Matty Dog
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| posted on 8/6/07 at 04:32 AM |
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Calculating Suspension Geometry
My donor car is a Mk3 Toyota Supra.
I'm using the front wishbones in all the stock locations, but the rear is a multi-link setup that I am changing to double wishbones.
To make sure I don't bugger it up the roll-centres etc, I drew up String Computer, as per Alan Staniforth. It's not all that accurate
though, and a pain to use.
What sort of software is available to do the same job.
I have downloaded the QBasic software from Racetech Magazine
(http://www.racetechmag.com/user/software/software.asp?menu=4), which would be
fine, apart from the measurements being all imperial and I grew up on metric.
Are there any other programmes out there that people have used?
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t.j.
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| posted on 8/6/07 at 06:05 AM |
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It is one big compromise!
I read a lot around here.
I read the book from http://www.amazon.co.uk/Modify-Sportscar-Kitcar-Suspension-Speedpro/dp/1903706734
then in 3D looked what happened.
So first try to understand it,
then come to the conclusion that most kit-cars geometry is no good. But hey they drive also around very fast, so be 
Then make your own,
- Most of the steering forces will be compensated in the tyres
- the lack of movement in the suspension (about 4-5 inches) is also one thing to consider.
Try to get your cambergain under control.
Try to get no bump-steer
try to get enough caster
My wishbone ratio is upper/lower front 0.79.
Good luck
[Edited on 8/6/07 by t.j.]
Please feel free to correct my bad English, i'm still learning. Your Dutch is awfull! :-)
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thunderace
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| posted on 8/6/07 at 09:03 AM |
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http://www.andersensmith.freeserve.co.uk/suspension.htm
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nitram38
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| posted on 8/6/07 at 10:09 AM |
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I used solidworks to check that my wishbone length and mounting positions would give me the correct camber gain/loss. The first picture shows
non-parrallel unequal wishbones at normal ride height.
The second and third show the camber gain and loss. In reality this will be minimal on my car as the wishbones will not normally go that far, but I
will be using adjustable height air shocks.
My ride height will be adjusted from 3"-6" at the touch of a switch and can even be lowered to 0" when parked.
Like it has been said, suspension is a compromise. I have designed mine at 3" ride height as at 6" it will only be used to get over
obstacles/speed humps etc.
 
Description
 
up
[img][/img]
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Minicooper
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| posted on 8/6/07 at 10:36 AM |
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http://www.racingaspirations.com/suspensiongeometry.php
Cheers
David
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t.j.
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| posted on 8/6/07 at 11:49 AM |
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quote:
Originally posted by Minicooper
http://www.racingaspirations.com/suspensiongeometry.php
Cheers
David
Handy!  
Learning all the time
Please feel free to correct my bad English, i'm still learning. Your Dutch is awfull! :-)
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Doug68
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| posted on 8/6/07 at 12:00 PM |
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Use this software.
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JoelP
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| posted on 8/6/07 at 12:02 PM |
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shame that link above doesnt let you include the kingpin angle, or let you type figures in. Several ways round the KPI though.
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