Downpipe Size

[Tatanko]

I'm in a bit of a dilemma here with my downpipe. I bought the car with a totally aftermarket exhaust and was TOLD the cat and cat-back were 3". Fine enough. Didn't think to ask on the size of the downpipe. It LOOKED to be 2.5", so that's what I assumed it was until I measured it last night. It appears to be 2" according to my measurements. Is this smaller than stock? I only found one thread when I searched and the consensus seemed to be that stock was 2.25" (makes sense to me). If indeed my downpipe is smaller than stock, does anyone have suggestions where to get a gasket for it?

I plan on going full 3" all the way back eventually (even the cat-back needs re-done) but for the time being I need a solution to drive the car. (This isn't my daily, no worries)

 

[turbosax2]

Did you measure the inner or outer diameter? The 3" or 2.25" measurement usually refers to the outer diameter.

 

[the_mork]

I kind of doubt that there are even downpipes available for our cars that are smaller than stock so I'm betting what you have is a stock downpipe, if not then that kind of sucks but you should still be able to use an oem gasket as long as the flanges are original.

 

[Tatanko]

Did you measure the inner or outer diameter? The 3" or 2.25" measurement usually refers to the outer diameter.

The piping is pretty thin but you're right, it might be 2.25". For the record, the entire exhaust was custom-made by the previous owner. If it is indeed 2.25" I can just grab a stock-sized gasket then. I guess I better re-measure it!

 

[the_mork]

For which gasket? If its the one going to the o2 housing then it doesn't really matter what size the downpipe is. If you are going to the cat then you need to be concerned more about the flange type than about the size of the pipe.

 

[Tatanko]

It's the one between the downpipe and O2 housing. Literally my downpipe, cat, and cat-back are all one piece welded together. No flanges. It sucks. This is why I am replacing the whole thing eventually

 

[chris9149]

It's the one between the downpipe and O2 housing. Literally my downpipe, cat, and cat-back are all one piece welded together. No flanges. It sucks. This is why I am replacing the whole thing eventually

I am guessing you purchased the car this way? WTF
What the hell, why would anyone weld that all together, what a freaking PAIN if you (read: when you) have to drop the downpipe for something else.

 

[Tatanko]

Yeah I bought it like this. Dropping the downpipe is no problem. The flex section allows me to move it out of the way to do most anything that would require you to remove the downpipe.