How to fix a leaking downpipe to turbo V-Band Connector
 

I recently installed a single turbo conversion kit on my 1993 Mazda RX-7. Unfortunately I can't get the downpipe to turbo connection to seal with the provided V-Band clamp. The downpipe was poor fitting and I had to have a an exhaust shop modify it so that it would fit flush. I even tried making a copper gasket. No luck - still an exhaust leak.

Any advice?

Connect your downpipe to the turbine housing but leave the connection somewhat loose. Then connect the downpipe to the midpipe, also leaving that connection loose. At this point you should be able to tighten the downpipe to turbine housing connection so that it seals properly being that there is some movement in the system from the loose connections. At last, tighten your midpipe connection and all should be good:)

If you are running a re-routed downpipe, follow the same procedure but install the wastegate prior to tightening the system. You will need some movement from the downpipe, therefore leave it as loose as possible w/o it falling off. Tighten the wastegate to the manifold and downpipe, then tighten the rest of the system as described above.

fwiw ... v-band gaskets are around you can try those, but I have also seen some V-band clamps that are wider or narrower than others ...