Quote:
Originally Posted by Duc Hunter
Stunning looking. My question.....the "larger" 41mm SSI's.....are for up to what horsepower engine? Or maybe what capacity (3.0, 3.2, 3.4, 3.6, etc)??
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Here's the theoretical flow into each pipe for 2.7 thru 3.8
the original SSI's that I had back in the day were 35mm ID w/ 47.6mm collectors, I've used them on 3.0 thru 3.6, they were fine for the 3.0 Carrera 3.0 and a nice improvement over stock
on a 964 3.6 they were fine around town at lower rpm but lost ~20hp at 6500 on the dyno
So it depends on use, displacement and the rest of the engines design, generally for stockish 3.2 and up 39mm ID(42mm OD) is much preferred
stock 964 use 41.275" ID and stock 993 uses 39mm ID but w/ a more efficient design than 964
factory race 3.0(SC/RS & RSR) used 42mm ID, 993 race used 42mm ID
I've used stock 993 and custom 42mm ID on 3.6 and 3.8 RS and don't se a difference on a dyno or seat of the pants