On The Dyno
Jose Casas' '08 Mustang GT arrived for surgery in predominantly stock form, with the exception of long-tube headers and a free-flowing exhaust system. Both AMP power systems were tested on the shop's Dynojet chassis dyno. Performance changes were recorded with the Ford Racing Performance Parts Three-Valve intake manifold installed, and then as each basic air-induction piece was added. The 'Stang was also tested after installing CNC-ported Fox Lake Three-Valve heads and Comp camshafts in addition to all of the initial hop-up parts.
Not surprisingly, enhanced breathing brought about by the HCI extended our test-Pony's rev window, allowing it to make impressive power from 4,900 to 6,900 rpm. It's hard to pinpoint exactly which piece is the key to the overall gains, as the entry-level pieces and intake manifold showed us only modest increases in rear-wheel horsepower and an across-the-board decline in rear-wheel torque within the 2,600- to 6,100-rpm parameters. But this doesn't mean the bolt-ons aren't effective and shouldn't be considered. To the contrary, we think the larger throttle body and CAI (and sharp tuning) are essential pieces for the overall HCI upgrade.
This HCI top-half mod from AMP Performance is a safe bet for enthusiasts who want to make steam naturally, and we're confident it will really show off for those who wish to add forced induction to their '05-'10 'Stangs.