This time it's different

In 2014, Marco Wittmann drove this M4 DTM to the DTM driver’s championship. Now it’s time for Bimmer’s own Helmut Werb to find out what makes Wittmann’s high-tech, high-downforce race car so successful…and to try out the M235i Racing, as well, before th

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February 26, 2015

It’s the brakes.

Hitting the ceramic brakes of the BMW M4 “Ice Watch” DTM race car feels like smashing into a concrete wall. The immense deceleration pulls my intestines into my shoes and makes my shoulders scream in pain where the six-point harness anchors me to what one might charitably call a seat. My right leg strains from the pressure, and my eyeballs want to pop out of my skull.

I’d driven my first lap on the Monteblanco race track near the Spanish town of Sevilla with barely any braking power at all; to work properly, the gigantic ceramic brakes needed to heat up, and it wasn’t until my second lap that the radio voice in my helmet declared those humongous discs hot enough for full pressure.

And boy, do they work fine now!

The start/finish straightaway at Monteblanco is about a kilometer long, roughly two-thirds of a mile. Half of it goes downhill, and then it dips and turns slightly uphill. You come barreling down the aforementioned straightaway as fast as the M4 lets you, around 150 mph in sixth gear, with the shift lights on the steering wheel beginning to turn red as you approach the brutal right at the end of it—a U-turn almost, which demands second gear at about 40 mph before opening up into a fast, left-hand sweeper.

The first brake sign on the straightaway comes up at 300 meters.

Ignore it.

The second comes up at 200 meters.

Ignore that one, too.

150 meters.

Ah, well…

“Marco Wittmann brakes here way under 100 meters,” says my old nemesis Dirk Adorf, the BMW Motorsport driver who humiliated me a couple of years ago when I drove Schubert Racing’s Z4 GT3 at Valencia. “So if you can get on the brakes between 150 and 100 meters, you’re good. At 100, you’re very good.”

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Okay. I can wait.

And that’s when it hits me: almost three Gs of brake force, according to the telemetry readout I see when I turn into the pit after my first three flying laps. As a monitor swings into the cockpit, Adorf and Markus Palttala, a new BMW Motorsport driver for the 2015 DTM season, lean in to review my lap times.

Dirk mentions rather casually that Wittmann, last year’s DTM champion and the guy whose car I’m driving, builds up 140 bar of pedal pressure at that crucial braking point shortly before Turn 1, a figure that is almost unbelievable even for professional drivers. You need 60 bar just to fully engage the M4 DTM’s ceramic brakes; on the street, most drivers never even hit 20 bar even when they’re driving hard.

As well as power, you also need subtlety to brake a DTM car properly. There’s no ABS in these cars, or DSC—or any other driver aids, for that matter. But when you over-brake and consequently lock up one of the front tires, two tiny blue lights blink on the steering-whatever, which isn’t a wheel, per se, but more of a yoke, something that looks like it belongs on a fighter jet. Those lights are telling you to ease up if you want to stay on track.

Nothing will warn you should you lose grip at the rear, however. At that point, it’s you, and only you, that can do the detecting and correcting. But for that to happen, my friends, it will take quite a bit.

DTM cars demand respect

When I was told I had a chance to drive Wittmann’s championship-winning DTM machine in Spain, I anticipated an experience like the one I had two years earlier in the Schubert Racing Z4 GT3, which was already quite a bit removed from the racing I had done over the years.

“Remember,” Adorf had said on the phone, “when you got into that Z4 it felt like, okay, we can just kick butt.”

I wasn’t too sure I agreed, but who am I to argue? This time it would be different, he added. “The DTM cars demand that you show some respect. In short: This time it’s different.”

Right he is.

My drive with BMW Motorsport in the Z4 GT3 was a low-key affair, and I had the car to myself that day. This time, BMW Motorsport has organized a track day for a handful of journalists with racing experience, who’ve been selected to try out the current state of the art in BMW race cars.

Unlike the endurance series in which the GT cars race, the DTM is the crown jewel of European sports car racing. It’s where BMW, Audi and Mercedes duke it out for supremacy, in front of huge audiences at the tracks and on TV, and nothing short of Formula One can match the Deutsche Tourenwagen Meisterschaft for importance among German manufacturers.

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The DTM might have lost a bit of luster during the last season due to its over-standardized regulations; it seems to have gone a bit NASCAR, with very similar cars racing under different colors. The carbon-fiber monocoques are all standard, and so are the brakes, tires, six-speed sequential gearboxes and Bosch MS 5.1 electronics. The minimum weight for car and driver plus 10 kg of “performance weight” is 1,120 kilograms or 2,464 lbs. Regardless of manufacturer, the engines are all 90-degree V8s, and they’re all inlet-restricted.

With so many performance factors determined by the formula, what each team can do to its cars is limited mainly to suspension and aerodynamics. Even so, the DTM cars themselves are quite high-tech, and the teams still have enough tricks at their disposal with which to outwit (or outspend) the competition…which explains the NSA-like secrecy surrounding the pits in Monteblanco that house the M4s.

Easy, with experience

My drive begins with a rigorous introduction to the car, the walking of the entire course, and instructions, instructions, instructions.

To get into a DTM car is an ordeal. The seat is cast as an integral part of the chassis and then padded to fit the driver’s body size, and it seems to be positioned a few feet inboard of the door sills. I need to learn how to climb in and out—fast!—while the mechanics and crew busy themselves unwrapping the tires and strapping me in.

