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BMW 3 Series E46 > M3 - Project Car

Part 6: Pipe Down, Charge Up, Go Around, Cover Up

Les Bidrawn
Jun 1, 2007 SHARE

Crevier BMW in Orange County, California, is one of the bigger dealerships in the United States. They service and maintain our long-term BMWs for free. Actually, they do the same for everyone. Free maintenance is included with every new BMW sold. For four years or 50,000 miles, anyway. After that you're on your own.

Lucky for me, the M3 has proven to be an exceptionally hardy car with few, if any, real issues. It must have been a Thursday car, built in Regensburg by happy, clever Germans fully focused on the task at hand.

Epcp_0706_02_z+bmw_m3+exhaust Photo 1/9   |   BMW 3 Series E46 > M3 - Project Car

The M3's distinctive exhaust note made me smile the same way an air-cooled 911 does. Its metallic exhaust note was intoxicating. I say 'was' because I have since changed my mind. Unlike the 911, whose exhaust note is a byproduct of its engine configuration, the M3 makes its unique sound due to an unusually long tube just behind the catalyst, a design determined by emissions regs. That longish pipe vibrates at certain frequencies, hence the sound. By itself, BMW's straight six has a glorious tone, a voice we would release with the help of Magnaflow.

There are at least a half dozen companies that build M3 exhausts and most of them range from good to excellent. I chose Magnaflow based on its 20 years of experience, sound design and performance. I also got the opportunity to access its 30,000-square-foot tech center and 150,000-square-foot manufacturing facility. This operation is one of three in Southern California (there's one in Italy too), all of which employ state-of-the-art computer-controlled robotics. So, a serious player in the performance exhaust industry.

Epcp_0706_13_z+bmw_m3+exhaust Photo 2/9   |   BMW 3 Series E46 > M3 - Project Car

Magnaflow's E46 M3 exhaust is fabricated from T304 stainless steel stock and features mandrel-bent curves, clean welds and highly polished quad tips. The company has done a fabulous job minimizing its exhaust, shedding some 38 pounds in the process while adding a crossover pipe for extra scavenging. The system uses the factory hangers and standard slip-type compression fittings.

For reasons unknown (perhaps our M3 is special), the Magnaflow exhaust needed some persuasion to fit properly; a few minor shim devices (bolts) were used to clear certain sections. It's been my experience that most aftermarket exhausts need some help-provided it's nothing major this is easy to forgive. Such was the case here, especially after hearing its new-found voice.

While the stock exhaust is no shrinking violet, the Magnaflow system has a much more authoritative sound, something like distant thunder. Under load, the M3 now has a full-fledged roar, giving the sensation that it has somehow dislodged something from its throat. At cruising speeds, the car is slightly louder than before, but never annoying. There is, however, a substantial drone at 2450 rpm (I seldom see those revs during relaxed cruising, so it's not really an issue).

Ultimately, the exhaust is a fairly aggressive piece. It has changed the M3's demeanor considerably, not just in sound but in power delivery too. Dyno results yielded a solid 10-hp gain over the stock system. Listening to the menacing growl, it feels more like 30 hp. I guess that's a bonus.

Epcp_0706_14_z+bmw_m3+exhaust Photo 3/9   |   BMW 3 Series E46 > M3 - Project Car

The M3 emerged from its engine- and gear-oil change (Motul) washed and ready for action... sort of. A small contingent of Crevier people surrounded the car, ogling the wheels and brakes. As I got in to drive away, the tell-tale buzz of a dead battery scattered everyone. A sheepish service rep came out and informed me that it was time for a new one.

Given the on-and-off type of usage the M3 sees, a standard battery wasn't the best choice. I needed something able to retain big cranking amps after prolonged periods of inactivity. I needed an Optima Yellow Top battery.

This is the second Optima battery I've used. The first unit came from our studio, where it sat for more than a year powering various head units for a car stereo magazine. I stuffed it in the M3 and was shocked when the car started instantly. How it retained a charge for so long is remarkable. I guess that's why Optima is so big with the custom car audio crowd. Optima batteries are fairly compact, can be placed in any orientation (including upside down), have great charge retention and plenty of cold cranking amps.

Epcp_0706_05_z+bmw_m3+optima_battery Photo 4/9   |   BMW 3 Series E46 > M3 - Project Car

Featuring patented Spiralcell technology, these batteries are highly resistant to vibration-induced failure and their coil configuration maintains a charge for nearly twice as long as a standard battery. They are available in two flavors: Red Top for standard/off-road duty and Yellow Top for extreme/audio duty. Although both models offer superior performance, Ben Oh at sister publication Car Audio and Electronics recommended the Yellow Top. Dimension-wise, Optima units are typically smaller than OE batteries and include mounting brackets for all sorts of fancy installs.

The rear-mounted M3 battery tray provided more than enough room for the Optima unit and it's a shame the battery is totally hidden, as its smart looks match its performance. In any case, it's a good feeling knowing your car has a strong, reliable power source, no matter where it's located.

Epcp_0706_08_s+bmw_m3+eibach_anti_roll Photo 5/9   |   BMW 3 Series E46 > M3 - Project Car

Unlike many of my colleagues, I tend to favor a more relaxed ride quality. I don't mind a car that leans through the corners, provided the suspension continues to do its job. Given the Koni adjustable shocks (dialed to the softest setting), the M3 was moving just a little too much during aggressive driving, specifically track use. To counter the lean, I used Eibach's larger anti-roll bars and polyurethane bushings, a system that has left me very happy.

Although many adhere to the idea that all suspension tuning should come via the shocks and struts (typically a European convention), stiffer anti-roll bars can be an effective tuning tool as well. For my needs, I was able to retain the M3's compliant ride quality yet reduce chassis movement. The Eibach kit features 28mm/35mm front/rear bars powder-coated with a handsome red finish. The rear bar features two settings and allows for more neutral behavior or more tendency toward oversteer.

Under full cornering load, the M3's lean was considerably reduced and I've noticed its high speed straight-line tracking to be exceptional, better than before. The Eibach stuff works well, which probably explains why so many OEs (more than you'd think) use them.

Epcp_0706_09_z+bmw_m3+car_cover Photo 6/9   |   BMW 3 Series E46 > M3 - Project Car

Although I have a nice garage, it's chock full of 'stuff' that seems to serve no purpose other than to annoy me. Eliminating it would mean going to war with the wife, and I'm not going there-not now, anyway. I got the next best thing, a gorgeous custom car cover from Covercraft. Made from WeatherShield fabric, Covercraft did a special two-tone job for me, a light gray center flanked by brilliant blue side panels. There is a huge selection of pre-cut covers and the company can custom-sew covers for modified cars.

You can combine black, red, yellow, bright blue, green, light blue, taupe or gray into your choice of color scheme. The WeatherShield fabric possesses seemingly magical abilities to repel dirt, dust and moisture while still being able to breathe. Unfortunately, it doesn't repel cats. Certain neighborhood felines have begun using it as a scratching post (I'm talking to you, Rod). Paintball guns are handy in such situations, and their water-based paint just falls from the material.

Another bonus.

Next issue, we will feature fellow editor Jason Mulroney's M3. He's taken a decidedly different tack and dug deep into the Vorsteiner parts bin. Given the gorgeous results, we may do the same.

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Sources

MagnaFlow
Rancho Santa Margarita, CA 92688
800-824-8664
www.magnaflow.com
Covercraft
Pauls Valley, OK 73075
800-426-8377
www.covercraft.com
Eibach
Corona, CA 92879
800-507-2338
http://www.eibach.com
By Les Bidrawn
242 Articles

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