E90Post
 


GTB Performance
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Suspension | Brakes | Chassis > Upgrading front sway-bar only a bad idea?



Reply
 
Thread Tools Search this Thread
      02-27-2013, 11:10 PM   #1
robc1976
DIYER
 
robc1976's Avatar
 
Drives: E90 335i
Join Date: Mar 2012
Location: Illinois

Posts: 4,189
iTrader: (10)

Upgrading front sway-bar only a bad idea?

I was going to do front and rear M3 sway bars but really don't want to drop the rear subframe again (just did it a week ago) to do the rear, can I just upgrade the front swaybar or will this throw my car out of balance? I honestly can't see to much improvement with a upgraded sway bar in the back (have a pretty stiff rear suspension with mods I added last week) but maybe a bit in the front.

Here is the sway bar I want to get (want to do M3 since everything else is lol!)

http://hpashop.com/BMW-OEM-M3-Front-...bar-e9x-m3.htm
__________________
JB4 G5, WEDGE flash, 455 LPFP, HFS-4 meth kit, BMS OCC, RB turbos W/3.5 N20 sensor, RB valve, BMS DCI, 3" AR Dps, Custom OC W/ SS lines, ER FMIC, ER CP W/HKS BOV, M3 control arms, M3 guide rods, M3 upper links, M3 front & rear sway-bars, Meyle HD tie-rods, HPA rear toe arms, Wavetrac LSD, DEFIV kit, KW clubsport coilovers, Power-Flex subframe bushings, stoptech rotors, Rogue Tranny Mounts, 1M bumper, M3 CF hood, MORR VS8.2 rims 245/295
robc1976 is online now  
0
Reply With Quote
      02-27-2013, 11:20 PM   #2
CJ421
Brigadier General
 
CJ421's Avatar
 
Drives: 2011 E92 335i
Join Date: Feb 2011
Location: PA

Posts: 3,247
iTrader: (1)

Garage List
2011 BMW 335i  [4.66]
There's not much of a benefit to roll in the front of the car. Adding the M3 front sway will help curb that behavior. It won't be a night and day difference, but you'll notice. Go for it!
__________________
2011 BMW E92 335i, 6MT, Le Mans blue - Quaife LSD, JRZ RS Pro, JRZ camber plates, Eibach ERS, full M3 susp, custom toe arms, Powergrid end-links, SS brake lines, brake ducting, Michelin PSS, UUC SSK, ETS FMIC, ER CP, Perf. Exhaust, VAC RSIK, Sparcos; work by VAC Motorsports in Philadelphia
CJ421 is offline   United_States
0
Reply With Quote
      02-27-2013, 11:23 PM   #3
robc1976
DIYER
 
robc1976's Avatar
 
Drives: E90 335i
Join Date: Mar 2012
Location: Illinois

Posts: 4,189
iTrader: (10)

Quote:
Originally Posted by CJ421 View Post
There's not much of a benefit to roll in the front of the car. Adding the M3 front sway will noticeably curb body roll - go for it!
You mean no benefit to back but benefit to front...I was thinking the same....appears the damn M3 swaybar bar is on national back order until April. I saw one for sale for a E92....I assume this would be the same for a E90?
__________________
JB4 G5, WEDGE flash, 455 LPFP, HFS-4 meth kit, BMS OCC, RB turbos W/3.5 N20 sensor, RB valve, BMS DCI, 3" AR Dps, Custom OC W/ SS lines, ER FMIC, ER CP W/HKS BOV, M3 control arms, M3 guide rods, M3 upper links, M3 front & rear sway-bars, Meyle HD tie-rods, HPA rear toe arms, Wavetrac LSD, DEFIV kit, KW clubsport coilovers, Power-Flex subframe bushings, stoptech rotors, Rogue Tranny Mounts, 1M bumper, M3 CF hood, MORR VS8.2 rims 245/295
robc1976 is online now  
0
Reply With Quote
      02-27-2013, 11:38 PM   #4
CJ421
Brigadier General
 
CJ421's Avatar
 
Drives: 2011 E92 335i
Join Date: Feb 2011
Location: PA

Posts: 3,247
iTrader: (1)

Garage List
2011 BMW 335i  [4.66]
Yeah the front will turn in flatter w/ the front sway - it's just adding to the total effective spring rate up there by transferring forces from one side of the car to the other.
I see you already have coilovers so that should be plenty of stiffness in the rear. No need for rear sway; just apply throttle to rotate the rear.

