creating new susp for the monster, going dual A setup front and rear |
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creating new susp for the monster, going dual A setup front and rear |
byndbad914 |
Mar 31 2010, 02:19 PM
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#221
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shoehorn and some butter - it fits Group: Members Posts: 1,547 Joined: 23-January 06 From: Broomfield, CO Member No.: 5,463 Region Association: None |
Car currently has RSR front struts with custom lower arm setup (sorta like a 935 front end) and the rear is a 5-link setup that is much like any old school 60s-80s open wheel car, GT-40, etc all attached to my tube chassis setup.
Decided I wanted to lower the car more and fix a couple issues with the rear 5-link geom so I started laying out some parts, then decided F it, time for a whole new update (IMG:style_emoticons/default/laugh.gif) I can't leave anything alone. So I measured various available pickup points on the current chassis and whipped up this stuff in Pro/Engineer. The lower A is already a bit different than I have assembled in here, but close enough for convo - and JP was asking to see what I have going - I am sure so he can raz me about whether or not I actually win at DEs (IMG:style_emoticons/default/happy11.gif) I used Pro to lay out the geometry so I could measure camber gain, get zero toe positions for the toe link (which will be adjustable in case I want to put some bumpsteer into the rear), RC height and motion, etc. Is this perfectly optimal on all points? Hell no, but much better than what I have and works with existing structure - I am not about to really hack into this car. I can get tabs waterjet cut and welded into place, but not bending/notching tubes in my near future. Besides, it leaves me a little bit of excuse for why I am slow on the track cuz it certainly isn't my driving abilities hahaha (IMG:style_emoticons/default/driving.gif) So here is the rear design - it will be built using the stock trailing arm cut down to not much more than a bearing carrier. yeah, yeah, use this other thing, make that, blah blah - the stock rear bearing assy has worked for a few years now so it is fine. I intend to replace that big bearing every few years regardless of upright used anyways. I did the same layout stuff for the front and even am going to be able to use the exact same billet lower A front and rear so that is nice. I can have them waterjetted for about $170 each including the 1.5" plate material, so not bad at all. I bought a couple front strut housings from Carquip last week and had my machinist buddy endmill out that monster weld so gonna work on getting them apart down to the stock knuckle, then I have 2" diam chromoly I just got yesterday that I will have him machine down to make the front "upright". Note the two surface colors in the above image - the blue is turned down to fit in the knuckle (50mm) and the green is the stock 2" diam of the tubing - that ridge will be used to exactly place the tube relative to the knuckle so I get both spindles left to right in the exact same spot. The upper forward link will be made on the fly so I didn't bother modeling it. I need to get this stuff in the car with the right pickup points placed, then place some dual adjustable coil over assys which might be tough on the front, then build the forward link around the shock assy. At some point you stop fisting the design and just build it (IMG:style_emoticons/default/shades.gif) Being a structural analyst I also have access to finite element code so I fully analyzed the lower A designs (I have 5 of 'em now hahaha) to make sure they are structurally sufficient. If I get off track in a big way I will likely bend them, but that you can't design for without having a 10lb A arm. These are just over 5 lbs per the modeling software. |
ArtechnikA |
Mar 31 2010, 05:31 PM
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#222
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rich herzog Group: Members Posts: 7,390 Joined: 4-April 03 From: Salted Roads, PA Member No.: 513 Region Association: None |
Tell me about the RSR struts, especially if they're about to be surplus...
(2,8 RSR clone/homage in progress...) |
byndbad914 |
Mar 31 2010, 06:11 PM
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#223
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shoehorn and some butter - it fits Group: Members Posts: 1,547 Joined: 23-January 06 From: Broomfield, CO Member No.: 5,463 Region Association: None |
QUOTE It looks like you have set up to get some decent scrub radius with a wide wheel from that design. Going with a cantilevered shock/spring? I would really love to move the spring combo inboard but unfortunately I can't in the rear, and since I want to keep the front and rear as identical as possible (so I don't have to carry so many spares, would only need one shock for any corner), I am going with a normal setup with the assy attached to the lower A.Looks like a DE winner to me. (IMG:style_emoticons/default/smile.gif) I am gonna RULE at DE events JP (IMG:style_emoticons/default/lol-2.gif) QUOTE Tell me about the RSR struts, especially if they're about to be surplus... (2,8 RSR clone/homage in progress...) http://www.patrickmotorsports.com/part/1070/ http://www.pelicanparts.com/cgi-bin/ksearc...r=VE3-61017-M12 I have had them for five years but they have limited track time (one year of that was while I built the tube chassis for example) on them so they are for all intents and purposes like new. Interested? oh yeah - thanks Andy (IMG:style_emoticons/default/smile.gif) |
ArtechnikA |
Mar 31 2010, 07:40 PM
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#224
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rich herzog Group: Members Posts: 7,390 Joined: 4-April 03 From: Salted Roads, PA Member No.: 513 Region Association: None |
QUOTE they were bought new from Pelican, are the yellow ones with the better valving and the 19mm lowered spindle. The stock RSRs are the green ones - suffice it to say everyone uses the yellow ones - yellow is faster (IMG:style_emoticons/default/laugh.gif) Here is a couple links to see what they are - Patrick uses them on pretty much all of the customer stuff in their photo album so I will use his site as an example, and Pelican where I bought 'em when I lived about 5 blocks from their shop (IMG:style_emoticons/default/smile.gif) http://www.patrickmotorsports.com/part/1070/ http://www.pelicanparts.com/cgi-bin/ksearc...r=VE3-61017-M12 I have had them for five years but they have limited track time (one year of that was while I built the tube chassis for example) on them so they are for all intents and purposes like new. Interested? Let's say I'm not interested at Patrick pricing ;-) ... If you're dealing I'm interested. Neither picture/source looks like the steering arm has been modified to compensate for the spindle - Do you use a bump-steer extended tie rod end, or is there a bend I'm not seeing? Pelican lists two valving options - 220/100 and 161/160 - do you know which you've got? I have a set of RSR-spec inserts I had been planning on using but I'd have to go look at my notes to verify the valving numbers - they're not on the box anywhere I could see, although the part numbers are... It almost looks like those are coilover struts - yes? I hadn't thought the 2,8's used coilovers but a quick check of GrĂ¼ber's ,,Carrera RS'' book shows that they did, in a 'supplemental' role... Do you have the 'supplemental' coilovers? I'm sure the factory titanium springs are right out of my price range tho ... I'm in no panic hurry to make this deal so take your time and think on what it'd take for you to part with them. PM or email me if you want. |
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