I been hearing a low hissing sound at RPMs higher than 3k ever since i installed a cattman y-pipe (bought used). i was thinking it was a leak but someone told me some aftermarket y-pipes do that. is that true?

I have a cattman y and there are no "hissing" sounds or leaks. Did you put in new o-rings or use the old ones? How about the gasket to the cat?

Did you check the flex section out really well for problems? I would think that it would be louder than a hiss if it had some kind of leak. My original o-rings were pretty flat and worn out and they caused my stock y to leak and make all kinds of noise. I would have been fine by just replacing the gaskets, but I figured if I was going to take it off, I may as well get a better one.

I had my cattman on with the stock air box at first and it was very quiet, but still produced noticeable gains. Now, I have a PiggieRacing pop charger and that makes more noise than the y-pipe. I also have the stock cat and after cat still on.

i got new o rings from nissan when i had that put in, as well as the gasket for the cat. the flex section had a thermal wrap on it since i got it so i couldnt completely check it out.

my guess is that the shop that put it on didnt use the new o-rings and just put the pipe on like that OR its the flex section? the thing is....now when i take it to a muffler shop..they see the thermal wrap and think its there to stop some leak an immediately blame the flex section.

sounds like the flex section, if u jack the car up and have some turn the car on and lightly rev the engine while u are underneadth. wear some thermal gloves and slightly move the flex section onthe pip and see if u hear the hiss more? since the y-pipe doesnt use hangers if u have used the new gaskets the only other place for the hiss u would think is in the flex section.

Pretty sure that the hissing sound your hearing is a exhaust leak. I haven't heard of y-pipes making that kind of sound.

wouldn't an exhaust leak make a puffing or pulsing sound and not a continous hiss? i have such a hiss, as you described. and i have a y-pipe. but i cannot claim a correlation. but you mentioned it.

i got to hear the hissing sound thing from y-pipes at another forum. i was thinking the same thing...wouldnt a leak make a loud sound? like a usual leak in the exhaust does?

I had a wsp y pipe brand new on my 3rd gen and it hissed. I had wsp brand new on my 4th gen and it hissed. My best friend has a brand new budget and hisses. I barely hear or notice it though. It actualy helps me shift if I'm racing cause I just shift right after hissing dies down, and that's at 6k on my car wich is perfect cause there is not much up at 6500.

so what do u think..why does it hiss?

I looked at my pipe before it was installed and the part where the flex pipe is the same on the inside. I think that is where your hissing is coming from.

Just intalled a y pipe on KINGMAX's 4th gen, and we noticed a hissing type sound at WOT. His is a Budget. I checked for leaks while the car was at idle. I assume some setups just make this type of sound.

i don't have any discernable leaks or losses in power. i think the hissing may be inherent in the way the exhaust gas flows through and over the surfaces on the inside of the pipe.

yup...on mine..its the flex section leaking. just had it confirmed. now to find a flex section thats only 8 inches long. i got a qoute for $130 for changing the flex section...i think thats too much.

just get a new y-pipe from warpspeed talk to dallas it will almost be the same price, but with the madrel bent y-pipe u'll get more hp instead the OEM y-pipe!!!

Can you weld?
$25 + ship for a new flex section.

JKmay...yeah it is a cattman pipe...i dont wanna spend anymore on my exhaust and get a whole new y-pipe...if i can find a used one in good shape i'll take that...but not a new one.

internetautomar...nope, no welding skills here ...let me get back to u about the flex section in a couple of days.