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BMW Z4 chassis secrets March 22, 2009

Posted by Richard Aucock in Launch fever.
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Heinz Krusche is BMW’s chassis guru. I’ve met him several times, and always enjoyed top insight from him (not least his tales of how he keeps DSC turned on for the road – but ‘always’ turns it off when on track…).

bmw-z4-chassis-secretsSuch people exist in every car company, but they don’t always have the power of Krusche.

He wields the same sort of influence as Jost Capito at Ford. There’s another genial genius – and look at how well Fords drive. Lotus, too, has Matt Becker, ensuring that every model drives sublimely.

So, speaking to Krusche is always enthusing. Here, then, are five reasons why the Z4 is another tick against his name.

1. Stiff Body In White
The basic bodyshell is 25 percent stiffer than before. Vital, said Krusche, for the entire driving experience. This torsional rigidity is the starting point, the vital gear in the cog. Without such a good starting point, he said, it is impossible to make cars drive well.

‘It is a big step down if the tolerances are too great.’ You can’t turn a fundamentally bad car into a good one with tweaks alone.

2. 3 Series front axle
The new Z4 uses the 2-joint front axle from the E90 3 Series (and also the various iterations of 1 Series). It’s vital, said Krusche, not least for improving feedback to steering.

With it, BMW can independently tune directional stability, steering feel and lane change stability. Curing a major flaw of the E85 Z4: its wearisome camber steer.

The rear axle, incidentally, is a development of the old Z4 (and is also on the X3). ‘There was no reason to change it,’ said Krusche.

3. Axially parallel layout electric power steering
The new Z4 also uses the axially-parallel EPAS system from the 3 Series. It means the engine isn’t sat on the steering column, so mass is reduced and a purer feel from the road is allowed. The electric motor is in parallel to the steering rack.

The EPAS system has also allowed Krusche to tune the frequencies from the road surface. Basically, you want to isolate high frequencies, but allow through low frequencies. Cumulative learning from the old, oft-criticised Z4 EPAS has allowed BMW to do this.

‘You can vary steering torque with the switch in the car,’ said Krusche. It means it can be (over) light in normal mode, meatier in Sport +.’

He’s tuned it so there is no resistance for when you need to make steering corrections – tidying up snap oversteer, for example. ‘We also vary the feel for when you come to the limit, adjusting the Servotronic function for more feedback.’

4. Greater understanding of run-flat tyres
The E85 Z4 was a run-flat pioneer, and earned much criticism for being so. The tyres’ necessarily stiff sidewalls, and greater weight, both counter ride fluidity. Almost a decades’ learning, plus BMW’s close collaboration with tyre maker Bridgestone (the rubber’s bespoke for the new Z4) mean big improvements.

The evidence of this learning is illustrated by driving the E60 5 Series alongside the newer E90 3 Series, for example. But for greatest contrast, feel how the E85 and E89 Z4s deal with impact harshness and sudden surface imperfections.

Krusche makes a further revelation here, though: again, close work with the Body In White team has led to yet more improvements. By working out the intricacies of where run-flats need compliance in the structure, and where they’ll benefit from extra stiffness, BMW’s been able to tune and filter the natural frequencies of the bodyshell to dramatically improve ride quality.

It’s all about incremental understanding, he said.

5. Change in BMW setup philosophy
Since the 1 Series Coupe, BMW has subtly tweaked its basic chassis setup to improve comfort. Spring rates are slightly softer, and dampers a little stiffer. This has been influenced, again, by knowledge from the characteristics of run-flats.

The secret to doing this well, says Krusche, is in damper tuning. By playing with internal baffles, the size of the holes within them, the rates of flow between the three internal champers – goodness, even the material of the plunger on the strut! – depth is engineered in. Fine art? Call it black magic…

Despite all this, though, Krusche says he doesn’t get the final sign off. It’s always down to the BMW Board – who, at least thrice a year, will drive test cars and give the final say-so.

Krusche can only do so much. The final Z4 we drove on the launch was not one chosen by him, but the good Dr. Ings. You have to say, all have not done a bad job…


NEW: BMW Z4 photo stream on Flickr March 21, 2009

Posted by Richard Aucock in Launch fever.
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Want to see what I’ve been up to on the BMW Z4 launch? Well, check out my Z4 photo stream on Flickr.

bmw-z4-2009-launchAnd be sure to come back here over the next few days, as I plough through all my notes and feed back to you…

… clicking on the images should give you a taster, though!

Pre-launch impressions: BMW Z4 2009 March 21, 2009

Posted by Richard Aucock in Pre-launch impressions.
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Sitting on the plane, going through the press information for the Z4, writing this, I’m really rather intrigued.

See, I have a fair impression of what this car is going to be like. Fast, very crisp and agile. Sublimely cultured and smooth. Bigger and more grown up than the old one. And, vitally, smoother riding.

I don’t expect it to have lost the original’s alacrity and rear-balanced precision. Indeed, I expect this to be enhanced, as there’s surely no way the new one can tramline and follow the road surface as badly as the old?

pre-launch-impressions-bmw-z4-2009And, with the improvement in ride quality, it’s going to be a much easier car to drive on rough surfaces.

