I have a PLM header, Berk 63.5 mm test pipe, and the OEM AP1 exhaust. I noticed when I installed the Berk test pipe that there was quite a bit of clearance between the flanges of the header/test pipe and the test pipe/exhaust. I installed the triangle gasket between the test pipe and the exhaust, and also had a new OEM "doughnut" gasket that I put on the header where it mates to the test pipe. I figured that the two spring bolts that connect the header to the test pipe would pull the whole exhaust/test pipe system back far enough to make a good seal.

After driving it for a while I felt like I could hear a very slight exhaust leak when driving next to a wall or beside other cars. I just recently got back under the car and can see some black soot around the header/test pipe mating flange where there is an obvious (albeit small) leak.

I used a new OEM "doughnut" gasket and the triangle gasket is installed at the other flange, and the spring bolts were fully tightened down. How can I seal that flange better to get rid of the leak? Can I buy and install multiple triangle gaskets at the test pipe/exhaust flange to space the test pipe towards the header more? Or find some kind of doughnut spacer to slide onto the header before sliding the doughnut gasket on to push it further towards the test pipe?

 

My buddy had a similar issue with his car, and he fixed it by just stacking two triangle gaskets.

I also had a leak when i installed a header on my DC5, but i cured that by simply loosening the bolts and adjusting the two flanges.