Xi suspension- my $.02 - BMW 3-Series (E90 E92) Forum

BAL278 · 08-30-2012, 09:00 PM

Just sharing some experience tuning the suspension on an xi..
As you know, our cars tend to understeer.. The rwd's as well, but I think its worse on the awd platform..

In order to rectify this problem I first went and replaced the springs with Eibach ones.. I noticed the car was a bit more planted.. And there was significantly less body roll..

Step two was to replace the rear sway bar (what a flimsy POS) with an m3 one.. As was the recommendation from Sal at Autocouture to also replace the rear subframe bushings with m3 ones.. I did this probably six months ago.. So this is a bit overdue

What I've found is that the car feels SO much more balanced.. Understeer has been Dramatically reduced.. And dare I say it, i can even get the car to oversteer.. Turn in feels very sharp.. And the car feels the way it should have from the factory.. I will update this as soon as I install the Bilstein sports

I'm sure alot of you are running coilovers or lowering springs, but I HIGHLY recommend this mod.. It makes a big difference

BrokenMyWallet12 · 08-31-2012, 04:44 PM

Having the rear end on the XI feel a tad bit soft is excatly what i thought about when i drive it. Is that rear sway bar adjustable? Did you any of the tires get kicked out further than the stock bar?

802Bimmer · 08-31-2012, 04:57 PM

Thanks for the info! How are the Eibachs on the stock struts?? also how does the stance look, any reverse rake??

Quote:

Originally Posted by BAL278

Just sharing some experience tuning the suspension on an xi..
As you know, our cars tend to understeer.. The rwd's as well, but I think its worse on the awd platform..

In order to rectify this problem I first went and replaced the springs with Eibach ones.. I noticed the car was a bit more planted.. And there was significantly less body roll..

Step two was to replace the rear sway bar (what a flimsy POS) with an m3 one.. As was the recommendation from Sal at Autocouture to also replace the rear subframe bushings with m3 ones.. I did this probably six months ago.. So this is a bit overdue

What I've found is that the car feels SO much more balanced.. Understeer has been Dramatically reduced.. And dare I say it, i can even get the car to oversteer.. Turn in feels very sharp.. And the car feels the way it should have from the factory.. I will update this as soon as I install the Bilstein sports

I'm sure alot of you are running coilovers or lowering springs, but I HIGHLY recommend this mod.. It makes a big difference

pits200 · 08-31-2012, 05:46 PM

I lowly recommend springs only. Ride will suffer and rebound will be subpar if you're going over bumps or imperfections.

I agree with the rest

BAL278 · 09-01-2012, 03:46 PM

Quote:

Originally Posted by pits200

I lowly recommend springs only. Ride will suffer and rebound will be subpar if you're going over bumps or imperfections.

I agree with the rest

I agree with this.. Which is why I'm getting Bilsteins lol

BAL278 · 09-01-2012, 03:49 PM

Quote:

Originally Posted by 802Bimmer

Thanks for the info! How are the Eibachs on the stock struts?? also how does the stance look, any reverse rake??

Quote:

Originally Posted by BAL278

Just sharing some experience tuning the suspension on an xi..
As you know, our cars tend to understeer.. The rwd's as well, but I think its worse on the awd platform..

In order to rectify this problem I first went and replaced the springs with Eibach ones.. I noticed the car was a bit more planted.. And there was significantly less body roll..

Step two was to replace the rear sway bar (what a flimsy POS) with an m3 one.. As was the recommendation from Sal at Autocouture to also replace the rear subframe bushings with m3 ones.. I did this probably six months ago.. So this is a bit overdue

What I've found is that the car feels SO much more balanced.. Understeer has been Dramatically reduced.. And dare I say it, i can even get the car to oversteer.. Turn in feels very sharp.. And the car feels the way it should have from the factory.. I will update this as soon as I install the Bilstein sports

I'm sure alot of you are running coilovers or lowering springs, but I HIGHLY recommend this mod.. It makes a big difference

The eibachs on stock struts.. It is livable lol.. I would recommend to upgrade them, but the drop isnt as aggressive as HR (imo the perfect amount of drop) so the ride isnt as harsh as those

Stance is great.. Could benefit from upgraded shocks.. I will update this when the Bilsteins are on

Carl Morris · 09-01-2012, 04:14 PM

Interesting. I'm not much of a suspension guy...I was thinking that the easiest way to reduce understeer on our cars would be to use camber/caster plates to get the front camber to match the rear. Due to liability issues I tend to assume that the factory has pretty much maximized the traction at the rear and not at the front to make sure there's plenty of understeer and that the fix is just a matter of increasing traction at the front.

BAL278 · 09-01-2012, 05:16 PM

Quote:

Originally Posted by Carl Morris

Interesting. I'm not much of a suspension guy...I was thinking that the easiest way to reduce understeer on our cars would be to use camber/caster plates to get the front camber to match the rear. Due to liability issues I tend to assume that the factory has pretty much maximized the traction at the rear and not at the front to make sure there's plenty of understeer and that the fix is just a matter of increasing traction at the front.

I agree completely, Understeer is the "safe" route.. The rear sway bar is incredibly flimsy.. I'm sure camber would increase front grip, but from my experience with only these mods.. It does a fantastic job of balancing the car.. The rear end just feels too soft.. Using these M3 components makes a noticeable difference

MakkkD · 09-06-2012, 03:51 PM

what is the part number for the Eibach springs you installed?

don_zielke · 09-07-2012, 07:09 PM

Would this apply to coupe, sedan, or both?

Thanks,
Don Zielke
'07 328xi

rwgeld58 · 09-08-2012, 08:43 AM

I put kw V1s on last Dec. which markedly improved the floaty feeling, but still feel some sway in curves compared to my prior e92 non-x. Based on yours and others comments, am thinking of doing the rear M3 sway. However, a guy who runs a specialty bmw shop near me actually recommended against it, but I think he may not be as familiar with x-drive issues with suspension. How much should install run?

AWD Addict · 09-10-2012, 10:38 AM

Good tire pressure management can also go a long way to dialing out the understeer. On the stock setup before I upgraded, I found the bias to be pretty close to neutral (though it did still push a bit) with 32/36 F/R psi.

Combined with my new stuts, the car feels dramatically improved. I was thinking about a rear sway and bushings next, but given how much better the car feels, I'm probably going to hold off for a while.

BAL278 · 09-20-2012, 08:48 AM

Quote:

Originally Posted by rwgeld58

I put kw V1s on last Dec. which markedly improved the floaty feeling, but still feel some sway in curves compared to my prior e92 non-x. Based on yours and others comments, am thinking of doing the rear M3 sway. However, a guy who runs a specialty bmw shop near me actually recommended against it, but I think he may not be as familiar with x-drive issues with suspension. How much should install run?

Install was about 4 hours for the Rear Sway and subframe bushings

drsilvershot · 02-02-2013, 01:04 PM

still available?

suave5274 · 02-03-2013, 07:48 PM

Does the 22.5 m3 rear sway bar fit a 2007 e90 335xi

jeguth1s · 02-04-2013, 09:31 AM

Yes. All the E9x rears have the same config Sway. Just different thickness.

Richbot · 02-04-2013, 10:08 AM

Single best thing you can do to improve balance on a street BMW is add more front camber. The best way to do this, counterintuitively, is often to add a stiffer front swaybar to keep the front suspension in its happy place, because the front suspension geometry de-cambers the tire as it travels through its range of motion in bump. The E90 chassis is much better than past designs in this regard but still not as good as some double wishbone setups which can get by with less than a degree of negative camber and still keep the tire square to the road in a corner. A bigger rear bar just takes grip away from the rear especially under acceleration, what the car needs is more front grip

MSport35TT · 02-05-2013, 12:53 PM

Quote:

Originally Posted by Richbot

Single best thing you can do to improve balance on a street BMW is add more front camber. The best way to do this, counterintuitively, is often to add a stiffer front swaybar to keep the front suspension in its happy place, because the front suspension geometry de-cambers the tire as it travels through its range of motion in bump. The E90 chassis is much better than past designs in this regard but still not as good as some double wishbone setups which can get by with less than a degree of negative camber and still keep the tire square to the road in a corner. A bigger rear bar just takes grip away from the rear especially under acceleration, what the car needs is more front grip

I though most would disagree to replace the front sway vs the Rear...

suave5274 · 02-05-2013, 07:12 PM

Quote:

Originally Posted by MSport35TT

I though most would disagree to replace the front sway vs the Rear...

Correct thats what iv heard too. Rear> Front , although what he said about front>rear does make sense as he explained .

SDV325 · 02-11-2013, 01:36 PM

Changing out the swaybars and endlinks are usually the first step in tuning AWD suspension (well technically tires first). You will greatly benefit more from having stiffer swaybars/bushings prior to doing springs/shocks.

Coming from the Subaru scene this is quite common and companies like whiteline have a very good reputation and parts selection. Was quite surprised on how many BMW parts were made as well.

http://www.whiteline.com.au/do_segue...3%2F05-10%2F11

pits200 · 02-11-2013, 02:02 PM

Quote:

Originally Posted by SDV325

Changing out the swaybars and endlinks are usually the first step in tuning AWD suspension (well technically tires first). You will greatly benefit more from having stiffer swaybars/bushings prior to doing springs/shocks.

Coming from the Subaru scene this is quite common and companies like whiteline have a very good reputation and parts selection. Was quite surprised on how many BMW parts were made as well.

http://www.whiteline.com.au/do_segue...3%2F05-10%2F11

Unfortunately, such is not true with the bmw due to the complexity of swapping out the rear sway and needing to drop the subframe.

Bryan71 · 02-13-2013, 06:02 PM

with B8 bilstein's, correct? what is the part number for the Eibach's you put on?

08-30-2012, 09:00 PM	#1
BAL278 Captain Drives: E92 335xi JB Join Date: Jun 2011 Location: North NJ (FLakes) Posts: 708 iTrader: (0)	Xi suspension- my $.02 Just sharing some experience tuning the suspension on an xi.. As you know, our cars tend to understeer.. The rwd's as well, but I think its worse on the awd platform.. In order to rectify this problem I first went and replaced the springs with Eibach ones.. I noticed the car was a bit more planted.. And there was significantly less body roll.. Step two was to replace the rear sway bar (what a flimsy POS) with an m3 one.. As was the recommendation from Sal at Autocouture to also replace the rear subframe bushings with m3 ones.. I did this probably six months ago.. So this is a bit overdue What I've found is that the car feels SO much more balanced.. Understeer has been Dramatically reduced.. And dare I say it, i can even get the car to oversteer.. Turn in feels very sharp.. And the car feels the way it should have from the factory.. I will update this as soon as I install the Bilstein sports I'm sure alot of you are running coilovers or lowering springs, but I HIGHLY recommend this mod.. It makes a big difference __________________ 2008 335xi Jet Black//Coral Red Procede V5//AMS FMIC//KW V1//M3 Sways & Sub Bushings// Alpina AT flash
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02-04-2013, 10:08 AM	#17
Richbot Major Drives: Jerez Black E90 Join Date: Sep 2007 Location: STL Posts: 1,485 iTrader: (1)	Single best thing you can do to improve balance on a street BMW is add more front camber. The best way to do this, counterintuitively, is often to add a stiffer front swaybar to keep the front suspension in its happy place, because the front suspension geometry de-cambers the tire as it travels through its range of motion in bump. The E90 chassis is much better than past designs in this regard but still not as good as some double wishbone setups which can get by with less than a degree of negative camber and still keep the tire square to the road in a corner. A bigger rear bar just takes grip away from the rear especially under acceleration, what the car needs is more front grip __________________

02-11-2013, 01:36 PM	#20
SDV325 N54 or N55? Drives: 99 Impreza 2.5RS Join Date: Jan 2013 Location: Calgary, AB Posts: 49 iTrader: (0)	Changing out the swaybars and endlinks are usually the first step in tuning AWD suspension (well technically tires first). You will greatly benefit more from having stiffer swaybars/bushings prior to doing springs/shocks. Coming from the Subaru scene this is quite common and companies like whiteline have a very good reputation and parts selection. Was quite surprised on how many BMW parts were made as well. http://www.whiteline.com.au/do_segue...3%2F05-10%2F11 __________________ http://www.rs25.com/forums/f145/t136...d-my99-rs.html 335Xi shopping

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08-31-2012, 04:44 PM	#2
BrokenMyWallet12 Enlisted Member Drives: 2009 335xi Join Date: Jul 2012 Location: New Jersey Posts: 44 iTrader: (1)	Having the rear end on the XI feel a tad bit soft is excatly what i thought about when i drive it. Is that rear sway bar adjustable? Did you any of the tires get kicked out further than the stock bar?

08-31-2012, 05:46 PM	#4
pits200 Lieutenant Colonel Drives: 09 335i X-Drive Black Sapphire Join Date: Mar 2010 Location: Pittsburgh Posts: 1,577 iTrader: (0)	I lowly recommend springs only. Ride will suffer and rebound will be subpar if you're going over bumps or imperfections. I agree with the rest

09-01-2012, 04:14 PM	#7
Carl Morris Lieutenant Drives: 2008 335xi 6MT Join Date: Feb 2012 Location: Boulder, CO Posts: 551 iTrader: (0)	Interesting. I'm not much of a suspension guy...I was thinking that the easiest way to reduce understeer on our cars would be to use camber/caster plates to get the front camber to match the rear. Due to liability issues I tend to assume that the factory has pretty much maximized the traction at the rear and not at the front to make sure there's plenty of understeer and that the fix is just a matter of increasing traction at the front.

09-06-2012, 03:51 PM	#9
MakkkD Private First Class Drives: 09 e92 335xi Join Date: Sep 2011 Location: Westchester, NY Posts: 195 iTrader: (3)	what is the part number for the Eibach springs you installed?

09-07-2012, 07:09 PM	#10
don_zielke New Member Drives: 2007 328XI Sedan Join Date: Aug 2012 Location: Columbus OH Posts: 6 iTrader: (0)	Would this apply to coupe, sedan, or both? Thanks, Don Zielke '07 328xi

09-08-2012, 08:43 AM	#11
rwgeld58 New Member Drives: 335i xdrive coupe Join Date: Nov 2011 Location: Boone, NC Posts: 12 iTrader: (0)	I put kw V1s on last Dec. which markedly improved the floaty feeling, but still feel some sway in curves compared to my prior e92 non-x. Based on yours and others comments, am thinking of doing the rear M3 sway. However, a guy who runs a specialty bmw shop near me actually recommended against it, but I think he may not be as familiar with x-drive issues with suspension. How much should install run?

09-10-2012, 10:38 AM	#12
AWD Addict Chief Executive Drives: 2008 335xi 6spd Coupe Join Date: Dec 2007 Location: Boston Posts: 2,318 iTrader: (1) Garage List 2008 335xi [0.00]	Good tire pressure management can also go a long way to dialing out the understeer. On the stock setup before I upgraded, I found the bias to be pretty close to neutral (though it did still push a bit) with 32/36 F/R psi. Combined with my new stuts, the car feels dramatically improved. I was thinking about a rear sway and bushings next, but given how much better the car feels, I'm probably going to hold off for a while.

02-02-2013, 01:04 PM	#14
drsilvershot Private First Class Drives: 08 335xi jet black Join Date: Dec 2011 Location: providence, ri Posts: 133 iTrader: (2)	still available?

02-03-2013, 07:48 PM	#15
suave5274 Enlisted Member Drives: 335xi Join Date: Dec 2010 Location: CT Posts: 47 iTrader: (0)	Does the 22.5 m3 rear sway bar fit a 2007 e90 335xi

02-04-2013, 09:31 AM	#16
jeguth1s Private Drives: 2006 BMW 330xi Join Date: Nov 2010 Location: Cincinnati Posts: 85 iTrader: (1)	Yes. All the E9x rears have the same config Sway. Just different thickness.

02-13-2013, 06:02 PM	#22
Bryan71 New Member Drives: 2006 325XI Join Date: Feb 2011 Location: Harrisburg, PA Posts: 6 iTrader: (0)	with B8 bilstein's, correct? what is the part number for the Eibach's you put on?