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Ron Sutton 10-21-2016 01:59 PM

Quote:

Originally Posted by CJD Automotive (Post 647725)
Posted up the seat mount question in Ron's Safety Thread. I'm curious too as to what is the best/safest mount style.


I answered the seat question over on my Safety Thread Craig.

Link: https://lateral-g.net/forums/show...t=48392&page=7

:cheers:



preston 10-21-2016 09:22 PM

Ron if you have time could you indulge one question from me -

Maybe its just a feature of the TA2 design, but it seems the arm design on this clip went out of the way to put the lower rod ends in a single axis. To me this is normally done on OEM style arms so that they can use bushings. With rod ends, it seems like it doesn't matter that much how you align the pivots (for example in your GT clip) since they will articulate. I'm also wondering if that's why the front pivot is skewed as it looks like there would be still be clearance if it came in straight from the ball joint along the FACL, or at least very close. Even though that arm is plenty stout, the amateur engineer in me just see's a big bend right in the load path.

Is there anything you're willing to share on why or why not one would want to keep rod end pivots on axis vs just putting them in the correct 3d space ? And was this skewing of the FLCA pivot mostly done for clearance ?

Ron Sutton 10-22-2016 11:44 AM

2 Attachment(s)
Quote:

Originally Posted by preston (Post 647760)
Ron if you have time could you indulge one question from me -

Maybe its just a feature of the TA2 design, but it seems the arm design on this clip went out of the way to put the lower rod ends in a single axis. To me this is normally done on OEM style arms so that they can use bushings. With rod ends, it seems like it doesn't matter that much how you align the pivots (for example in your GT clip) since they will articulate. I'm also wondering if that's why the front pivot is skewed as it looks like there would be still be clearance if it came in straight from the ball joint along the FACL, or at least very close. Even though that arm is plenty stout, the amateur engineer in me just see's a big bend right in the load path.

Is there anything you're willing to share on why or why not one would want to keep rod end pivots on axis vs just putting them in the correct 3d space ? And was this skewing of the FLCA pivot mostly done for clearance ?


Hi Preston,

This might be one of the more technical questions I've received. You're correct about part of it & incorrect about parts of it.

Let's get the incorrect items (which I have bolded in your text above) out of the way ...
a. The front LCA mount & rod end is in the optimum location & is in line with the load forces better than if we had run the rod end straight out to the LBJ, like we do with my GT front end. On the GT front end, which uses 2-piece LCAs, I had to really be cognizant of the forces pulling on the rod end at an angle not true with the rod end design. I handled this with both design & material solutions. With the TA LCA here, the forces pulling on the front LCA rod end are closest to being in line with the front LCA rod end.

So you may have a skewed view of which direction the forces are actually pushing & pulling. The forces are not pulling straight out from the rod end to the LBJ. The forces are pulling out & forward on the front rod end, in an arc, based on the rear LCA rod end acting as a pivot location for the LCA ... like a sideways rocker arm. See the photos below.

b. I am not clear on what you mean by the "big bend right in the load path" ... as the front rod end & LCA receptacle for the rod end are very close to the load direction. *You can't be perfect with a non-articulating part (top view), as the load pulling on the front rod end is in an arc, not straight. The rod end in this LCA is at the optimum angle & the LCA design itself is triangulated & braced internally to handle the circular loading that occurs.

c. If by skewing, you mean why are the LCA pivots on the same plane as each other to form a true pivot axis? ... the answer is no, this wasn't done for clearance. It actually hurt clearance a bit & forced the rack forward a bit more then the GT. Is was done so the special adjusters & rod ends on the LCA would function properly over a wide range without binding.

Any time you have a 1-piece LCA, if you don't put the rod ends on the same pivot axis, you have a very small window or sweet spot the rod ends have to be to bolt up to the frame. There is less than a turn or two ... to adjust the rod ends without binding in a 1-piece L:CA if the rod ends aren't parallel. If the rod ends run at opposing angles on a 1-piece LCA ... if you adjust the rod ends to adjust camber, caster and/or track width ... we'd bind up the rod ends in the LCA frame buckets with very little adjustment. So I don't design 1-piece LCAs with the rod ends at opposing angles, only parallel.

The trick adjusters on this 1-piece LCA for my TA & TA2 front suspensions (you can see them as a Gold Hex on the frame side of the LCAs) have the rod ends screw into them, with a jam nut on the other side. The cool part about these is you can adjust track width, camber or caster, at the LCA quickly & easily. They have a wide range of adjustment because the rod ends are parallel. We couldn't achieve that if they were at opposing angles in a 1-piece LCA.

