Let's face it. Some people get to do things most of us will never experience; things so far-fetched and adrenaline-filled we can't even imagine the feeling. This occurred to me after watching a video about wing-suit base-jumping. With people literally flying alongside cliffs in excess of 100mph, it's the closest we can come to playing Superman.
We'll probably never get to do that, but we recently had our own unique experience; something you can try to imagine - driving the menacing HorsepowerFreaks 900whp BMW M3 turbo.
Based out of Portland, OR, Horsepower-Freaks (HPF) is dedicated to building some of the fastest, most reliable cars on the road. They've done so well that Entrepreneur Magazine included it in its 2007 Top 500 fastest growing companies.
While HPF provides a plethora of go-fast parts for a variety of cars, it's focused on the E46 M3 and developed a turbo system for it in four stages, ranging from scary-fast to stupid.
Polished intake plenum is the first clue this isn't a stock motor, but would you predict 9
HPF Turbo Systems
When looking at the turbo kit, the most noticeable item is the huge intake plenum feeding pressurized air into the individual throttle bodies. Flowbench tested to a 1% variance between all six cylinders, it won't lean-out one cylinder during tuning. Its design also optimizes mid-range and top-end power, and houses one of two supplied HKS sequential blow-off valves.
The intake piping is 3" (stage 4 is 4"). It connects to the turbo under the engine, that's bolted to HPF's unique two-piece exhaust manifold. This manifold features short-runners for quick spooling, yet unlike a log-style manifolds, it also features individual flow paths for optimal flow. All six runners direct air to the wastegates, helping prevent boost spikes. And because the turbocharger sits low, oil running through it is pumped to the pan via a silent oil pump.
Attached to the exhaust manifold is the 3" downpipe (stages 1-2.5), which works with the factory exhaust system. Stages 3 and 4 use a 4" downpipe to allow the larger turbo to spool quicker. A Tial wastegate is then plumbed into either downpipe.
The tuner supplies a bar 'n plate intercooler system in either a polished or black finish. It houses the second HKS BOV. Despite its size, the intercooler retains the factory crash support and fan, so engine cooling and vehicle safety aren't compromised.
Key locks out full-boost settings to prevent unwanted use
Software
Boost and air-fuel ratio gauges are installed in a steering wheel-mounted pod for easy viewing. It features a small key that toggles between race and pump fuel modes to prevent others driving in high-boost.
Probably the best feature of the turbo kit is its plug-n-play engine management system. Developed to work in conjunction with the stock DME, it allows every other components to work as BMW intended. The EMS uses an AEM 3.5bar MAP (manifold air pressure) sensor, eliminating the MAF (mass air flow) sensor, and provides precise dual Vanos control based on RPM and boost.
Each map is tuned under a number of parameters, including altitude, gear selection, boost, weather, etc. In case of knock from poor fuel, a loud 120db siren alerts you to get off the throttle. With this system, HPF also has precise control of its high-impedance fuel injectors and is able to use the factory coil packs without an auxiliary ignition system.
HPF/AEM engine management controls all the on-boost functions of this motor, including fue
Gas
For stages 1-2.5, HPF's kits use with 750cc injectors and an extra Walbro 255 liters-per-hour inline pump. Controlled by the EMS, the pump is programmed to activate at 3psi.
For stages 3-4, an additional Walbro pump matches the higher volume of air pumped by the larger turbo. Stage 4 also has 1200cc low-impedance injectors, an AEM fuel-pressure regulator, Edelbrock and Aeromotive fuel filters as well as a dual-feed fuel rail.
Everything except stage 1 features a methanol injection system, pre-mounted to a bracket that installs under the front bumper and plugs into the EMS. The system uses a modified FJO methanol pump and a unique FJO fogger that creates a cool, high-octane methanol fog.