Improving steering response/feel and floatiness

[cjv998]

Hi everyone. I've been lurking on the forums lately, and figured I'd introduce myself.

I picked up a CPO 2012 135i M-Sport coupe a year ago as my DD, and I've been itching to do some work on it. I don't plan on tracking the car, and the car will remain my daily driver. I don't want the car to ride much rougher than it does now with the OEM Dunlop RFTs. (I'm quickly growing to hate them, but they have a lot of tread left.)

Here are the main things I'd like to improve:

1. Steering feel and response. The best way I've heard it described is "doughy". It's heavy, but I don't have a good feel what the car is doing, and I'd like turn-in to be a tad sharper.
2. Body roll. The car just leans more than I like in corners.
3. Overall "floatiness". This surprised me, because the car is harsh over bumps (presumably due to the RFTs), but at the same time it feels floaty and disconnected/loose.

On a related note, my other car is an '01 Miata that I've done springs, shocks, and swaybars on (and a performance alignment, and wheels & tires). It's currently so much more fun than the 1 to toss into corners; there's no comparison. I want to change that. My plan is to sell the Miata, and put some of that money back into the 1.

So here are some upgrades I've thought about. My problem is I don't know where to start.

• Replace RFTs with Michelin PSS's (non-RFT) on wider wheels
• M3 front sway bar
• RSFBs
• Shocks and springs (or maybe coilovers)
• M3 front control arms

Alternatively, I could keep the Miata around and get into autocrossing it like I've been meaning to, and just just live with the 135 as-is...

I'm looking for suggestions on where to start modifying the 1. I may find that I don't need to do all the stuff on my list, so I want to know where to start for the most bang for the buck. Thanks.

[HP Autosport]

The best you can do to address all 3 of your concerns will be a set of good struts and shocks. This is also a good time to add sport springs. Coilovers is an excellent choice if it fits within your budget.

M3 control arms will address #1 only.

M3 sway bar will address #2 only.

Tires will address #1 only.

Feel free to PM us if you have further questions.

[Lmw160]

First mod should be rfsb then ditching the run flats. Whether you go poly or m3 bushings, you'll have a solid frame to build on. Coilovers or control arms will dealing with the soft rear bushings which may or may not address your concerns.

[John_01]

Originally Posted by cjv998

So here are some upgrades I've thought about. My problem is I don't know where to start.

• Replace RFTs with Michelin PSS's (non-RFT) on wider wheels
• M3 front sway bar
• RSFBs
• Shocks and springs (or maybe coilovers)
• M3 front control arms

Alternatively, I could keep the Miata around and get into autocrossing it like I've been meaning to, and just just live with the 135 as-is...

I'm looking for suggestions on where to start modifying the 1. I may find that I don't need to do all the stuff on my list, so I want to know where to start for the most bang for the buck. Thanks.

I did all of the things on your list in three separate stages. Initially I didn't want the expense of getting the RSFB changed, but in hind-sight it was probably the most important individual change. That one is a no-brainer to me. Considering your experience with the Miata, you will definitely appreciate all of the individual changes. I think you made a very good list and they are all worthwhile IMO.

It probably makes sense to do all 5 items on the list at once. If you want to do it in two steps, it might make sense to leave the stock springs and shocks and do the other 4 items in one go. Then you will have a soft and comfortable car with much better handling.

If you want to get coilovers straight away, then I suggest doing all the other upgrades except the front sway bar. It's easy to add the sway bar later, and you may not need it with the higher spring rates of coilovers. Although if you keep the M-sport springs or fit comparable lowering springs, then I'd recommend getting the M3 front sway in that case.

[lowbudgethero]

the ride is downright cushy when you put non runflat tires on it

[Dilmorecg]

Originally Posted by cjv998

• Replace RFTs with Michelin PSS's (non-RFT) on wider wheels
• M3 front sway bar
• RSFBs
• Shocks and springs (or maybe coilovers)
• M3 front control arms

I have done all of these...except I still only have whiteline inserts in the rear subframe...eventually I will do the M3 bushings but its good for now. Love how the car drives now. This is the order I did:

1) M3 Front Sway Bar
2) Whiteline RSFB inserts
3) Shocks and Springs + MPSS tires
4) M3 front control arms

Just wanted to give you an idea of how I did it. My biggest concern when I got the car was the leaning in corners....then the rear wiggle when accelerating out of corners. Thats why I did 1 & 2 first. I would do tires before shocks and springs...I just happened to do them at the same time.

[gap]

I have a 2000 Miata fully prepped for SCCA STR autocross, 2,150 lbs and my 135i with mods listed in my signature. The 135 is 1,200 lbs heavier so it isn't as toss-able. With mods the BMW is a great GT sports road coupe. On a tight autocross course the Miata wins, on a open road course the BMW wins. Two different driving experiences but to me both equally enjoyable.

