Very impressive results from just adding headers. For those who have a hard time reading the results, here's how it went:
Baseline with Vararam CAI, muffler delete, stock tune: 320rwhp/341rwtq
See the bottom curve in the graph comparison for baseline numbers.
Added ARH 1 7/8" long tube headers, stock tune: 354rwhp/363rwtq
(a gain of 34/22 from headers alone). The bottom curve is the graph with headers and no tune. The top graph is after the tune.
Added EFI Live dyno tune: 370rwhp/383rwtq
(a gain from tune of 16/20 from the tune)
Total gain for headers and dyno tune: 50rwhp/42rwtq
Hats off to American Racing Headers for making an outstanding product. The 1 7/8" headers lose nothing to 1 3/4" headers down low, but gain at higher rpm. On a hotter 6.2L G8 GXP, the gains would be even larger. http://www.youtube.com/watch?v=wI8ws...layer_embedded