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2003 BMW M3 SMG - Proven

Anthony Gelinas
Sep 16, 2010

When it comes to fixing up vehicles of the European persuasion everybody from the magazine's parent company seems to come knocking at our door. While I don't mind answering a few questions here and there, over the years I've discovered that the best thing to do is make introductions and match the tunee directly with the tuner. So when one of our companyguys wanted to squeeze some extra power from his E46 M3 I immediately referred him to Tom from European Auto Source to help him sort through it. After sorting through all options, taking into account the vehicle is a daily driver and frequently he hauls precious cargo (kids) he decided to start with the tuning basics: a chip and intake.

Epcp_1010_01_o+2003_bmw_m3_smg+front Photo 2/10   |   2003 BMW M3 SMG - Proven

Vehicle Data

Engine: 3.2-liter I6, dohc, 24-valve
Transmission: Six-speed SMG
Drivetrain: RWD
Mileage: 84,016
Current Modifications: Volk Racing CE28N wheels (8.5x19 front, 10.5x19 x 10.5 rear), Nitto NT05 tires (245/35 front, 275/30 rear), KW Clubsport coilovers, BMP rear shock mounts

Dyno Data
Dyno Type:
Dynojet 224XLC with WinPEP7 software
Transmission Test Gear: Fourth
Fuel Grade: 91 octane

83° F
Humidity: 21%
Peak power: 274 hp @ 7300 rpm
Peak torque: 234 lb-ft @ 4700 rpm

Test Notes
All horsepower and torque numbers are quoted at the wheels. Testing was done with the same tank of 91 octane fuel for the baseline and subsequent dyno runs with the VF Intake and GIAC software. To insure consistency, the intake and coolant temps were monitored via the Bavarian Technic USB OBDII cable and software, with each dyno run starting with a coolant temp of 80 degrees C and an intake temp of 35 degrees C. All of the horsepower and torque numbers shown were SAE corrected by the Dynojet WinPEP software utilizing a correction factor of 0.99.

VF Engineering
E46 M3 Cold-Air Intake

Peak power: 280 hp @ 7200 rpm
Peak torque: 236 lb-ft @ 4700 rpm
Max power gain: 7 hp @ 6500 rpm
Max torque gain: 3 lb-ft @ 2700 rpm

Epcp_1010_04_o+2003_bmw_m3_smg+vf_intake Photo 3/10   |   2003 BMW M3 SMG - Proven

Parts: Airbox w/lid, air filter, MAF adapter, polyurethane wedge, grommets, aluminum spacers, MAF housing, polyurethane MAF ring, silicone coupler, clamps, bolts
Tools: T20 torx, 10/13 mm socket, 3/8-inch ratchet and 6-inch extension, flat screwdriver
MSRP: $475
Installation time: 1 hour

• Billet MAF sensor retaining factory air flow straightener ensures the ECU gets the proper readings and eliminates the risk of throwing "check engine" lights
• Serviceable air filter
• Retains factory fresh air intake from front grille
• Roto-molded plastic airbox maximizes air volume and reduces heat transfer into the intake
• Removable airbox lid allows for easy filter inspection and debris removal
• Airbox is rubber mounted to help isolate vibration and allow flexibility between engine and intake
• Airbox helps direct and optimize the air flow directly into the air filter

• In extreme conditions, the lower bumper cold air feed could allow water or excess debris into the airbox

GIAC Software
91 octane program

Test 2

Peak power: 283 hp @ 7229 rpm
Peak torque: 236 lb-ft @ 4600 rpm
Max power gain: 15 hp @ 7700 rpm
Max torque gain: 2 lb-ft @ 5200 rpm

Epcp_1010_07_o+2003_bmw_m3_smg+giac_software Photo 6/10   |   2003 BMW M3 SMG - Proven

Parts: OBD Port Flash
MSRP: $475
Installation time: 30 minutes

• 100% reversible with no physical modifications
• Increased throttle response
• Retains all factory safety and emissions protocols
• Removes top-speed limiter
• Designed to take advantage of the increase air flow from the VFE intake
• 91 or 93 octane programming available

Test Notes
In order to accurately gauge the horsepower and torque gains from the GIAC software flash, it is recommended that you put the vehicle through at least two 15-mile driving cycles. This allows the vehicles' engine control unit to fully adapt to the new set of parameters. We ended up putting 120 miles on the vehicle before we ran this test.

Epcp_1010_09_o+2003_bmw_m3_smg+front_of_car Photo 9/10   |   2003 BMW M3 SMG - Proven

What can I say about the E46 M3 that hasn't been said before? The car has it all-looks, solid suspension, a powerful inline six, rear-wheel drive. It's an overall well-oiled machine and even with over 80k miles on this particular M3, it performed as if it was factory fresh.

After the intake was installed, I took the Bimmer out for a quick spin. But something was amiss-as a certain audible notification traditionally associated with intakes was missing. The usual induction growl was nowhere to be found as I ran through the gears and took the M3 to its redline. Besides the increase in part throttle and full throttle response, you would never know that an intake had been installed-a result of the enclosed design of VFE's cold-air intake.

Over the years, after almost exclusively owning turbocharged vehicles, I have learned not to get overly excited about a chip for a naturally aspirated engine running 91 octane. They are typically only useful in smoothing out the power curve and increasing throttle response and rarely offer large horsepower and torque gains. The GIAC software did just that: increasing throttle response and smoothing out the powerband. The real surprise was how the software combined with the intake allowed the motor to pull so strongly. The high revving S54 took well to the new software and pulled all the way to 8000 rpm instead of dropping off around 7200 rpm. Together, the GIAC and VFE intake are quick and simple ways to enhance the E46 M3's performance without completely overhauling or changing an engine that is near perfection from the factory.

Epcp_1010_08_o+2003_bmw_m3_smg+compare_all Photo 10/10   |   Graph 3: Compare All

When it comes time to address the horsepower plan for your BMW E46 M3 you have to make a decision go for big power (forced induction) or just enhance what's already there, as we did here. Because those two paths go in completely different directions and require a complete different set of upgrades.

Costs Summary

VFE Cold-air intake $475
GIAC Software $475
MSRP total. $950


VF Engineering
Anaheim, CA 92806
European Auto Source
Anaheim, CA 92807
Irvine, CA 92614
By Anthony Gelinas
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