SurfDog

I have dyno results From sea level (ZcarGarage in San Jose California) and at 6000 feet (MAC Autosports in Parker Colorado.)

Stock dyno (base/reference dyno) in California: 293.6 whp/248.27 q
after JWT pop chargers, Berk HFC/CBE and tune: 318.20whp/265.33 q
Total improvement: +24.6whp/+17.06 q

At 6000 feet with tune (and same mods): 299.03 whp/???.?? q
At 6000 feet with Z1 400hp kit(Berk CBE)/tune: 317.84 whp/251.13 q
Total change: +18.81whp/???.?? q

Conclusion. Going from sea level to Colorado (5-6000 feet) you lose about 20 whp (roughly 25 crankcase hp)

also:
JWT pop chargers and Berk HFC/CBE gained me about 25 whp and Z1 400 hp kit did about 19 whp better still.

I'd guess Z1 kit total gain is +43.4 whp with humble gains in q due to removing cats (back pressure)

I just thought it was interesting.

Z1 kit (at sea level) would be (best guess) about 340 whp assuming 18% drive-line loss about 401.2 crank hp.

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09 6spd Berk CBE, JWT cams, ZSpeed CSC, Stillen (25 row oil, brake cooling, sways, gen3 CAI), Passport (9500ci), Quaife LSD, Z1 400 hp kit, ss lines, pads, rotors, clutch etc, Phunk's pan and fuel starve fix