Is there a way to make coilovers less bouncy?
 

Hi guys,

I have just fitted soem Apexi World sport coilovers and had 4 wheel alignment today. The handling is great, and I don't mind it being stiffer but the suspension seems really bouncy. Driving on a relatively smooth road at 80 feels like you are sitting on a bouncy castle whilst other people are bouncing.
I was justwondering if there is anything I can do to tone this down a bit? Or do I just have to suffer?

Thanks
Steve

Do they have adjustable damping control (they should have)
If so you need to tune the dampers to the spring rate.

This is trial and error, but not difficult.

Get the dampers to the softest setting.
Turn the adjustment to the opposite extreme and count the clicks (if that is how they 'feel') or the number of turns.
Could be 12 turns or 24 clicks, i don't know.

Lets say it is 12 clicks from soft to hard.

Set the fronts to 6 clicks and the rears to 4 clicks from 'soft'
That is a starting point.

BEFORE YOU BLAST OFF INTO THE DISTANCE, DRIVE THE CAR CAREFULLY AND FEEL WHAT IS GOING ON.

Click down the front and click down the rear equal amounts until it starts to feel 'ok'.
Then you can start to change the bias front to rear.

Usually there is a good general rule og thumb:

The rear spring rates need to be 80% of whatever the fronts are, so ie

Front rate = 250 Lbf/in, rears are 250 x 0.8 (80%) = 200 lbf/in

you should contact the installer too for help!

Hope that helps (I've been there...)

Graham.

Sorry mate, I completely forgot to mention, they are only ride height adjustable, not dampening :(
I can only make them harder or softer by changing the ride height and therefore compressing the spring more or less.
Just had another drive and they don't seem too bad. I don't do many long journeys so I guess I'll just deal with it for now.

My next problem is the front wheel bearings :( Both need replacing. Been quoted over £450 so far, but I'm sure I can get it done way cheaper than that. Found the bearings for £45 each on camskill.co.uk which is pretty good. Still might be able to do better than that.

Anyway, thanks for your help Graham.

Steve

Unless you mean you can change the preload on the spring, changing the ride height wont affect the spring rate at all.

Andy

Could the worn front wheel bearings be to blame by anychance..?

Scoobyclinic supllied and fitted my NSF wheel bearing for some change over £100 - give them a bell if you don't want to fit them yourself.

RE Camskil - I've bought Impreza parts from them for DIY fitting and they are excellent value for money:thumb:

I have booked the car in for both front wheel bearings to be changed at a local mechanics. He deals with a lot of performance cars and has only quoted £80 for labour so I should be looking at around £200 or so in total.

I had the front coilovers fitted for a couple of months before I did the rears and had the alignment done, so its my fault that the wheel bearings got knackered. The alignment was way out.

In response to Fuzz, I thought that by changing the ride height you are changing the length of the spring and therefore making it harder or softer?

Regards
Steve

No mate spring rate is set no matter how much you compress it

Changing the ride height only will not make the slightest difference as the car still weighs the same and will compress the spring the same amount no matter what the height.

Preload adjustment is a different matter though.


Andy

http://www.sidtech.co.uk/iu/Fantom022458462.jpg

These are the coilovers I have. By spinning the gold thing up surely I am compressing the spring making the car lower and the ride harder???
And spinning the gold thing down I am making the spring longer and therefore the car higher and the ride softer due to the extra movement the spring can make???

Maybe I am just being thick, that just how I thought it worked. Otherwise you could make the ride height so low that the car would hit the ground on fast corners unless the spring was harder to compensate??

preload does not change the spring rate only changing the spring to a stiffer or softer can do that. pre load alters the static sag if your springs to hard reducing preload will not alter it it will just give more sag or vice versa. more sag ie less preload will allow the dampers to work better if they are matched to the correct spring rate for the weight of the car and contents this should reduce the choppyness he is feeling

ie wind them gold spinny things down the legs a bit it wont make the ride hight change but will allow the units to work

ahhhhhhhhh, I see, so if I wind them down, it should feel a bit better.
I will have to try that. So how do you adjust the ride height then??

I give up. :brickwall:

:lol:

Hi,

By the sounds of it, you should leave the set-up of your car to professionals.........

