Would increasing the bore of the exhaust on a standard 3.6 to a Sag / Tusc S / Red Rose system have an appreciable effect on low end torque? I.e is it worth doing? Would it need a remap as with decatting?
Presumably the Power 4.3 upgrade requires the larger bore item?
Advice from the engineers who built them is that the larger bore gives a slight increase of top-end power, but there is always a trade-off with gas flow, so low and mid range are slightly reduced, assuming no other changes.
