October 18, 2011
It gained a noticable amount of power on the low end and it really gets after it on the high end. Notice it doesn`t take as much throttle to get it moving and keeping it moving. I datalogged throttle position and engine load before and after and it was almost a 15% decrease after the install
The 1500-2000rpm resonance is kind of annoying when driving around town. A change of muffler would probably fix that but it`s still nice and quiet at cruising speeds. MPG went up about 0.5-1 around town and the one time I`ve driven to Denver, it was about 2 MPG better.
I just finished swapping the valve springs for the 6.1L springs since the 2003 have a nasty tendency of them breaking. Anyone wanna buy my awesome Superior Automotive valve spring compressor? haha