Useful suspension links

[_Ryan_]

Hi,

After a discussion with another member I told him I would collate some reading for him, so figured I would make it public!

I've owned a few cars (10+), mostly modified. One topic that is often misunderstood is what constitutes a good shock absorber, or 'coil-over'. Rather than reinvent the wheel, i am going to start a thread with some recommended reading and when I have more time will provide a summary of options for BMW's and who they might best suit. (Note, if you track your car, chances are my comments will be of little value although the links I provide might be). Most of my experience comes from 10yrs in the car scene and many a discussion with some of the better suspension engineers in Australia.

Start here:
http://farnorthracing.com/autocross_secrets.html ($#@!loads on dynamics and shock selection, why adjustable is often $#@!, read the shock stuff!)
http://www.skylinesaustralia.com/for...kabsorber-101/ (Entry level post on shock design)
http://www.skylinesaustralia.com/for...ing-rates-are/ (basics of working out spring rates)
http://www.ozebiz.com.au/racetech/theory/wttrans.html (Dynamics 101)
http://phors.locost7.info/contents.htm (More in depth Dynamics/Physics)
http://www.carbibles.com/suspension_bible.html (Suspension parts)
http://www.ozebiz.com.au/racetech/theory/align.html (Alignment)
http://www.modified.com/tech/0605_sc...5/dampers.html (Damper tuning)
http://www.modified.com/tech/0607_sc..._stick_part_6/ (Monotube stuff)

Notes:
(The threads on SAU were written by Gary Cook, a suspension engineer whom designer most of the older items in the Whiteline catalogue)


Cliffnotes-
- Bilstein > most for a street car
- Bilstein B14 PSS > Bilstein B16 PSS9 due to adjuster design
- Bilstein B16 PSS10 > PSS9
- Bilstein B14 PSS + Swift/Hyperco springs and revalve are a great budget option
- KW are built using Koni (IIRC), Koni are meh.
- Ohlins are great, the above custom option MIGHT be better value for money if you have access to a suspension engineer
- Adjusters don't often do what is advertised
- Don't believe marketing.
- The guy writing this post has owned: Bilstein, Koni, Tokico, Tein, KYB and driven many more. He has also gotten to the point of having parts CNC machined to get the geo he wanted.
- Good shocks: Bilstein, Koni, Ohlins, Penske, Sachs, DMS, MCA, Proflex, Moton

If you already knew more than the aforementioned links provide, feel free to add value rather than flame.

-R.

[Sticky]

I may sticky this, great stuff!

[_Ryan_]

What should I buy? (AKA, Which coilovers do I need?)

You should buy the product that suits your requirements.

What product suits my requirements...

...If I want to spend <$USD1k, don't need height adjustability

- Bilstein B12 Sport or Pro kit (B8 with matched springs)
- Koni dampers with <insert spring kit>

...If I want to spend <$USD1.5k and need height adjustability

- SpeedTech/ST Coilovers: Twin-tube, Height adjustable
- KW Street Comfort: Twin-tube, Height adjustable
- KW V1: Twin-tube, height adjustable
- Bilstein B14 PSS: Monotube, height adjustable
Where is the damper adjustability? Chances are it is $#@!, doesn't work, or you don't need it. OR you didn't read the above links.

What if I MUST have damper adjustability because <insert some forum expert> said so, or <some brand> says I need it or <super person> has it? $USD2k+

- Ohlins
- Bilstein B16 PSS10 (PSS9 have $#@! adjusters)
- KW V2
- KW V3
- KW clubsport
- AST
- DMS
- Maybe I should go and speak to a pro suspension shop before i drop 2k+


What about adjustable stuff? post later...


As always, check your local laws, insurance etc before modifying, don't blame me.

[Sticky]

What should I buy? (AKA, Which coilovers do I need?)

You should buy the product that suits your requirements.

What product suits my requirements...

