Lowering?

[dpoorsBenz]

i am wondering wether or not to lower my 190e, i know you can get springs from ecp for around £65, but its only gonna be for the look (just wanna remove the cavern from the arches) nothing else, would it be wise if i were to go ahead to change all the bushes. opinions please.

 

[clive williams]

i am wondering wether or not to lower my 190e, i know you can get springs from ecp for around £65, but its only gonna be for the look (just wanna remove the cavern from the arches) nothing else, would it be wise if i were to go ahead to change all the bushes. opinions please.

dpoors,

Have a look at the thread lower down the page re "Some tw*t lowered my car et sec", which discusses at length the merits of lowering. However, if you must lower the car then its not just a simple case of exchanging springs:
1) Spring Rates. Are you going for a modest 25mm lowering or a fashionable 40mm lowering? Currently, your tired old (160K mls) springs will probably have around 140mm of full travel on the front springs (down from 160 ish), with a bump travel of ~60mm and droop of 80mm from static. You can see that lowering the car by 40mm reduces the bump travel to 20/40mm old/new springs respectively. This is ridiculously small amount of bump travel for our pot-holed and bump infested roads. The springs must be stiffened to cope with the static and full load so therefore the spring rates ought to be doubled to cope with the reduced travel distance. On rebound (or droop) this increase in spring rate creates a car which crashes over bumps and into pot holes upsetting the balance and safe driveability.
2) Dampers(shock absorbers). As the damper will have to control a spring of maybe 2x the standard rate over about half the stroke, its effectiveness is almost non-existant particularly considering its probably 160K mls old! Therefore, any lowering MUST be accompanied with new purpose designed short stroke dampers. If you misguidedly use the standard dampers you will run the risk (apart from underdamped suspension) of the shorter springs dropping out of their upper seat on droop with uncontrollable effects as they reseat or remain out of seat.
3) The Anti-Roll bar. This is a torsion device which provides a spring effect between the wheels of an axle. In a corner the wheels try to twist the roll bar in opposite directions. The rate of this twist is normally linear. If you half the stroke of the wheel for a given cornering load the loading on the anti-roll bar will be quartered i.e. half stoke each side therefore, it is only providing a quarter of the resistance to the roll. This can be off-set in part by the change to the roll centre of the axle so its not a simple linear equation.
4) Bushings and bump stops. The bushings and bump stops play a key role in controlling wheel movement and are designed to respond to normal wheel movements at the normal wheel rates i.e. damper and spring rates. For example in competition where a car has been lowered it is desireable to increase the bump stop rate to help control the spring over the last few mm of travel, but this adds extra stain on the mounting point of the damper. Bushes on lowered cars generally have to cope with greater shock loadings and are expected to compliment the handling benefits sought from lowering. your 160K ml bushes are well past their sell by date.
5) Under body protection. Lowering the car obviously reduces the ground clearence and increases the potential for damage over street obstacles such as street cushions etc. The ride height set by the manufacturers will be the safe height given the obstacles encountered and the maximum load height. Damaging a radiator/engine/gearbox/rear axle/exhaust/barake lines/fuel lines/underbody panels/propshaft will be expensive.
6) Suspension settings. It goes without saying that the amount of work even to change the springs will require the suspension resetting. What settings apply will be determined by whats been done and may involve personalised settings - do you know how to assess this?
7) Insurance. You have an obligation to inform your insurance company. Apart from loading the premium for the perceived 'boy racer' they may well require a full motor engineers assessment of the mofdifications. His assessment will probably be coloured in your favour if you can show a proper engineering understanding and application to the lowering. The better the job the less the premium hike.
8) Advertising. Finally, sgt Plod loves to screw 'boy racers'. Have a look at the recent police attention to the car customisers in Nottingham. I'd rather not have a car with all show and no go. My philosophy is "all go no show", its much more fun watching the faces of those with the opposite attitude when they are shown up by a 'standard' motor car.

If you must lower the car, then take a close look at what the manufacturers have done to provide their quick motor - in your case the Cossie - and copy some of their ideas.

Clive

500E Only the cognisenti know what it is/can do.
E320CDIT210

 

[dpoorsBenz]

Clive

Many thanks, I knew from other threads that it can be quite an ivolved bit of kit, suppose thats why there are specialist kits available at extra cost to cover the likely outcome

shaun