2G Let's build a Front UCA

[Black95TSIawd]

I am willing to test

Me first!

 

[calgst95]

Hey guys, I figured I'd pop in with a small update.

I've decided to build this around the Moog 2G replacement balljoint. They're well-built, easy to find, reasonably priced, and uniquely small enough to fit the application.

I've got all of the components drawn in CAD. I'm awaiting a quote from my CNC laser guy. But I could have a prototype arm ready to be used in as little as 3-4 weeks.

That is amazing news!! Put me down for a set!!

 

[99gst_racer]

Do you have any cad pics?

I don't have the whole arm modeled, but here's some of the basic components:

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[Black95TSIawd]

"Borrowed" this from a guy making his own set for a CRX.

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[dsmcrzy]

That bolted joint on the end is interesting. I assume it's to quickly swap out the ball joint? Or maybe for something else?

 

[Black95TSIawd]

That bolted joint on the end is interesting. I assume it's to quickly swap out the ball joint? Or maybe for something else?

For setting camber. Add or subtract spacers to get it where you need it.

Maybe the bolt holes can be slotted in a way too...? for caster changes.

 

[dsmcrzy]

Duhh I didn't think of that. Expected something more inboard.

 

[TSiAWD666]

If slotting is a bad idea then the ball joint portion could alternatively be made with multiple versions, each with a different pair of hole locations for bolting into place, changing the offset and thus the caster. If that portion was simple enough the cost might not be so bad, just drilling the bolt holes in different positions relative to the ball joint. I picture like a ball joint cup welded to a flat strip of metal. Might be annoying at first to set up and test, but once done you're done. Caster typically isn't something you play with much once you get enough of it and make it even across the car.

 

[99gst_racer]

If slotting is a bad idea then the ball joint portion could alternatively be made with multiple versions, each with a different pair of hole locations for bolting into place, changing the offset and thus the caster. If that portion was simple enough the cost might not be so bad, just drilling the bolt holes in different positions relative to the ball joint. I picture like a ball joint cup welded to a flat strip of metal. Might be annoying at first to set up and test, but once done you're done. Caster typically isn't something you play with much once you get enough of it and make it even across the car.

I'm having a hard time picturing this.

I've considered an outboard adjustable plate using holes rather than slots. The biggest issue is having adjustability and keeping it compact enough to fit the footprint of the OE arm. This drove me to keep adjustment on the inboard end.

 

[rabenne]

I don't have the whole arm modeled, but here's some of the basic components:

Creo ? SW? looks familiar but having trouble figuring it out from your screens. Are you pretty solid with FEA?

just curious

 

[99gst_racer]

Creo ? SW? looks familiar but having trouble figuring it out from your screens. Are you pretty solid with FEA?

just curious

Solidworks and eMachineshop's CAD. I've never done FEA, but I've been itching to learn it for years.

 

[rabenne]

I could share my experience a bit. I am taking a grad course in finite methods right now. Most of our work revolves around Creo or Ansys but importing geometries is usually easy. I could probably share some useful pdf books, pm if you are interested.

 

[mitsumikey]

research of old suspension tuning threads leads me to believe we want this arm shorter than OE? I read the whole thread before but forget all that has been concluded...

 

[99gst_racer]

These will be capable of being shorter or longer than the OE arm.

I planned to build these with the ability of being slightly shorter, or vastly longer (due to the nature of heims and thread engagement). But I could certainly change that if need be.

 

[ileagleracing]

These will be capable of being shorter or longer than the OE arm.

But I wonder if most guys are running these at the OE length or other?

I typically build these with the ability of being slightly shorter, but vastly longer. And I could certainly change that if need be.

I've cut about .75 inches out of the stock arms on my 95 and I probably could use a little more when I do the arms on my 98 (which will also get your LCA's).
I'd say if you could allow for 1 inch shorter on your Upper arms that would be perfect.

 

[Black95TSIawd]

I agree with ileagle.

My arms are half inch shorter and the majority of the reason how I got to -3 degrees camber.

 

[99gst_racer]

I edited my last post. I had had a few vodka cranberries last night when I posted and I was accidently talking about the LCA's.


