does this front suspension look ok?
emsfactory - 10/10/07 at 11:33 AM
hi all. Tacked up my upper coil mounts and wondered wether they look ok. Is it better to get the lower bones horizontal.
Rescued attachment PICT0311.JPG
emsfactory - 10/10/07 at 11:33 AM
this is the nose that'll be going on
Rescued attachment PICT0312.JPG
Agriv8 - 10/10/07 at 11:49 AM
Your sump clearance is good but you are going to need one hell of a bonnet buldge !!!
I bilve that its best to have them horizontal ( but you can fit different poundage springs )
REgards
Agriv8
craig1410 - 10/10/07 at 12:08 PM
quote:
Originally posted by emsfactory
hi all. Tacked up my upper coil mounts and wondered wether they look ok. Is it better to get the lower bones horizontal.
Hi,
Ideally you want your lower 'bone mounts level with the centre of the lower balljoint when the car is at ride height so I'd say you
have it pretty much spot on. The top 'bone should slope down from upright to chassis which it does so you should gain negative dymanic camber on
compression which is what you want.
HTH,
Craig.
Peteff - 10/10/07 at 12:17 PM
Take the bricks out from under the bottom rail and see where it settles ?
worX - 10/10/07 at 12:38 PM
Without the engine in?
quote:
Originally posted by Peteff
Take the bricks out from under the bottom rail and see where it settles ?
Peteff - 10/10/07 at 12:43 PM
Isn't that the engine in the picture? You don't want to be setting the ride height by altering the spring poundage, it should be done by
using the spring seat adjustment.
craig1410 - 10/10/07 at 12:54 PM
quote:
Originally posted by Peteff
Isn't that the engine in the picture? You don't want to be setting the ride height by altering the spring poundage, it should be done by
using the spring seat adjustment.
Sorry Pete but I'd disagree - you should set ride height according to the length of your shock absorbers irrespective of the weight of the car.
You then need to choose springs to suit or wind up the spring bases.
All shock absorbers are designed with a specific "length when at ride height" specified which (IIRC) is about 1/3 compressed from the fully
extended position. In other words you get twice as much bump as rebound available.
I used the GTS Tuning shockers and if I recall correctly they are 12" fully extended and 11.25" when at optimum ride height. Therefore you
should set ride height when the shockers are at 11.25". I did this using a piece of 3/4" square section tubing with holes drilled at the
required spacing to keep everything in position.
Cheers,
Craig.
Peteff - 10/10/07 at 01:05 PM
Take the springs off then see where your ride height goes 
I obviously assumed he'd bought the right length dampers, silly me.
[Edited on 10/10/07 by Peteff]
craig1410 - 10/10/07 at 01:20 PM
Pete,
Yes, he would be better without the springs although I see the spring platforms are wound down so maybe the shockers are compressed to the appropriate
length. On my car I have to wind the platforms up to the top just to keep my sump off the ground but that's because I need different springs
really.
For setting the position of the upper shocker mount I would recommend using a fixed length piece of steel tubing with holes drille din it. Just make
sure that you leave enough room inside the upper wishbone for the shocker diameter to avoid fouling.
Cheers,
Craig.
britishtrident - 10/10/07 at 01:38 PM
Looks in the right ball park, if you want to lower the front roll centre a litle raise the inner pivots of the upper wishbone a smidgen.
Position of lower wishbone inner pivots relative to outer ball joints is just fine.
emsfactory - 10/10/07 at 05:29 PM
Cheers guys,
I have moved the upper mounting point higher up so the lower bone is noe pretty flat.
Does this look better?
Rescued attachment PICT0313.JPG
Avoneer - 10/10/07 at 05:48 PM
Looks so much better in the last pic.
Are the lower shocker brackets welded on the bottom bones?
If not, see if you can move them much nearer to the bottom upright ball joint.
Apart from that, looks good.
Pat...
emsfactory - 10/10/07 at 05:52 PM
Yes the lower brackets are welded to the bones.
I read that the closer the shockers to verticle the better, so I brought them in slightly from the last time.
britishtrident - 10/10/07 at 07:38 PM
quote:
Originally posted by emsfactory
Cheers guys,
I have moved the upper mounting point higher up so the lower bone is noe pretty flat.
Does this look better?
The Locost lore about getting the lower wishbone flat is an urban myth
Getting the lower wishbone flat has no significance on it own ---- what matters is the roll centre height at the desired ride height.
The original setup was probably better.
If you raise the pivots of the upper wishbone an inch will give a lower roll centre and a shorter virtual swing axle.
[Edited on 10/10/07 by britishtrident]
Avoneer - 10/10/07 at 10:07 PM
Vertical is better, but so is getting the bottom mount as close to the bottom ball joint as possible, but it should be fine where it is.
Pat...
craig1410 - 10/10/07 at 10:47 PM
quote:
Originally posted by Avoneer
Vertical is better, but so is getting the bottom mount as close to the bottom ball joint as possible, but it should be fine where it is.
Pat...
Yes, Pat is right here - you can avoid nasty bending loads on the lower wishbones by getting the lower shocker mount as close as possible to the lower
balljoint. This is more important than having the shocker vertical.
British Trident, I know where you are coming from with regards to roll centres but this is a fairly advanced subject and I fear that the search for
perfection can lead to a misunderstanding of the basics. My advice would be as follows:
1. Set you chassis on blocks at desired ride height (eg. 5 inches)
2. Using intended wheels and tyres (at very low pressure) set the lower wishbone angle so that the lower balljoint centre is level with the lower
pivots. The chassis pivots can be up to around 0.5 inches higher than the lower balljoint centre but should never be lower than it.
3. Set the upper wishbone so that the pivots are ideally 1 inch lower than the centre of the upper balljoint.
4. Use a pair of steel square section tubes with holes drilled at the spacing indicated by your shocker manufacturer as optimum ride height length to
link your upper and lower shocker mounts. This length will typically be 33% closed from the fully open position but ideally get the spec from the
manufacturer.
5. Centre the upper mount within the top wishbone and tack the upper mount in position where it hits the chassis. Use the shocker to test for desired
clearance.
That's how I approached my setup and it seems to be pretty decent. Just a shame my sump hangs 2" below the chassis...
Cheers,
Craig.
ps. All my "knowledge" comes from reading various books as shown on the front page of my website
here. Of particular help is the book by Des Hamill
here.
[Edited on 10/10/2007 by craig1410]
MikeRJ - 11/10/07 at 11:05 AM
quote:
Originally posted by emsfactory
Does this look better?
It might just be the angle of the picture, but it sure looks like you have quite a bit of positive camber, and not much thread left on the upper
balljoint to correct it?
craig1410 - 11/10/07 at 11:38 AM
You could be right Mike but it might be the "bowl" effect that you often get from cameras.
emsfactory, can you check your camber or take a photo looking down the outer edge of the wheel?
The other thing to watch - is the suspension in full droop in the photo's? If so then you would expect a bit of positive camber. As per my
previous posts, set your shockers at ride height length and take another photo.
Cheers,
Craig.
[Edited on 11/10/2007 by craig1410]
emsfactory - 11/10/07 at 12:12 PM
quote:
Originally posted by MikeRJ
quote:
Originally posted by emsfactory
Does this look better?
It might just be the angle of the picture, but it sure looks like you have quite a bit of positive camber, and not much thread left on the upper
balljoint to correct it?
They are quite verticle, i think it was more the picture.
I may have a problem in the future with it though as i made the upper bones to the book size but used bigger bush tubes so the
ball joint end of the bush has been pushed out a little.
If I have to make a new set of top bones its no biggie.
I would take a pic of the top but i have stripped it all down to do the welding, Back together in a day or 2.
