I have just installed a new Header, I am running the stock Cat, and Exhaust on back. I have checked and triple checked the torque settings, I have even added 10lbs more torque to the cat bolts, I added 5 extra to the flange from the two pieces of the header, and I added 6 extra pounds of torque to the exhaust manifold bolts. I can still hear the leak when I run the throttle half open an it gets worse at wide open. To remove the stock nuts from the catlytic converter I had to do some pounding, So I am not sure if I damaged anything. I want to find out where the leak is coming from. What is the easiest way to determine where my leak is coming from? I tried to stuff a rag in the muffler and check to see if I could find the leak. I could not find it. Any suggestions?

 

I always find my leaks by the little bit of black (carbon maybe right where the leak is (you have to drvie awhile). But I am also not running a cat. did you mess up the cat flanges when you where pounding on them.

 

Throw a rag down the throat and test. This means to find an old rag, and semi-plug your exhaust and use your hand to feel for any air under the car. If you can't find it, it's just the new sound of the header/exhaust. DO NOT continue just to torque bolts. GET A NEW GASKET.

 

Thanks Kulrevon, I didn't think to check out the flange. I will take it off and check for any damage to the flange.

 

I've got an exhaust leak in the flex pipe. It sucks too.

Cheers!

 

Thanks, TimeRacer, I will try to stuff the rag in better and check for leaks. I thought about doing it when it was good and cold to see if I would be able to see it. From the sound of it I am not sure it is the new sound of the header/exhaust combo, it is kind of loud. I may have to get new gaskets, but I was under the impression the metal gaskets can be reused. I didn't want to go much above the helms manual torque settings, so I was not planning on torqueing the bolts any further. I have tried backing them all off and retorquing them to the correct settings but I can still hear the leak. I think I am going to try to take a look the flange on the cat converter, I may even get a high flow cat, No emissions in Indiana, and all new gaskets. I may even have to drive it for a while and check for carbon deposits as suggested from Kelrevon, It just sounds bad.

Do you know a good site I can get new gaskets from? I bought a Knock off Megan for the upper part, and eventually will do a customer collect to a 2.5 diameter, I know the ebay claims 2.5" collector but I measured and it is the same size as stock, the only difference between the stock and this is the stainless steel and better bends to the collector all diameters are the same. But for now I need a gasket that will fit the megan or a DC sport will work, They look the same.

 

Lonely Driver, How did you find the leak in the flex pipe, and how do you fix that, Other then weld on a new section of flex pipe?

 

You won't be able to "see" the leak. The only way is to feel for it. Carbon deposits can be misleading as well as there is also water after the catalytic converter (it's one of the elements carbon monoxide and ozone convert into) and it can look it's leaking out carbon when in actuality it's not. As water can seep though the gaskets after periods of time and take the carbon with it which is what you might see.

If you don't feel any air leaks (oh, I forgot to mention you need the car idling/running when you do this but I assumed it would be common sense ) Then I doubt you have any leaks and just need to learn with the new noises. My header made my car sound a little funny below 3000 RPM, but I've triple checked and I don't have any exhaust leaks so it's just the new sound. My dyno shows good power so I doubt I have one.

 

i had a leak after we took apart my exhaust and it was actually the last piece of the exhaust coming together. try to find the last section of your exhaust, or even where your muffler is. track your exhaust all the way back and you should be able to feel air sneaking out, or even have a friend rev for you when your checking it out. you should be able to find the leak just by feeling for the air escaping... hope this helps