Had your eye on the V8 M3, but with the economy in its state of duress, you're not sure what the future may bring? Here's a low cost alternative worth looking into. With depreciation and the state of our auto sales, it is now possible to locate and purchase a previously-owned E46 M3 in excellent condition for under $20K. If you take that lower cost E46 M3 and add VF Engineering's Streetsport bolt-on supercharger kit you can boost the 3.2-liter engine horsepower output to the same levels as the new E92 M3 V8. This will allow you to get the performance you desire at half the price.
Vehicle Data
2004 BMW M3
Mileage: 31,000
Engine: 3.2-liter I6
Transmission: Six-speed manual
Testing octane: 91
Notes
The baseline and all subsequent testing were performed utilizing the same tank of 91-octane fuel. All horsepower and torque numbers are SAE corrected and quoted at the wheels. The vehicle did have a catalytic converter efficiency below threshold fault code stored in the ECU, with no check engine light. We were informed this was a common issue on the E46 M3 and it would not affect the results
Current Modifications
HKS coilovers, HRE wheels, Brembo brakes, Vorsteiner aerodynamics
Baseline*
Peak Power: 275 hp @ 7300 rpm
Peak Torque: 233 lb-ft @ 5100 rpm
Dyno Data
Dynojet 224XLC
Ambient temp: 72 F
Test gear: Fourth
*All horsepower and torque figures quoted are measured at the wheels
VF Engineering
Streetsport
In late 2006, after three years of development, VF Engineering released its 480-hp Stage 1 blower kit for the E46 M3. Problem was the $10,000 price tag put it just out of reach of some enthusiasts, so to cut cost and increase its market share VFE chose to design a low-boost version that did not require the use of an aftercooler. It has been designed so consumers can upgrade their "Streetsport" kit to Stage 1 or 2 by adding an aftercooler system and swapping out a few parts.
The supercharger mounting bracket is CNC machined from aircraft-grade billet 6061-T6 aluminum. The CNC process allows precise fitment to the front of the S54 motor and does not require the relocation of any factory components. The bracket, combined with a chrome-moly support brace, creates a triangulated support system for the Vortech V3 Si-trim centrifugal supercharger. This mounting system retains the stock active belt tensioner and features additional OEM BMW idler pullies that help position the belt allowing for the maximum amount of the belt to wrap around the supercharger pulley. The Vortech V3 still requires regular oil changes, so it has been fitted with an oil drain line that allows the synthetic fluid to be evacuated without having to remove the supercharger from the vehicle.
The Superstreet system includes a cast aluminum replacement intake plenum to replace the restrictive factory unit. The final one-piece manifold's internal flow dynamic was optimized using multiple 3D prototypes and extensive test data gathered by VFE's in-house Superflow bench. The manifold was designed to accommodate a slide-in air/water heat exchanger cartridge, allowing it to be easily upgraded to an aftercooler system when it comes time to upgrade.
The cast aluminum supercharger inlet pipe features smooth internal surfaces and is shaped to keep air turbulence to a minimum. This allows VFE to retain the factory mass air flow (MAF) sensor, a critical part of making sure the vehicle ECU accurately reads the amount of air coming into the motor. The intake design also prevents off-throttle and deceleration turbulence.
Dyno 2
VFE Supercharger system
Notes
Because of the amount to time it took for installation, the after test was performed the next day.
Performance
Peak power: 350 hp @ 8000 rpm
Peak torque: 261 lb-ft @ 6000 rpm
Max power gain: 83 hp @ 7900 rpm
Max torque gain: 36 lb-ft @ 6000 rpm