OK, I've had experience with NA exhaust sizings and turbo exhaust sizings - what do you do with supercharged cars?

For the A14 NA cammed etc, I'd go a 2" mandrel bent system.

Turboed it'd be 2.5" straight through, maybe 3" dump to firewall.

What about with the blower? I assume it needs more size due to the extra gas flowing through the engine, is 2.5" overkill/would 2" restict it?

I'm making my own out of stainless with mandrel bends, so no oversizing for pressbends reqd.

Opinions? Abuse? Comments?

Edit: Oh yeah, I haven't measured my headers yet - they are 4 into one design, about 35-40mm primarys so I assume 50mm collector - I'm only guessing though from a quick look downwards through the engine bay. If NA I'd go with the collector size for the rest of the pipe, but being supercharged I just don't know.

i'd get nice long primaries made up, say 60cm (or 24 inches for the imperials out there) and about 38mm ID (or 1

The headers that came with the A14 are very similar to what you describe, I'll measure them up & compare.