Exhaust for S/C

[Alister_McRae]

Hey i gotta question i was curious about. When you guys that have the supercharger, did you upgrade the exhaust size to 3 inch, or do you guys have it at 2.5 all around?....mike

[Auto-9]

If it were me I'd upgrade to 3 inches. 2.5 seems a little small for boosted applications, especially since many of us V6 naturally aspirated guys upgrade to 2.5. Just for your info, the Magna (Diamante) and Galant sold in the Pacific rim use 2.5 from the factory. The U.S. seems to be the only 2.25 inch non-mandrel bent from the factory.

[TWISTED II]

i'm in the process of building my motor, and once its done, i'm puting on a supercharger. i already have my HKS titanium muffler. so yeah, 3 inch is what ya need.

[SuperchargedGTZ]

well right now the only exhaust modification i have is the RIPP/AMSS headers with a hks muffler. i am pretty sure that RIPP is coming out with a full true-header system for the eclipse. now i know it wont fit our cars exactly, but depending on how demanding WE ALL ARE for this product maybe he will make it for the galants as well. but as far as the 2.5 or 3, i am still completely stock. but i am sure that a 3" exhaust would help, but the headers are only 2.5", so what is the point of 3"

[Auto-9]

<div class='quotetop'>QUOTE(GTZ27)</div><div class='quotemain'>but the headers are only 2.5", so what is the point of 3"</div>

The same reason why the AMSS downpipe is only 2.25 but yet my custom cat-back is 2.5 inch. You need the slightly smaller diameter up near the hot gases. I forget the technical stuff behind all of this but think about it this way as well. The factory is say, 2.25 inches. The GReddy cat-back for the Eclipse is 2.5 inch. You still see a gain of about 4 hp due to opening up the exhaust. Otherwise what'd be the point of upgrading cat-backs right?