E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > Tuning & Tech > Suspension & Braking Forum by BimmerWorld

Suspension & Braking Forum by BimmerWorld
Have some questions about suspension or brake setups for your E46 BMW? Get all your answers here!
Sponsored by BimmerWorld

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 09-08-2012, 10:41 AM   #1
Weste46
Registered User
 
Join Date: Dec 2011
Location: Westfield, IN
Posts: 679
My Ride: 2001 330ci
E46 handling?

I have a 2001 330ci with Koni orange shocks and struts with KYB mounts, OEM sports springs. I squeal my tires going around medium sized round-abouts at 25. I also get a pop from the rear occasionally when going around one. I'm on 225 and 245 all year continental DWS tires.
Is my handling really just this bad? Or is something wrong? I heard about the RTAB going bad and causing handling to decrease at some point. Could that be it? Thanks!

Sent from my DROID RAZR using Bimmer App
__________________

Koni STR.T, poly RTABs, headers, SSK.
Three Pedals, ZSP.
Weste46 is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 09-08-2012, 10:42 AM   #2
tock172
Beachtown Bill Collector
 
tock172's Avatar
 
Join Date: Jan 2011
Location: San Diego
Posts: 2,905
My Ride: '99 Techno Violet M3
What tire pressure are you running?
__________________


1999 Techno Violet Metallic BMW M3
2005 Audi B6 S4 quattro 6MT
2004 BMW 330i
1986 BMW 535i

tock172 is offline   Reply With Quote
Old 09-08-2012, 10:59 AM   #3
WDE46
Registered User
 
Join Date: Sep 2012
Location: Old Greg's Cavern
Posts: 9,036
My Ride: 2004 330Ci OBM
Squealing tires doesn't mean bad handling, but the pop concerns me. What would you estimate as the diameter of this roundabout you speak of? If you are around 0.75-0.8g at that point the tires will definitely be squealing on any normal car.
WDE46 is offline   Reply With Quote
Old 09-08-2012, 11:33 AM   #4
DiscoStu
Sienna Red Coupe
 
DiscoStu's Avatar
 
Join Date: Apr 2003
Location: Northern Virginia
Posts: 6,619
My Ride: 2013 VW GLI
New RTABs would definitely help to settle down the rear. Especially if they are original, or haven't been replaced in some time. Same goes for the rear ball joints and lower control arm bushings. These items also might be causing the popping noise you hear.
__________________
-Gary
DiscoStu is offline   Reply With Quote
Old 09-08-2012, 11:43 AM   #5
dcwright
Registered User
 
Join Date: Sep 2012
Location: Orlando,FL
Posts: 4
My Ride: '04 325iC
In reference to the pop, you might also want to get the rear subframe mounts and mounting points looked at. As to the squealing, different manufacturers tire compounds start to squeal at different load points. Some start at lower loads to give you early feedback before breakaway, some give you almost none.........

Last edited by dcwright; 09-08-2012 at 11:46 AM.
dcwright is offline   Reply With Quote
Old 09-10-2012, 09:57 AM   #6
Weste46
Registered User
 
Join Date: Dec 2011
Location: Westfield, IN
Posts: 679
My Ride: 2001 330ci
Pressure is fine. RTABs have never been replaced as far as I know, nor any of the bushings in rear.. at 164k miles. Haha. I can't turn as hard as my buddy's civic if that gives you anything..

Sent from my DROID RAZR using Bimmer App
__________________

Koni STR.T, poly RTABs, headers, SSK.
Three Pedals, ZSP.
Weste46 is offline   Reply With Quote
Old 09-10-2012, 10:06 AM   #7
HiHoBrian
OEM ///Member
 
HiHoBrian's Avatar
 
Join Date: Jul 2011
Location: Connecticut
Posts: 1,113
My Ride: 05 M3
+1 on rtabs! I just changed mine at 56,000 miles and they were 100% blown out. The center spacer was seperated from the bush and the TA was knocking side to side on heavy shifts. I blew threw 1 set of Pilot SS tires in 7k and almost wasted my replacements already. When people say Bmw bushing need to be changed at 60k they aren't kidding.

sent from my ATARI sc1224
__________________
HiHoBrian is offline   Reply With Quote
Old 09-10-2012, 11:34 AM   #8
jasonbimmer
Registered User
 
Join Date: Sep 2011
Location: Omaha, NE
Posts: 5,686
My Ride: 2001 BMW 330xi
Quote:
Originally Posted by Weste46 View Post
Pressure is fine. RTABs have never been replaced as far as I know, nor any of the bushings in rear.. at 164k miles. Haha. I can't turn as hard as my buddy's civic if that gives you anything..

