Perrin front pipe + stock cat back, what gasket?
 

Anyone know which gasket is the correct one to use with a perrin front pipe and stock cat-back?

There's simply no way the included gasket will work with the stock cat-back, the hole spacing is about 1/4" too wide on the flange. The gasket works fine with the front pipe, it's the stock mid pipe that's the problem maker.

I got it together using the perrin bolts but stock donut gasket, doesn't seem to be leaking but it doesn't seem ideal to me.

Thoughts?

It's the donut gasket.

Ok perfect. It didn't seem right when I was doing it, but it seems to work great.

Bump
Is it really ok to use the stock donut gasket to connect the perrin front pipe to stock exhaust?

I have the Motiv frontpipe on stock exhaust and they said to use the stock donut gasket as well. Perfect fit for me.

Yep, mine worked great until I replaced the cat-back as well. The instructions for most front pipes will tell you to use it with the stock cat-back.

I just did this with the q300 and it worked great. Couldn't get flat gaskets to seal properly. Donut gasket FTW!

Just to add my 2 pence, I also used the stock donut gasket when fitting my milltek front pipe to the stock cat back.

For grins though, you should fit it without using any gasket between the front pipe and the cat back, sounds pretty good in my opinion! Albeit a bit broken.

As per your PM, are you sure it's leaking at that joint and not the overpipe/frontpipe connection?

What does the Q300 say to use with the front pipe?

FR-S Matt here since I got banned... lol

Q300 says to use the donut gasket. I have the invidia catted FP and Q300. The gap between both has the smoothed edges for the donut gasket.

You should be using that. Perrin on the other hand uses a flat gasket with their catbacks from my understanding.

I have the Perrin frontpipe and the Q300, it uses the donut indeed. Just having a hell of a time getting it silent and sealed. I want to avoid using sealants since those a pain to clean up if you ever need to remove. I doubled checked all my other joints, they are perfect with no air escaping. Its the bloody frontpipe to midpipe connection, I may just say the hell with it and get it chopped and welded together like one guy in the U.S. did with his Q300.

You could try the flat gasket on the Q300 side combined with the donut? Possibly just try a new donut itself?

Yep. Tried that combo as well.

This is the first car in 24 yrs of driving and 10 cars that has been a total ball buster for getting the exhaust to seal properly.

Off topic, but why the hell did they ban you!?