The gasket is just a paper one from what I am told, and not too durable. With the V-band clamp style mounting that the brake body and turbo use, its not real easy to get a real good solid seal. Add to this heat, and different matierals expanding at different amounts (cast steel for turbo/brake body, sainless for V-band clamp, paper gasket) and maybe even a little bit of bumps makin the exaust do the whatsusy. All I know is every time I blow it out I have just finnishe pulling a hill with a trailer, so she's HOT, like 1250-1350 hot, and I push over the hill, let her coast a bit, and engage the brake before hitting 65 mph (to keep here under 70, chp preferrs that with a trailer
) and it engages for a short time and just gets progressivly louder. It's a nasty whisle when it goes at 2800 rpms with a load!
