can you cut your bump stops down and what is bump streer ??

[Phat VR6 3]

Hello, Ive wound my car alot lower on my coilovers and after this my cars noticeably wont go round corners aswell as it used to and the ride has become really hard and bumpy, Over some bumps in the road at say 80 ive come out my seat about 5" lol

Do you think im resting on my bump stops? I was thinking and this would stop the dampers working and would exsplane the rubbish ride and handling??

The main question lol, Is it safe to cut my bump stops down in size?

Also what is bump steer? Ive hurd it said and that if you go two low so the wishbones angle upwards and not square than this causes it ? I always thought the lower you went the better the Center of Gravitly better round corners ect but it doesn't seem to be the case

Is there away to go LOW and have no bump steer and good handling ?

[Knightrider 1]

The steering arms from rack to wheel are designed to operate correctly within a range defined by the engineer who designed the suspension originally. By lowering the car excessively, you can take the steering arm angle outside that range. At this point the suspension geometry becomes badly impacted by bump steer. Whilst you have lowered the centre of gravity, the suspension is no longer working as designed. Bumps steer is due to the radii of the steering arm and the wishbone being disproportionate. As the suspension compresses the radii acts on the steering arm and momentarily steers the offending wheel.

There are various solutions like re-positioning the steering rack or more commonly changing the perpendicular position of the track-rod-end through pin.

Have a look here http://www.wheels-inmotion.co.uk/forum/index.php?showtopic=2549

The image shows a lowered car’s steering arms position as off horizontal (at theirabsolute upper limit) and you can clearly see the rod-ends through pin very extended in a perpendicular position.

[Knightrider 1]

Phat, all you ever wanted to know about bump steer and a lot you didn't here: http://www.longacreracing.com/articles/art.asp?ARTID=13

[Phat VR6 3]

spot on mate. so it looks like i can make it alot better than it is buy getting the track rod arms leave.

Any ideas how i could do this?

Do you think the really bumpy ride is down to bump steer or car resting on the bump stops? Personly i can't see anythink wrong with cutting them down a tad?

[Knightrider 1]

Hope that was useful Phat. I don't know about the bump stops, sorry. A bit like the guy at Balance Motorsport, I am on a slight mission to at least explain to folk that really slam their cars that it will actually screw the handling - probably looks good though!!

[VR6 VDF 0]

There was a thread on the uk-mkivs forum about lowering and handling.

There was a company doing some research and developing some coilovers I think for the 20v turbos. They used one of the guys cars form the forum, installed the kit they developed and aligned it all up getting the suspension geometry perfect and done some corner weighting/balancing thing aswell, then tested it out on the track.

Anyway, The outcome from the research was that the best handling came when the car was actually sitting quite high! like 4x4 style lol, anything lower than that and the handling started to deteriorate. So you cant really go low in a road car and have good handling unless you re-jig how the suspension geometry sits.

Also with the bump stops, I work as an engineer and I dont know about cars but, whenever we design end/bump stops for something, its usually meant to stop something going to the point of catastrophic failure!! i.e. the stops keep it within the safe limit so no i personally wouldn't recommend cutting them!! lol u nutta!!

[VR6 VDF 0]

Hope that was useful Phat. I don't know about the bump stops' date=' sorry. A bit like the guy at Balance Motorsport, I am on a slight mission to at least explain to folk that really slam their cars that it will actually screw the handling - probably looks good though!!

[/quote']

Yea I think it was balance motorsport that were developing the kit that I mentioned earlier.

[Phat VR6 3]

There was a thread on the uk-mkivs forum about lowering and handling.

There was a company doing some research and developing some coilovers I think for the 20v turbos. They used one of the guys cars form the forum' date=' installed the kit they developed and aligned it all up getting the suspension geometry perfect and done some corner weighting/balancing thing aswell, then tested it out on the track.

Anyway, The outcome from the research was that the best handling came when the car was actually sitting quite high! like 4x4 style lol, anything lower than that and the handling started to deteriorate. So you cant really go low in a road car and have good handling unless you re-jig how the suspension geometry sits.

Also with the bump stops, I work as an engineer and I dont know about cars but, whenever we design end/bump stops for something, its usually meant to stop something going to the point of catastrophic failure!! i.e. the stops keep it within the safe limit so no i personally wouldn't recommend cutting them!! lol u nutta!!

[/quote']

haha Yep you got a good point there. Think ill leave my bump stops as they are lol, If you think thats been a nutter ive been looking at a spare front sub frame with a grinder in my hand and scratching my head lol. Simply can't be done tho due how the front wishbone mount bolts onto the sub frame and chassis of the car :-(

Starting uni in September to do automotive engineering so that should teach me some useful stuff

atm tho it looks like my only options are, jack it back up again which i really don't want to do and thats it really lol

One thing i can do tho to make it better is take the track rod ball joint out and turn it round so it goes in the other way. All though this would mean welding up the hole in the hub knuckle and getting it tapper d from the other side, Would an engineering place be able to do this do you think?

[craggsy 91]

Its not just about lowering the car to make it handle.....ARBs, and poly/ OEM bushes, geometry etc

[Knightrider 1]

Why not set the coilovers to a height where the lower wishbone and steering arm are parallel to the ground? I've not used coilovers so I don't know how much of a mission that would be. Then see how it handles.

[ingham 5]

Why not set the coilovers to a height where the lower wishbone and steering arm are parallel to the ground? I've not used coilovers so I don't know how much of a mission that would be. Then see how it handles.

thats what i did and it handles great(camber set to -1.6)

[vr6newcomer 1]

the car will be more bumpy the lower you take it, simply because you are putting more pressure on your components, so its on new suspension, but do you have new bushes, ARB's all round, its all part of seup.

[Phat VR6 3]

ive got new polly bushes all round, Still need ARB. Before i wound it down more the wishbones where pretty much level and it handled great, Ive lost all that since i went alot lower. What i wanted to do was work see if theres any way of going silly low while keeping the handling but it looks like there isn't