...If I want to spend <$USD1k, don't need height adjustability

- Bilstein B12 Sport or Pro kit (B8 with matched springs)
- Koni dampers with

...If I want to spend <$USD1.5k and need height adjustability

- SpeedTech/ST Coilovers: Twin-tube, Height adjustable
- KW Street Comfort: Twin-tube, Height adjustable
- KW V1: Twin-tube, height adjustable
- Bilstein B14 PSS: Monotube, height adjustable
Where is the damper adjustability? Chances are it is $#@!, doesn't work, or you don't need it. OR you didn't read the above links.

What if I MUST have damper adjustability because said so, or says I need it or has it? $USD2k+

- Ohlins
- Bilstein B16 PSS10 (PSS9 have $#@! adjusters)
- KW V2
- KW V3
- KW clubsport
- AST
- DMS
- Maybe I should go and speak to a pro suspension shop before i drop 2k+


What about adjustable stuff? post later...


As always, check your local laws, insurance etc before modifying, don't blame me.

repped

[Jaxon]

Very helpful. Thx for sharing! I'd rep ya if I had the power.

[Sticky2]

Bumping this

[mjmarovi]

Great stuff! I was thinking KW or BC Racing before this thread...now I'll still be looking at KW, but Ohlins and Bilstein as well. I will say I have some Bilstein adjustable shocks on my truck and they made such a huge improvement!

[R.G.]

One of my favorite threads of all time. Well done @_Ryan_

Love when info that's parroted from one guy to the next gets put to the test.

[_Ryan_]

Great stuff! I was thinking KW or BC Racing before this thread...now I'll still be looking at KW, but Ohlins and Bilstein as well. I will say I have some Bilstein adjustable shocks on my truck and they made such a huge improvement!

What are your requirements?

One of my favorite threads of all time. Well done @_Ryan_Love when info that's parroted from one guy to the next gets put to the test.

Thanks. I'll add some more content as I do my next round of mods.

[_Ryan_]

Rear subframe
OEM rear subframe bushes for non-M cars are liquid filled trash.
Whiteline do a poly lock kit for under $100 which can be fitted without removing the subframe (requires loosening)
OEM M3 bushes are rubber, approx. $300 and require more effort to fit

I personally went with the Whiteline kit and can report that it improves rear end feel, stability and traction. I test my car on the mountain upon which I reside- I don't have to push my car to notice the difference.

[_Ryan_]

Spring rates
(note- admin removed the link to the other forum and pasted the text)

Stock

135i
Front: 120 lb/in
Rear : 350 lb/in

e90 ZSP or e92
Front: 145 lb/in
Rear: 460 lb/in

e90/e92 BMW Performance (Calculated given that the material of this spring is the same as the ZSP springs)
Front: 195 lb/in
Rear: 505 lb/in

M3
Front: 160 lb/in
Rear: 550 lb/in

Aftermarket

KW v1-v3 (non M3)
Front: 190-256 lb/in (progressive average)
Rear: 545-570 lb/in (progressive average)

KW Street Comfort
Front: 286 lb/in
Rear: 572 lb/in

KW Clubsport (non M3)
Front: 400 lb/in
Rear: 570 lb/in

M3 KW v3
Front: 285 lb/in
Rear: 630 lb/in

M3 KW Clubsport
Front: 508 lb/in
Rear: 800 lb/in

Bilstein PSS10
Front: 385 lb/in
Rear: 615 lb/in

Eibach Pro-kit
Front: 148 lb/in
Rear: 456 lb/in

Eibach Multi-Pro-R1
Front: 200 lb/in
Rear: 500 lb/in

Eibach Pro Street S
Front: 134 - 271 lb/in (Progressive)
Rear: 456 lb/in (Linear)

HKS Hypermax
Front: 448 lb/in
Rear: 504 lb/in

Tein Stech
Front: 191 lb/in
Rear: 593 lb/in

Tein Euro Damper System
Front: 280 lb/in
Rear: 392 lb/in

Tein ss-p
Front: 392 lb/in
Rear: 671 lb/in

JIC-Magic Cross
Front: 450 lb/in
Rear: 674 lb/in

TC Kline Coils
Front: 350 lb/in
Rear: 700 lb/in

HP Autowerks Coilover System
Front: Custom Tailored 300-500 lb/in (Contact HP Autowerks)
Rear: Custom Tailored 500-1000 lb/in (Contact HP Autowerks)

