2.25" is probably optimal for a stock 3.0L and the OE exhaust is less than that. The smaller size is good for low end torque but not for high rpms. With large tires, the worst place on the 3.0L curve seems to be around 1800-2000 rpms - just before it comes up on the cam.

I plan to build a 2.5" exhaust after the blower addition is complete... anything lost on the low end due to reduced exhaust scavenging should be more than made back in boost.

Frank

'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum