Changing springs in matched suspension

[Lionflyer]

hi, my car currently comes equipped with a Sachs sports suspension setup installed by the previous owner. I find it too stiff and too lowered, resulting in bottoming out at the fenders. As I don't want to roll the fenders, I was thinking whether is it possible just to change the springs instead of the entire setup.

 

I understand the Sach set was a matched suspension. I am thinking of using stock springs or maybe Bilstein. Not sure if Eibachs / H & Rs are available.

[Yc86]

If it bottoms out, it's not too stiff.

 

If it's a height adjustable coilover, depending if it's adjusting via preloading the spring (not so good as it takes up some travel of the damper) or changing the length of the damper (better), you can just raise the car. Depending on whether your spring is linear (it's never really linear) or progressive, you could be stiffening up the car more, helping in the bottoming out issue.

 

Yes lowering the car will lower the CG, which affects the car heaps. but most of the time, you also lower the roll center, which lowers the effective spring rate that you have. The severity depends on the config of suspension you have (double wishbone or mcpherson). Therefore, you have a stiff set of springs which are not really stiff.

 

And yes, shocks are matched to the springs (wheel rate actually). If you have stock springs with an aftermarket (stiffer) shocks, you might be running an over damped system which would be slower in response. Would be more useful to know the damping rates than the brands, although i don't think its available and tbh, most drivers might not even feel the difference.

 

btw, if you use the stock springs with the current damper, your ride will be scraping the floor. The length of the damper and spring stiffness controls your ride height. so if u don't want to go stiffer, u have to change the height of the damper.

[Lionflyer]

thanks for the reply. it is very useful.

 

My main problem is that the tires are hitting the fenders, resulting in deep cuts on the tires. I would probably be changing the tires but it does not make sense if I don't solve the root cause. The stiffness issue, I think I can still accept. What do you mean by scrapping the floor?

[Bulls_is_back]

For bilstein shocks, B4 are OE replacements, B6 are sports (stiffer) and B8 are sports+lowering.

If your springs are stock currently, you should be replacing the sach with B4 or B6 to restore the ride height.

 

Are your rims aftermarket. The larger width and offset may also be the cause of tyre rubbing fender.

Edited December 25, 2010 by Bulls_is_back

[Itsec]

ur worries are stiff suspension or bottom out or tire bua fender or all????

[Good-Carbuyer]

That may not be the only reason the previous owner sold the car. Some people simply instruct the workshop to modify without clear idea what they said. When the result is not what they wanted, they sold it off. My got roof spoiler installed when the previous owner sold it. Could be among reasons I never managed to achieve the AD advertised FC, even by surcharging the tire inflation 20%

[Yc86]

The root cause is your car is too low (assuming you're on reasonably sized rims and not 20"s). If you want to solve from there, you need to increase your ride height.

To increase your ride height, you can change it via:

 

- screwing the shock body/spring perch if it's a height adjustable coilover unit

- change the spring to a longer one with the same stiffness (or keep the same length with higher stiffness)

- or change the damper to one that has a longer body.

 

If you want to solve from the consequence, u can roll your fenders, change the rims to a smaller offset one so it sits inside the fender, or dial in more camber if it clears just nicely, or change your wheel size.

 

Personally I would prefer solving from the cause since rolling around with wheels scraping the fender or even inside it shows poor tuning.

 

If you're using Sachs, they're good stuff and should be a height adjustable. You'd probably be better off taking them to a good workshop where they have the tools and can ensure that the 4 dampers are adjusted to the same height. Remember to get a wheel alignment after as camber/toe might change.

 

a small vid to show roughly what I was talking about, not perfect but gives an idea:

[Lionflyer]

Thanks. I am running 17" BBS RC rims and I think 35mm offset on 235/45 tires. Think new springs are in order.

 

http://rimier.com/eshop/item.php?item=1626&cat=478240

[Hondauto]

If it bottoms out, it's not too stiff.

 

If it's a height adjustable coilover, depending if it's adjusting via preloading the spring (not so good as it takes up some travel of the damper) or changing the length of the damper (better), you can just raise the car. Depending on whether your spring is linear (it's never really linear) or progressive, you could be stiffening up the car more, helping in the bottoming out issue.

 

Yes lowering the car will lower the CG, which affects the car heaps. but most of the time, you also lower the roll center, which lowers the effective spring rate that you have. The severity depends on the config of suspension you have (double wishbone or mcpherson). Therefore, you have a stiff set of springs which are not really stiff.

 

And yes, shocks are matched to the springs (wheel rate actually). If you have stock springs with an aftermarket (stiffer) shocks, you might be running an over damped system which would be slower in response. Would be more useful to know the damping rates than the brands, although i don't think its available and tbh, most drivers might not even feel the difference.

 

btw, if you use the stock springs with the current damper, your ride will be scraping the floor. The length of the damper and spring stiffness controls your ride height. so if u don't want to go stiffer, u have to change the height of the damper.

 

 

 

very chim to me.

[Tune2themax]

hi, maybe you can try rolling your fenders a little?