The kit we used is the Stage-2 Boost Cooler (PN 20010),
which is recommended for all centrifugal superchargers.
We also added the optional SafeInjection (PN 30010) with a
blow-off valve upgrade (PN 30030), which includes a solenoid
to open the blow-off valve to release boost and protect the
engine if the flow of Boost Juice should be too low.
Snow
Performance Boost Cooler
Snow
Performance
www.snowperformance.de
Boost is your
friend, but detonation is your worst enemy. Unfortunately, the
two often go hand-in-hand in forced-induction engines, and it's
a fine line between fine-tuning to get those last few numbers
out of the engine and crossing over into potentially disastrous
territory. Intercooling goes a long way toward helping
the situation, but oftentimes packaging can be a concern on
street cars. Such was the case with our '04 Z06 Corvette test
subject. The ProCharger kit for this car actually uses two
intercoolers behind the vents in the front fascia, but because
of space and airflow limitations on the stock Vette, they were
roughly the size of a heater core. Water/methanol injection,
essentially a chemical intercooler, is supposedly more effective
than standard air-to-air intercoolers at less than 20 psi of
boost, so we spoke with Matt Snow of Snow Performance
to put together a water/methanol injection kit to see what we
could safely squeeze out of the Z06.
We used a piece of 4-inch-od exhaust pipe and two hex nuts
to fabricate the adapter for the Boost Cooler nozzles. In
any installation, be careful to keep the nozzles several
inches away from the mass air meter.
The now double-intercooled Vette laid down an impressive
639.5 hp at 6,364 rpm and 553.8 lb-ft of torque at 5,388 rpm
with 91-octane and a safe air/fuel ratio.
With
91-octane in the tank, even 14 degrees of timing was causing the
knock retard sensor to dial back the advance. Using HP Tuning
software and a few test pulls on the dyno, Robert Barth from
Strictly Performance in Van Nuys, California, was able to get
the Vette into the 12.25-12.50 air/fuel ratio range, and at the
aforementioned 14 degrees of timing, we saw 585.6 hp at 5,906
rpm with 540.3 lb-ft of torque at 5,430 rpm on Westech's chassis
dyno with 10 psi of boost.
This is the
ideal air/fuel ratio to begin with when installing the Boost
Cooler, and with patient tuning of the ECU and the Boost Cooler
kicking in around 3 psi (~3,500 rpm), we were able to dial in an
impressive 24 degrees of timing with the knock retard
occasionally dialing back about 1 degree. With a little more
dyno time, we would have most likely remedied this as well. Best
of all, the car picked up more than 50 hp to the wheels and the
air/fuel ratio stayed well within the safe 12.00-12.25 range for
most of the dyno pull. --Christopher Campbell
