I recently purchased on of the eBay exhaust systems that some people love, and some people love to hate. I love it since it only cost me $245 shipped. Anyways, I have a question about the downpipe donut gasket thing.

My exhaust came with a gasket that is probably intended for the 3" o2 housing since it doesn't sit flush. I read a couple threads and contacted a couple people who have installed a similar eBay exhaust. It seems as though most people just reuse the stock donut. My question is, is it necessary to have the donut gasket thing in there at all? It seems like all it does is restrict air flow to the downpipe and exhaust.

I saw one thread where people said "you have to use it so the exhause doesn't leak like crazy" and another where someone said "you don't have to use it."

Please don't let this turn into an eBay exhaust bashing thread, I just want some opinions on the question above. Thanks!

 

Unless the stock gasket is actually inside of the flow of the piping, it wont make a difference. Use a gasket though, otherwise it will leak, but other than sounding and probibly smelling like ****, and dirtying up the engine bay, it wont make a huge difference.

 

Haha, so I probably shouldn't use it??

Thanks for the input.

 

Dont get me wrong, I have gaskets in all my exhaust flanges, just make sure the gasket you are using is of a good quality, just go to a local autoparts depot like Pepboys and get a three inch exhaust flange gasket. They might have them at napa or advance too, but in my experence Pepboys is the best for gaskets.

 

We might be talking about two different things. I am referring to the "donut" looking thing that sits in the downpipe. It isn't the gasket that has bolt holes.

 

you should definitely use it. it doesn't restrict flow at all because it isn't in the path of the exhaust flow. it fits around the outlet of the 02 housing, not in it.

 

Im guessing the deal is, if it fits leave it, if you have problems getting the springbolts in, the donut gasket isnt supposed to be there and you need some other sort of gasket. It has been said that the donut gasket is there for movement of the pipe while other DPs have a flex section eliminating the need for a donut gasket.

 

you can tell if your downpipe is made for the doughnut gasket by looking at the section that bolts to the 02. some downpipes don't use it and don't have a flex section, like buschurs. if the pipe/flange going to the 02 is flat, no gasket. if it's tapered going into the pipe, gasket. hope that helps.