Mar48

Are the exhausts different on the C2/C4 (3.4L) vs. the C2S/C4S (3.8L)? I am not talking about the optional PSE exhausts, but the standard ones on both cars.

Is the piping a different diameter? And lastly, are the exhaust tips interchangeable between the various models?

Thanks in advance!

RobC4sX51

Yes, there are "valves" that open & close in the S models (I believe at 3300 rpm), even w/o PSE. Other than that, they are very similar & tips are interchangeable. Hope this helps. A dealer services manager could probably tell you anything else you need to know.

Mar48

Oh okay thanks! Yeah I knew about the valves but wasn't sure about diameter of the exhaust and if the tips were interchangeable, that helps!

WCE

Yes to S valves, no to tips (S has four pipes due to that valved bypass vs 2 w/o)

Mar48

^ Good call, so they aren't interchangeable!

STG

Base 991's have a different exhaust than the S's


Also:

The tips on the PSE and S stock exhaust are similar, but don't fit exactly the same. The S tips will bolt on to the PSE exhaust, but the inner exhaust on the dual tip falls short in length and doesn't make a snug fit.

RobC4sX51

You can put stock S tips on a base 991 w no issue! Suncoast will sell you this upgrade for over $600! GL.

STG

That's a bargain, the PSE tips are double that!! $$$

RobC4sX51

And chrome ones are $895!

Mar48

Ohh so S can go on Base but not vice versa?