The sway bars aren't differently designed between E9x variants, so one from an E90 will fit fine. The E93 M3 sway bar is a bit more powerful, you could try that.
__________________
2011 BMW E92 335i, 6MT, Le Mans blue - Quaife LSD, JRZ RS Pro, JRZ camber plates, Eibach ERS, full M3 susp, custom toe arms, Powergrid end-links, SS brake lines, brake ducting, Michelin PSS, UUC SSK, ETS FMIC, ER CP, Perf. Exhaust, VAC RSIK, Sparcos; work by VAC Motorsports in Philadelphia
CJ421 is offline   United_States
0
Reply With Quote
      02-27-2013, 11:59 PM   #5
HP Autosport
BimmerPost Supporting Vendor

 
Drives: E82 1M
Join Date: Mar 2007
Location: Santa Barbara, AP, Brembo, GIAC, Koni, Ohlins, Quaife, Stoptech, Vorshlag

Posts: 10,897
iTrader: (29)

Quote:
Originally Posted by CJ421 View Post
Yeah the front will turn in flatter w/ the front sway - it's just adding to the total effective spring rate up there by transferring forces from one side of the car to the other.
I see you already have coilovers so that should be plenty of stiffness in the rear. No need for rear sway; just apply throttle to rotate the rear.

The sway bars aren't differently designed between E9x variants, so one from an E90 will fit fine. The E93 M3 sway bar is a bit more powerful, you could try that.
What he said!
HP Autosport is online now   United_States
0
Reply With Quote
      02-28-2013, 12:05 AM   #6
robc1976
DIYER
 
robc1976's Avatar
 
Drives: E90 335i
Join Date: Mar 2012
Location: Illinois

Posts: 4,189
iTrader: (10)

Quote:
Originally Posted by HP Autowerks View Post
What he said!
harold you have one I can get or are they on back order? I like ordering from you lol!! Also lengthening the endlinks in front was great advice...my buddy had shortened his and tried your way of lengthening them and it is much better
__________________
JB4 G5, WEDGE flash, 455 LPFP, HFS-4 meth kit, BMS OCC, RB turbos W/3.5 N20 sensor, RB valve, BMS DCI, 3" AR Dps, Custom OC W/ SS lines, ER FMIC, ER CP W/HKS BOV, M3 control arms, M3 guide rods, M3 upper links, M3 front & rear sway-bars, Meyle HD tie-rods, HPA rear toe arms, Wavetrac LSD, DEFIV kit, KW clubsport coilovers, Power-Flex subframe bushings, stoptech rotors, Rogue Tranny Mounts, 1M bumper, M3 CF hood, MORR VS8.2 rims 245/295
robc1976 is online now  
0
Reply With Quote
      02-28-2013, 12:06 AM   #7
robc1976
DIYER
 
robc1976's Avatar
 
Drives: E90 335i
Join Date: Mar 2012
Location: Illinois

Posts: 4,189
iTrader: (10)

Quote:
Originally Posted by CJ421 View Post
Yeah the front will turn in flatter w/ the front sway - it's just adding to the total effective spring rate up there by transferring forces from one side of the car to the other.
I see you already have coilovers so that should be plenty of stiffness in the rear. No need for rear sway; just apply throttle to rotate the rear.

The sway bars aren't differently designed between E9x variants, so one from an E90 will fit fine. The E93 M3 sway bar is a bit more powerful, you could try that.
Great post & info
__________________
JB4 G5, WEDGE flash, 455 LPFP, HFS-4 meth kit, BMS OCC, RB turbos W/3.5 N20 sensor, RB valve, BMS DCI, 3" AR Dps, Custom OC W/ SS lines, ER FMIC, ER CP W/HKS BOV, M3 control arms, M3 guide rods, M3 upper links, M3 front & rear sway-bars, Meyle HD tie-rods, HPA rear toe arms, Wavetrac LSD, DEFIV kit, KW clubsport coilovers, Power-Flex subframe bushings, stoptech rotors, Rogue Tranny Mounts, 1M bumper, M3 CF hood, MORR VS8.2 rims 245/295
robc1976 is online now  
0
Reply With Quote
      02-28-2013, 12:09 AM   #8
HeelToe
Major
 
HeelToe's Avatar
 
Drives: Rapidly from A to B
Join Date: Jun 2005
Location: Illinois

Posts: 1,044
iTrader: (2)

Garage List
2014 X1 2.8i xDrive  [0.00]
2000 323Ci  [3.00]
2006 330i  [4.50]
2013 BMW 135is  [4.50]
If you replace only the front bar with a beefier one you'll get more under steer than without the replacement bar. I'm not sure why you would want to do this. But then I guess it depends on what you are trying to accomplish. For me, I'm looking for better overall handling with less under steer. I've made my tire sizes more square and have added a camber plate from Dinan and gotten a significantly better handling car. I've also upgrade the bars but did so front and rear.
HeelToe is offline   United_States
0
Reply With Quote
      02-28-2013, 12:25 AM   #9
HP Autosport
BimmerPost Supporting Vendor

 
Drives: E82 1M
Join Date: Mar 2007
Location: Santa Barbara, AP, Brembo, GIAC, Koni, Ohlins, Quaife, Stoptech, Vorshlag

Posts: 10,897
iTrader: (29)

Quote:
Originally Posted by HeelToe View Post
If you replace only the front bar with a beefier one you'll get more under steer than without the replacement bar. I'm not sure why you would want to do this. But then I guess it depends on what you are trying to accomplish. For me, I'm looking for better overall handling with less under steer. I've made my tire sizes more square and have added a camber plate from Dinan and gotten a significantly better handling car. I've also upgrade the bars but did so front and rear.
You would think that, but in the BMW's the opposite is true. You get much better turn-in, less understeer and less body roll.
HP Autosport is online now   United_States
0
Reply With Quote
      03-03-2013, 10:44 PM   #10
HeelToe
Major
 
HeelToe's Avatar
 
Drives: Rapidly from A to B
Join Date: Jun 2005
Location: Illinois

Posts: 1,044
iTrader: (2)

Garage List
2014 X1 2.8i xDrive  [0.00]
2000 323Ci  [3.00]
2006 330i  [4.50]
2013 BMW 135is  [4.50]
Quote:
Originally Posted by HP Autowerks View Post
You would think that, but in the BMW's the opposite is true. You get much better turn-in, less understeer and less body roll.
Gotta help me on this one. The physics don't change by brand. If what you are saying is true then help explain further.
HeelToe is offline   United_States
0
Reply With Quote
      03-04-2013, 12:21 AM   #11
The HACK
Garland Operator 7G
 
The HACK's Avatar
 
Drives: 2006 MZ4C, 2013 Veloster Turbo
Join Date: Oct 2007
Location: Jerry Brown's little tree-huggin' state

Posts: 3,318
iTrader: (1)

Quote:
Originally Posted by HeelToe View Post
Gotta help me on this one. The physics don't change by brand. If what you are saying is true then help explain further.
MacPherson Strut.

Typical "race car" geometry would dictate, yes, thicker front bar would result in less grip up front thus increasing a chassis's tendency to understeer. But the MacPherson type strut design has unfavorable camber gain once the suspension compress past roll center. Therefore, on a car with limited camber, preventing additional roll increase in the front MIGHT actually improve grip in the front rather than take it away.

HAVING SAID THAT. You can't just throw thicker front bar and assume it'll reduce understeer. It has to be a combination of factors, one mainly of reducing the suspension's compression past roll center. If you have a very stiff suspension, with moderate amount of camber, the result will likely be positive. If you have a soft-ish suspension and factory camber, the problem might actually be exacerbated. If you have any combination there of, or if the vehcile's lowered significantly, the result then become a little bit less predictable.
__________________
Quote:
No way I'd ever take my BMW to the track.
Quote:
Then why do you have $3,000 worth of suspension mods on your car?
Quote:
...
-Overheard at the last B****rfest.
The HACK is offline  
0
Reply With Quote
      03-04-2013, 01:03 AM   #12
robc1976
DIYER
 
robc1976's Avatar
 
Drives: E90 335i
Join Date: Mar 2012
Location: Illinois

Posts: 4,189
iTrader: (10)

Quote:
Originally Posted by The HACK View Post
MacPherson Strut.

Typical "race car" geometry would dictate, yes, thicker front bar would result in less grip up front thus increasing a chassis's tendency to understeer. But the MacPherson type strut design has unfavorable camber gain once the suspension compress past roll center. Therefore, on a car with limited camber, preventing additional roll increase in the front MIGHT actually improve grip in the front rather than take it away.

HAVING SAID THAT. You can't just throw thicker front bar and assume it'll reduce understeer. It has to be a combination of factors, one mainly of reducing the suspension's compression past roll center. If you have a very stiff suspension, with moderate amount of camber, the result will likely be positive. If you have a soft-ish suspension and factory camber, the problem might actually be exacerbated. If you have any combination there of, or if the vehcile's lowered significantly, the result then become a little bit less predictable.
great post! I have all M3 upper/lower control arms, Meyle HD tie-rods & coil-overs so my suspension is very stiff. .... so this should work well.
__________________
JB4 G5, WEDGE flash, 455 LPFP, HFS-4 meth kit, BMS OCC, RB turbos W/3.5 N20 sensor, RB valve, BMS DCI, 3" AR Dps, Custom OC W/ SS lines, ER FMIC, ER CP W/HKS BOV, M3 control arms, M3 guide rods, M3 upper links, M3 front & rear sway-bars, Meyle HD tie-rods, HPA rear toe arms, Wavetrac LSD, DEFIV kit, KW clubsport coilovers, Power-Flex subframe bushings, stoptech rotors, Rogue Tranny Mounts, 1M bumper, M3 CF hood, MORR VS8.2 rims 245/295
robc1976 is online now  
0
Reply With Quote
      03-06-2013, 07:37 AM   #13
MSport35TT
Captain
 
Drives: 335i
Join Date: Oct 2012
Location: NJ & MA

Posts: 676
iTrader: (4)

Garage List
2010 BMW 335ix  [0.75]
Do the rear, a big difference in reduced body roll. You'll be happy you did. It's almost x2 thickness than the stock one.
__________________
TiAg N54 xDrive M-Sport 6MT 2010 I:I N54 I:I CPO-2016
335i SOLD

TMPS Sensor 09+ For Sale
x1 Seat Belt For Sale
MSport35TT is offline   United_States
0
Reply With Quote
      03-06-2013, 09:58 AM   #14
nitehawk
Lieutenant Colonel
 
nitehawk's Avatar
 
Drives: e92 335i 6MT
Join Date: May 2011
Location: Toronto

Posts: 1,612
iTrader: (15)

Garage List
Quote:
Originally Posted by MSport35TT View Post
Do the rear, a big difference in reduced body roll. You'll be happy you did. It's almost x2 thickness than the stock one.
Did you install your sway before or after or same time as coilovers?...coilovers alone might be enough to reduce most of that body roll.
nitehawk is offline   Canada
0
Reply With Quote
      03-06-2013, 10:23 AM   #15
scflaw
Lieutenant
 
Drives: E93 3'r
Join Date: Jan 2011
Location: HKG

Posts: 500
iTrader: (1)

Quote:
Originally Posted by nitehawk View Post
Did you install your sway before or after or same time as coilovers?...coilovers alone might be enough to reduce most of that body roll.
I agree, for an E90 the coils should reduce the body roll and give your ride that sexy drop.
scflaw is offline  
0
Reply With Quote
      03-06-2013, 04:46 PM   #16
MSport35TT
Captain
 
Drives: 335i
Join Date: Oct 2012
Location: NJ & MA

Posts: 676
iTrader: (4)

Garage List
2010 BMW 335ix  [0.75]
Quote:
Originally Posted by nitehawk View Post
Did you install your sway before or after or same time as coilovers?...coilovers alone might be enough to reduce most of that body roll.
before... and with summer tires the car sticks!!! afterwards, the Coils when on I also did M3 rear end links and now the handling is MINT!!!


Deff do the rear sway!
__________________
TiAg N54 xDrive M-Sport 6MT 2010 I:I N54 I:I CPO-2016
335i SOLD

TMPS Sensor 09+ For Sale
x1 Seat Belt For Sale
MSport35TT is offline   United_States
0
Reply With Quote
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
Forum Jump


All times are GMT -5. The time now is 06:09 AM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
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