GTE Z4 BREAKS COVER WITH HISTORY LESSON IN TOW

copy from http://www.speedhunters.com/2013/02/gte-z4-breaks-cover-with-history-lesson-in-tow/

GTE Z4 BREAKS COVER WITH HISTORY LESSON IN TOW

February 14, 2013
by Jonathan Moore
11 comments

BMW have undertaken a major change of platform for their 2013 North American sportscar campaign – the latest chapter in an illustrious history on the continent that stretches back over 40 years. Ahead of the introduction of the E80 next year, the outgoing E92 M3 model has been honourably retired after four seasons on point in the American Le Mans Series,. In its place, BMW’s new global racecar is being slotted in for 2013: the Z4 coupé.

This is a car that has been doing sterling service over in Europe and further afield over the last couple of season in FIA GT3 guise – but make no mistake, this GTE version is a ground-up rebuild of the GT3 Z4.

The reveal of the GTE Z4 took place at the famous Daytona International Speedway in Florida, which had heavy significance on a number of levels. BMW have seen plenty of historical success at the Daytona oval in the past, particularly in the 24 Hours. A BMW-engined Riley MkXXVI won the race this year, and the BMW CSL in which Brian Redman, Peter Gregg and John Fitzpatrick took the victory in 1976 was present as guest of honour at the Z4 launch. More on this amazing car to come in a following story…

The other factor was that Daytona isn’t currently on the Z4′s radar: the race is currently on the Grand AM side of the fence. That is, until next year when the two series join together, and the choice of Daytona as the launch venue sent a very clear – and positive – message about BMW’s view of the merger.

The Z4 has big shoes to fill: the M3 GT won the team and manufacturer titles in 2010 and the triple crown of driver, team and manufacturer in 2011. To make the launch of the Z4 even more exciting, the new car was preceded out on track by five of its antecedents – two of which were the M3 GT model.

Whilst the new car was fettled ready for a midday demonstration, the assembled guests were able to take a look at the mouth-watering line-up of racers and also to sample just what it’s like to lap Daytona’s 3.8-mile sportscar course from the cockpit – a track that had only just settled down after the recent 24 Hours, and which in a week’s time plays host to the NASCAR 500.

Two M3 GTs had been brought out to play, with the #56 E92 no less than the two-time Sebring-winning chassis. New BMW signee John Edwards took that car out, whilst another driver new to BMW, Belgium’s Maxime Martin, was at the helm of #55.

Those two would make a day. The remaining three cars set me up for the year. Moving back in time, next up was a 2001-6 BMW M3 GTR, which was driven by long-time BMW stalwart Dirk Müller.

Next, the 1998 Daytona 24 Hours-winning M3 GT2 – not a factory car, but the PTG car run by factory Corvette driver Tom Milner’s father.

The GT2 was driven by Bill Auberlan, who seems to have been driving BMWs in North America forever.

Finally, there was this 1993 M5 IMSA Supercar driven by David Donohue – GT2 class winner of the Le Mans 24 Hours in ’98, and son of the legendary CanAm driver Mark Donohue.

Did I say finally? No. Brian Redman himself, who now lives in Florida, was on hand and powering round a lithe M6 at unfathomable speed that would show up people half his age. A legend.

Passenger rides always seem to be for other people when you’re working, but I was incredibly pleased to be offered a ride alongside Maxime Martin in #55. It seems I’ve been on a very pleasing upward trajectory in regards to the speeds of cars I’ve been able to sample over the last couple of years, and the M3 GT continued that. This is a Le Mans-spec car, but even so I wasn’t prepared for the brutal experience ahead.

The car was absolutely planted to the track: I only felt the smallest of slides on the exit of the Bus Stop, though that was also the time my brain just caught up with the sheer speed of the M3 GT. The brutality of the acceleration was just ridiculous, and it started from the moment Maxime pulled #55 out of its space on the pitlane. With no session on, the pitlane limiter wasn’t called for – except in my head and every fibre of my body. The moment the car was clear of the others, he simply nailed the throttle and fired up through the gears as my eyes popped out on stalks.

Surely at this speed we’ll never make the tight and very narrow pit exit? So maybe we’ll jink out right at the last moment and take Turn One? Or follow the NASCAR exit and join the main track directly? Nope. With a braking force like we’d just been hit by The Hulk, Maxime turned the BMW into the impossibly narrow aperture and threaded the BMW through to the exit, barely hesitating before joining the main track and blasting down to the first hairpin. Blap, blap, blap up through the gears, flat on the throttle before the second big stop.

Again, through the corner like it wasn’t there and haring off down towards the left kink and following hairpin. Feet pressed hard against the bulkhead, it looked like we were driving directly towards – and therefore into – the tyre wall that divided the entrance into and exit out of the infield. Somehow, again, the M3 just turned and went through, then arcing out and riding up onto the relative calm of the banking. Which was not how I was expecting the banking to be. It was very relative.

Then the Bus Stop. Hard on the brakes, two turns of the wheel: the in of the left-right carved off and the out right-left completed before I realised we’d arrived. Back on the banking through NASCAR Turns 3 and 4, and another glorious lap of me shouting profanities, constantly and happily, for two minutes. At the end, of course for Maxime this was nothing out of the ordinary: it’s his office. For me, I wish the desk I often have to fly was this fast. Astonishing.

With all this happening, waiting for the Z4 to show up on track was hardly a chore…

Development has been swift on the GTE Z4, with a compressed programme leading to this unveiling: work only began at the BMW Motorsports HQ last July.

Looking around the car, you quickly notice where the changes have been from the GT3. That car has certainly be used as the base, both for the chassis and general ethos, but the GTE Z4 is effectively a brand new racecar both outside and in.

Realistically, the M3 GT has been as much to do with the genesis of the GTE Z4 as the GT3 version of the Z4. That said, the GT3 has been a useful way of testing development parts for the GTE (as was seen at the Dubai 24 Hours last month when the Saudi Falcons team mounted some parts destined for this programme) and definitely helped balance the short lead time.

Underneath the all the carbon is a steel body with a welded-in rollover protection structure, and a new rear aerodynamic profile necessitated by the ACO rules naturally led to the need to completely restyle the car from there forward to balance it out. Heavy use of the BMW wind tunnel has resulted in this revised shape.

There are two very obvious aesthetic differences from the GT3, both at the rear. The back-end is probably the most radical departure from the GT3 model: the extreme styling on the fenders has a real Group 5 feel to it (though yes, I will use that reference wherever possible…), with the super wide fenders and inserts at the trailing edge that follows the lines of the tail-lights.

The cut-outs at the base of each rear corner that form an inverted wing shape with the flat diffuser panel are familiar to most modern GTE cars. You can imagine just how much downforce this thing will produce when you have that big wing up top in combination with the large surface area of the diffuser.

The rear wing is smaller than the aircraft-sized plank used in GT3, though still in no way able to be described as ‘small’.

It’s still a big old piece of carbon, with, as you’d expect, a huge amount of adjustability built in.

In between the two is a pronounced, curving lip wing running along the boot-line, which further highlights the awesome boxy over-fenders.

At the front the differences are less noticeable at first, but the big fenders now rise up in a more linear fashion to butt up to the headlight clusters, almost like the DTM M3.

The front fenders also flare out further to the rear before cropping into where the position lights are, with a significant cut-out underneath.

Along the sides are the same style of NACA ducts, but with a small lip of bodywork beneath them.

From above you really get a sense of just how broad the car is. Whereas from the front and sides it seems quite dinky, and you get the sense that it might be dominated in size by the opposition GTs, from up above you can clearly see that this car has been taken to the extremes of the allowed dimensions.

It’s enormously wide!

The compact dimensions of the base car and short roofline fool you into thinking that the Z4 is smaller than it actually is.

The roofline of the two-seater cabin is not only short lengthways, but it also stands just 1.2 metres off the ground.

The Z4 is actually 4.3 metres long and 2.1 metres wide. That’s not a small car! The base weight is the regulation 1,245kg as per the ACO regulations, but you can be pretty sure that there’ll be some tactical ballast in use.

Like the SRT Vipers, there have been some significant waivers required to fit the Z4 into the ACO-derived rules package. One of the biggest things is the engine: the GTE racer has a 4.4-litre V8 under the long hood, whereas the production models all come with inline fours or sixes.

The naturally-aspirated 4.4-litre V8 is a development of the unit used in the GT3 car: it still has its unique sound which makes it so identifiable out on track, like an old propellor-driven fighter with machine-gun downshifts. Aural heaven! Power is limited to 480hp, with an air restrictor keeping a lid on excess power. One of the many good things about the V8 is its big power band and solid construction, which means that getting that kind of power out isn’t going to be an issue, even for a 24 hour race.