Starting the car is done by…not doing very much. The crew turns the engine until the oil pressure builds up, then starts the ignition. All I need to do is to push in the clutch and hold the yellow neutral button on the steering wheel, then pull the paddle shifter to engage first gear.

“You wait until we give you the sign,” the crew boss says, and then VRAAAMMMM! The sharp sound of the V8 fills pit lane, and out of the box I go.

Easy. I can do that.

“Your car is always faster than you,” Adorf had warned me, kind of, before my first start. “In these cars, it’s the driver who is the weaker point and not the car.”

It’s the aerodynamics, he said. Modern DTM cars generate more than 2,000 lbs. of downforce, almost equivalent to a Formula One racer that, theoretically speaking, can drive upside-down. With all that downforce, this 2,464-lb. race car seems glued to the road, and it doesn’t flinch even when you think there is absolutely no way you can make that fast Number 9 corner.

“To bring the car to its limits in fast corners, you need experience.”

And plenty of it.

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Downforce difficulties

There are other difficulties with sophisticated downforce, however, namely the slower corners, those taken at up to about 60 mph, where the aerodynamics don’t have much effect. Until you’re going faster than that, the car handles like a car without aerodynamic help. The Monteblanco circuit is full of those tighter turns, and adaptating to the changing handling modes is challenging.

I drive out of Turn 3 under full acceleration, the left wheels hitting the curbs so hard that it hurts my teeth. I lift quickly before turning right into Turn 4 and off we go again.

Besides the brakes, the truly strange experience, however, is the almost otherworldly stiffness of the carbon fiber chassis. There is no body roll. Zero. The M4 DTM goes exactly where you aim it, like it runs on rails, never bending, not giving up a millimeter to the surface of the track. And yet the body has this supreme lightness that makes you think you’re piloting a go-kart.

Amazingly, the M4 DTM doesn’t feel all that powerful. The 4-liter P66 V8 delivers a restricted 480 hp and needs around three seconds to hit 62 mph. At 370 lb-ft, torque is a bit underwhelming, if not exactly tame, so the heavy lifting is done through high revs.

“In that respect, it’s a real race car,” Adorf says. I try to keep the revs up through the tight chicane, down a little into a sharp right-hander. The car understeers quite appreciably, a problem BMW had to deal with throughout the 2014 season, and I really don’t dare to hit the gas fully through here lest I end up in the grass.

After that things happen real fast.

It’s the following uphill left sweeper where the M4 DTM shines. It takes Turn 7 under full power, then I touch the brakes before the sharp left-hander that follows. The car struggles a bit to turn in, but there’s more than enough power to correct the understeer. I accelerate hard on the short straight and hit fourth before the next right-hander. I’ll never make it, I think, I’m going in way too fast. In any other car I would take it in third—and carefully. But with the downforce working, the M4 doesn’t even blink.

“It’s amazing what kind of reserves these cars have in cornering,” says António Félix da Costa, another BMW driver here to assist the media rookies. “The downforce is so tremendous that even after a few thousand laps you still think you’re not going fast enough.”

Another problem with heavy downforce racing is the bump you feel when a little air gets under the car. I feel one right out of the next corner.

It’s a good thing the telemetry doesn’t transmit my heart rate, nor my breathing—let alone my sweaty palms. Sharp right in third. Fourth. No way.

I can feel my pulse behind my eyes.

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Braking. Down to third, right-hander onto the straightaway.

“You can take that last corner in fourth,” says Palttala when we review the lap times from my first round. He’s gotta be kidding. But the thing is, Markus is obviously trying to be nice to his journalists: According to the reference data, Marco Wittmann would have taken about ten seconds off me…in one lap.

“Okay,” the Finn says, pointing at the monitor, “you’ve lost a bit of time here. And here. Here, too. Braked too early here. And there, you could be faster. Way faster.”

Basically, he’s pointing out my shortcomings over the entire track. I hate these gizmos—you can’t hide from telemetry! But hey, I can improve. I have four laps to go before I have to hand over the M4 to the next driver.

The act of suppression

And I do go faster.

I have to suppress that little voice in my head that tells me that I’ll die a spectacular death if I don’t hit the brakes right now, but getting past that intellectual resistance is all that’s needed, really. I keep pushing at what feels like the limit, but old habits are hard to break, and my survival instinct still makes me brake way too early…in every corner.

“Forget all that old stuff,” Dirk Adorf had said, trying to build my confidence in the pit box. “The way we used to brake in cars without downforce, the old braking points? In the DTM car, you have the feeling you never even get to the apex, you still could hit the gas and make it.”

So that’s what I do.

At the end of Turn 3, that fast left-hander after the U at Turn 2, I get into fourth gear this time, and the car still laughs at me. I’m flying through the uphill left from the tight Turn 6 up to 8, and so is my head, banging against the restraint. Before the intimidating Turn 10, I lift briefly, and I know this is insanity. The M4 feels solid and tight. The short straight to the right-hander at the entrance of the straightaway to start/finish comes at me, and the infernal noise of the V8 and the transmission right next to my kidney seem to push me on. I take it in fourth at higher revs than before, and not a whimper from the M4.

It is a new game, a different kind of racing. It’s no longer a matter of keeping the car under control in way-too-fast corners, more like it’s daring you to even reach the limit. The Wittmanns and Palttalas of this world must have cojones the size of a truck, I mutter when my four additional laps are finished. Markus laughs when he sees the telemetry after I come into the pits.

I did go faster, kinda.

Wittmann’s lead has shrunk to seven


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