I don't like electric assist stearing.

"Dave Plowman (News)" > wrote
> Floyd Rogers > wrote:
>> My statement stands that all cars (including BMWs) understeer.
>
> 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.

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

On Thu, 15 Mar 2007 19:20:28 GMT, "grinder" >
wrote:
>
>It's a matter of degree. I have not found any articles referring to
>understeer in Boxsters or the Toyota 2000 but have countless on the topic
>for Z4s.
>
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
--
How can you know where I'm at if you haven't been where I been?
Can you see where I'm coming from? "How I Could Just Kill A Man" Cypress Hill

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".

In article .com>,
adder1969 > wrote:
> 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".

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.

--
*Why is 'abbreviation' such a long word?

Dave Plowman London SW
To e-mail, change noise into sound.

"E Brown" > wrote in message
...
> On Thu, 15 Mar 2007 19:20:28 GMT, "grinder" >
> wrote:
>>
>>It's a matter of degree. I have not found any articles referring to
>>understeer in Boxsters or the Toyota 2000 but have countless on the topic
>>for Z4s.
>>
> Well that's peculiar. My Google search for "boxster understeer"
> turned up 14,800 articles.

I can't do anything better than that. Mine turned up over 18,000.

Many mention how *all* cars these days are
> set up to understeer.

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.d...t=understee r

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
Å 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

"Dave Plowman (News)" > wrote in message
...
> In article .com>,
> adder1969 > wrote:
>> 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".
>
> 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.
>
>

I experienced serious understeer on an off ramp from 280 merging on 92 in
Half Moon Bay. It was not on a track.