It all looks quite familiar under the hood, and absolutely spotless – not just because it’s a new car, but because this is a factory-prepared car.

Of course, the changes aren’t just cosmetic. The car has been fundamentally redesigned underneath, with a lot of the GT3-spec allowances having to be thrown out: particularly the electronic aids like traction control and ABS.

In the cockpit, the steering wheel has a feeling of F1 complexity about it: as many functions as possible have been put at the drivers’ fingertips.

The Z4 uses a sequential six-speed gearbox. A mis-spelling when writing this said ‘fearbox’ instead, which after taking that ride in the M3 GT seems all too appropriate.

Another move for the team has been the change of rubber supplier: long-time collaborators Dunlop have moved aside, as they already had in FIA GT3, and Michelin have moved in. Although the Dunlops had performed sterling work when the temperatures were warmer, getting heat in the tyres always proved to be a challenge and BMW have decided to join the majority in switching to the French brand.

With the morning runs complete it was time for the Z4 to burble round to the pitlane for its demonstration…

…followed by some runs behind an M6 so laden down with cameras front and rear that it must have been seriously compromised on aero! And just think of the cost of all that kit hanging off it…

But they got to see the pack of Bimmer racers hugging the banking from close up!

The team running the pair of BMWs in North America is unchanged. Famous racer Bobby Rahal heads up the Rahal-Letterman-Lanigan operation, and this time have been far more involved in the development of the car they will be racing than they were with the turnkey M3.

BMW Motorsport also announced the driving pairs for the coming season. Car #55 will be driven by Bill Auberlen and ALMS rookie Maxime Martin, with #56 pedalled by Dirk Müller and alternate co-drivers depending on the schedule. Joey Hand will be the primary second driver in #56, but his DTM ride will take precedence, so when he’s away on DTM duty John Edwards will be stepping up.

For the endurance races another pair of quick Germans will join the crews: Jörg Müller in #55 and Uwe Alzen in #56 for Sebring and Road Atlanta.

Dirk Müller is the only driver to have had any significant testing time in the Z4 so far, so the other drivers could be seen poking around the Z4 as much as the press!

RLL’s pair of Z4s and will be going up against the toughest competition on the planet as far as GT racing is concerned: Corvette, Ferrari, Porsche, Aston Martin and the new SRT Viper provide the formidable opposition, so there’s no shortcut to success except having a fast car and faster drivers.

And as if that wasn’t enough, the first race of the season – the massive challenge of the 12 Hours Of Sebring – is just a month away and the car has barely hit the ground yet, so RLL have a lot of work ahead of them. The team are under no illusions that it’s going to be a frantic time leading up to the first race.

However, RLL’s mechanics have been over in Germany to get a head start on their new charge. They put in two months of work alongside the BMW engineers, assembling and learning the car, so they expect to hit the ground running. And although 2013 is being termed as a development year, you can sense that the team will be hugely disappointed if the Z4 isn’t up there from the start. We’ll find out soon enough!
Jonathan Moore

BMW Z4 GTE Technical Specifications
Chassis/body: Steel body with welded safety cell
Transmission: six-speed sequential sport transmission, operated via shifting paddles mounted on the steering wheel
Multiple ZF Sachs clutch
Suspension/Brakes:
Front axle: McPherson axle with pushrods and wishbone with adjustable shock absorbers
H&R coil springs
Rear axle: Longitudinal links with wishbone with adjustable shock absorbers
H&R coil springs Brake system: hydraulic dual-circuit brake
Monobloc multi-piston light alloy brake callipers
Innver-vented steel brake discs
Seamless brake balance adjustment (front and rear) by the driver
Wheels: BBS forged aluminum wheels
Front: 12,5×18″
Rear: 13×18″
Tyres: Michelin
Front: 300-680-18
Rear: 310-710-18
Engine type: Eight-cylinder, V-configuration, four valves per cylinder
Mandatory air restrictor (2×29.4mm) Capacity: 4,400cc
Max output: 480bhp (with mandatory air restrictor)
Max torque: 480Nm
Cylinder block: Aluminium cylinder block construction
Engine management: BMW Motorsport ECU 408, without fuses, central display
Dimensions
Length: 4,395mm (excl. rear wing)
Width: 2,010mm
Height: 1,205mm (depending on set-up)
Weight: 1,245kg (according to ACO regulations)
Tank capacity: 110 litres (according to IMSA classification)