I'm running dual SUs on my 1500 (removed from a Midget 1500 sitting in an
English "Breaker's Yard"), a PaceSetter 4-into-1 manifold, but an otherwise
pretty stock engine. Afer some experimentation, I settled on a 1 3/4"
system running a low-restriction muffler.
At 2" the "seat of the pants dynamometer" told me that I was losing some low
RPM torque (off the line aceleration suffered). At 1 1/2" it seemed to run
out of breathing ability at the top-end. It was all subjective, but 1 3/4"
seems to be the driveability "sweet spot" at least for my driving style and
The Weber set-up may make a difference, but I don't imagine that it will be
huge. Anyway, I hope that helps...
On Wed, 15 Feb 2006 10:40:59 -0700, de Brebisson, Cyrille (Calculator
> I am looking for help on setting up my exhaust system for my 1500cc
> I have weber carbs (downdraft) and 4 -> exhaust system, but I need to
> find what diameter to use for the rest of the system (no cat
> Any suggestions?