Preparation for the STILLEN supercharger

Snakes709

Correct me if im wrong because im not sure how the 370z handles the size of exhaust. But with my Supercharged Cobalt. Aftermarket exhaust with 2.5" piping was good until 270whp....anything more it was recommend 3". I was making 20psi of boost on a Harrop TVS 1320...ran stock exhaust at 265whp and it restricted alot. Changed to a 3" downpipe and 3" exhaust and it bumped it up to 281whp. No disrespect intended but does your statement still stand or no? Like i said i dont know how the 370z exhaust, since its dual, handles the size. I'm guessing since its dual that theory still applies but to a greater number....for example, 400whp.

Kyle@STILLEN

Yup...2.5 inch is the right size unless your talking about running a lot more boost and have headers and race pipes to take full advantage of the improved efficiency. Keep in mind the amount of boost your talking about on that cobalt. 20 pounds of boost is HUGE. That is a tremendous amount of air being forced into that motor and therefore it requires a large enough exhaust to allow it to vacate effectively and efficiently. Our standard kit will probably only run around 6 or 7 pounds of boost so the dual 2.5 inch pipes are more than sufficient.

If people decide to bump up their boost pressure A LOT higher than our standard kit and support it with the exhaust components I mentioned then ya 3 inch might be ideal but for 95% of the people who buy our kits the 2.5 inch is the desired size. 3 inch piping would more than likely be too large and decrease your bottom end performance.

Snakes709

ok thanks for clearing that up. I forgot that your superchargers wont be pushing that much psi due to the compression ratio. Also one other question. Do the superchargers that you are using make a whine sound or a blow off sound?

ChrisSlicks

Volume of 2 x 2.5" exhaust is 9.8 sq/in.
Volume of single 3" exhaust is 7.0 sq/in.

The dual intake / dual exhaust will carry more air mass with less restriction than the single exhaust on your supercharge 4-cylinder did, regardless of boost level.

kannibul

Yep, there's basically one less cylinder involved per header.

Inline 4 cylinder = 4 cylinders into header @ 3" = .75" per cylinder
Half of a V-6 = 3 cylinder into header @ .75" = 2.25"

spearfish25

I think you mean to refer to area, not volume.

__________________
2013 Cadillac V-Wagon, RIP Z

ChrisSlicks

Yes, although cross-sectional area in this case implies volumetric flow.