What can I say, the dyno speaks for itself: 678 whp and 634 ft/lbs of torque all turbo using VP C16 fuel.
The dyno is a Dynapack 3500 owned by Slow Motion in Ohio.
This STI had once before been tuned by me to just under 600 whp and ran a quarter mile time of 11.0 @ 135.5 mph without N20. I feel the Dynajet I normally use reads on the low side or the car simply picked up a little more power in the real world. Fast forward a few months and some new modifications were performed. The heads and block were decked to get a better seal on the head gasket. I requested that the thinnest head gasket be used so we could benefit from the slight increase in compression ratio. An unequal length header was also installed, along with a fresh GT35R 1.06 turbocharger. The engine is an Axis Power Racing engine but still uses the stock block and the heads are ported with larger valves and 272 cams.
Here’s a quick list of mods:
Axis Power Racing STI engine (rods, pistons, stock block)
Axis Power Racing STI heads (bigger valves, porting, springs, 272 cams, no AVCS)
Element STI Hydra EMS (custom tuned by Element)
Aeromotive Fuel pump
Unequal length header
GT35R 1.06 AR
Here’s the interesting part, with those modifications, 2 psi more boost (29.2 vs 27 absolute), and more tuning, we hit about 648 whp. So where did the extra power come from? Removing the intake completely and bypassing the power steering pump netted 30 whp more at this power level. Unfortunately we did not test these two items separately but I suspect the majority of the gain was from the removal of the air filter.
Tuning was what I consider moderately aggressive but at this power level we didn’t want to push beyond this point. The AFR was 12:1, boost was 29.2 psi (absolute), and ignition timing peaked at 26 degrees. The 1000cc injectors hit a peak of 98% duty cycle.