What Spring Rates Are You Running?

[3002 tii]

Just curious to know what spring rates some of you are using. Can you specify

1) Chassis and motor (roadster vs coupe, m54/n52/s54)
2) Which coilover brand?
3) What size springs and rates front/rear?
4) Is your car track only or street & track?
5) What kind of events and how many events per year? (ie, auto-x, DE, TT, club racing)
6) Are you using aftermarket swaybars?

Trying to get a better understanding of what rates people are using and what they find to be most effective (given the type of driving they do).

[3002 tii]

I'll start...

1) coupe, n52
2) AST 4100
3) front: 6" 550#, rear: 5.5" 650#
4) street & track
5) DE events, 10 days per year
6) H&R front sway full stiff, stock rear, (sway mounting reinforced)

[seank]

What a great thread. I hope others will add their info.

[mfanatic325]

1) coupe, S54
2) TCL D/A
3) front: 500#, rear: 500#
4) street & track
5) DE events, <= 8 days per year
6) stock oem swaybars

I had an option of 450# or 500# front spring rates when I bought the TCKs, and I opted for the stiffer ones.
So far as good, even though rears are supposed to be stiffer

I have no idea about spring height, but if I had to guess, maybe 6" fronts, and 5" rears?

[dorifto88]

e86 s54
ground control coilovers
12k rear, 10k front (6" front, 5" rear)
street and track
auto-x, and maybe track days if money comes up
stock swaybars

[mfanatic325]

^ So that's like 560# fronts; 672# rears Mike. Since 1 kg/mm = 56 lbs./in

[dorifto88]

yup =)

[seank]

Interesting that everyone so far has stock sway bars. I assume they have adjustable linkages. And why did everyone decide to not increase sway bar diameter or get one that is adjustable?

[mfanatic325]

Originally Posted by seank

Interesting that everyone so far has stock sway bars. I assume they have adjustable linkages. And why did everyone decide to not increase sway bar diameter or get one that is adjustable?

Perhaps I'm not at a level yet where I could put uprated sways to full use, but I feel like the car doesn't need it the way it is right now

In fact, if I were to do it all over again, I would spend another year tracking on bone stock suspension first before putting an uprated system in. I only tracked the car three times in stock form prior to putting my TCK D/As in.

Maybe it's also because my training wheels was my MR2 turbo, which has quite different vehicle dynamics; and when I hopped in the Z4M, even in bone stock form, I found it ridiculously easy to control in comparison
I just feel like honestly the car is already damned good, especially for a good 80-90% of trackers out there (as most people aren't even good enough to need any uprating; myself included of course)

[jmillet]

2007 E86 Z4MC S54
TCK DA coil overs with 500#F and 600#R. TCK camber/caster plates.
Primarily track but does see some limited street use.
Instruct at BMW CCA and PCA driving school events; about 12 track events a year.
Running stock sway bars.
For track use run Toyo R-888 tires and PF-06 brake pads.

Originally Posted by Dubbedown

Just curious to know what spring rates some of you are using. Can you specify

1) Chassis and motor (roadster vs coupe, m54/n52/s54)
2) Which coilover brand?
3) what size springs and rates front/rear?
4) Is your car track only or street & track?
5) What kind of events and how many events per year? (ie, auto-x, DE, TT, club racing)
6) Are you using aftermarket swaybars?

Trying to get a better understanding of what rates people are using and what they find to be most effective (given the type of driving they do).

[The HACK]

2006 MZ4 Coupe
Ground Control School/Track kit, single adjustable Koni with GC camber plate.
440#" front, 550#" rear
Driven on street once a week, otherwise all track
HPDE, 8-10 days a year (used to be around 20days but a 4 year old child has pretty much ruled THAT out)
OE Swaybars

[AUTOX08MC]

1) Chassis and motor (roadster vs coupe, m54/n52/s54): 08 M Coupe
2) Which coilover brand? Ground Control w/Ground Control Camber Plates
3) what size springs and rates front/rear? 440 F 650R
4) Is your car track only or street & track? Some Street/Many Autocross
5) What kind of events and how many events per year? (ie,20-25 auto-x)
6) Are you using aftermarket swaybars? Ground Control Med Front (set to full stiff) Soft Rear set to full soft
7) Hoosier A6 285/30/18 all around on 18 x 9.5" 35mmoffset front with 3mm spacers, 18 x 10" rear 25 mm offset rear ride height 1/4" higher than stock for autocross

[seank]

jmillet

Nice pic, but do you have any figures for us?