With most LCAs using rod ends, you have to unbolt the rod end from the frame bracket ... loosen the jam nut ... make an SWAG length adjustment by threading the rod end in or out either in half or full turns ... then bolt it back up & see if we hit the target on the camber, caster or track width changes we're looking for. With these special adjusters on the TA & TA2 LCAs, we can loosen the jam nut(s) and turn the gold hex adjuster ... to adjust camber, caster and/or track width .... without unbolting the LCA rod ends from the frame. Quick, easy & more precise.

To clarify, we can run the rod ends at opposing angles in a LCA.
If it is a 1-piece LCA, you just don't have much rod end adjustment without binding. So on my GT cars where I do run the rod ends at opposing angles, the LCAs are 2-piece. There is a main LCA that comes straight out from the frame to the LBJ ... and a strut rod that comes from the chassis to the LCA mounting point. That mounting point is what allows us to adjust the rod ends without creating bind like a welded 1-piece control would. The bolt together design simply allows us to adjust the LCA rod end at the frame mount ... and/or the strut rod rod end at the frame ... a pretty good amount, without binding the rod ends.

As you can see from the photos, the load arc is more in line with the rod ends being parallel, and not when the rod ends are at opposing angles. So when we build 2-piece LCAs, we need to insure the design & materials are super strong, and the rod end is a wide body chromoly rod end, not the standard mild steel or even narrow body chromoly. The wide body provides more contact area & control of the monoball in the rod end body, which is critical, because this rod ends sees more side loading.

Make sense?

.

Ron Sutton 10-22-2016 11:48 AM

Hey Guys,

I am super busy right now & need to hold off answering any more technical questions until I get back from SEMA.

:cheers:

Ron Sutton


preston 10-22-2016 02:24 PM

Wow that was a great explanation, I really appreciate it.

CJD Automotive 11-07-2016 04:17 PM

Got the front clip in epoxy and started mocking up the rear. As you can see in this pic, the X brace that was in my blueprint is actually touching the 3 link at the housing. This took a lot of time fitting and welding, guess I'll cut that out...


http://i1060.photobucket.com/albums/...psxx20ecit.jpg


It wasn't until I cleaned and epoxied it that I noticed some pretty sub standard welds. Ron said it's "race car quality", not show. I'll let you decide.

http://i1060.photobucket.com/albums/...psjkifv6z4.jpg
http://i1060.photobucket.com/albums/...psdezmg7pj.jpg
http://i1060.photobucket.com/albums/...psmeqgc5um.jpg
http://i1060.photobucket.com/albums/...pst6bv4xr3.jpg
http://i1060.photobucket.com/albums/...pseabmtmai.jpg
http://i1060.photobucket.com/albums/...psw4nwfdbh.jpg

Got Fuel Safe working on the cell.

I'm using a Holley VR2 brushless pump, internally mounted, that pulls from the custom collector. It also has two internal lift pumps that pull from the corners and fill the collector. Lot of stuff going on/in that cell.


http://i1060.photobucket.com/albums/...psubmrxrsx.jpg
http://i1060.photobucket.com/albums/...psulnz0r5j.jpg
http://i1060.photobucket.com/albums/...ps6rcxf6ld.jpg

preston 11-07-2016 09:31 PM

I usually get more excited by front suspensions but that fully adjustable shock dampened de-coupled 3 link looks so bad ass.

CJD Automotive 11-09-2016 07:13 AM

Quote:

Originally Posted by preston (Post 648504)
I usually get more excited by front suspensions but that fully adjustable shock dampened de-coupled 3 link looks so bad ass.

Well then, here's a few more...

http://i1060.photobucket.com/albums/...psdhaf4bro.jpg
http://i1060.photobucket.com/albums/...ps5gnu3dmc.jpg

CJD Automotive 11-14-2016 11:19 AM

Few more...

At a stopping point on the rear waiting the cell, so going to move to the front. You can see the lower leg of the X brace removed here.



http://i1060.photobucket.com/albums/...psqxednuks.jpg
http://i1060.photobucket.com/albums/...psju2cep0n.jpg
http://i1060.photobucket.com/albums/...psfpgkim1x.jpg
http://i1060.photobucket.com/albums/...pskrjvl6xn.jpg

preston 11-14-2016 11:39 AM

Thanks we always appreciate the photos. Not sure about the olive green paint scheme though - c'mon this is pro-touring we need the undercarriage to be bondoed and painted in a flip flop chameleon color to be taken seriously :lmao:

Far be it from me to second guess the Sutton-meister, but it sure surprises me not to see any triangulation on either of those watt links mount. I've seen his math on the loads but 1 lb of metal gussets would give me a lot of peace of mind.

Really looking forward to seeing the front clip put in place. What ride height are you targetting ? I saw some numbers on your drawing that looked very low. Is this a race car that can survive the street or do you plan on a fair amount of street driving ?


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