Horsepowerfreaks Goliath?

joel w · 12-20-2005, 02:46 AM

hope this is ok, but i read Xmans post and jeff from hpf said this on sm once and i though it was interesting for sure and it stuck with me....

Quote:For the naysayers who think 4" is just for show, read this:

Originally Posted by X-man
I dynoed tonite with my 3 inch exhaust system back on the car and found out some interesting comparisons. My previous dyno runs had been at 19 psi on my SP67 p trim with a .68 a/r with 4 inch exhaust and had produced a best of 518 rwhp/ 475 rwtq... Tonite with no other changes produced 425 rwhp/ 418 rwtq and dropped the boost to 17 psi.

In short:
3" exhaust with SP67: 425 rwhp/ 418 rwtq (17psi)
4" exhaust with SP67: 518 rwhp/ 475 rwtq (less backpressure raised boost to 19psi with no change to boost controller setting!) Quote:

so i would tend to believe 4" it definately worth it for big turbos..

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12-20-2005, 02:46 AM	#8
joel w Lexus & 550's Join Date: Aug 2005 Location: In the shadows Posts: 506	hope this is ok, but i read Xmans post and jeff from hpf said this on sm once and i though it was interesting for sure and it stuck with me.... Quote:For the naysayers who think 4" is just for show, read this: Originally Posted by X-man I dynoed tonite with my 3 inch exhaust system back on the car and found out some interesting comparisons. My previous dyno runs had been at 19 psi on my SP67 p trim with a .68 a/r with 4 inch exhaust and had produced a best of 518 rwhp/ 475 rwtq... Tonite with no other changes produced 425 rwhp/ 418 rwtq and dropped the boost to 17 psi. In short: 3" exhaust with SP67: 425 rwhp/ 418 rwtq (17psi) 4" exhaust with SP67: 518 rwhp/ 475 rwtq (less backpressure raised boost to 19psi with no change to boost controller setting!) Quote: so i would tend to believe 4" it definately worth it for big turbos..