There should be a sat-back, powerful feeling, judging by how close the seats are positioned to the rear axle. That will be enhanced by an engine I adore – the 3.0-litre twin-turbo. 306bhp, 62mph in 5.2 seconds… it’s just dawning on me how fast this is likely to be.

Negatives? Well, I reckon they could have done more with the interior which, apart from a Z8 style centre console, lacks the special style of Audi’s TT. The instrument panel also looks a bit cheap, still, despite apparent improvements elsewhere.

Back to ride, though. They’ve got to, got to, have improved it, surely? In fact, I can guess they have. The press pack tells me the optional electronic damper’s stiffest setting is only as stiff as the old car’s standard set-up…

I have doubts over the price, though. The sDrive35i I’m driving today is £4400 dearer than the sDrive30i – that car’s almost as fast. What are the benefits of the sDrive35i? I’ll be grilling them to find out the intricacies.

My aim now is to always record these pre-impressions, then to see how the reality fares. You can follow my thought processes, and any preconceptions I take into the road test, for a more accurate representation of how a car actually is.

Mini search over already? If I’m lucky… March 16, 2009

Posted by Richard Aucock in What I've mused upon today.
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I’ve been immersing myself in the classic Mini community over the past few days. It’s all come from last week’s conclusion that I need a classic Mini in 2009. But how to go about getting one?

Well, research is all – so I’ve signed up for all the big forums, such as The Mini Forum, Mini World and the British Mini Club.

It was the latter’s David Hollis who e-mailed me today, with quite a tempting deal. Attend the club’s British Mini Day at Dudley’s Himley Hall on 10 May – and potentially drive home in a peach of a Mayfair! All for the price of a raffle ticket. Heavens, Footman James will even throw in £250 for insurance. He even popped an image in the post, for my delectation.

himley-mayfair-2Now, clearly the 10,500-mile, one-owner-from-new car will be mine. Not will be, IS mine. It’s just a small matter of buying a ticket on the day to confirm this. Problem, therefore, solved!

It’s got the velour I’m after, looks a peach in the pic and, I’m sure, will absolutely rock. Particularly when I’ve completed my custom iPod install, using all accumulated knowledge from The Mini Forum.

Yes, Richard. Of course.

However, just in case, by some quirk of fate, I don’t happen to be given it on the day, I’ve decided to ensure a backup plan is in place. I like the look of this car, so will be dropping Dave a line to see if I can’t get a closer look beforehand. If I do, I’ll report back here.

In the meantime, the search will continue…

Can you help me buy a Mini in 2009? March 14, 2009

Posted by Richard Aucock in What I've mused upon today.
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We motoring journos are a lucky lot. We drive a heck of a lot of cars – this week alone, I’ve had an Audi A5, a Merc A 150, plus the current steed, a Toyota Avensis estate.

The trick, Chris ‘Drivers Republic’ Harris told me, during work experience at Autocar back in the day, is to approach it thus.

Whenever you’re driving, you’re working.

Good motoring journos don’t drive and switch off, he said. They’re thinking, comparing, contrasting, questioning. And this, curiously, makes even the dullest cars interesting. WHY are the brakes on a Citroen C3 so tiresome? WHAT is it about the ride quality of an Avensis on 18”s that’s so contradictory? And so on.

This creates problems for the cars we drive in our spare time. Here, we’re looking for drug cars – a quick-hit fix of insanity, that we can get into and be wired straight into. Ones with immediacy. Long-distance seat lumbar support and high-speed wind noise suppression is less vital.

It’s why most motoring journos’ stables are so nutty. Lord knows, when some of us do meet up for a tea in deepest Wales on Saturday mornings, the sort of stuff you see is crazy: stripped 205 GTIs, Clio Cups, Caterhams, scratch-built 1950s MGs, Minis with Honda engines, really dodgy old bikes, even dodgier old BMW 6 Series with no interior trim, etc and so forth.

Me? Golf GTI MkII. It was. Until this week.

can-you-help-me-buy-a-mini-in-20091Now I need an original Mini.

I drove a single-seater at Silverstone, you see. Bit random, but there is a connection: I Loved it. Had forgotten just how special they are. Remembered what a buzz ‘pure’ motoring is. And the logical way of recreating this is with a noisy, uncomfortable, hard-riding old Mini.

With, of course, impeccable FWD handling, plus feel, intensity and spirit by the bucketload. I can tinker with it, get involved in the scene, maybe even bang a VTEC in it at some point. All for well under a grand for my favoured route of 1980s Mayfair (for the uber discreet look – and velour – no?).

How wrong could I be.

Minis. Not cheap, are they? As in, thousands. Grands. Many of. Oh, my.

So now, I’m a journo on a mission. To find a good 1980s Mayfair, for decent money. Does such a thing exist? For obvious reasons, I think I need one by this August, which gives us plenty of time. Are they out there?

And in the meantime, if anyone can offer me a quick-fire education course on buying and running all things Issigonis masterpiece (that’s not dissin’ the 9X and ADO17, of course), do please take the opp. I think I’ll be needing it…