leak, there were no hiss, just a change of exhaust tone, and lost of low end torque. So I guess you'd have to pay more attention to the exhaust tone, or you can always just jack it up and look underneath to be sure.

 

Will HFC's throw a CEL? This is the only thing keeping me from doing this. I want to stay CEL free.

 

^no

 

Are you guys getting some rasp with your Berks + Nismo? I went with HFC's so I wouldn't get rasp, but some times it's pretty bad.

 

Mine had it bad but I replaced the old gaskets to make sure they fit right took away some of it. Ceramic ar the only HFC that reduce rasp. The metalic will have the test pipe tin sound.

 

I have that little rattling sound on my setup. I have Nismo Catback and Kinetix HFC's. I think the reason they rattle is because there is no mounting bracket that attaches to the two cats. The stock ones have this bar that connects the two and make it secure. Maybe if the cats we're connected like the stock ones, they wouldn't do that 2-3k rattle. I've also noticed that after the engine is at full operating temp the rattle becomes less noticeable. Anyone have cats that connect like the stockers???

 

maybe some of you guys with cracking issues are because of a poor fit my stillen hfcs had a 3/4 inch gap i had to cut the flange off another cat frmo some random car and use it like a spacer

 

Yes those connections you speak of are the OEM mounting braces. Some HFCs, like the Berks, come with brackets that allow the OEM braces to bolt up to, hence supporting less movement. But that does not necessarily mean that they will remain crack free, it just decreases your chances of cracks.

I do not have any rattles with my Berks though. It's just this faint hiss I hear every now and then. The car feels the same though.