2G 2g SPC Upper A-Arm replacements discontinued

[jtmcinder]

I don't know if this belongs here or the other thread on 2G suspensions, but another idea just hit me. (Ow!) See if you can swap in the lower balljoints from a WhiteLine Roll Center Correction kit for an Evo X. Raising the roll center back up after lowering is very very good.

 

[greengoblin]

That's the thing. It'd be a huge undertaking. At least for myself or the occasional track goer. But, really, I think we were thinking along similar lines.

Charles, if you were rewelding so often, was it just simpler and faster to maintain the car that way? Basically what I'm interested to know is if you did or why you did not enlist an enhanced support for the tubes?

I don't think his class allows him to reinforce his chassis.

For those that can. I think a simple 4X4 plate with the spacer weled on it with some gusset coould be made. Then you could weld this plate on to the area adding strength. It would not be that hard to do.

This is a rough idea in my head so feel free to pick it apart.

Kevin

 

[PieEyedPiper]

I shit you not, I was dreaming of the washers being welded to the tubes this morning. I wonder if just those would provide all the support required, not that the gusseting shouldn't work. Just seems like there could be large bang for buck. I need a hobby..

EDIT: Can the bottom of the tube be accessed, for the purposes of welding a washer in on that side, too?
I don't particularly feel like peeling back my fender liner right now.

 

[greengoblin]

I shit you not, I was dreaming of the washers being welded to the tubes this morning. I wonder if just those would provide all the support required, not that the gusseting shouldn't work. Just seems like there could be large bang for buck. I need a hobby..

EDIT: Can the bottom of the tube be accessed, for the purposes of welding a washer in on that side, too?
I don't particularly feel like peeling back my fender liner right now.

No you can not get to the bottom of the post with out compromising what little strength there is.

Here look at this photo the post are welded to the bottom panel. It's in purple.

In red are two spot weld that are on the bottom panel and very close to the tube edge.

Green show the other spot weld that hold the gusset/tube plate

Blue is the weld (there are one on each side) that hold the tube to the gusset.

If you are going to try to add strength the only thing that is going to work is adding a plate that mirrors the the shape of the underside. You can weld your spacer on that and add some gusset off the sides so it will not just tear off. Swiss cheese the plate and plug weld it into place and around the sides to for good measure. I would also make sure the plate is large enough to cross over the existing seams where the other panels are joined. Sorry if that is long winded and clear as mud.

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[ACM]

That's the thing. It'd be a huge undertaking. At least for myself or the occasional track goer. But, really, I think we were thinking along similar lines.

Charles, if you were rewelding so often, was it just simpler and faster to maintain the car that way? Basically what I'm interested to know is if you did or why you did not enlist an enhanced support for the tubes?

Kevin is quite correct - I run SCCA E Street Prepared (ESP) - I can only execute modifications explicitly called out in the ruleset, and there are no allowances for strengthening weak portions of the chassis, only for repairing damage in the simplest form possible unless the factory documentation allows for something more complex, which ours does not.

Most likely, I am not understanding Kevin's comments, but from my myopic position, you can access both upper and lower installation points of the "eyebolt" mounting tubes, and welding (large) washers around them should not be an issue. Hmm - since this is so clear to me then it is quite obvious I am not appreciating Kevin's comments ! Time to shut up...

What we need to appreciate is that these cars were never designed to experience the stresses we routinely put them through. These cars pulled ~0.8G from the factory, and they were engineered to pull that (or a little more) though infinite CAD/FEA cycles. We are now pulling peak Gs that are getting close to 2Gs, with sustained loads in the 1.5G range all day long.

Never in their wildest dreams did Mitsus' engineers expect these loadings to be fed through a vaguely stock chassis. Nor should they have.

These are not motorcycles, where an extra $5 of material allows the vehicle to double the engineered loads with impunity.

This is why domestic "sports cars" weigh 4000lbs+ - and suffer badly for it - and DSMs weigh 3000lbs. Our cars run rings around theirs when asked to turn corners. That was a choice. And a good one as far as I'm concerned.

I'll shut up now

 

[jtmcinder]

Wait a second, dude. ESP allows STBs. Yes, all OTS STBs for 2Gs actually attach to the bolts from the shock (which makes zero sense on a double-wishbone car), but you could make your own STBs that actually attach to to the eye-bolts, as they should. Do this right and they'll add strength to that part of the chassis, as well.

In any event, it doesn't make much sense to worry about the limits of Street Prepared when you're thinking about a complete change to the geometry via longer eye-bolts, since the longer eye-bolts would be illegal. This is a Street Mod or Prepared question. I know that you can do pretty much what you want to strengthen the chassis in Prepared. I thought that SM had a catch-all sort of "minor strengthening" rule, too.