Sent from my DROID RAZR using Bimmer App
well you car weights 3400lbs and you buddy's civic is probably 2400lbs or less.
besides DWS is not for its grip at limit.
__________________
2009 Mazda RX-8 R3
2013 Toyota FJ Cruiser
2008 YAMAHA YZF-R6
jasonbimmer is offline   Reply With Quote
Old 09-10-2012, 11:45 AM   #9
Mango
A full five stars, son
 
Mango's Avatar
 
Join Date: Mar 2006
Location: Southern California
Posts: 22,797
My Ride: M54B30
Quote:
Originally Posted by HiHoBrian View Post
+1 on rtabs! I just changed mine at 56,000 miles and they were 100% blown out. The center spacer was seperated from the bush and the TA was knocking side to side on heavy shifts. I blew threw 1 set of Pilot SS tires in 7k and almost wasted my replacements already. When people say Bmw bushing need to be changed at 60k they aren't kidding.

sent from my ATARI sc1224
I would imagine M3s are a lot more punishing on RTABs. But good job at replacing them anyway. they needed it for sure. I just did a friend's E36 M3 rtabs at 160,000 miles and they were completely blown out. center torn away.
__________________
A lifetime free of problems if you follow my guides
Cooling | Maintenance | Suspension | Vacuum | Supreme Reliability | Details

OVER A MILLION VIEWS
Mango is offline   Reply With Quote
Old 09-10-2012, 11:49 AM   #10
hokiebimmer
Registered User
 
Join Date: Jun 2011
Location: Chapel Hill, NC/ Virginia Tech
Posts: 123
My Ride: 2003 BMW 330i ZHP
I had dws' as my last set of tires and they squealed like crazy! Most all season tires squeal a lot. My car handled just fine on them, they were just loud.
__________________
2007 335i Coupe: current
2003 330i ZHP: (for sale)

hokiebimmer is offline   Reply With Quote
Old 09-10-2012, 11:50 AM   #11
WDE46
Registered User
 
Join Date: Sep 2012
Location: Old Greg's Cavern
Posts: 9,036
My Ride: 2004 330Ci OBM
Max lateral tire force increases with applied weight so the mass doesn't really affect the maximum lateral acceleration as much as you think. The BMW should be able to turn with the civic. If you want to see if it really isn't turning as hard as it should, set up a large diameter skidpad (about 150 ft diameter). See how fast you can go around it until you can't keep the radius any longer. That is your max lateral acceleration (a = (v^2)/R) where R is half the diameter of the circle and v is your velocity. Convert your speed into ft/s and your radius into feet then divide a by 32.2 to get your estimate in G's. If you are good at graphs look at the one attached. It is a computer sim of a G35. Should be similar.
Attached Thumbnails
Click image for larger version

Name:	HW5_3.jpg
Views:	44
Size:	24.6 KB
ID:	468502  
WDE46 is offline   Reply With Quote
Old 09-10-2012, 01:01 PM   #12
jasonbimmer
Registered User
 
Join Date: Sep 2011
Location: Omaha, NE
Posts: 5,686
My Ride: 2001 BMW 330xi
Quote:
Originally Posted by WDE46 View Post
Max lateral tire force increases with applied weight so the mass doesn't really affect the maximum lateral acceleration as much as you think. The BMW should be able to turn with the civic. If you want to see if it really isn't turning as hard as it should, set up a large diameter skidpad (about 150 ft diameter). See how fast you can go around it until you can't keep the radius any longer. That is your max lateral acceleration (a = (v^2)/R) where R is half the diameter of the circle and v is your velocity. Convert your speed into ft/s and your radius into feet then divide a by 32.2 to get your estimate in G's. If you are good at graphs look at the one attached. It is a computer sim of a G35. Should be similar.
well the civic is heavier in the front so more front grip also shorter wheel base.
__________________
2009 Mazda RX-8 R3
2013 Toyota FJ Cruiser
2008 YAMAHA YZF-R6