[F360C]

1) E86 S54
2) Ground Control
3) 600lbs 6" front and 750lbs 5" rear
4) Track/autox/fun street driving it does it all
5) 10 tracks days last year and many autox's
6) Ground control front and rear bars but I took the rear bar out and I am currently running no rear bar. Traction was improved with the elimination of the rear bar.

I think in the near future I will be going with 700lbs front and 850lbs rear.

[dorifto88]

Originally Posted by F360C

1) E86 S54
2) Ground Control
3) 600lbs 6" front and 750lbs 5" rear
4) Track/autox/fun street driving it does it all
5) 10 tracks days last year and many autox's
6) Ground control front and rear bars but I took the rear bar out and I am currently running no rear bar. Traction was improved with the elimination of the rear bar.

I think in the near future I will be going with 700lbs front and 850lbs rear.

do you have the 'stock' rear height adjusters with that 5" spring? ive always been really scared because the 5' spring can come off completely when the wheels are in the air and the parking brake released.

[F360C]

Originally Posted by dorifto88

do you have the 'stock' rear height adjusters with that 5" spring? ive always been really scared because the 5' spring can come off completely when the wheels are in the air and the parking brake released.

Yep running the regular GC rear adjuster. Never had a problem with the spring coming off yet.

[z3papa]

1) Chassis and motor (roadster vs coupe, m54/n52/s54) -- M5430
2) Which coilover brand? AST 4200
3) what size springs and rates front/rear? 6"x570#F/5.5"x683#R
4) Is your car track only or street & track? Mixed street and autox with occasional track
5) What kind of events and how many events per year? (ie, auto-x, DE, TT, club racing) +25 autox
6) Are you using aftermarket swaybars? H&R fronts/OE rear

[runnerx]

1) E85 S54
2) Ground Control Track School kit with race camber plates
3) 500lb/in front / 600lb/in rear
4) primarily track, but probably street driven once or twice a week
5) ~10 track days per year
6) OE sway bar

[Z///Ms]

2006 E86 Z4MC s54)
Bilstein PSS10
Track Car
Instruct at BMW CCA driving school events; about 15 track events a year
GroundControl swaybars front and rear.
Tuner camber plates, solid rear bushings, BFGoodridge R-1 tires with PF-01 brake pads.

[pal]

Very interesting thread. Here is my information and I have a question as to why you all are running a higher spring rate out back?

(1) 2007 Z4MC, S54
(2) KW Clubsports
(3) Stock KWC springs- 400lbs front and progressive rear
(4) Street (weekends and occasional wkdy) & track
(5) DEs - 10-16 days a year (8-12 events)
(6) Stock sways

(7) PS2 tires (31psi front/30psi rear- cold)
(8) No camber plates; using Turner washer kit to get around -2.3° front; -1.8° rear.
(9) Happy with the setup so far- comfy enough on the street and great on track. Want to reduce roll some more and increase mechanical grip so plan to go for 450lb front and ?? rear this winter for next year.

[Spreadsheet]

1) Chassis and motor (roadster vs coupe, m54/n52/s54) - Z4MC
2) Which coilover brand? - AST4100
3) What size springs and rates front/rear? - 550lb Front/650lb Rear
4) Is your car track only or street & track? - Street, about 8-10K a year
5) What kind of events and how many events per year? (ie, auto-x, DE, TT, club racing) - 1 to 2 auto-x a year
6) Are you using aftermarket swaybars? - No, but considering Ground Control swaybars

What you didn't ask:

7) What camber/caster units are you using - Vorslag
8) Are you happy with the system you are using? - Yes. Once past 'walking speeds', suspension is really more comfortable than stock. More noise comes in due to less rubber isolation, but true seat in the pants feel is better road isolation.

[TSM330i]

Anyone know what the spring rates should be for a full-blown race car? No street driving at all.
More than likely, going to run AST4200 or 5200.
This would be for a non-M.
Thanks