Wingnut
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| posted on 4/2/08 at 02:21 PM |
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Camber change in bump & droop
I'm aware that this is a complex subject... *but* I was wondering if anyone had any opinions, in laymans terms!
My chassis has unequal length wishbone suspension front & rear.
At the rear the camber goes from 0 deg at ride height to aroung -5 deg in full bump.
At the front the camber goes from -1 deg at ride height to around -2 deg in full bump.
From what I've read on this chassis (GTD) it's possible to remake chassis brackets & move the top inboard wishbone pickup points
vertically, which I understand will change the amont the camber changes during bump.
So when I start mocking up some brackets, should I be trying to acheive the same camber change front & rear?? Or is it not that simple??
[Edited on 4/2/08 by Wingnut]
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nitram38
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| posted on 4/2/08 at 03:01 PM |
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This comes down to car usage, road or race?
You will need to know the range of movement so that you can work things backward from the required camber gains.
Simply moving the brackets could change the set up to someting less desireable.
You may even need to change the length and angle of your bones aswell.
A simple method to check is to use some cardboard cut to the same lengths of your wishbones in side profile, plus hub etc.
Experiment with pins to change the pivot points and measure the camber gain.
Alternatively, draw them in solidworks and play around with the lengths etc.
That's what I did when designing my MotaLeira project.
 
Description
 
down
 
up
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Wingnut
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| posted on 4/2/08 at 03:30 PM |
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Nitram,
The car is sprint/trackday use mainly with a bit of road use inbetween.
Thx for the diagrams....
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red22
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| posted on 4/2/08 at 03:46 PM |
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Or you could try this.......
http://www.racingaspirations.com/suspensiongeometry.php
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britishtrident
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| posted on 4/2/08 at 07:17 PM |
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It has to be a comprimise between camber while cornering and braking/accelerating
Remember the car isn't going to be on the bumpstops when cornering, accelerating or braking so the full travel camber figures can be a bit
misleading.
Normally on a lot of Sevenish cars the rear ride height laden is 10 to 20 mm higher than front ---- this called rake.
Normal static camber angles laden are in the range 0 to -2 degrees.
Radial tyres are more tolerant of camber than xplys but radial corner best with a fair bit of negative camber.
Raising the rear upper wishbone pivots will have a effect on the rear roll centre --- normally I would expect it to lower it. This is similar in
effect to softening the rear roll stiffness --- which will increase any tendancy to understeer.
[Edited on 4/2/08 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Wingnut
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| posted on 5/2/08 at 01:34 AM |
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quote:
Originally posted by red22
Or you could try this.......
http://www.racingaspirations.com/suspensiongeometry.php
WOW! That's fantastic, saves a load of work/time THx for posting!
Britishrident, thx for the info... I think what I'm trying to acertain is wether the ratio of bump/camber change should be the same at the front
& rear?
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