ZPOST
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   ZPOST > BMW Z4 Technical Talk > Suspension and Braking Chat
  TireRack

SUPPORT ZPOST BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER, THANKS!
Post Reply
 
Thread Tools Search this Thread
      10-06-2010, 12:31 PM   #1
chanzs
Private
10
Rep
55
Posts

Drives: 2006 Z4 M Coupe
Join Date: Aug 2010
Location: HK

iTrader: (0)

Suggestions to cure poor turn-in

I've owned the MC for a little over a month now but I find the turn-in response a little slow. The car rows quite a fair bit before settling down for the corner, adequate for sweeping corners in a road course but rather lacking for autocross or tight twisty canyon sprints. I find it particularly difficult when negotiating quick S-bends as there is too much weight transfer from the excessive body roll.

Anyone here autocross with their MC?

Anyone here with KW V3s that can share their experience? Thks!
__________________
2006 Interlagos Blue Z4 M Coupe
2011 Starlight Black Exige S
2011 Montego Blue 323i
1996 Repsol Honda NSR250SP
Appreciate 0
      10-06-2010, 12:45 PM   #2
The HACK
Midlife Crises Racing Silent but Deadly Class
The HACK's Avatar
1817
Rep
5,337
Posts

Drives: 2006 MZ4C, 2021 Tesla Model 3
Join Date: Oct 2007
Location: Welcome to Jamaica have a nice day

iTrader: (1)

Toe-out and/or camber. [/thread]
Appreciate 0
      10-06-2010, 01:24 PM   #3
esqu1re
Lieutenant Colonel
esqu1re's Avatar
41
Rep
1,855
Posts

Drives: M Coupe
Join Date: Jul 2010
Location: East Coast

iTrader: (0)

Auto-X with the M. Slalom kills my time, among other things.
__________________


///M Coupe: RPI Scoop, OE Strut, CDV, Volk RE30, SS Brake Lines, Stromung Exhaust
Appreciate 0
      10-06-2010, 01:30 PM   #4
inTgr8r
Lieutenant General
inTgr8r's Avatar
Canada
2422
Rep
11,665
Posts

Drives: M2 Comp
Join Date: Mar 2006
Location: Toronto

iTrader: (10)

Quote:
Originally Posted by The HACK View Post
Toe-out and/or camber. [/thread]
lol... that about says it.

For a quick one, you can also run higher tire pressure up front.
__________________
'21 M2C Hockenheim Silver
'18 718 Cayman S Lava Orange (sold)
'13 E92 M3 Santorini Blue (sold)
'07 Z4 M Coupe Alpine White (sold)
Appreciate 0
      10-06-2010, 07:56 PM   #5
Master Apex
Private
United_States
17
Rep
99
Posts

Drives: '17 F80 M3 '07 Z4M '06 E60M5
Join Date: Apr 2010
Location: Austin, TX

iTrader: (0)

In my experiment with turn-in response (finish braking to turning in) and steady state balance (from apex to track out), I found that lowering the front ride height by 0.5" (from stock) improves the turn-in response without altering the steady state balance significantly.
I used 245/35/18 in the front and set the coilover to 0.5" lower last weekend and was happy with the result.
Here is a short clip
Appreciate 0
      10-06-2010, 10:06 PM   #6
r4gs
Viper Driver
Singapore
36
Rep
1,311
Posts

Drives: F-16
Join Date: Aug 2010
Location: Singapore

iTrader: (2)

^master apex, which track is that?
Appreciate 0
      10-06-2010, 10:24 PM   #7
O-cha
Brigadier General
O-cha's Avatar
218
Rep
4,726
Posts

Drives: Mcoupe
Join Date: Oct 2007
Location: In front of you

iTrader: (2)

WTH are you talking about? I can't believe you're calling the Mcoupe unresponsive with poor turn in.
__________________
Appreciate 0
      10-06-2010, 11:14 PM   #8
chanzs
Private
10
Rep
55
Posts

Drives: 2006 Z4 M Coupe
Join Date: Aug 2010
Location: HK

iTrader: (0)

Think the post title is wrong and misleading. Initial turn-in is fine but rather its the time it takes the car to settle that bothers me. I find that the body rolls and pitches a little too much for my liking, particularly in quick S-bends where the body weight takes a long time to roll from one side to the other, resulting in some instability and easy loss of rear traction? i apologise if I made this even more confusing... newbie.

