sgraber
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| posted on 21/2/07 at 04:40 PM |
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I must say, I REALLY like that shape. I think you nailed it.
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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iank
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| posted on 21/2/07 at 04:43 PM |
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Agree time to tack tubes I'd say.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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FUORISERIE
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| posted on 21/2/07 at 09:59 PM |
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quote:
Originally posted by cloudy
I see you've been working your magic again in the MEV thread Fuoriserie - feel free to experiment on mine too!
Thoughts?
http://www.digital-car.co.uk/wr4/r4_engine.wmv
Thanks....will see what i can do. , but yuo've done a great job so far!
[Edited on 21/2/07 by FUORISERIE]
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Doug68
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| posted on 22/2/07 at 12:43 AM |
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Looks superb 
If it were me and for give the rubbish photochop I'd make the mods below:
Also the front tube going over the dash is shown as 3 bits welded together if this were one bent tube with the fore-aft tube butting into it it'd
look much better I think.
Top man for sticking at it!
 
Rescued attachment altrollbar1.jpg
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Fred W B
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| posted on 22/2/07 at 06:05 AM |
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I also wanted to suggest Doug's mods.
Cheers
Fred W B
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rpmagazine
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| posted on 22/2/07 at 08:51 AM |
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Doug has a point, the previous setup would risk folding in half in a serious rollover.
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cloudy
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| posted on 22/2/07 at 10:56 AM |
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I like you're thinking doug although it would be destroying a lot of chassis that has already been built - would look something like this....
[Edited on 22/2/07 by cloudy]
[Edited on 22/2/07 by cloudy]
[Edited on 22/2/07 by cloudy]
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Doug68
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| posted on 22/2/07 at 12:39 PM |
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Yep, that's it.
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cloudy
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| posted on 4/3/07 at 06:28 PM |
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I'm moving forward with this new design - thanks everyone for the great input 
Sorry about the messy garage! 
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cloudy
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| posted on 5/3/07 at 04:58 PM |
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OK the fun old job of mounting the steering rack this coming weekend. I've bought myself a laser level to visualize my bump steer, but where
should I be mounting rack fore/aft? should the rack arms be straight at centered steer?
James
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Doug68
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| posted on 7/3/07 at 12:58 AM |
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Go get yourself a copy of the Race & Rally Car Source book it'll explain what you need to do better than any answer you'll (probably)
get here.
[Edited on 7/3/07 by Doug68]
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cloudy
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| posted on 13/3/07 at 01:38 PM |
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It's too quiet in the middy section of late, we are all slacking!
Last weekend I put my new digital angle gauge to good use, by setting up the front suspension for 6 degrees of castor. Also tested out the laser level
method of bump steer checking, which seems to work a treat. Next weekend I hope to get the rack positioned and mounted. Cleared up the build area a
little....
A bigger job is to extend the car to give another 10-15cm in the cabin, another mis-calculation on my part 
All part of the learning experience I suppose - although I seem to be having more of the experience than most 
Another render as I'm bored in work today!
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cloudy
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| posted on 16/3/07 at 06:46 PM |
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any comments on suitability/improvements to this rack mount i've designed? It's based around the locost mount, but uses 3mm plate boxed
into an L profile for strength
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Alan B
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| posted on 16/3/07 at 07:51 PM |
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I'd brace directly between the mounts parallel to the tubes as close as possible to the rack and then use just one diagonal.
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cloudy
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| posted on 18/3/07 at 08:07 PM |
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Something strange happened when I tried to position out the bump steer, the rack had to sit a lot lower than the line between the pivots rule would
suggest.
I believe the reason for this is because of the unequal length wishbones, which obviously add camber in bump, which in turn move the steering arm in
and toe out occurs. Presumably this applies to locosts that also have unequal length wishbones, I cannot see any others with such a low mounting
point however?
Any ideas? Should I just go with it here as it's resulting in least bump steer - or do I have another problem at play here?
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Ratman
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| posted on 19/3/07 at 03:41 AM |
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I resently worked through a similar rack and bump-stear problem with a friend's car. I suspect, that low position that you have indicated will
give a small amount of bump stear with small suspension movement, and then will get very bad if the suspension moves further.
