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Author: Subject: Warner R4 Build Diary
sgraber

posted on 21/2/07 at 04:40 PM Reply With Quote
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

posted on 21/2/07 at 04:43 PM Reply With Quote
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

posted on 21/2/07 at 09:59 PM Reply With Quote
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

posted on 22/2/07 at 12:43 AM Reply With Quote
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
Rescued attachment altrollbar1.jpg

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Fred W B

posted on 22/2/07 at 06:05 AM Reply With Quote
I also wanted to suggest Doug's mods.

Cheers

Fred W B

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rpmagazine

posted on 22/2/07 at 08:51 AM Reply With Quote
Doug has a point, the previous setup would risk folding in half in a serious rollover.
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cloudy

posted on 22/2/07 at 10:56 AM Reply With Quote
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

posted on 22/2/07 at 12:39 PM Reply With Quote
Yep, that's it.
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cloudy

posted on 4/3/07 at 06:28 PM Reply With Quote
I'm moving forward with this new design - thanks everyone for the great input

Sorry about the messy garage!






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cloudy

posted on 5/3/07 at 04:58 PM Reply With Quote
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

posted on 7/3/07 at 12:58 AM Reply With Quote
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

posted on 13/3/07 at 01:38 PM Reply With Quote
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

posted on 16/3/07 at 06:46 PM Reply With Quote
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

posted on 16/3/07 at 07:51 PM Reply With Quote
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

posted on 18/3/07 at 08:07 PM Reply With Quote
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

posted on 19/3/07 at 03:41 AM Reply With Quote
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

posted on 19/3/07 at 09:18 AM Reply With Quote
looks like the rack is too wide to me.....





Andygtt

Please redefine your limits

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cloudy

posted on 19/3/07 at 09:36 AM Reply With Quote
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

posted on 20/3/07 at 06:59 AM Reply With Quote
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

posted on 20/3/07 at 02:33 PM Reply With Quote
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

posted on 2/4/07 at 01:54 PM Reply With Quote
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

posted on 15/4/07 at 01:05 PM Reply With Quote
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

posted on 27/5/07 at 08:11 PM Reply With Quote
Sorry no updated pictures yet - i've been slacking!!

I have a new render though



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DIY Si

posted on 27/5/07 at 08:31 PM Reply With Quote
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

posted on 27/5/07 at 11:11 PM Reply With Quote
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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