[chris82]

Originally Posted by HP Autosport

The best you can do to address all 3 of your concerns will be a set of good struts and shocks. This is also a good time to add sport springs. Coilovers is an excellent choice if it fits within your budget.

M3 control arms will address #1 only.

M3 sway bar will address #2 only.

Tires will address #1 only.

Feel free to PM us if you have further questions.

+1 I would do coilovers, springs, camber plates, upgraded RSFB, and call it a day

[cjv998]

Thanks for all the replies! Here's my plan:

1. E90/92 M3 front sway bar
2. Swift Spec-R springs with Koni yellows or Bilstein HD's, plus M3 RSFB and front control arms
3. Replace RFTs & wheels as the current tires wear down. How many miles do people get on these awful Dunlops anyway? (I have trouble justifying getting rid of tires that still have tons of tread left)

gap: Nice hearing from a fellow Miata owner! My '01 has the Flyin Miata Stage 2 suspension on it, and I love how it rides/handles. I'm still itching to auto-x it, but I have trouble justifying keeping two sporty cars around, especially considering I hardly ever drive the Miata any more.

On a related note, I'm really surprised at how hyped-up BMWs are for their suspension. Don't get me wrong, the 1's suspension isn't bad, it just doesn't blow me away either. Maybe I'm just too picky, but I'm just surprised that I'm going to end up putting $2-3k into this suspension (plus wheels & tires) to get it to perform like I want.

[bmw1racer]

Originally Posted by cjv998

I'm just surprised that I'm going to end up putting $2-3k into this suspension (plus wheels & tires) to get it to perform like I want.

Didn't you have to do the same for your Miata?

[cjv998]

Originally Posted by bmw1racer

Didn't you have to do the same for your Miata?

True. I just figured with the BMW being more expensive it wouldn't need as much of that.

[bmw1racer]

Originally Posted by cjv998

True. I just figured with the BMW being more expensive it wouldn't need as much of that.

That's a misconception, as you've found out.

It would hold true for the M versions, though.

[MightyMouseTech]

Originally Posted by chris82

+1 I would do coilovers, springs, and camber plates and call it a day

Honestly, I would say it is pointless to do springs and shocks before fixing the horrible soft bushings in the suspension.

After doing all the M3 arms and RSFB's, I almost see no point in changing the springs to something stiffer.

[chris82]

Originally Posted by MightyMouseTech

Honestly, I would say it is pointless to do springs and shocks before fixing the horrible soft bushings in the suspension.

After doing all the M3 arms and RSFB's, I almost see no point in changing the springs to something stiffer.

You may be right and it's probably cheaper than a coilover upgrade (depending what you go with). I've never driven an M-Sport 1er with all the M3 arms and upgraded RSFB but I wish I had. I think it depends on what dampers/spring rates you go with if all you plan on doing is coilovers and leaving the rest alone. In my experience you can cover up most of the problems with the 1er suspension with a quality damper, appropriate spring rates, and upgraded RSFB. And now I need to edit my original post to include the RSFB

[AtlRyan]

Able to find a dealer for the Swift Springs? Not having any luck :/

[chris82]

Originally Posted by AtlRyan

Able to find a dealer for the Swift Springs? Not having any luck :/

HP Autosport has them

[HP Autosport]

Originally Posted by AtlRyan

Able to find a dealer for the Swift Springs? Not having any luck :/

Really! All dealers are listed on Swift Springs official site.

A search function here should also net you some results.

[HP Autosport]

Originally Posted by MightyMouseTech

Honestly, I would say it is pointless to do springs and shocks before fixing the horrible soft bushings in the suspension.

After doing all the M3 arms and RSFB's, I almost see no point in changing the springs to something stiffer.

The OEM dampers are horrible. Over damped in compression and well under damped in rebound.

[MightyMouseTech]

Originally Posted by HP Autosport

The OEM dampers are horrible. Over damped in compression and well under damped in rebound.

That is why I said springs.

[HP Autosport]

Originally Posted by MightyMouseTech

That is why I said springs.

Upgraded springs and dampers will net better results than doing the bushings alone.

[chris82]

Originally Posted by HP Autosport

The OEM dampers are horrible. Over damped in compression and well under damped in rebound.

Not to jack OP's thread but isn't the compression the issue? Going over a series of bumps, it only takes a few before you run into the floaty/crashy feeling which I thought was due to the damper blowing straight through the compression stroke.

[HP Autosport]

Originally Posted by chris82

Not to jack OP's thread but isn't the compression the issue? Going over a series of bumps, it only takes a few before you run into the floaty/crashy feeling which I thought was due to the damper blowing straight through the compression stroke.

With worn out dampers that can definitely happen. With new dampers there is way too much compression.