They all hiss on deceleration. If you hear air while accelerating you got a leak. Motordyne does make some badass products however its pricey. Unleash the VQs with LTH don't contain it. I'd rather have power vs dealing with a lil hissing noise. This car is not that fast being NA seriously IMO.

not sure what you are getting at. i didnt say anything about a noise during acceleration. try reading my post again....

You guys worry too much about the hiss and the rasp. It's part of the charm and character that the car has. :D

Read yours again then try reading mine again. Lol. It wasnt all about you bro. Just the part u said about..ark cats will minimize hiss on decel ONLY. I'm sorry I didn't know you we're suppose to hear the hiss any other way. The air leak was my insight. Along with why would u contain power just cause a silly noise. Sorry for the confusion. :tiphat:

Lmao!!!...this post had me dying!!!..:inoutroflpuke:

I got the Z1 hfc on. I only hear the hiss when the engine is cold. Once its warmed up I don't hear it at all. I like the z1 hfc's, they add a nice growl.

Sent from my DROID4

What hissing means?? It is like a whistle or some??

My car has a horrendous rasp with FI test pipes, not at all a "hissing" noise.
From 2500rpm and up on accelleration, and then at about 4000rpm and down on decel. I think it sounds absolutely terrible and not classy.

Had to drive my Z to know wtf you all mean. No idea why you guys complain too much i like it tho.

With the windows up you can't hear it. And if the radio is on there is no way. Such a noticeable power increase for a little bit of noise on deceleration. Mine only hisses from about 2000-1500 rpm with the FI res. high flow cats.