I don't like electric assist stearing.

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I may have been confusing rec.autos.driving postings with postings here - I've certainly seen many postings on this matter.
However, you are wrong if you think that a Boxster (my wife has one) does not understeer - at least for initial and middling responses. My NSX understeered. Modern Porsche 911's are tuned for understeer - although if you go to the limit it oversteers. My statement stands that all cars (including BMWs) understeer.
FloydR
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Modern ones yes - and rightly so for safety in extremis. But it's not so long ago the semi trailing arm equipped ones like the E28 etc could oversteer pretty easily and bite the unwary.
The very first BMW I drove was a 525 auto - the one before the E28 - and lost it at a pretty low speed on a wet roundabout. No harm was done and I caught it before it spun, but it surprised me - my car was a considerably more powerful auto and would have taken the same treatment easily. But then it had a De Dion rear axle.
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Indeed. I had an E12 530i and it was that way. We also had an E21 320i that we lost in a ditch spinning just like that.
FloydR
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wrote:

    Well that's peculiar. My Google search for "boxster understeer" turned up 14,800 articles. Many mention how *all* cars these days are set up to understeer.     For Z4 understeer, the most common fix I've seen is adding an extra degree of negative camber, iirc. I think there's a DIY for this on www.z4um.com.     epbrown
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Seems like grinder now justs want to complain. As someone else wrote you're not stuck with the set-up you have - you can change it. Contrary to popular opinion BMW do NOT always produce car with everything being at the best it can be. What's best for BMW isn't always what's best for the driver. I can a bit tired when people say "BMW know what they're doing leave things alone".
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What annoys me is when 'they' take a car on a track and criticise the outright handling. The design of a track car has little to do with a road one - especially if that road one is more of a fast tourer than out and out sports car.
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wrote:

I experienced serious understeer on an off ramp from 280 merging on 92 in Half Moon Bay. It was not on a track.
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I can't do anything better than that. Mine turned up over 18,000.
Many mention how *all* cars these days are

That is like saying all tires provide traction. Your statement is true but there is a matter of degree. "It is common practice among automobile manufacturers to configure production cars deliberately to have a slight linear range understeer by default. If a car understeers slightly, it tends to be more stable (within the realms of a driver of average ability) if a violent change of direction occurs, improving safety."
I own a Mini S and a Z4. There are situations where the Mini is glued where the Z4 slips.
http://www.goupstate.com/apps/pbcs.dll/section?category=NEWS&template=wiki&text=understeer
Understeer values
How much a car understeers can be measured in the number of degrees more the steering wheel have to be turned per G of lateral acceleration. Here are the measured linear range values for some cars. The higher the number the more the car understeers.
Nissan 350Z 19 Mazda MX-5 21 Nissan 350Z Roadster 21 Ford Mustang GT 22 Renault Megane Sport 22 Maserati Gran Sport 23 Mini Cooper S 23 BMW 330i 25 Alfa Romeo 147 GTA 27 Corvette C6 27 Corvette Z06 28 Lotus Elise 111R 28 Porsche 997 Carrera S 28 Saab 9-3 Aero combi 28 koda Octavia RS 28 Porsche 997 Carrera 29 Porsche Cayman S 29 VW Golf GTI 29 Porsche 987 Boxter S 31 BMW M6 32 Range Rover Sport Supertech 32 Ford Focus ST 33 Mitsubishi Lancer EVO8 34 Porsche 968CS 34 Audi RS4 35 BMW M5 35 BMW Z4 Roadster M 35 BMW M3 Comp Package 36 Opel Astra OPC 36 BMW Z4 3.0i 37 Subaru Impreza WRX STi 37 Subaru Legacy 3.0 aut 38 Volvo V70 T5 39 Audi A4 2.0 T Q 41 Mercedes E55 AMG 42 Audi A4 V6 3.2 Q Avant 43 Porsche Cayenne Turbo 45 Smart ForFour Brabus 45 Mercedes SLK 350 47 TVR Tuscan 49 Alfa Romeo 159 2.2 JTS 51 Morgan Roadster V6 71
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wrote:

    As *opposed* to your original position there were no articles to be found? What happened there?

    Point conceded. However, your original post didn't claim to be unhappy with the *degree* of understeer; you were in a state of high dudgeon that understeer existed at all, claiming the Boxster had none. As you continue to research this, I think you'll find that the Z4 steering tells you as you're about to lose it. What I've read about the Boxster is that you're in complete control until, suddenly, things are hopeless.     Weird how high the 3-series placed on that list you posted. Less understeer than a Lotus Elise?     epbrown
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Well the understeer is the front end losing (some) traction. The process of hard cornering doesn't change the steering geometry so much that it doesn't steer enough.
Almost all cars will have that characteristic if you barrel into a corner, it's simply physics. You can reduce the effect by tweaking the suspension, springs, dampers, anti-roll/sway bars, different tyres etc etc.
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grinder wrote:

Yes. The car understeers. But your complaint was the electric assist. Know how I know this to be true? Read the subject line (above) that you entered.
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You're right. I was wrong to attribute it to electrical assist steering.
That should make you feel better.
Unfortunately the understeer is still there regardless of the source.
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grinder wrote:

OK, sorry to be redundant.
So... now we get to the crux of the matter. The car exhibits more understeer than you'd like.
How to reduce understeer (or induce oversteer if taken far enough):
Increase front tire pressure Decrease Rear tire pressure Shave Front tires (decrease tread depth) Wider Front Tires Narrower Rear Tires Make Front Camber more Negative Make Front Caster more Positive Reduce Front Toe-in Softer front swap bar Stiffer rear sway Bar Soften front springs Stiffen rear springs Softer front shocks Stiffer rear shocks
So you see... you aren't exactly stuck with the handling you have right now.
Many BMWs come with staggered tires. Get rid of that as a first step. Put the same size tire and wheel on both axles and you may find things are much more "balanced" right there. Of course it won't look like a dragster anymore... C'est la vie.
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Actually my first step will be to change tires away from run flats. The softer sidewall will provide better traction. The second choice will be to put a STIFFER roll bar (25mm) on the front AND a softer (22mm) on the rear.
http://www.dinancars.com/Series.asp?Series0&Chassis2&Modelt&Class=Chassis%20Tuning#1665
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wrote:

    I'd love to hear how this works out for you. Please post again once you've done this.     epbrown
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It will be a while. I will change tires first to see how that works. If the understeer is still more pronounced than I would like, I will put on the roll bars. BTW, I will purchase the M5 mobility kit and stick it into the trunk after the tires are changed.
I spoke with the DINAN engineers and the wanted to upgrade to the Stage 2 suspension which I cannot afford right now. Their second choice was to add roll bars which "adds larger and adjustable front and rear anti-roll bars to reduce body roll for superior handling. The adjustable anti-roll bars provide the ability to fine-tune the system for closer to neutral balance reducing understeer. "
CLOSER to neutral balance is what I want. The tire changes should also improve traction.
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wrote:

    They will. Since switching to my Goodyears, it takes a lot of silliness for my little triangle to start flashing. On the run-flats, hitting the on-ramp aggressively did it every time.     epbrown
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grinder wrote:

http://www.dinancars.com/Series.asp?Series0&Chassis2&Modelt&Class=Chassis%20Tuning#1665

If you do, it will increase the understeer.
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Not if selected and adjusted correctly.
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grinder wrote:

If the result of the selection and adjustment is a stiffer front bar and a softer rear bar than the ones you have now, the car will understeer more.
JRE
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