Long and short wishbones is not a problem. But the suspended tierod needs to be in proportion. As an initial set up, if the outer end is at say 30% of
the vertical distance between the suspension joints, then it should also be 30% of the vertical distance between the suspension joints at the inboard
end. The length of the suspended tierod should then be proportional to it's location. i.e. average of upper and lower wishbone if it is located
at mid point, ands correspondingly longer or shorter if it is not.
When I was doing this we made up a very crude dummy tierod for one side and made endless 5mm adjustments with clamps and blocks of wood etc. Using a
two meter long bar attached to the hub, to measure bump stear, you can expect to get the end of a 2m bar staying within 20mm of a vertical line as
you move the hub up and down 200mm.
because there are several dimensions that you can change, and you can't be sure what the effect is going to be, keeping good records of your
trials is important. We used a spreadsheet to plot the results, and that helped zero in on the optimal tierod length and inboard location.
You are very likely to find that your rack is too long or too short. Nothing you can do about this except change the length some how. be sure that you
have the ackerman angles that you want at this stage, as any change in the stearing arm on the hub for this reason will directly affect the length of
the rack, if you want to keep zero bump stear.
let me know if you want more (clearer) description of the way we did this.
Cheers, Brian
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gttman
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| posted on 19/3/07 at 09:18 AM |
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looks like the rack is too wide to me.....
Andygtt
Please redefine your limits
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cloudy
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| posted on 19/3/07 at 09:36 AM |
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That's the odd thing though, it is adhering to the proportion rule in that it's sitting proportionally about the same height as the
steering arm. I'm only measuring around 2 cm of deviation of the laser on the wall about 4 meters away, which by my calculations is about half a
degree of bump steer, which must be pretty good?
James
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Ratman
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| posted on 20/3/07 at 06:59 AM |
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That sounds very good. For that deviation, is that moving the hub through it's full range of suspension movement?
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cloudy
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| posted on 20/3/07 at 02:33 PM |
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damn, now the bump steer is better (rack still needs shortening) The TRE's bind at full bump
It would be ok if the pivot went through the uprights, upright - but its at a funny angle, common problem?
James
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cloudy
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| posted on 2/4/07 at 01:54 PM |
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I don't know if you stumbled across my other threads, but was basically having all sorts of travel issues.
I've managed to get around this by raising all mounts and moving upper mounts inboard allowing for a longer top wishbone (via adjuster) and
therefore less angle on the top joint for a given deflection...
(The top mounts will be webbed in, just temporarily mounted in the pic)
Only complete on one side, but happy to be over this hurdle. Well aside from needing to find different TRE's or bend the rack ends 
I promise better updates soon!
[Edited on 2/4/07 by cloudy]
[Edited on 2/4/07 by cloudy]
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FUORISERIE
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| posted on 15/4/07 at 01:05 PM |
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quote:
Originally posted by cloudy
I don't know if you stumbled across my other threads, but was basically having all sorts of travel issues.
I've managed to get around this by raising all mounts and moving upper mounts inboard allowing for a longer top wishbone (via adjuster) and
therefore less angle on the top joint for a given deflection...
(The top mounts will be webbed in, just temporarily mounted in the pic)
Only complete on one side, but happy to be over this hurdle. Well aside from needing to find different TRE's or bend the rack ends
I promise better updates soon!
[Edited on 2/4/07 by cloudy]
[Edited on 2/4/07 by cloudy]
Looking very good so far, any updated pictures of your project? I like how it's progressing........
Cheers
Italo
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cloudy
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| posted on 27/5/07 at 08:11 PM |
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Sorry no updated pictures yet - i've been slacking!!
I have a new render though
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DIY Si
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| posted on 27/5/07 at 08:31 PM |
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Just stop doing renders then you lazy bum!
Looking good though so far.
“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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cloudy
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| posted on 27/5/07 at 11:11 PM |
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I'll go out and get cracking tomorrow if the garage isn't underwater of course....
[Edited on 27/5/07 by cloudy]
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