Thanks for the input, guys. It's going to be impossible to have the ability to be at the stock length and have 1" of adjustment. I'll be using 5/8" heims, and the general rule of thumb for thread engagement is 1.5x thread diameter. But they can be at a minimum of 1x. At .625" thread engagement, that leaves about .975" of thread that is not engaged. Minus the thickness of the jam nut (the thinnest one I have available is an aluminum one at .315" thick), that leaves us with only .660" of available length adjustment.

So the question is, where exactly should the range be? Stock to -.660"? Or -.340" to -1.00"? Or somewhere in between? I wonder if anyone would need or want to run these at the OE length?

 

[mitsumikey]

Hopefully we can compromise something that works for street and track not just one or the other , like where this discussion is going but we need someone who has the experince to give some feedback so we don't overdo it with camber while in street mode. Upper arm length shouldn't affect toe enough to eat tires with various settings street vs track ?

Be nice to have an arm that is just superior in every way not compromising

 

[ileagleracing]

I edited my last post. I had had a few vodka cranberries last night when I posted and I was accidently talking about the LCA's.


Thanks for the input, guys. It's going to be impossible to have the ability to be at the stock length and have 1" of adjustment. I'll be using 5/8" heims, and the general rule of thumb for thread engagement is 1.5x thread diameter. But they can be at a minimum of 1x. At .625" thread engagement, that leaves about .975" of thread that is not engaged. Minus the thickness of the jam nut (the thinnest one I have available is an aluminum one at .315" thick), that leaves us with only .660" of available length adjustment.

So the question is, where exactly should the range be? Stock to -.660"? Or -.340" to -1.00"? Or somewhere in between? I wonder if anyone would need or want to run these at the OE length?

Working on the car this weekend, I'll measure my cut arms and compare to stock, confirm that I'm not mis-remembering.

 

[Black95TSIawd]

Well, half inch shorter worked for me only because I have your lower control arms and used those for camber correction as well. (by adjusting the heim) 3/4 inch inward would have worked in conjuction with the stock LCAs if I had to guess.

I certainly wouldn't waste my money on these if I couldn't get a more performance driven setting out of it. -3 degrees might not be enough either as my outer tire wear was a bit alarming last year. Shooting for a little more negative in 2017.

 

[ileagleracing]

I measured my spare stock arms and the arms on my STX car have been shortened ~.75", they also have the (+/-1 degree) ingalls adjustable anchor bolts, I think they are adjusted all the way negative and I’ve got -2.5 degrees camber.

My SM car has Charles Moss’s (ACM) cut arms measured at ~.75” shorter then stock and with custom offset bushings in the stock anchor bolts (which need to be disassembled to adjust). This setup is good for at least -3.5 degrees of camber.

How difficult would it be to bend up all the arms the same, but trim them at 2 different “lengths” before welding in the threaded tube inserts?

Have a 1” shorter than stock arm for the racers, and a .5” shorter for the ricers

 

[99gst_racer]

I think what I'm going to do is build a trick adjustable jig, and I'll allow buyers to specify any changes to length. I could also relocate the balljoint for built-in caster. And they could be tweaked from there by adjusting he heims. Thoughts?

 

[Black95TSIawd]

I think what I'm going to do is build a trick adjustable jig, and I'll allow buyers to specify any changes to length. I could also relocate the balljoint for built-in caster. And they could be tweaked from there by adjusting he heims. Thoughts?

Yes. Send mine now. Extra rice for me.

 

[ileagleracing]

I think what I'm going to do is build a trick adjustable jig, and I'll allow buyers to specify any changes to length. I could also relocate the balljoint for built-in caster. And they could be tweaked from there by adjusting he heims. Thoughts?

That works. No racing this weekend with the blizzard, I'll spend some time with my 3d model to estimate what the different lengths would actually translate to in camber (including stock and your LCA's in the mix)

Yes. Send mine now. Extra rice for me.

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[ileagleracing]

I haven't measured the front chassis mounting points, as I'm concentrating on modeling the rear, but laying out only the suspension components with my crude 3d scan of the chassis and assuming that a 100% stock setup is at 0 camber: each .25" decrease in upper arm length gets a degree of camber.

I took a quick stab at designing a Front UCA, and came up with this, obviously this probably would be a little more expensive because there are a couple of machined parts, but a quantity order should knock the price down a bit. It would probably need some tweaks as I double check clearances. The Ball Joint is a Moog K90264.

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