"Fred W" > wrote in message
. ..
> grinder wrote:
>> "Fred W" > wrote in message
>> . ..
>>
>>>grinder wrote:
>>>
>>>>"adder1969" > wrote in message
legroups.com...
>>>>
>>>>
>>>>>On Mar 15, 2:24 pm, "grinder" > wrote:
>>>>>
>>>>>
>>>>>>"Fred W" > wrote in message
>>>>>>
>>>>>>news:TLidnYNt9rfhfWrYnZ2dnUVZ_hKdnZ2d@comcas t.com...
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>grinder wrote:
>>>>>>>
>>>>>>>
>>>>>>>>"Fred W" > wrote in message
>>>>>>>>news:ftqdnROx0ds4CGjYnZ2dnUVZ_o6gnZ2d@comc ast.com...
>>>>>>
>>>>>>>>>grinder wrote:
>>>>>>
>>>>>>>>>>"Fred W" > wrote in message
>>>>>>>>>>news:rcudnVO4druAGmnYnZ2dnUVZ_s3inZ2d@co mcast.com...
>>>>>>
>>>>>>>>>>>grinder wrote:
>>>>>>
>>>>>>>>>>>>I have had my Z4 since November and normally drive it on
>>>>>>>>>>>>weekends.
>>>>>>>>>>>>My everyday vehicle is a 4Runner.
>>>>>>
>>>>>>>>>>>>I can see where if one drove the Z every day one could get used
>>>>>>>>>>>>to the
>>>>>>>>>>>>understeer of the electrical assist. But it feels sluggish to
>>>>>>>>>>>>me and
>>>>>>>>>>>>I think could contribute to accidents. That almost happened to
>>>>>>>>>>>>me. I
>>>>>>>>>>>>came into a corner a little hot, I turned the wheel and then had
>>>>>>>>>>>>to
>>>>>>>>>>>>quickly compensate for the understeer. I hate to say it but the
>>>>>>>>>>>>4Runner is more responsive.
>>>>>>
>>>>>>>>>>>>I don't know why they had to mess with something that worked.
>>>>>>>>>>>>Maybe
>>>>>>>>>>>>adding tower braces will help.
>>>>>>
>>>>>>>>>>>I don't see how adding braces would change anything. Sell the
>>>>>>>>>>>car and
>>>>>>>>>>>buy one you like to drive. Oh, and test drive the next one.
>>>>>>
>>>>>>>>>>>--
>>>>>>>>>>>-Fred W
>>>>>>
>>>>>>>>>>Braces will reduce flex on hard corners thereby keeping more tire
>>>>>>>>>>on the
>>>>>>>>>>road and improving cornering performance.
>>>>>>
>>>>>>>>>Undoubtedly true. But that was not your initial complaint. You
>>>>>>>>>said you
>>>>>>>>>did not care for the feel of the electric assist. Reducing or
>>>>>>>>>eliminating chassis flex will help reduce understeer, but not
>>>>>>>>>really
>>>>>>>>>change the feeling of the electric assist.
>>>>>>
>>>>>>>>>--
>>>>>>>>>-Fred W
>>>>>>
>>>>>>>>I guess I should have been more explicity. The "feeling" I was
>>>>>>>>describing was understeer. Another description might be sluggish
>>>>>>>>(not
>>>>>>>>unresponsive but not quick). I realize it is better than found on a
>>>>>>>>SLK
>>>>>>>>but is not as good as a Boxster or Miata.
>>>>>>
>>>>>>>I have a feeling that you are misunderstanding and misusing the term
>>>>>>>"understeer", which may be leading to a lot of the confusing answers
>>>>>>>that
>>>>>>>you are getting.
>>>>>>
>>>>>>>Understeer is the condition that occurs during cornering where the
>>>>>>>car
>>>>>>>wants to "push out" the front end, pointing the car toward the
>>>>>>>outside of
>>>>>>>the corner. In essence you are "under steering" the corner.
>>>>>>>Oversteer is
>>>>>>>exactly the opposite, where the rear end kicks out and points the car
>>>>>>>toward the inside of the corner.
>>>>>>
>>>>>>> These have mostly to do with chassis balance, weight distribution
>>>>>>> and
>>>>>>>dynamic weight transfer during cornering. It has very little to do
>>>>>>>with
>>>>>>>the amount of steering "power assist" or the steering ratio.
>>>>>>
>>>>>>>--
>>>>>>>-Fred W
>>>>>>
>>>>>>From another review (this happened to me):
>>>>>
>>>>>>Out on the fabulous Jerez circuit, the dull steering doesn't really
>>>>>>dent
>>>>>>your progress, but the Z4 M's quite pronounced understeer does. If you
>>>>>>misjudge your entry speed it's not easy to rein it in and exit the
>>>>>>corner
>>>>>>cleanly. Through the slower corners particularly you have to work hard
>>>>>>to
>>>>>>keep it neat and tidy.- Hide quoted text -
>>>>>>
>>>>>>- Show quoted text -
>>>>>
>>>>>
>>>>>Yes but you say the problem is the wheels don't turn as quickly as you
>>>>>want them to, not that the front end was losing traction.
>>>>>
>>>>>
>>>>
>>>>
>>>>I never said the front end was losing traction. I described understeer
>>>>("That almost happened to me. I came into a corner a little hot, I
>>>>turned the wheel and then had to quickly compensate for the
>>>>understeer.") . Now I think the electric assist steering is not the
>>>>problem. The problem is the way the car is set up.
>>>>
>>>>From another review:
>>>>
>>>>"Basically, it is tuned to be an inherent understeerer. Always
>>>>understeer, understeer and understeer. Whenever you push it harder and
>>>>faster, understeer will get into the picture. The harder it corners, the
>>>>more understeer it shows. Now we don't know why BMW needs
>>>>rear-wheel-drive and an engine locating behind the front axle to create
>>>>an understeerer. "
>>>>
>>>>Frankly I am surprised this has not been discussed in the forum before.
>>>>Maybe people don't recognize it for what it is or maybe they don't drive
>>>>the car hard enough to realize the problem.
>>>
>>>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.
>>>
>>>--
>>>-Fred W
>>
>>
>> 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.
>
> 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.
>
> --
> -Fred W

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?...%20Tuning#1665

On Fri, 16 Mar 2007 15:19:39 GMT, "grinder" >
wrote:
>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.
>
I'd love to hear how this works out for you. Please post again once
you've done this.
epbrown
--
How can you know where I'm at if you haven't been where I been?
Can you see where I'm coming from? "How I Could Just Kill A Man" Cypress Hill

"E Brown" > wrote in message
...
> On Fri, 16 Mar 2007 15:19:39 GMT, "grinder" >
> wrote:
>>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.
>>
> I'd love to hear how this works out for you. Please post again once
> you've done this.
> epbrown
> --
> How can you know where I'm at if you haven't been where I been?
> Can you see where I'm coming from? "How I Could Just Kill A Man" Cypress
> Hill

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.

grinder wrote:

>
> 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?...%20Tuning#1665
>
>

If you do, it will increase the understeer.

--
-Fred W