coil-over

[romkasponka]

what do you think? F500/R450 lbs/in

http://img134.imageshack.us/img134/6207/surinkimasvh2.jpg

[Gunni]

according to the internet the ratio of the rear springs is .65
100lbs work as 65lbs and so on,

500front and 292lbs doesn´t sound right,
What are you basing the numbers on?

Also if the sleeve is more then 51mm it will fit, I had a 51mm sleeve opened up by 1mm the other day to make things fit

[romkasponka]

The rear will be direct fit on the damper. So the ratio will be ~1,1 or more.

suspensio frequency wiil be F 163 cpm, R 186 cpm.

[Gunni]

Well in that case,
I belive I read on the gustave site or elsewhere that the rear needs a little more stiffness then the front to neutralize understeer tendency

[romkasponka]

In my case efective stiffnes is F500/R540

[D. Clay]

What about the upper shock mounting area. You're gonna need beef! 500+ pounds/inch into that? Get out the welder!

[romkasponka]

I'm thinking about rear strut bar.........

[romkasponka]

What about the upper shock mounting area. You're gonna need beef! 500+ pounds/inch into that? Get out the welder!

What do you mean by saying beef? Sorry for my poor english.
I found that M3 had 685/1027. :D

[Gunni]

In my case efective stiffnes is F500/R540

Could you explain why you get that effective ratio?

[romkasponka]

rear shock is mounted behaind halfshaft, so the shock lever is bigger than wheel lever.

[Gunni]

could you explain the painting a little bit more?
where exactly are you thinking about mounting the rear shock?

[romkasponka]

http://img105.imageshack.us/img105/7303/strutbarsb5.gif

http://img105.imageshack.us/img105/485/scanneditems034oa1.jpg

http://img163.imageshack.us/img163/5337/rearcoilover1ld9.jpg

[Gunni]

If you use a strut brace in the back you will probably need to add strenght from it to the body with welding,

[D. Clay]

What do you mean by saying beef? Sorry for my poor english
As in the expression "beef it up". Meaning to reinforce, brace, and strengthen. It may be a US expression. All of the rear suspension load will be entering the structure at the upper shock mount. It was designed for the shock only and not the shock and spring load.
Here's a link to a picture and text explaining some of the ratios discussed above:
http://e30m3performance.com/tech_articles/susp-tech/eff_rate/eff_rate2.htm
This is the best article I am aware of. Note on the first page the author indicates that his earlier determination was in error. Suspension is art, craft, science, and voodoo.

[romkasponka]

http://e30m3performance.com/tech_articles/susp-tech/eff_rate/eff_rate2.htm
This is the best article I am aware of. Note on the first page the author indicates that his earlier determination was in error. Suspension is art, craft, science, and voodoo.

Yes, I know this article.

I would like to be a woodoo master :)

[2002maniac]

sounds good! My effective spring rates are 400/422 (using the .65 calculation for the rear) and I think the balance is perfect! are you going to build the setup yourself?

What about valving?

If I had the money, I know my car would bebefit by revalving the shocks.

[romkasponka]

front 300/300 rear 200/200, or 150/300 100/200. I will ask bilstein for best setup.

[D. Clay]

The short track stock car racers now use Penske adjustables. They put the car on a skid pad (a big circle) and spring it for desired wheel travel and neutral handling at max lateral G's. This results in a slight under steer in the real world. Then they use the shocks to fine tune the car. They now change springs 2-3 times a season instead of 6-8 times. In real terms, front engine sedans are almost always stiffer in the front than the rear. A 2600# stock car usually runs 400# front and 200# rear springs. A TransAm Camaro or Mustang. will run 500#-700# front and 250#-400# rears. E30's usually run with 15" wheels and tires with a soft spring rate. E30 types in general use springs to control body roll in place of sway bars. They put stiff springs on the rear and take off the rear bar.

[romkasponka]

How much cost penske adjustable shocks?

[D. Clay]

How much cost penske adjustable shocks?
http://www.lefthanderchassis.com/107.html
http://www.lefthanderchassis.com/108.html (http://www.lefthanderchassis.com/107.html)
http://www.lefthanderchassis.com/109.html (http://www.lefthanderchassis.com/107.html)
$200 to $1000 each depending on the model. I don't know of any adjustable valving strut inserts.

[romkasponka]

http://www.avouk.com/pm/123

[dino245]

The AVO struts are nice but the E30 has an itegral hub and strut so you would need to build a strut assy. with the axel stub onit.

[romkasponka]

AVO inserts nice too ;)

http://www.avouk.com/mediastore//IMG/10138.jpg

[romkasponka]

A 2600# stock car usually runs 400# front and 200# rear springs. A TransAm Camaro or Mustang. will run 500#-700# front and 250#-400# rears. E30's usually run with 15" wheels and tires with a soft spring rate. E30 types in general use springs to control body roll in place of sway bars. They put stiff springs on the rear and take off the rear bar.

Spring mean nothing, you should say frequency.

[Gunni]

could you explain why frequency make more sense then spring stiffness?

[romkasponka]

because to make setup you selecting suspension frequency which you want to have, after calculation you get wheel ratio, and only after you calculate spring ratio. Your wheel rate could be affected by suspension type and geometry, so spring doesn't mean nothing if we are talking about various cars, because you dont know what you get on the wheels.

[Gunni]

Can you give me an example of how you calculate diffrence frequencies using 2 E30´s? only diffrence beeing wheels and spring rates.

Thanks

[romkasponka]

http://hometown.aol.com/EURORALLY/Suspension1.htm

[romkasponka]

update :)

http://img140.imageshack.us/img140/7429/img0001mediumrd0.jpg

http://img266.imageshack.us/img266/3579/img0002mediumfu3.jpg

http://img266.imageshack.us/img266/4111/img0003mediumyc8.jpg

[romkasponka]

almost done :D

http://romkasponka.blogspot.com/2007/06/tuoj-bus-surinkimas.html

[romkasponka]

http://bp3.blogger.com/_MjQwpLOTuIM/RogW58XeqfI/AAAAAAAAAEw/A3_zlbYrV5Q/s1600/IMG_0081%2B(Large).JPG