DIY Si
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| posted on 13/3/07 at 08:18 PM |
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Which uprights
Right, with out causing WW3, if you had an open choice of upright for the front end of a seven what would you choose and why? I'm looking at
starting again with a high powered, probably not even remotely locost, and won't have a single donor so choice is open.
Over to you lot, NO arguing please! 
Oh, cheaper is better, but am willing to spend a bit extra for better geometry,lower weight etc.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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COREdevelopments
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| posted on 13/3/07 at 09:35 PM |
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well i was thinking about getting a set of raceleda uprights from MNR/locostparts.net they are a good choice because they look great unlike the crappy
sierra ones i am stuck with, plus they are on offer with MNR.
thats my opinion anyway
rob
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JoelP
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| posted on 13/3/07 at 09:47 PM |
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i think he means which uprights as in what spec, kpi etc. Raceleda uprights are just replacements for existing uprights.
What varibles are there with uprights? Obviously the king pin angle, i guess scrub varies with wheel offset for isnt fixed. What is an ideal KPI?
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flak monkey
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| posted on 13/3/07 at 09:50 PM |
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You can use KPI to affect scrub radius. I have heard of wildly varying angles for KPI though. It does help with self centreing to a certain degree.
The cortina has about 4.3deg of KPI. 6-7 would be better on a locost I would think.
Scrub radius is variable depending on wheel offset, ideally you need to design for a specific offset.
The main variables are KPI, scrub rad and length/position of steering arm
Sera
http://www.motosera.com
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JoelP
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| posted on 13/3/07 at 10:19 PM |
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reading through a few old thread, it seems we want near zero scrub and kpi as flak says, 7 to 10 degrees maybe. Also read that castor should be a few
degrees more than kpi, so if thats right maybe 10 degrees is too much. Then we just want super light weight and a nice short steering arm to quicken
the rack.
[Edited on 13/3/07 by JoelP]
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flak monkey
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| posted on 13/3/07 at 10:25 PM |
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If you decide to make something like this you can use off the shelf bits. 1.8kg including the hubs, without the discs and calipers. Welded uprights
can lead to problems though in the long term. Hence why I wont release drawings for this one. Cast ali ones are even more prone to serious issues, so
dont get me started.
Scrub rad was about 22mm, with a of KPI to 7 deg.
David
[Edited on 13/3/07 by flak monkey]
 
Rescued attachment render3.jpg
Sera
http://www.motosera.com
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JoelP
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| posted on 13/3/07 at 10:26 PM |
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i'd have a go but i havent worked out the stub and hub bit.  more research required 
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flak monkey
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| posted on 13/3/07 at 10:28 PM |
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Stub axle is a screw in cortina one from Randall motorsport (£20 each). Hub is one of Jasons ali cortina ones.
Stub screws into a turned boss which is welded into the upright tube, with a turned locking nut on the back to stop it coming undone.
Sera
http://www.motosera.com
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DIY Si
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| posted on 14/3/07 at 04:28 PM |
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Whilst that is all very helpful, I feel I may have mis-worded my question.
Which buyable/available upright would you use? IE cortina, sierra, MGF/TF, Elise, S2000, MX5 etc.
I don't want to make them, as I don't feel that confident in my own abilities to do it well.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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