Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series / 4 Series

3 Series / 4 Series
The 3 Series / 4 Series Forum. If you would like to see all new posts in all the forums, click here.

 
 
Thread Tools Display Modes
  #1  
Old 03-01-2002, 05:34 PM
Magna's Avatar
Magna Magna is offline
Officially Welcomed to the 'Fest
Location: Boston
 
Join Date: Jan 2002
Posts: 498
Mein Auto: 2004 325xi
Pros and Cons of Speed sensitive steering assist v. Engine speed sensitive

BMW offers two kinds of steering assist. I read that on the 4.6is X5 there's speed sensitive steering which I think makes more sense since you need assist when the car is going slow. But on the 3 series, the steering assist is engine-speed sensitive. Is engine-speed sensitive easier to manufacture or is easier regarding maintenance?
Advertisement
  #2  
Old 03-01-2002, 07:11 PM
Nick325xiT 5spd's Avatar
Nick325xiT 5spd Nick325xiT 5spd is offline
Registered User
Location: Bethesda, MD
 
Join Date: Dec 2001
Posts: 10,856
Send a message via ICQ to Nick325xiT 5spd Send a message via AIM to Nick325xiT 5spd Send a message via Yahoo to Nick325xiT 5spd
Mein Auto: M3 & 323i/999 KP
I don't know, but I wish I could turn it off above 5MPH. There is absolutely no need for it, aside from parking.

Nick
__________________
2006 GMC Sierra 2500HD 4WD Duramax LBZ/Allison 6-speed
2002 BMW M3 Alpinweiß/Black
1999 323i KP/GTS2 Alpinweiß
1990 325is Brilliantrot/Tan
1989 325is S50B30US Alpinweiß/Black
1989 M3 Alpinweiß/Black S50B32 (321hp, ITBs)


  #3  
Old 03-01-2002, 08:58 PM
Kaz's Avatar
Kaz Kaz is offline
King of Rear Clunks
Location: OC, CA
 
Join Date: Dec 2001
Posts: 12,907
Mein Auto: 01 325iT, 88 M6
Most cars with variable assist use engine speed. I've heard that with many cars assist is tied to engine speed so much so that it affects steering at the track, when you tend to run higher RPMs when there's less boost.

Its probably easier to design engine speed-dependent systems since the PS pump runs off the engine (though it turns more at higher speeds, giving more boost... anyhow...).

Now that electrically driven PS pumps are starting to come out (MINI, and I believe the Insight), changing this to vehicle speed should be easy.

I will say that my car's PS is far less speed-sensitive than most Japanese cars I've driven.
__________________
2001 325i Touring Alpinweiss/Anthracite cloth, Alpina Softline
1988 M6 Royalblau/Silbergrau Nappa
  #4  
Old 03-02-2002, 09:28 PM
bmw325 bmw325 is offline
Officially Welcomed to the 'Fest
Location: New York, NY
 
Join Date: Dec 2001
Posts: 8,455
Mein Auto: 528i
yep-- engine speed steering is cheaper and simpler. I guess it works to some extend-- although it doesn't help too much when you're crusing in the US at around 70mph turning 3k rpm. I don't think you can really notice a boost difference until over 4k-- and no one in the US is cruising at that speed. I'd imagine this type of system would feel less "linear" since everytime the car revs and shifts the steering is going to go from heaver to ligher at the same road speed. I've never really noticed much difference-- except when I had the car in Germany-- I did notice that power steering was reduced at 5k rpm (when i was cruising at 125mph).

I've actually noticed that most Japanese manufaturers use acutal speed sensitive steering (and have for quite some time).

BMW calls this system "servotronic" and reserves to for the 5 and 7 series. It seems like it would be a pretty obvious way to address all of the steering effort controversey. My dad has an e38 7 series with this--and the steering feels light as a feather at parking speeds. Then again, its pretty light at highway speeds too (it also has recirculating ball steering) so that may have something to do w/ the overal light feeling.

I bet (but I'm not sure) that on the E65 you can adjust the boost t your preferences-- I know that on the M5 pressing the sport button makes the steering firmer.

In conclusion the only "advantage" to engine speed sensitve steering is that its cheaper to make.
__________________
  #5  
Old 03-02-2002, 10:07 PM
Emission's Avatar
Emission Emission is offline
Automotive Monomaniac
Location: North of Los Angeles, CA
 
Join Date: Dec 2001
Posts: 10,688
Mein Auto: Schnelle Autos
Quote:
Originally posted by Kaz


Now that electrically driven PS pumps are starting to come out (MINI, and I believe the Insight), changing this to vehicle speed should be easy.

Kaz is right, most manufacturers are going towards (future) electric pumps and accessories not belt driven. This will make the speed sensitive steering easy to make... and maybe it will trickle down to the 3-series!
__________________
I am fortunate to have unique press cars delivered weekly, but I own:

'13 Audi Q5 2.0T Quattro 8AT
'86 Porsche 911 Turbo 4MT


Gone, but never forgotten... my E70 X5 35d, E90 335i, E46 330i, E36 328i, E70 X5 3.0si, E53 X5 3.0i.
~~~~~~~~~~~~~~~~~~~~~~~~~
Read my work as West Coast Editor for Autoblog!
  #6  
Old 07-02-2004, 01:49 PM
guzplace guzplace is offline
Live for the moment :)
Location: Amman, JORDAN
 
Join Date: Apr 2004
Posts: 75
Mein Auto: BMW 318i E46
Is it true that japanese cars .. like Hondas had this vehicle speed sensitive steering since ages and BMW just added it to its line ......!!!
 

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series / 4 Series
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump


All times are GMT -7. The time now is 02:17 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms