[Ausmurry]

Hey guys, fairly new 340i owner here, previously had a Shelby GT350 as a track car and a 128i.

I took my 340i to the first autocross event, Car did okay, tires where shit. What i noticed and my friends noticed most of all was the body roll. It was massive. I have the Track Handling Package, the Dinan shockware tuning and also installed the m3 chassis brace and a strut tower brace. Even with all that this car had more bodyroll than I was expecting. (see pic)

I would of thought it wouldn't be this bad especially with THP. What are some good next mods to correct this? I am very okay with a stiffer car, especially having previously owned a gt350. I was thinking sway bars, lowering springs... Etc.

Thank you

[johnung]

Originally Posted by Ausmurry

Hey guys, fairly new 340i owner here, previously had a Shelby GT350 as a track car and a 128i.

I took my 340i to the first autocross event, Car did okay, tires where shit. What i noticed and my friends noticed most of all was the body roll. It was massive. I have the Track Handling Package, the Dinan shockware tuning and also installed the m3 chassis brace and a strut tower brace. Even with all that this car had more bodyroll than I was expecting. (see pic)

I would of thought it wouldn't be this bad especially with THP. What are some good next mods to correct this? I am very okay with a stiffer car, especially having previously owned a gt350. I was thinking sway bars, lowering springs... Etc.

Thank you

I'm assuming that your car is RWD and not XDrive. RWD or XDrive will determine what part numbers you might need. From a quick search, the so called Track Handling Package is go flat tires, and better brakes along with the Adaptive/EDC dampers.

If they made any changes to springs or sway bars, they were only very mild upgrades. BMW doesn't really have any real heavy duty parts for those for the F30 chassis.

Assuming that you are going to stick with your Adaptive Dampers/Shockware, you'll first need to choose a spring upgrade that will match well with the BMW EDC dampers. FaRKle! has done extensive F30 suspension testing and posts.

Check out his YouTube videos like this one.

The most common spring upgrades include Eibach, H&R and Dinan. I tend to recommend Eibach. They have many more spring options designed for the axle weight of the various models, not one part number fits all. Plus Eibach is stiffer than stock but not outrageously so. H&R and Dinan can both be super stiff which may be a poor match for Adaptive dampers.

The Eibach Germany catalog is more complete and shows the breakdown of individual front and rear part numbers. The Eibach tech support line has been very helpful with spring rates and chassis heights.

EIBACH GERMANY CATALOG
http://web2.carparts-cat.com/default...004&12=100

Once you choose springs, then you can determine if you could use sway bar upgrades to further eliminate body roll.

On my F30 I have upgraded Konis which may be similar to Adaptive dampers, and Eibach springs that are roughly 10% stiffer than stock.

Many companies sell F30 sway bars. Sway bar mods aren't that popular on F30's because the labor is expensive. It's not difficult, just time consuming. Lots of stuff needs to be removed to get to them, especially the front bar. The rear is easier. Installation videos from FaRKle!'s channel below.

FRONT SWAY BAR INSTALLATION

REAR SWAY BAR INSTALLATION

So because sway labor costs a lot (and sway bar's may not be as well understood), guys make the mistake of throwing heavy dampers and heavy springs at the body roll issue, which can really make the ride harsh and uncomfortable. Proper sway bars are often the best solution.

I only consider solid bars because I've seen hollow bars snap. I'm partial to H&R sway bars. I've been using them on various cars for decades.

I installed the H&R front 28mm solid sway bar and the 20mm rear bar. My stock rear bar was only 12mm. See photos. My car really corners flat! I think that the 28mm front bar is perfect.

Although at some point when I revisit my rear suspension I'll probably swap out the 20mm for the next size down, a 17mm rear bar from KC Design. In some conversations with FaRKle! he suggested that the very heavy rear bar may inhibit the independent suspension on high speed curves on rough roads. It causes the tire patch contacting the road to shrink, lowering the rear grip. I found a few daily driving situations where that was the case so I think that 17mm may be optimal. The BMW 15mm is the next size down from that. (I'm not including hollow bars)

Monoball front control arm bushings are a huge steering upgrade. The stock F30 steering is very vague but the monoball bushings make it much more precise. I highly recommend the VAC monoball bushings. I've posted a lot about them. If you can only afford one pair, then do the uppers first. They have more effect on steering.

RWD VAC UPPER CONTROL ARMS
(XDrive Control Arms take a different part number)
https://www.kiesmotorsports.com/prod...8;_ss=r?aff=22

Hope this helps!

[Ausmurry]

Originally Posted by johnung

I'm assuming that your car is RWD and not XDrive. RWD or XDrive will determine what part numbers you might need. From a quick search, the so called Track Handling Package is go flat tires, and better brakes along with the Adaptive/EDC dampers.

If they made any changes to springs or sway bars, they were only very mild upgrades. BMW doesn't really have any real heavy duty parts for those for the F30 chassis.

Assuming that you are going to stick with your Adaptive Dampers/Shockware, you'll first need to choose a spring upgrade that will match well with the BMW EDC dampers. FaRKle! has done extensive F30 suspension testing and posts.

Check out his YouTube videos like this one.

The most common spring upgrades include Eibach, H&R and Dinan. I tend to recommend Eibach. They have many more spring options designed for the axle weight of the various models, not one part number fits all. Plus Eibach is stiffer than stock but not outrageously so. H&R and Dinan can both be super stiff which may be a poor match for Adaptive dampers.

The Eibach Germany catalog is more complete and shows the breakdown of individual front and rear part numbers. The Eibach tech support line has been very helpful with spring rates and chassis heights.

EIBACH GERMANY CATALOG
http://web2.carparts-cat.com/default...E279004&12=100

Once you choose springs, then you can determine if you could use sway bar upgrades to further eliminate body roll.

On my F30 I have upgraded Konis which may be similar to Adaptive dampers, and Eibach springs that are roughly 10% stiffer than stock.

Many companies sell F30 sway bars. Sway bar mods aren't that popular on F30's because the labor is expensive. It's not difficult, just time consuming. Lots of stuff needs to be removed to get to them, especially the front bar. The rear is easier. Installation videos from FaRKle!'s channel below.

FRONT SWAY BAR INSTALLATION

REAR SWAY BAR INSTALLATION

So because sway labor costs a lot (and sway bar's may not be as well understood), guys make the mistake of throwing heavy dampers and heavy springs at the body roll issue, which can really make the ride harsh and uncomfortable. Proper sway bars are often the best solution.

I only consider solid bars because I've seen hollow bars snap. I'm partial to H&R sway bars. I've been using them on various cars for decades.

I installed the H&R front 28mm solid sway bar and the 20mm rear bar. My stock rear bar was only 12mm. See photos. My car really corners flat! I think that the 28mm front bar is perfect.

Although at some point when I revisit my rear suspension I'll probably swap out the 20mm for the next size down, a 17mm rear bar from KC Design. In some conversations with FaRKle! he suggested that the very heavy rear bar may inhibit the independent suspension on high speed curves on rough roads. It causes the tire patch contacting the road to shrink, lowering the rear grip. I found a few daily driving situations where that was the case so I think that 17mm may be optimal. The BMW 15mm is the next size down from that. (I'm not including hollow bars)

Monoball front control arm bushings are a huge steering upgrade. The stock F30 steering is very vague but the monoball bushings make it much more precise. I highly recommend the VAC monoball bushings. I've posted a lot about them. If you can only afford one pair, then do the uppers first. They have more effect on steering.

RWD VAC UPPER CONTROL ARMS
(XDrive Control Arms take a different part number)
https://www.kiesmotorsports.com/prod...0&_ss=r?aff=22

Hope this helps!

What an awesome job you did with this reply. Thank you for all of the extensive detailed knowledge. My preference with any of my cars is stiff, especially with the adaptive dampers I can switch to comfort if the abuse gets too high. its clear the springs are extremely soft, even just push the car up and down at the autocross and comparing to my friends g37, and my friends m235i shows. I will look at some eibach options for springs and H&R for sways.

[thisismikeyb]

Depending on if you want to be competitive in autocross, be careful with swaybars. Stock class only allows you to change either the front or the rear swaybar, but not both. You will go from FS (0.814 PAX) to STU (0.829 PAX), STX(0.817) could be possible if you have just 8" wide wheels, but if you have stock staggered you'll be bumped out.

[Ausmurry]

Originally Posted by thisismikeyb

Depending on if you want to be competitive in autocross, be careful with swaybars. Stock class only allows you to change either the front or the rear swaybar, but not both. You will go from FS (0.814 PAX) to STU (0.829 PAX), STX(0.817) could be possible if you have just 8" wide wheels, but if you have stock staggered you'll be bumped out.

Originally Posted by thisismikeyb

Depending on if you want to be competitive in autocross, be careful with swaybars. Stock class only allows you to change either the front or the rear swaybar, but not both. You will go from FS (0.814 PAX) to STU (0.829 PAX), STX(0.817) could be possible if you have just 8" wide wheels, but if you have stock staggered you'll be bumped out.

Just building it for fun. As much as I like my f30 it would not be competitive .

[thisismikeyb]

Originally Posted by Ausmurry

Just building it for fun. As much as I like my f30 it would not be competitive .

I said the same thing at the beginning of the season! I started to realize that my car had more in it than I expected. I was already heavily modified suspension wise, with camber plates and an LSD pushing me into STU class.

Before the end of the season, I was able to get some 275/35r18's V730's on the car for the last few events and those made a huge difference once worn in. I had been on 245/45r18 MP4S' for most of the season. Attached are the cars that put down faster RAW times than me. All of them are on 200TW tires, I'm really just losing out on either power or weight at this point but putting up a great fight for my first season.

With the power advantage you have, stiffer springs and 200TW tires will make huge difference. I don't know how many miles you have on your shocks, but mine were worn out by 50k miles.

[BMWILUVU]

Originally Posted by Ausmurry

Just building it for fun. As much as I like my f30 it would not be competitive .

If you do it for fun to see how far you can push it its fine but the weight, suspension, and turbo of the 340i are not really a competitive match for an autox rather a somewhat better fit for a racetrack.

[weehe126]

A simple option is to get M3/4 zhp springs. Been a while since I looked but could pick them up used for $100. There is a thread on here that goes over the different letter codes for different stiffness.

[Ausmurry]

Originally Posted by weehe126

A simple option is to get M3/4 zhp springs. Been a while since I looked but could pick them up used for $100. There is a thread on here that goes over the different letter codes for different stiffness.

I saw a write up and it looked like the Swift springs where the stiffest. The m3/m4 comp springs seem to be a little less stiff than the swift springs. Ive heard a lot of people complain swapping certain springs onto their EDC system and it not handling well, I suspect it may be because they are still too soft of a spring. I figure with the "shockware" tuning I have on my shocks along with a stiff swift spring it could be a good handling combination hopefully.

I also dont mind a stiff ride as my previous car was a gt350.

[Pussiwillow]

Originally Posted by johnung

I'm assuming that your car is RWD and not XDrive. RWD or XDrive will determine what part numbers you might need. From a quick search, the so called Track Handling Package is go flat tires, and better brakes along with the Adaptive/EDC dampers.

If they made any changes to springs or sway bars, they were only very mild upgrades. BMW doesn't really have any real heavy duty parts for those for the F30 chassis.

Assuming that you are going to stick with your Adaptive Dampers/Shockware, you'll first need to choose a spring upgrade that will match well with the BMW EDC dampers. FaRKle! has done extensive F30 suspension testing and posts.

Check out his YouTube videos like this one.

The most common spring upgrades include Eibach, H&R and Dinan. I tend to recommend Eibach. They have many more spring options designed for the axle weight of the various models, not one part number fits all. Plus Eibach is stiffer than stock but not outrageously so. H&R and Dinan can both be super stiff which may be a poor match for Adaptive dampers.

The Eibach Germany catalog is more complete and shows the breakdown of individual front and rear part numbers. The Eibach tech support line has been very helpful with spring rates and chassis heights.

EIBACH GERMANY CATALOG
http://web2.carparts-cat.com/default...004&12=100

Once you choose springs, then you can determine if you could use sway bar upgrades to further eliminate body roll.

On my F30 I have upgraded Konis which may be similar to Adaptive dampers, and Eibach springs that are roughly 10% stiffer than stock.

Many companies sell F30 sway bars. Sway bar mods aren't that popular on F30's because the labor is expensive. It's not difficult, just time consuming. Lots of stuff needs to be removed to get to them, especially the front bar. The rear is easier. Installation videos from FaRKle!'s channel below.

FRONT SWAY BAR INSTALLATION

REAR SWAY BAR INSTALLATION

So because sway labor costs a lot (and sway bar's may not be as well understood), guys make the mistake of throwing heavy dampers and heavy springs at the body roll issue, which can really make the ride harsh and uncomfortable. Proper sway bars are often the best solution.

I only consider solid bars because I've seen hollow bars snap. I'm partial to H&R sway bars. I've been using them on various cars for decades.

I installed the H&R front 28mm solid sway bar and the 20mm rear bar. My stock rear bar was only 12mm. See photos. My car really corners flat! I think that the 28mm front bar is perfect.

Although at some point when I revisit my rear suspension I'll probably swap out the 20mm for the next size down, a 17mm rear bar from KC Design. In some conversations with FaRKle! he suggested that the very heavy rear bar may inhibit the independent suspension on high speed curves on rough roads. It causes the tire patch contacting the road to shrink, lowering the rear grip. I found a few daily driving situations where that was the case so I think that 17mm may be optimal. The BMW 15mm is the next size down from that. (I'm not including hollow bars)

Monoball front control arm bushings are a huge steering upgrade. The stock F30 steering is very vague but the monoball bushings make it much more precise. I highly recommend the VAC monoball bushings. I've posted a lot about them. If you can only afford one pair, then do the uppers first. They have more effect on steering.

RWD VAC UPPER CONTROL ARMS
(XDrive Control Arms take a different part number)
https://www.kiesmotorsports.com/prod...8;_ss=r?aff=22

Hope this helps!

Reading through this now, you're on koni struts and eibach springs? Paired with h&r sway bars?
I'm about to update my coil overs as they're wayyyy too stiff (b14) with my h&r sways. Trying to get ideas. My old e36 had a modified koni and eibach set up with height adjusters, with upgraded bars and it was incredible on the road, the b14 is a bit harsh at low speeds and rough roads.

[johnung]

Originally Posted by Pussiwillow

Reading through this now, you're on koni struts and eibach springs? Paired with h&r sway bars?
I'm about to update my coil overs as they're wayyyy too stiff (b14) with my h&r sways. Trying to get ideas. My old e36 had a modified koni and eibach set up with height adjusters, with upgraded bars and it was incredible on the road, the b14 is a bit harsh at low speeds and rough roads.

Yes, that's my setup.
Bilstein doesn't do a great job of matching springs and dampers in their coilovers. So if you are finding them too stiff, I would suggest KW Street Comforts. If I was going to move from my setup to a coilover, that's what I would get. Not sure which car you have, but some links below:

FOR XDRIVE
https://www.kiesmotorsports.com/prod...8;_ss=r?aff=22

FOR RWD
https://www.kiesmotorsports.com/prod...8;_ss=r?aff=22

[Pussiwillow]

Originally Posted by johnung

Yes, that's my setup.
Bilstein doesn't do a great job of matching springs and dampers in their coilovers. So if you are finding them too stiff, I would suggest KW Street Comforts. If I was going to move from my setup to a coilover, that's what I would get. Not sure which car you have, but some links below:

FOR XDRIVE
https://www.kiesmotorsports.com/prod...8;_ss=r?aff=22

FOR RWD
https://www.kiesmotorsports.com/prod...8;_ss=r?aff=22

I have a 14 335i RWD
I was leaning on the fence towards kw v3 for the adjustability but I have limited experience matching suspension parts to each other, the b14's were awesome until sway bars went in, then they became entirely too unbalanced for the chassis.

I had a koni and eibach set up with bigger bars on my e36 and on the street it was just perfect, very compliant and flat in the corners but you didn't need to wear a kidney belt lol. I'm after something that matches the sway bars nicely, can adjust dampening down when I want a little more comfort but can also dial it in to be competitive.

Do you have any pics of how your car sits, I don't care if I lose height adjustment as I'm never chasing a desired stance, but would love to have atleast adjustable dampening, rebound would be nice, but this isn't a dedicated track car or anything, and If koni can meet what I need, I may just go this route.