mkblade
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| posted on 14/9/05 at 10:44 PM |
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camber settings plus springs
im trying to fine tune my steering and suspenion.
running blade engine and de-deion rear end.
1, what is the correct way to do the camber adjustment ie turning the mushroom which way ,and how many turns do i turn the top suspenion joint ??
2. ive backed off the springs on each shock,but to be honest i do not seem to notice any difference where i set them.
3, the shocks are set to 3 clicks all round
thanks
simon
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progers
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| posted on 15/9/05 at 08:39 AM |
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Setting up the Indy
Sounds as though you are a little mixed up on what does what on the suspension!
1) Changing the camber you should only screw the top balljoint in/out of the wishbone and keep the mushroom in the SAME location each time. The
mushroom is there to adjust castor and should normally be set such that the top of the balljoint is as far forward as possible. Running standard
radials you should aim for 1-2 degrees of camber, the lower end is suitable for road use, more camber if you are hammering it on track. I'm not
sure what the setting is for a dedion rear - Others maybe able to advise. I thought all Indys have been independent rear for >3 years now?
2) There are several important things to note with setting the springs and shocks
- Set the rear of the car approx 20mm higher than the front. This will improve turn in and front end grip.The ride height is set by adjusting the
spring base up and down
- Initially start with the front end at say 5/6 clicks and rear end soft (2/3 clicks) and gradually increase the stifness of the rear until you get
the handling balance you like (as you increase the rear it will get more oversteery on power and cornering). After that you can change the front or
rear click settings to fine tune things. Typically if you stiffen the front too much you will get understeer. You want to run soft enough on the road
to give you good ride/bounce absorbancy, if the ride is too hard the handling will be skittish on our uneven roads. If you do a trackday you can wind
each corner up 2/3 clicks to maximise grip on the smooth track surface .
3) Indys handle a whole lot better with a front anti roll bar.
4) Note I have not even mentioned changing springs etc. This opens up another word of options but the ones supplied by MK should be roughly whats
needed for average use.
4) Make sure your wheel tracking is set up correctly - small amount of toe-in both front and rear is a good place to start.
Hope the above helps. You should be able to notice things changing once you find somewhere consistent you can check how the car behaves - an airfield
trackday is an ideal place to do this.
Cheers
Paul
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mkblade
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| posted on 15/9/05 at 01:29 PM |
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thanks for the info paul i will have another go at it ,im going to brands hatch as well so i will have a look at there cars as well
simon
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britishtrident
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| posted on 15/9/05 at 04:44 PM |
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Just to point out that the mushrom offset has absolutely NO EFFECT on caster. The only suspension geometry angle it effects is the relationship
between king pin inclination and camber.
Caster is dictated by the relative position of the top and bottom ball joints -- when viewed from bove the top ball joint should always be behind
(aft) of the lower of the lower balljoint by at least 25 mm -- both sides MUST be equal or the steering will pul to one side.
I would sugest you search through other posts on this subject.
[Edited on 15/9/05 by britishtrident]
[Edited on 15/9/05 by britishtrident]
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matt_claydon
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| posted on 15/9/05 at 06:03 PM |
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britishtrident: Correct me if I'm wrong, but your two statements seem to contradict. By rotating the mushroom insert you can't help but
alter the horizontal distance between the top and bottom balljoints. From memory, with the hole at the rear it would be almost directly above the
lower balljoint and with the hole at the front you have about the 25mm you suggest.
Cheers,
Matt.
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progers
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| posted on 15/9/05 at 07:03 PM |
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I agree, rotating the mushroom insert effectively changes the position of the ball joints relative to each other and therefore changes the castor (and
camber too....).
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andygtt
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| posted on 15/9/05 at 08:10 PM |
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I regard to the mushroom, How does the ball joints move possition? I think the only way the ball joint possition could move is by changing the
wishbone in some way!
Therefore I'd agree that it wont change the kingpin angle at all....... and that it will only effect caster in as much as it changes the
possition of the wheel centre slightly in relation to the kingpin angle.
Andy
please redefine your limits.
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mkblade
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| posted on 15/9/05 at 08:50 PM |
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sorry guys now im even more confused
im going to take it to have the trcking set up properly do i get it set to 0 or toe in or out ?
2. CAMBER ! on reading other posts it looks like the norm is around 1-1.5 degrees is this positive or negitive plus how do i measure this an idoits
way .
do i need to get a tool ???
if set the car roughly so its the same both sides ar moe .
ie turned the top ball joints out the same amount so that they would fit in the top insert (mushroom)
tracking i have set the same amount of turns/threads ,
does this make sense ????
thanks
simon
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progers
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| posted on 16/9/05 at 07:47 AM |
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I must admit my earlier post was phrased wrong... Although the balljoints remain in the same place when the mushroom is rotated, the actual vertical
inclination of the hub does change i.e. the castor angle is altered.
MKblade - I can understand why you may be confused, the bottom line is that you need accurate measurements to set up toe-in and camber. You can make
home made measurement devices but unless you know what you are doing I would take it along to someone who has the correct gear to do this for you. You
cannot accurately set the tracking (toe) by turning the track rod threads to an equal number both sides....Same applies to the camber as the geometry
from one side to the other is unlikely to be the same.
You may also consider getting the car corner weighted also which will help distribute the weight of the car evenly among the wheels and improve
handling. Depends how much you can afford really.
Adjusting the camber and toe shouldn't be more than £50. Its well worth getting done as the handling can be drastically affected by these
settings.
A good starting point
Front camber 1.5 degrees negative both sides
Rear camber 1 degree negative
Front Toe - 1 degree toe-in
Rear toe - not easily adjustable on the Indy, get it checked it should toe in slightly
Don't forget to set the rear suspension higher than the front by 15-20mm. Put a heavy load in the driver seat (roughly equal to you) and then
set the ride heights so that they are roughly level at the front and rear. The actual ride height you set will depend on how much clearance you have
under your sump. Typically its around 4.5 inches at the front.
Hope that helps
Cheers
Paul
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britishtrident
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| posted on 16/9/05 at 02:43 PM |
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THE CASTER ANGLE IS DEFINED BY THE POSTION OF THE BALL JOINTS -- Joining the centre points of ball joints creates a virtual king plin line.
As the position of the ball joints is fixed by the wishbones altering the rotation of an offset mushroom wil not change the caster.
It will however have 2 effects
(1) The height of the outer track rod end will change -- which has bump steer implications.
(2) The relationship between camber caster and king pin inclination changes, this can be used to give more negative camber in turns without running
crazy ammounts of static negative camber in the straight ahead position.
I might add it is very easy to set camber accurately using a precision spirit level.
[Edited on 16/9/05 by britishtrident]
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mkblade
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| posted on 18/9/05 at 09:55 PM |
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i measured the the rear end of my car today 19 cm
(thats form the very bottom of the lower trailing arm to the ground)
to me i need to measure the same height some how front and back to work out the 15-20mm difference in ride height
i guess im messuring the right place at the rear not sure about the fort
can anyone suggest the measuring points
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progers
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| posted on 19/9/05 at 07:35 AM |
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You need to measure the bottom of the chassis, not the wishbones. Measure at the rearmost part of the chassis on both sides and then repeat at the
front most part of the chassis. Initially try and keep left and right the same (with you in the seat) until you can get the car corner weighted
properly.
Cheers
Paul
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