help with suspension upgrade for bad roads

[tuj]

Hi all!

First off let me start by saying where I live has some BAD roads... serious potholes, wavy bumpy roads, etc. BUT...we also have a racetrack.

So I am seeking the best steet-able car for these conditions, that can turn into a time attack animal at the track.

Therefore, the logical choice is a set of full coil-overs with a wide range of damping. one problem I'm running into is that is seems all the coil-over sets lower the car by some amount. I don't think I want to lower the car at all, I need to maintain maximum ground clearance and suspension travel around town.

Impossible dream? Or can you guys suggest some options?

[2PUTT]

Budget also matters with this inquiry...

[tuj]

let's say around 2-3k.

[swagon]

M3 rear subframe bushings
Dinan rear shock mounts

Bilstein B16 PSS10 (20-40mm)
Öhlins R&T
TC Kline
KW V3

I've ordered KW V2's last week... So I can't say I have got experience with aftermarket stuff. You can search around, there are quite a lot of threads regarding aftermarket suspension.

[John_01]

BMW performance springs (T3 & T2 set), BMW performance bump stops, Koni yellow dampers.

Also suggest to add: Ground control street camber plates, 1M front strut brace, M3 front arms, M3 RSFB. Upgrade rear shock mount and Sway bars too.

[850tgul]

My Bilstein HD and Swift Spring combo, along with Dinan rear shock kit made my car much sharper AND more comfortable than the stock suspension. Also dropped my car maybe, maybe 0.25" from my sport suspension. You could also do rear subframe bushings and M3 front end bits for well under your budget.

[_Ryan_]

I drive on gravel/hard pack a few days a week, drive to work daily in a city with tram tracks (bad roads) and we used metal to join our tarmac on bridges.
I manage with approx 100mm ground clearance and the mods in 'my garage'.

What is your tolerance for these things? Your car will be a compromise given your wide range of conditions...

[tuj]

My main concern is bottoming out in places like speed bumps and thinks like that. And not getting stuck in a gigantic pothole! I could live with the car lowered daily maybe 0.25-0.5" but I would ideally like to get it lower than that at the track with adjustable perches?

I know the new Dinan/upgraded shock mounts are a good idea, that will give the car more travel. I already have the M-sport package.

[_Ryan_]

Originally Posted by tuj

My main concern is bottoming out in places like speed bumps and thinks like that. And not getting stuck in a gigantic pothole! I could live with the car lowered daily maybe 0.25-0.5" but I would ideally like to get it lower than that at the track with adjustable perches?

I know the new Dinan/upgraded shock mounts are a good idea, that will give the car more travel. I already have the M-sport package.

I haven't bothered with those shock mounts.

Speed bumps are manageable- don't go flying over them.

What is your current ride height (for context) ?

[tuj]

Originally Posted by _Ryan_

What is your current ride height (for context) ?

whatever a completely stock N55 M-sport is. Not sure exactly, but pretty high.

[_Ryan_]

Originally Posted by tuj

whatever a completely stock N55 M-sport is. Not sure exactly, but pretty high.

Awesome, unfortunately I'm too far away from your car to measure it for you.

[slonik]

we have bad roads in russia, and i prefer two brands - kw and bilstein.
if we talk about steering/comfort, i'd choose kw(or budget, st suspension).

sometimes i'm driving 135 on st xta and it works excellent.

also i saw how this 135 drives on b8 with stock m pack springs - on acceleration, after 200kmh i thought i'm starting takeoff. it feels like steering wheel work separately from wheels

[_Ryan_]

Originally Posted by slonik

we have bad roads in russia, and i prefer two brands - kw and bilstein.
if we talk about steering/comfort, i'd choose kw(or budget, st suspension).

sometimes i'm driving 135 on st xta and it works excellent.

also i saw how this 135 drives on b8 with stock m pack springs - on acceleration, after 200kmh i thought i'm starting takeoff. it feels like steering wheel work separately from wheels

Interesting, I live in what many would consider an almost-rural area and typically pick Bilstein over KW or Koni due to durability and valving consistency. That 135i probably needed an alignment.

[slonik]

Interesting, I live in what many would consider an almost-rural area and typically pick Bilstein over KW or Koni due to durability and valving consistency. That 135i probably needed an alignment.

theoretically, bilstein must work much longer on bad roads (cause they are upside down), but in real on our bad roads, i have no problems with kw or st, and bilstein starts knocking much earlier - it's some feature of these shock absorbers. they work good for a long time after that, but comfort goes away (some people try to put some greece into shocks body, it helps for 10-20tkm)

and, even if we don't take this bilstein future, kw settings works much better on bumpy and wavy roads.

[HP Autosport]

Both TCKR and Ohlins can be run at stock or lower height.

The other option is keep the stock springs, but replace them with Koni Yellows. The money you just saved can go to M3 bits to replaced the likely beat up OEM parts if the roads are really that bad there.

Don't forget a new strut top mount. Those get beat up with potholes.

[TheSt|G]

How much tracking are you going to be doing? If it's limited, Koni FSDs are pretty comfort focused.

[tuj]

hey Stig :-)

We do about 6 track days a year. So not a ton, it's not like every weekend, but it is enough were I want to start to improve my times. We are doing a track day this weekend and I'll be running bone stock again on the RFT's which are S L O W. I am hoping by our next track day in Aug. that I can get some sticky rubber and another set of wheels. I know the most time will come from tires.

[lowbudgethero]

I would change tires over any suspension work

[TheSt|G]

Well, the question really comes down to how hard you are pushing it on track. FSDs are pretty bad at the limit, but up to 80% or so they are fine.