Backing up a step, the one question for me in SM was whether it was ever really clarified what is parts of the car are suspension. DG often said "strip the car down to the holes in the chassis ... put what you want in those and only those holes." But the SEB said "see the stuff that moves with the wheels? ... that's what's free." This is where the original conflict was. When you strip the car to the holes in the suspension, the eye-bolts come off, so DG said they were free. But the eye-bolt doesn't move, so the SEB wouldn't include those in the SM allowance. Thus, the only things you could do with the eye-bolts is use SP's camber-kit rule and you'd have a hard time arguing that extending the eye-bolts is part of a camber kit.

 

[ACM]

Yes, we are allowed STBs - even done right, they only attach to the top of the eyebolts, all the cracking and damage happens around the bottom of the tube, so an STB is of very limited use.

Anyway, back to the original plot. Once lowered, 2G upper A-arms are at a significant angle, you don't want to needlessly increase this angle as it plays havoc with the dynamic geometry - if you believe in classic suspension theory that is, there is considerable debate today that such matters can be considered almost irrelevant when working wich handicapped vehicle classes.

What I will do if I ever get back to autocrossing is to create a version of the generic oval track GM arms, using the OTS upper ball joints and use threaded female clevises to alter the camber & caster. SMM can use spherical bearings pressed into the eyebolts, SP & ST has to make do with Delrin bushings instead. Simple, effective, and won't smack the inner fender on full compression (which is often the root cause of the eyebolt tubes getting ripped out)

Take these :
http://www.amazon.com/gp/product/B000C560WU

And use them in a version of this :
Adjustable A-Arms without Cross Shafts - Speedway Motors, America's Oldest Speed Shop

With this arm, you'd have female clevises replacing the eyebolts, SM and non-SCCA legal, for SCCA you'd replace the spherical bearings in the arm ends with female clevises and retain a variation on the OEM eyebolts.

 

[jtmcinder]

Once lowered, 2G upper A-arms are at a significant angle, you don't want to needlessly increase this angle as it plays havoc with the dynamic geometry - if you believe in classic suspension theory that is, there is considerable debate today that such matters can be considered almost irrelevant when working wich handicapped vehicle classes.

One person's havoc is another person's cool mod. The whole idea is to change the geometry, making the non-parallel double-wishbone even more non-parallel. This will cause you to gain more camber in bump (and, therefore, roll), allowing you to run less static camber.

There could be some downside that I'm not seeing, but changing the geometry is the goal, not the side-effect.

Note: as I pointed out elsewhere, the other way to get more non-parallelism is to somehow swap in something like WhiteLine lower ball-joints, which have extended stalks to lower the roll center of an Evo X.

 

[PieEyedPiper]

*cough* to raise it *cough*

It appears that the Whiteline parts are 1/4" taller than OEM. The tie rods likely bolt right up but I'm sure you'd need to be very creative with the lower balljoints. Unfortunately, 1/4" of spacers is likely out of the question.

But could you see it? The evolution of the DIY washer method..

 

[ACM]

One person's havoc is another person's cool mod. The whole idea is to change the geometry, making the non-parallel double-wishbone even more non-parallel. This will cause you to gain more camber in bump (and, therefore, roll), allowing you to run less static camber.

There could be some downside that I'm not seeing, but changing the geometry is the goal, not the side-effect.

Note: as I pointed out elsewhere, the other way to get more non-parallelism is to somehow swap in something like WhiteLine lower ball-joints, which have extended stalks to lower the roll center of an Evo X.

One immediate downside is that same camber gain from bump will diminish the car's braking performance, by unweighting the outer edge of the tyre. Ford created their own mechanical ABS on the Ranger by employing a stupidly short swing arm front suspension design which achieved exactly the same thing...

Another alternative would be to lower the outboard pickup(s) on the upright, which should achieve a similar goal with less effect on the roll centre movement and scrub ? Better yet would be to model it, either computationally (cheap good solution = SusProg3D by Bevan Young) or mechanically (see Design To Win, Carrol Smith). I personally don't like doing more than minor tweaks without having a good idea of the side effects.

 

[greengoblin]

Most likely, I am not understanding Kevin's comments, but from my myopic position, you can access both upper and lower installation points of the "eyebolt" mounting tubes, and welding (large) washers around them should not be an issue. Hmm - since this is so clear to me then it is quite obvious I am not appreciating Kevin's comments ! Time to shut up...

I have welded washer on the upper portion of the tubes. I think that is a great idea and reallly simple to do.

The lower end of the tube inside the fender well do not protrude through the sheetmetal. They are actualy welded ontop the sheetmetal. (the side you can't see)
So you could welded washer to the sheetmetal but not directly to the tubes. I assumed PieEyedPiper wanted to weld directly to the tubes.

This is why I said and feel that a larger patch type plate would be need to spread the load across a much larger area.

Kevin

 

[jtmcinder]

Yeah, I meant raise the roll center.

Good point on the problem of more camber gain when braking; only solution to that is to never slow down, I guess. Can't really lower the mount on the spindle; the tire is there.

 

[PieEyedPiper]

How much more camber are we talking about? Is it common to have full suspension compression during braking? What's the worst case scenario?