Last edited by jasonbimmer; 09-10-2012 at 01:03 PM.
jasonbimmer is offline   Reply With Quote
Old 09-11-2012, 08:04 AM   #13
WDE46
Registered User
 
Join Date: Sep 2012
Location: Old Greg's Cavern
Posts: 9,036
My Ride: 2004 330Ci OBM
Quote:
Originally Posted by jasonbimmer View Post
well the civic is heavier in the front so more front grip also shorter wheel base.
More weight on the front actually induces understeer. The additional vertical force applied to the tire increases the cornering stiffness of the tire, but this is almost always offset by having additional mass to accelerate. Basically, even though the front tires may be capable of providing greater lateral force, the force is wasted on the additonal mass of the front of the car. A front heavy car will be understeer all other things being equal. So, the civic probably has more understeer than the BMW.

To break it down a little more: If I add 10 lb of load to the front axle, the maximum lateral force of the tire will not increase by 10 lb. I have attached two more graphs. They are based on the Pacejka tire model (look it up) which is quite accurate and interesting to look at.

Ca vs Fz shows the Tire Cornering Stiffness (Side force per slip angle, y-axis) vs the vertical load (Vertical force on tire). Note the peak of the graph. After a certain point, adding downforce will actually decrease the cornering stiffness (though the max lateral force continues to increase).

Fymax vs Fz shows the maximum lateral force the tire can provide versus the vertical load.

The wheelbase affects the yaw moment of the vehicle. Given two vehicles with the same weight distribution, the one with the longer wheelbase will have larger yaw moment. All other things being equal, the shorter car will have a higher peak lateral acceleration in stead state cornering. The length affects other things though. The longer car will be more stable at higher speeds. The shorter car will become unstable at a lower velocity, so there is a balance you want to reach between keeping your yaw moment low and your critical velocity (the speed at which the vehicle becomes unstable) high. There is a reason Formula 1 cars are so long.

I have a ton of other graphs for this stuff and I can make more on my home PC with almost any variables. If you want to see more just ask, I love writing about this stuff.
Attached Thumbnails
Click image for larger version

Name:	Ca vs Fz.jpg
Views:	23
Size:	26.4 KB
ID:	468655   Click image for larger version

Name:	Fymax vs Fz.jpg
Views:	21
Size:	27.1 KB
ID:	468656  

Last edited by WDE46; 09-11-2012 at 08:12 AM.
WDE46 is offline   Reply With Quote
Old 09-11-2012, 12:08 PM   #14
Weste46
Registered User
 
Join Date: Dec 2011
Location: Westfield, IN
Posts: 679
My Ride: 2001 330ci
How did you guys do your RTABs? I don't wanna have to buy the tool to press them out.. thanks!

Sent from my DROID RAZR using Bimmer App
__________________

Koni STR.T, poly RTABs, headers, SSK.
Three Pedals, ZSP.
Weste46 is offline   Reply With Quote
Old 09-11-2012, 12:57 PM   #15
WDE46
Registered User
 
Join Date: Sep 2012
Location: Old Greg's Cavern
Posts: 9,036
My Ride: 2004 330Ci OBM
Quote:
Originally Posted by Weste46 View Post
How did you guys do your RTABs? I don't wanna have to buy the tool to press them out.. thanks!

Sent from my DROID RAZR using Bimmer App
I just order the parts to do mine from BimmerWorld. They have a tool you can rent. It is $99.99 and you get $60 back upon return and they include return shipping. $30 for the right tool is worth it IMO.
WDE46 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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
Censor is ON





All times are GMT -5. The time now is 05:24 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use