Page updated 5-Sep-2006
No special tools or modifications required, fully reversible.
The VF-Engineering supercharger system
for the 996 Porsche is a result of 12 months of ongoing development
and testing with development partner Evolution Motorsports, Inc.
(AZ). The specification for this kit was set as:
• Bolt-on and reversible conversion
• All hardware must fit under factory engine compartment lid
• Non-invasive installation OEM quality
• 6 psi with air-water intercooling
• Hp target in the 996TT range with stock reliability and driveability
The VF-Engineering designers set about
designing the billet supercharger mounting bracket with CAD software
creating solid models of parts to be CNC manufactured. The bracket
was designed to utilize OEM bolt patterns and requires no alteration
or relocation of any engine parts to be fitted. Made from 6061-Tx
aircraft grade aluminum the bracket mounts to factory machined surface
points on the aluminum engine block for a precision fit.
A V2 model Vortech Engineering supercharger
unit was chosen after consultation with Vortech engineers and matching
the engine's volumetric efficiency with supercharger compressor maps.
The V2 unit contains helical-cut gears for super quite performance
- virtually silent with the engine compartment lid closed. The V2
supercharger has a 20psi and 1000cfm maximum capacity and is an over-engineered
part for this Porsche application which is geared to produce a conservative
6psi in the engine's intake manifold.
The fastidious design of the supercharger
bracket, positions the belt driven supercharger to maintain use of
the OEM spring loaded belt tensioner. The serpentine belt routing
was designed to maintain the correct rotation of all the accessories
and maintain optimal pulley wrap for maximum friction.
The Vortech air to water intercooler
(charge cooler) was integrated into the tight fit engine bay as means
of reducing charged induction (boost) temperatures. Lower charge
temperatures promote engine safety by reducing knock and improving
the quality of the combustion cycle. Air charge (boost) from the
supercharger is directed through the chargecooler core before entering
the throttle body. The cooler core contains isolated channels circulating
with water from a separate self contained system cooled by its own
radiator. VF-Engineering integrated a Porsche OEM front radiator
and front bumper vents into the kit. Water is circulated by means
of an added OEM Bosch water pump through OEM Good Year water lines.
Intake air temperatures in the manifold were measured to be approx
140 deg F even with 'spirited' driving at 118 deg F ambient temperatures
in Arizona desert conditions mid-Summer. This dramatic drop in charge
temperature helps the 996 create consistent power. For added safety
the chargecooler is designed to perform continuously whilst the ignition
is on.
With all major components in place
the head of R&D at VF-Engineering, set about shaping the air ducts
from the filter to the throttle body. The intake pipe is specially
tuned for its air flow characteristics and pressure relief system.
Production pipes are manufactured from a lightweight molded high
temperature polymer. The thermal insulating properties of the plastic
pipes prevent heat transfer into the cooled charged air traveling
inside them.
Engine management software was by
written by GIAC with extensive testing performed independently by
Evolution Motorsports. Multiple factors such as charge air temperatures,
ignition timing, fuel trims, maps and injector performance were taken
into account. The Carrera 2 and 4 test vehicles were extensively
dynoed on the GIAC 4WD Mustang and monitored for wide band air fuel
ratios at load levels often greater than would be experienced on
the road. The results are an increase of 120 horsepower and 80 ft.lbs
of fully useable torque.