I installed a Megan header with a stock and I have a hissing sound after 3000 rpms. I have a one ball exhast and the there is no exhast leaks
I think it"s the cat
It's driving me crazy becase it sounds like a street sweeper driving down the the block
Thanks

 

you have an exhaust leak! if there aren't any leaks from the cat back. then the header is leaking at the block. did you use a new stock gasket?
and evenly torque the bolts??
maybe the header flange is warped??

 

I have to thoughts you have an exhaust leak or there is a cat stuck under your ride

 

There are no leaks from the cat back.
I took the header off and looked at the gasket and it was fine
The thing is when a check for leaks the car is at idle I don't have anyone to rev the engine
So you guys don't think it's the cat?
I have off this week so I going to take the whole system apart and check everything

 

bump

 

I'll repeat: you have a leak. The only way to check is to go to an exhaust place, they will lift your car on a hoist while it is running, and then check all parts with a special stethiscope (sp?). I guarantee it's a leak, and not the cat.
Oh, yeh, btw I have a Megan header, and both of them leaked (the first one, and the one I have now for 8k miles)

 

Its a leak, everyone i know who has the megans header has a leak. Don't ask for help if your not willing to use it.

 

I just started having the same problem with mine. I found the leak in mine was in the expantion joint.

 

I'v taken the header off twice
took the car to the muffer shop to fix all the leaks on the exhaust
Draggonmann what did sound like?(the leak)
I think when they welded the cat the exhaust is to long there is very little play

I am willing to use the help but like I said I fix all the leaks and the car still sounds like v Bug

 

Check the car while its fully warmed up.....
fixed bunch of exhaust , header noises by doing that..

 

OK, so it's a leak. But where... The Megan flex joint is particularly low quality and very short for our system. Both my Megans leaked there. Best bet is to get a different header, but that's costly. In the mean time you could wrap the flex joint with header wrap. It will reduce the noise a little. How many miles on your header? My second one stopped leaking badly after 1000 miles--it sort of "bedded in." Still leaks a little.
Also, as the exhaust heats up it expands--a lot. Mine gets almost 1" longer when excited--ah, I mean hot. (I know I'm revealing way too much here...) This can put a lot of stress on the flex joint causing it to leak even more. It also causes other joints/flanges to leak when they would not when colder.

good luck finding the problem.

 

Hey Tony, I just had the same problem on my Megan header, It winds up its the flex joint thats leaking on mine, Since i only got the header 3 months ago i called Megan and they are glad to send me a replacement in 2 to 3 weeks, the reason for the wait is that they are coming out with a new design that flows better and they arent in stock yet.

Charlie

 

Thanks guys like you said it was the flex joint
The thing is that is was leaking from when I installed it, thats what I couldn't under stand'so I thought it was the cat
I did three track days this week at pocono for a total of 15 sessons and the flex joint is done
My car sounds like and old beat up truck
I wish I never installed it
live and learn