Flange trouble between DP and catback. help...
 

We welded in a new high-flow cat on my exhaust and also my friends exhaust this weekend. I replaced the flange on my dp and catback with a v-band flange kit(works awesome). The flange on my friends is the standard 2 bolt flange. For some reason since we took it off, no matter how much you tighten the bolts, there is air getting out on both sides opposite the bolts.

Should I add another gasket or make a permatex gasket like Dean said and then bolt it down and let dry?

I say just hook him up with the v-band too. I bet it works 10 times better than that donut gasket! I don't see the permatex lasting very long before it starts leaking.

Yeah the V-band is probably the coolest thing ever. He wasn't willing to spend the $45 for it though so he used the permatex. Perhaps if that fails down the road he will feel the need to spend the money and replace it with the v-band.

Are you trying to seal flat flange to donut flange?

no.

The flanges are probably warped. Try a new gasket and consider resurfacing the flanges.

Yeah, I have no doubt that they are warped. A new gasket was tried to no avail. Its currently sealed with permatex like Dean suggested. So far, so good.