I was thinking a thicker anti-roll bar may help but there doesnt seem to be any options out there. I'm also considering coilovers but would like to be sure that it would help cure thie 'issue' before investing big $$$ into a coilover system.
__________________
2006 Interlagos Blue Z4 M Coupe
2011 Starlight Black Exige S
2011 Montego Blue 323i
1996 Repsol Honda NSR250SP
Appreciate 0
      10-07-2010, 10:58 PM   #9
Master Apex
Private
United_States
17
Rep
99
Posts

Drives: '17 F80 M3 '07 Z4M '06 E60M5
Join Date: Apr 2010
Location: Austin, TX

iTrader: (0)

Quote:
Originally Posted by r4gs View Post
^master apex, which track is that?
Texas World Speedway.
Highest speed HPDE track in Texas.
Z4M red line 4th gear at 140mph on the straight.
The Viper ACR reached 165mph before braking.
Appreciate 0
      10-08-2010, 10:00 AM   #10
03BeastCharmer
Lieutenant Colonel
03BeastCharmer's Avatar
257
Rep
1,660
Posts

Drives: '13 M3
Join Date: Oct 2007
Location: Houston

iTrader: (3)

Quote:
Originally Posted by Master Apex View Post
Texas World Speedway.
Highest speed HPDE track in Texas.
Z4M red line 4th gear at 140mph on the straight.
The Viper ACR reached 165mph before braking.
Nice video. I've only been to TWS once so far in the coupe, and I have a ways to go before I reach 140. I do enjoy that track, and the Coupe is much better there than my E39 M5 Talk about waiting for the weight to settle. Did it once, will not do it again.
__________________

Current: '13 E92 M3 Euro Delivery
Gone: E86 M Coupe; E30 M3, E39 M5, E36 M3
Appreciate 0
      10-22-2010, 08:23 PM   #11
silversprint
Private First Class
3
Rep
164
Posts

Drives: Z4M
Join Date: Nov 2007
Location: SOCAL

iTrader: (0)

It ain't no lotus.

You have to basically drive it slower into corners.
__________________
MR-S Track -2100lbs/300hp
Miata
Z4M Coupe (Sold)
Appreciate 0
      10-27-2010, 08:49 PM   #12
blender
Custom User Title
blender's Avatar
United_States
141
Rep
661
Posts

Drives: black
Join Date: Feb 2009
Location: n

iTrader: (0)

Stiffer springs and matched dampers [typically lowered but not always] will reduce body roll at the cost of some ride comfort. Most of the quality coil-over setups will reduce sway and provide significantly better handling. Several vendors offer bigger anti-roll bars for reducing side-to-side sway.

Alignment and especially corner balancing will help reduce any pendular front-to-rear sway.

This car is not lotus-light but it it stiff and can be made to corner flat and fast.
Appreciate 0
      12-21-2010, 11:24 PM   #13
tarheel91
Private First Class
3
Rep
171
Posts

Drives: ESS Z4 3.0i
Join Date: Nov 2010
Location: Carolina

iTrader: (0)

Quote:
Originally Posted by rclem05 View Post
Stiffer springs and matched dampers [typically lowered but not always] will reduce body roll at the cost of some ride comfort. Most of the quality coil-over setups will reduce sway and provide significantly better handling. Several vendors offer bigger anti-roll bars for reducing side-to-side sway.

Alignment and especially corner balancing will help reduce any pendular front-to-rear sway.

This car is not lotus-light but it it stiff and can be made to corner flat and fast.
Short of increasing the roll center height (which requires reworking the suspension geometry) and thus changing the ratio of geometric to elastic weight transfer, stiffer springs and matched dampers are the way to go.

One thing this will NOT do, though, is reduce weight transfer. It just makes it transfer faster.
Appreciate 0
      03-10-2011, 04:11 AM   #14
IRunOnE
New Member
0
Rep
5
Posts

Drives: Z4
Join Date: Mar 2011
Location: CA Bay Area

iTrader: (0)

Quote:
Originally Posted by inTgr8r View Post
lol... that about says it.

For a quick one, you can also run higher tire pressure up front.
i prefer 0 toe and running higher front air pressure will lead to understeer mid corner.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off



All times are GMT -5. The time now is 04:48 AM.




zpost
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST