technical M140i suspension options and M4 control arm upgrade

[Salt]

Hi all,

Reason for my post is this:
1. I am keen to try improve the handling by decreasing the floaty feel under hard accelleration.
2. Not increase the already relatively hard/bouncy ride.

On point no 1 - my control arms (wishbone & tension struts) are approaching replacement time. I've read a few posts on the net about installing the F82 M4 control arms. The lower control arm apparently gives more camber which improves handling. It widens the track of the front. You can also add the upper control arm to essentially centrer the wheel again as it was with the stock arms but still leaving you with a wider track. Some posts mention you need to adjust the head lights after as well and that special washers are required (12.2mm and 6.3mm (12mm ID, 30mm OD) stainless spacers/washers - which need to be custom made, these are not off-the-shelf BMW parts.) - not sure on that. Has anyone done the M4 control arm upgrade - is it worth the effort and cost really? Is it a simple bolt on change - no custom bits required? Did it improve the handling that made it worth it? Or do I just replace with OEM/similar and hope the fresh kit makes a difference?

On point no 2 - I have considered the Koni Active Specials as they seem to offer something in the middle of a little better comfort but still good for spirited driving with the passive dampening - I've done some reseach online and the reviews are pretty good.

Appreciate any input or advice.

 

[momo1]

I havent done it (as yet) but this vid may help.

 

[Salt]

I havent done it (as yet) but this vid may help.

Thank you...its certainly taken me a rabbit hole of plenty informative videos...hopefully I emerge with the answer 😂

 

[whiteunderarm]

Check these guys out. I just recently started down the suspension road, fitted their solid control arm bushes and have been blown away…more to come for sure!

BMW F20 M135I / M140I

"M Gene included." Take BMW's twin-turbocharged pocket rocket to the next level with our range of chassis and suspension upgrades.

shop.suspensionsecrets.co.uk

 

[Teezoh]

I've been in a few 1ers and was never happy with the feel most of them gave, if they looked great and stanced out, the rides was mostly hard enough to force you into driving with a kidney belt and if they drove soft the float factor was a problem.

I personally opted for the AC Schnitzer sport suspension at the end of the day. The car feels less "light" with it, drives very comfortable, stance is perfect in my opinion and there is no float through the entire speedo gauge.

Pros in my opinion:
Handling is sharpened up dramatically, body roll is basically non existent and there's no nosedive under hard braking.
Cornering is a dream.
While being sport suspension it retains comfort. It's firm and responsive but still dampens bumps.

Cons:
The cost

 

[AshG108]

I've been in a few 1ers and was never happy with the feel most of them gave, if they looked great and stanced out, the rides was mostly hard enough to force you into driving with a kidney belt and if they drove soft the float factor was a problem.

I personally opted for the AC Schnitzer sport suspension at the end of the day. The car feels less "light" with it, drives very comfortable, stance is perfect in my opinion and there is no float through the entire speedo gauge.

Pros in my opinion:
Handling is sharpened up dramatically, body roll is basically non existent and there's no nosedive under hard braking.
Cornering is a dream.
While being sport suspension it retains comfort. It's firm and responsive but still dampens bumps.

Cons:
The cost

I concur here, I fitted the HnR Sport (barely had a few mm's clearance between fender and tyre but never bottomed out). Was superb, with the adaptive ride, the car was still comfy and held like a go cart when in Sport or Sport Plus. In comfort, drive absolutely comfy.

 

[Mytfine]

not mocking you in way but unless you track the car, why would you want the added cost and complexity on a road car ?

 

[Teezoh]

not mocking you in way but unless you track the car, why would you want the added cost and complexity on a road car ?

I can't answer for @Salt , each to their own, but here's my take:

I hear what you’re saying, and it’s a fair point. But for me it’s not only about tracking the car. The F20/F21 is the last of the true RWD 1-Series, and that alone makes it a special platform that’s unlikely to come around again. Investing in proper suspension is my way of both preserving and enhancing that driving experience.

You don’t need to be on a track to appreciate the difference either, spirited drives on the right roads really bring out the balance and control. For me, it’s money well spent because it makes every drive more enjoyable, and it compliments the car’s character perfectly. Just my take.

 

[AshG108]

not mocking you in way but unless you track the car, why would you want the added cost and complexity on a road car ?

I don't think this is a mocking question more of interest to give some thought to usage vs the effort to fit it.
Fair point - but then again like Teezoh says, could just be the personal preference and maybe Salt is an undercover Stig on most of his drives

 

[Salt]

not mocking you in way but unless you track the car, why would you want the added cost and complexity on a road car ?

Hi...fair question 🙂. I do enjoy some spirited driving. I also attend as many of the BMW GP Car Club Skidpan events as I can. And even for example joining a freeway and having to accelerate hard, one experiences the floaty feel. It's not terrible but can be better. I'm looking for the sweet spot between less bouncyness and less floatyness. A daily with a more planted feel. From all my research it seems like the M Perf springs with Koni Special Active shocks might be the way to go for me. It will mean a slight drop...might be the sacrifice for a better ride.