Cat-Like Reflexes Make M3/M4 Irresistible

ELKHART LAKE, WI – Get the re-engineered ’15 BMW M3 sedan or M4 coupe up to speed on a 2-lane country road, and this high-performance car with a long legacy in motorsports becomes positively feline.

At 2,500 rpm, the all-new 425-hp inline 6-cyl. twin-turbo purrs along in fifth or sixth gear. Drop a few rungs, watch the tach needle climb to 4,000 rpm and the dinner-time meows gain a bit of urgency. At 5,500 rpm, the testy cat begins batting around a smaller house mate, asserting dominance.

When the lightweight forged crank is spinning 6,500 times a minute, this reasonably docile pet has spotted an unfamiliar cat in the backyard through the doorwall, studies it intently and lets out eerie howls as a warning.

As the needle pushes confidently toward the 7,600-rpm redline and Valvetronic is allowing maximum air and fuel into the combustion chambers, the doorwall opens, the territorial ball of spiky fur dashes for the hapless intruder, hissing, clawing, tumbling and biting.

It’s a full-on kit-kat smackdown. The intruder limps away while the victor saunters back indoors.

Four generations of M3 have earned BMW the kind of respect every automaker envies. The dual-purpose car is designed to be just at home on the racetrack as tootling through suburbia.

Having done a little of both here at the legendary Road America track and in and around this quaint Upper Midwestern town, it’s easy to understand this car’s vaunted status.

The M3, quite literally, embodies every brand attribute BMW holds dear. The product-development process begins with good stock, the 3-Series sedan, hands-down the best-selling luxury car in the U.S.

From 3-Series to M3 and Beyond

Once the suspension is reinforced, weight taken out, horsepower and torque boosted, beefier brakes added and the M3 has received its aggressively taut fascia, it then serves as the basis for BMW race cars.

This cadence has played out since 1985, when the first-generation M3 bowed. Three iterations followed, and now arrives the fifth-generation model.

But there’s a twist. Sedans and coupe body styles have been available in the past, but the new M3 is sedan only. Those preferring two doors can opt for the M4 and get the same spectacular powertrain, the same chiseled rocker panels, the same progressively aggressive drive modes and steering and suspension settings.

This strategy reinforces BMW’s decision last year to split the body styles into two high-volume models, the 3-Series sedan and 4-Series coupe.

Through May, both cars have been flying off showroom floors: 36,993 deliveries of 3-Series and 8,121 of 4-Series, according to WardsAuto data. For those who thought buyers would be confused, think again.

Of course, volumes will be significantly less for the M3/M4, although the price premium is not outrageous for this much performance. 3-Series sedans start at $37,300 and cap out at $49,900. The M3's previous best year was 2011, with 4,900 deliveries. 

M3 prices begin at $62,925 (up from $60,100 on prior model), while the M4 starting point is $65,125. With options, BMW executives say most U.S. transaction prices will be between $70,000 and $80,000.

Worthy of the upcharge is the all-new (code-name S55) twin-turbo 3.0L I-6 that replaces the heavier naturally aspirated 4.0L V-8 that made 38% less torque and 2% less horsepower.

Twin-Turbo S55 I-6 Light, Lively

The V-8 was good, but no one will clamor for it after experiencing the new engine, with its low-mass 18-psi (1.2-bar) mono-scroll turbochargers spinning at up to 200,000 rpm and offsetting any hint of lag.

Because of its inline architecture, the S55 engine shares more in common with the N55 3.0L twin-scroll turbo-6 that is ubiquitous across the BMW lineup and earned Ward’s 10 Best Engines trophies in 2011, 2012 and 2013.

But the S55 gets lightweight high-revving pistons, and an innovative new 1-piece carbon-fiber driveshaft extends to the high-performance Active M electronically controlled fully lockable limited-slip differential that turns the rear wheels. The shaft is 11.7 lbs. (5.3 kg) lighter than the conventional one it replaces.

Relative to the N55, which makes a lot less horsepower and torque, the S55 engine has a magnesium oil pan that is 2.2 lbs. (1 kg) lighter, a crankshaft that is 4 lbs. (1.8 kg) lighter and an aluminum engine block that is 4.9 lbs. (2.2 kg) lighter (and makes do without cylinder liners).

A high revver needs to remain a cool cat, so the S55 integrates seven heat exchangers, including two intercoolers and two water coolers. Plus, there’s an electric coolant pump for the intercooler circuit.

Like the previous car, the new one is offered with both 6-speed manual and 7-speed dual-clutch ($2,900 option) transmissions. Both deliver rev-matching and get the job done nicely, but our test drive on the track is limited to the DCT, whose shift speed can be dialed up (for high impact) or down (for comfort).

Cycling up through gears on the long straight-aways that invite speeds over 140 mph (225 km/h), the DCT on the top setting shifts with the clean-cut precision of a guillotine. It’s about this time the driver recognizes the M3/M4 as the king of the sports-car jungle.

Have no fear carrying this much speed into Road America’s tight corners, thanks to carbon-ceramic brakes, option priced at $8,150 but worth every penny for the serious weekend racer.

The car and this powertrain are easy to drive, no matter the skill level, and command respect. The package instills confidence instead of twitchy fear.

Respectable Fuel Economy

The new M3/M4 has an EPA rating of 19 mpg (12.3 L/100 km) in combined fuel economy, definitely better than the V-8 in the prior model, which achieved 16 mpg (14.6 L/100 km).

On a spirited 30-minute drive in and around Elkhart Lake, the new M3 manages to top 20 mpg (11.7 L/100 km), according to the trip computer.

Contributing to the impressive fuel efficiency are a host of lightweight components, including an aluminum hood, front fenders and suspension and carbon-fiber roof panel and front strut brace. The M4 also employs a carbon-fiber trunk lid and roof bow support.

Electric power steering (used for the first time on the M3) reduces mass as well, while providing quick response and a good feel for the road.

Overall curb weight falls 176 lbs. (80 kg) compared with the old M3.

Insulation generally is packed into the body to quell engine and road noise, but BMW actually removed a fair amount of the stuff to enhance the experience. Having flogged the car hard on the track, it’s hard to say the M3/M4 is excessively loud. Then again, a snug racing helmet dampens a lot of noise.

The M3/M4 represents the pinnacle of BMW performance, but the cars also take the brand into bold new aesthetic territory as well.

Bolder Colors Inside and Out

Predictable exterior shades of grey, silver, black and white are joined by Austin Yellow Metallic, which is like dipping the car in a simmering pot of liquid gold, and Sakhir Orange Metallic, the color of burning rust. Another edgy hue is Yas Marina Blue Metallic, which could get lost in a cloudless sky.

Inside, the M3/M4 layout and dimensions are identical to the 3-Series and 4-Series from which they are derived, but the new variant gets a sleek, sportier steering wheel and a lot more color and decorative carbon fiber splashed about.

Black and beige leather are available, but more fitting are the dramatic Sakhir Orange, which looks more like red, and Silverstone, which is a mix of white, gray and light blue. The seats are unique as well, with large wraparound shoulder bolsters for extra support.

On sale in late June, the sedan hails from BMW’s plant in Regensburg, Germany, while the M4 comes from Munich. New standard features include navigation, power heated front seats, auto-dimming power-folding mirrors and BMW TeleServices.

But in this car, gadgets and gizmos take a back seat to the fundamental aspects of ride quality, handling and straight-out performance.

Among its competitors, the new M3 and M4 will play the role of predator more often than prey.

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