The 'gold thing' on you dampers are the lower spring platforms. With these you adjust the rideheight. Wind them up - car goes up. Wind them down - car goes down.

Remember, when you change the rideheight, the alignment changes as well.

thats what I though jgevers, but accoding to struv:

"ie wind them gold spinny things down the legs a bit it wont make the ride height change but will allow the units to work"

no wonder I'm getting confused. People keep saying different things.

So I guess I should just drive the car and forget all about it then?

Steve

PS: Sorry for frustrating you Fuzz. I should have taken a coilover course at college, or maybe just have been born rich and maybe I wouldn't have this problem.

This topic is about basic common sense and understanding the mechanics of the suspension, and you don't have to be a rich-kid either.

Fuzz is dead right in what he says (he knows what he is on about).

The basic problem with your front end is that the springs are not being damped effectively.
I am sure the apexi system is adjustable for damping, so it may be possible to adjust the damping to stop the bouncing which is a dangerous condition for handling and braking.

If you want to get it all sorted you must seek professional advice (ie Fuzz) and they will know exactly what to look for.
This is not expensive (hence no need to be a rich kid).

You need to assure:

The dampers are in good condition (not leaking etc)
The spring rates fitted (you need about 50N/mm front/40 N/mm ) any harder and thing will get bouncy on UK B roads.
Ride height set to about 20mm lower than stock or stock height
A good alignment (ie by Fuzz)

From that starting point you will be able to tune the damping to the springs and the car will be great, smooth, tyres in contact with the road when it matters (ie all the time) and your eyeballs still in their sockets.

Coil overs can work on the road very very well I can promise you.

Hope this helps.
Keep asking the questions as this is how to learn; you will also find the people who understand and know what they talk about.

Graham.

Cheers Graham, I try to just give advise as I know it rather than as an employee of you know where, all gets far to political other wise and I would have to log in under works name.
They can take my advise or leave it, as they can with anyone else, maybe I was a little harsh with the headbang smiley, at the time it felt like "at least try to understand what I'm saying even if you dont take the advise"

Being a farmers son, I am hardly what you might call "well educated" :lol1:, just an ounce or two of common sense maybe.
and I think being £30k in debt makes me far far from being a rich kid. ;)

Andy

You need to determine: is it the car thats bouncing on the road (bad damping) or is the car planted on the road but you're bouncing in your seat due to stiff (too stiff?) suspension but springy seat?

Have a think about it.

if he is winding them upwards, he is preloading the springs to death, which will make it a bit crap TBH

Winding up would only increase preload if the suspension was running zero droop which is unlikely on a road car. In this case it only increases the ride height.

:notworthy

You should listen to these blokes Fantom :D

Andy

Bloomin heck. My comment about being a rich kid was not aimed at anyone. i was just saying that if I was rich then I wouldn't be playing about with a 94 wrx and second hand coilovers!

The suspension has just been fully aligned by Leda Suspension 6 days ago.

I can not adjust the dampening rates according to the guy who sold me them. The only adjustment I can make is by spinning the gold things up or down. People on here are telling me two different things, and no one is saying that anyone else is wrong.

The suspension is on the car exactly as it is in the picture I've posted.
So what do I do? Spin the gold things up 1 inch and test? or spin them 1 inch down and test??
I just want to know which way is more likely to help solve the problem.

I have no idea what the sping rates are btw.

I also have to clear up one thing, considering people keep contradicting each other. Spinning the gold thing up or down is how I adjust the ride height. Correct?? And the lower the car goes the harder the suspension will get. The higher the car goes the softer it will get. Correct??
If not, why not? If the spring is already crushed, the suspension is gonna be bloody hard, as there will be little movement in the spring. No? And the opposite if the spring is hardly crushed at all.

Anyway, I really would like to see if I can make it better.

Another clue. I am sure that the car feels less bumpy when I had 4 people in the car, and worse when I am on my own. Is this possible? Or am I just imagining it?

Thanks for everyones advice btw.

Steve

Another thing..........

I fitted the front coilovers about 2 months before the rears. I didn't get them aligned and thats obviously why I ended up with knackered wheel bearings.
However, the car felt a lot better back then than it does now. The front was stiff and felt good but the car didnt bounce me about like it does now.
So maybe the rear is too stiff and needs raising a bit?
Here are a couple of pics..........Does the rear look too low?

http://www.sidtech.co.uk/iu/Fantom698455937411.jpg
http://www.sidtech.co.uk/iu/Fantom76947948817.jpg

Steve:

The gold rings are adjutable spring collars.
If you wind them up the strut the car will go up almost by the same amount, and to lower the car wind them down.

If you wind them UP until the springs have no play in them then that is about as high as the car can go. reasonably.
If you continue to wind the rings up the springs will be pre loaded..don't go there.

OK, the car now looks like a gravel rally car.

In my opinion, an Impreza is best when the car is 20mm lower than standard. This standard height can be measured in several ways, but easy one is from the road to the apex of the wheelarch.
Find someone on here who can tell you what their standard height is and wind the gold rinds up or down until you get standard height minus 20mm.

That done (this is probably what LEDA did) the car is set right.

Drive the car.(carefully)

If LEDA set it as I say above then the overall geometry will be good.

If you wind the ring up or down from the position they were set to when alignment was done the alignment WILL be affected, especially the toe angle.

If the toe andles are not right the car will be 'nasty' to drive when pressing on.

Winding the rings up or down in the way I say will NOT harden or soften the suspension.

Springs do that, and damping rate of the dampers stop the springs from bouncing up and down (generally speaking).

To get the car back to a normal position you need to get it back to LEDA spec. They will tell you where they set the ride height.

If after all this the car bounced and nods down the road, the damping is either shot, or cannot cope with the spring rate.

You then have to find out what spring rates you have.
Jap spec suspension is very herd indeed, and crazy on our roads.

Of course you could simply take the car back to LEDA (a very good company) and seek their advice further.

Graham.

Hi mate,

Without testing the springs for their rates and checking the dampers on the dyno, I doubt that your coilover kit will ever be 'comfortable'.

To make the best of it though, start turning the spring platforms up to get the static ride height to 345mm at the front and 340mm at the back measured from the centre of the wheel to the wheel arch.

This should ensure that you will have enough compression travel as well as the roll centres staying in a reasonable position.

The geometry will have to be redone after this.

Good luck

Thanks for taking the time to reply Graham :)

I don't think Leda changed the ride height at all, as it was exactly the same before I took it to them. Its definitley got worse since having the rears fitted, so I will try raising the rear by about 20mm. I'm sure I've read somewhere that the rear arch gap should be about 10mm bigger than the front? They look about the same on my car.
Will putting the rears up by this much really affect my alignment much? Enough for me to have to get it done again? Leda charged £100+vat but I have since found out that Elite who are not far away do it for £49. And a discount may be possible due to my girlfriends dad being an account manager there. I guess I could take it to them again if need be.

I should point out really that one of the rear struts was at the wrong camber angle, but they are not camber adjustable on the rear, so leda could do nothing to correct it. Do you think that could be due to the rear being too low?

Here are the current measurements:

Left front: Right front:
Camber: -0.09 Camber: 0.00
Caster: 3.16 Caster: 3.26
Toe: 0.00 Toe: 0.00

Front: Total Toe: -0.01, Steer Ahead 0.00

Left rear: Right Rear:
Camber: -0.25 Camber: 0.23
Toe: 0.01 Toe: -0.02

Rear: Total Toe: -0.01, Thrust Angle: 0.01

All these measurements are in green, except the right rear camber which is in RED.

Anyway, I guess I will have to have a play about at the weekend and see if I can make it a bit better.
The only way I can describe the feeling, is like, when you hit one bump, the car acts like you have hit 3 in a row. So when the road is a bit bumpy, you seem to be bouncing up and down all the time. At 80 mph on a nice smooth not too old a road, it just was bouncing all the time. My friends evo 6 with standard suspension is very stiff, but does not bounce like mine. Thats what I was aiming for when I bought the coilovers. Anyway, if the weather is nice at the weekend, I will start by raising the rear a bit.

Thanks
Steve

bloody hell, my nice tidy spacing of the measurements didnt work very well :(

The car does look too low to me.
If the wheels are 17's then it is about 10mm too low.
Here is my car on 16's at a good ride height:
http://tinypic.com/view/?pic=t0s2mr
http://tinypic.com/view/?pic=t0s3lj

Hope this helps.

To get the rear camber set correctly you almost always need camber bolts.

Graham