Crazy Hissing sound
 

I just had my FI Test pipes installed.. I have the Stillen cold air intake along with the stock Nismo Exhaust. Anyone else notice this car has a crazy Hissing sound at around 4500+ RPM?

Yes I has hissing with my berk hfc as well

nature of the beast
 

Unfortunately, that is the downside to changing to HFCs. Nothing wrong with the exhaust or car. The non-resonated are louder than the resonanted. But some people cannot deal with the hiss at all since it is their daily driver and revert back to stock cats with just the catback exhaust.
I have Berk HFCs non-resonated with FI exhaust 18 inch resonaters. Loud hiss but louder exhaust.

as they said^ this is normal. they all do this when switching to test-pipes or HFC's

The car does it when it's mad. Perfectly normal.

It does sound like a King Cobra when its pissed off..

Maybe there's a snake under your seat?

Came here to post this.

It's the nature of the VQs motor making its hiss. This topic is covered all over.
The real question is. You think Randy Rodriguez knew about the hiss when he designed the front fascia on the Z?

What hissing miss?

LOL... I Love my Fangs even more now!

I have resonated HFC's (FI). The hiss is barely audible. I really have to slow down, cut the radio off, put the windows down, then accelerate in a low gear and lift off the throttle, and I can just make out the hiss. The resonators in a set of upgraded HFC's will mute about 90% of the hissing noise. As you open up the HFC's further (non-resonated, lower Count - I have the 300 count HFC's, but you can specify 100 count - better breathing), the louder the hiss. And then there are the test pipes that are pretty much wide open for noise. I have not heard a 370 with test pipes yet, but I can imagine it would be King Cobra hissing on Steroids...

Don't know what TP's hiss like but I can tell you from experience that LTH's with a non-res CBE, hiss louder than any snake I've ever heard.

I have an Invidia Gemini CBE I first went with Invidia TP's I had a little rasp and loud hiss. Then switched to Invidia 200 cell HFC's due to state inspection and the rasp is gone but the hiss is there on a decel but nothing to crazy. the majority of the posts I read pretty much everyone has the hiss if they are running TP's or HFC's

Lol King cobra on the juice. I actually didn't realize the noise until I read this thread. I guess my ears just got used to it. Now I hear more hissing then a snakes charmers basket in India. Still this car needs more power. I'd give my left testicle for a tt kit right now. Lol just saying. That noise is the least of my concerns. Causes its normal. If your rasp over powers your exhaust note then something isn't right. I had Invidia headers & nonres tp on factory cbe on my 350 niz and it bled rice. Choosing your setup wisely is key.

Get the ARK cats. The hiss is minimal and can only be heard when decelerating under 20mph. It is very subtle and sounds baddass. Not annoying at all