If you're now running less static camber, is it possible to be gaining only as much with the new curve as you would have any way, by say mid-stroke of the suspension travel, by running more static camber with less of a curve?

Where those two lines cross on a graph would be very interesting.

 

[jtmcinder]

Well, this is where the question of whether you're using bars or springs to control body-roll comes in. If you're using lots of spring, which are equally effective against dive, then you could shift more of your camber to coming from geometry and away from static. But if you have big bars, then your car will dive more and you might need to stay away from this new mod.

Keep in mind that the wheelbase of a DSM is much longer than the track is wide, so less longitudinal than lateral weight transfer occurs for the same amount of acceleration. So a stiffly-sprung car could easily get benefits from a steeper front bump-camber curve. But there are other factors ... several of which I'm sure I'm forgetting.

 

[Scott McIntyre]

Scott,

How much static camber are you running? Curious since you are already seeing wear on the ball joints from them being extended beyond their full range of motion.

Thanks,

Kevin

The most static camber I've run since installing the SPC arms is -3.0°, IIRC. I might have had -3.5° briefly, but I don't believe so.

Also, my ride height has always been relatively high due to the big 275 width tires. I run 1.75" to 2.0" between the tire & fender lip. By my calculations, that equates to a ride height of 14.5" to 14.75" from the axle center-line to the fender lip.

 

[PieEyedPiper]

Here's another data point on the failure of SPC's retainer mechanism that holds the boot to the balljoint.

<iframe width="560" height="315" src="http://www.youtube.com/embed/SQDKKkoBvFc" frameborder="0" allowfullscreen></iframe>

6 months ago I noticed the passenger joint had some play and the boot was full of water/dirt. I cleaned it up the best I could and re-applied some marine grease to the ball, socket and boot and threw it all back together. Oddly there was no more play but obviously the damage wasn't gone, nor going to get better. So whatever, I drove it till just today. When I was in there I also replaced the retainer with safety wire, both sides. The driver's side got it's water dumped out, but no added grease. This joint was less impaired.

6 months later I'd begun to hear it clicking at extreme steering extensions on the passenger side so it was finally time break out one of my gold nuggets and replace the joint. Both sides actually, as I knew that driver's side was also compromised even though I couldn't get either joint to budge by hand.

New joints went in this afternoon with my plates set to max caster. I'm crossing my fingers for a nice 6* flat on both sides. We'll see. Alignment is on Thursday.

..still have to figure out a solution for the bushings. I want those eliminated, badly.

 

[pksystems]

Old bump, but I didn't see this posted on dsmtuners yet.....

Megan Racing looks to be making adjustable upper control arms now.

http://www.meganracing.com/products/product_detail.asp?prodid=1894&catid=96

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[FIBA M - EC17PSE]

Old bump, but I didn't see this posted on dsmtuners yet.....

Megan Racing looks to be making adjustable upper control arms now.

http://www.meganracing.com/products/product_detail.asp?prodid=1894&catid=96

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That pic is not going to do them justice. They have bent the arms up rather then straight, that means less room to move and your limited anyway, nice and cheap but thats it cheap, i doubt these by the picture will be any good. There toe arm arnt so........

 

[Black95TSIawd]

"PRODUCT NOTE: Due to the re-design to incorporate an adjustable ball joint, clearance compromises are made and may interfere with the frame at extremely lowered ride heights Please compare to the OEM front upper control arm for arm to frame clearances before purchase."

Since SPC's did this as well, and adding adjustable ball joints alone do this as well, the only option without fender clearing would be cut stock arms.

I am glad someone else built something however and I will purchase a set if I keep my car.

 

[99ECLIPSEGSXDSM]

Would be interested in seeing how low you can go without hitting the control arm. Doesn't look like much at all.

 

[ACM]

Even worse are the 6 socket head fasteners - if the ball joint doesn't kill the clearance the screws certainly will. Hard to tell from the image just how much clearance is lost, but since there's a warnig about it, probably quite a bit.

Why someone doesn't simply make an arm with the adjustable inboard pickups and an OEM-style ball joint is beyond me. Marginally more expensive perhaps - but at least the supplier would be able to sell lots of them ?

 

[TSiAWD666]

Aw no caster. Pewp. Still might be a backup for when I run out of ball joints Just need to know the camber adjustment range as it's not even listed.

Thanks for sharing this, had no idea these came out.

 

[jakelandry]

Even though theyre curved upward it won't impact clearance. Only the ball joint and fasteners on top will. If the ball joint isn't as large as the factory one, this may actually be useable.

 

[Black95TSIawd]

Well someone hurry up and buy one so you can tell us how wonderful they are.

 

[gofer]

Not to bump an old thread but I found myself needing a set of SPC UCA ball joints too. I contacted SPC as a hail mary and gave them the PN off of the ones that came on the UCA (720361) and they gave me a new PN that superscedes it, PN 660306. They weren't $40/ea (closer to $70) but if they're identical then I'll pay it.
Placed the order and will take pictures and measurements with the original 720361 ball joints to compare. Here's to hoping though!