So if you have an aftermarket catback will you still have the hissing sound?

 

NO idea hahaha.

 

Hey I was downstairs so i decided to try and find the sound again, I figured it might be the flex joints so i went down with towels soaked in water and wrapped it around the flex joint, seemed to dampen the sound quite a bit. Is my Flex pipe leaking or something? Or can the stock ones just not handle the flow?

 

It's very poosiable that the stockers cant handle the flow. The inside of the flex pipe is ribbed so the flow over it could be causing the sound..

 

Funny though its' only when you let go of the gas and as the revs fall. and it's only at a certain rpm, it possible it is the flex pipe as i was reading online i found this:

"The stainless design with the "quiet" flex joint results in no noise increase at all, unlike the infamous Stillen "hiss""

Maybe we don't have the quiet flex joints and thats why it's hissing, this was from some write up about a maxima. I wonder if it's related.

 

I have this same prob too and I have FI HFCs and Borla catback. Seems like the noise is coming from the H pipe. Sounds like a fluttering noise. Only on decleration, or when rpms drop from 2500 to 1500 rpms while reving. Drives me crazy. I wuz wondering if a resonated X pipe would solve this but I'm not sure

 

I got an Invidia HFC and Invidia Catback installed at Amplified motorsports last saturday. I didn't notice the hissing/rattling sound until I got on the surface streets. Most annoying sound ever, sounds like I have a $5 dollar exhaust system installed, makes my car feel like a cheap honda. Anyways, I'm taking my car back to Amplified tomorrow, I'll keep you guys posted. I hope there's a fix.

 

^^Sound clips?

 

^that would drive me nuts

 

Subscribed.

 

OK, waiting for somebody to find how to solve this "hissing" sound... Maybe some wrap?

 

I had my y-pipe wrapped about 6 months ago. It definitely reduced some of the noise, but I'd like to have the actual HFC wrapped to see if it totally removes the noise.

 

so the rattling went away, the o2 sensor was loose. but still a slight hissing sound. now my CEL is on. any suggestions?

 

Good luck with the CEL...I've been fighting this battle for a year now. I've tried the double anti-foul mod with no luck. Next I'm going to add the steel wool and see what happens.

 

4drsleeper...but is your car running perfectly fine? the last thing i want happening is my car breeaking down on me.