[_Ryan_]

Increased camber( & feel)
These cars feel crap standard, front camber is woeful. Before going down the path of front strut tops (personally I would do this with a change of springs) I invested in the TRW arms.
Advantages of these arms:
- More negative camber
- Lighter
- Stronger/stiffer
- Solid bushes
Disadvantages
- Increased noise transmission
Dynamics
- Improved turn in, feel, stability

You can compare the price of BMW to OEM TRW here: http://www.ecstuning.com/BMW-E82-135...011_2012_2013/

[mjmarovi]

What are your requirements?Thanks. I'll add some more content as I do my next round of mods.

I want something that will add traction for me in the rear, work for a possible autocross day down the road, and be fun on the street without being uncomfortable on a 1-2 hour road trip

I did some more looking around after reading your post and am currently liking the Bilstein PSS10 system. My thoughts are damper adjustment would be nice so that in the rare instance I would go to a road course day or something I could stiffen them up for the day. Is that correct thinking?

[mjmarovi]

Increased camber( & feel)
These cars feel crap standard, front camber is woeful. Before going down the path of front strut tops (personally I would do this with a change of springs) I invested in the TRW arms.
Advantages of these arms:
- More negative camber
- Lighter
- Stronger/stiffer
- Solid bushes
Disadvantages
- Increased noise transmission
Dynamics
- Improved turn in, feel, stability

You can compare the price of BMW to OEM TRW here: http://www.ecstuning.com/BMW-E82-135...011_2012_2013/

I plan on doing both TRW kits when I do the coilovers, I was looking that up awhile ago on Turner Motorsports, similar pricing if I recall

[_Ryan_]

I plan on doing both TRW kits when I do the coilovers, I was looking that up awhile ago on Turner Motorsports, similar pricing if I recall

Yeah, pricing is consistent. Was just an example. Don't forget to grab the hardware- it is recommended by BMW to replace it as they are stretch bolts.

[_Ryan_]

I want something that will add traction for me in the rear, work for a possible autocross day down the road, and be fun on the street without being uncomfortable on a 1-2 hour road trip

I did some more looking around after reading your post and am currently liking the Bilstein PSS10 system. My thoughts are damper adjustment would be nice so that in the rare instance I would go to a road course day or something I could stiffen them up for the day. Is that correct thinking?

Budget? For PSS10 money I would look at Ohlins DFV too. Drag traction is a very different setup to auto-X...

[mjmarovi]

Budget? For PSS10 money I would look at Ohlins DFV too. Drag traction is a very different setup to auto-X...

Having troubles finding pricing on Ohlins. Budget is ~$2k.

Turner has the PSS10 for just under $2k. Can't find much for how well their EDC system works and if it's worth an extra $500, I'm thinking a no go on that.

http://www.turnermotorsport.com/BMW-...uspension.aspx

[_Ryan_]

Having troubles finding pricing on Ohlins. Budget is ~$2k.

Turner has the PSS10 for just under $2k. Can't find much for how well their EDC system works and if it's worth an extra $500, I'm thinking a no go on that.

http://www.turnermotorsport.com/BMW-...uspension.aspx

Let's take this to PM or a new thread to avoid taking away from the intended purpose of this thread- reference.

HPA stock Ohlins but unsure how much. That PSS10 price is great. Perhaps try and go for a ride in PSS or PSS10 before you pull the trigger?

[alex@ABRhouston]

You mean some Öhlins, like this?

[R.G.]

Rear subframe
OEM rear subframe bushes for non-M cars are liquid filled trash.
Whiteline do a poly lock kit for under $100 which can be fitted without removing the subframe (requires loosening)
OEM M3 bushes are rubber, approx. $300 and require more effort to fit

I personally went with the Whiteline kit and can report that it improves rear end feel, stability and traction. I test my car on the mountain upon which I reside- I don't have to push my car to notice the difference.

Considering the whiteline kit for my diff. Wish I would have known about them before I jumped on the M3 subs. Rear is still too wiggly on hard accel. It's gotten a bit worse so I'm assuming my stock diff bushings are about ready to be replaced.