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2G Let's build a Front UCA

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99gst_racer

Moderator
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1,542
Apr 5, 2003
Coloma, Michigan
The purpose of this thread is to discuss ideas and features for a front upper control design for the 2G cars. It's an open forum, so let me know what you do and don't want to see in it.

My initial plan is to have a fixed balljoint and to use heims on the inboard end to make adjustments for camber and caster. To do this, one end will need to attach via a clevis. This will prevent binding when caster adjustments are being made. My only concern with this idea is that I don't know if there's sufficient clearance in the fender area when the suspension is fully compressed.

I don't have a balljoint selected yet. I'm open to suggestions. Options are limited, because it cannot be too large in diameter, and more importantly, it needs to be shallow in depth. I'm leaning toward using the Moog OE replacement balljoint for the 2G cars, but I am open to other suggestions.

I do have a set of prototype inboard mounts. These will be the connection of the heim to the strut tower. Final production pieces will be zinc coated to resist corrosion.

These are my ideas so far and nothing is set in stone, so feel free to make suggestions and share ideas.


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Does anyone have a pic of the stock UCA swung all the way up? I'd like to see how much clearance is around the balljoint area in the fender pocket. I miss being able to head out to the garage and answer questions like this myself.
 
Exciting stuff!

My initial thought process was to use a stock style ball joint so that's a good idea. Any taller and it strikes the shock housing. I would say that there isn't much more room to work with outside of the stock UCA dimensions. It just barely fits on full compression.

I have a dumb question... Are heim joints necessary on the inboard pickups? Don't we want the arm to move up and down only, and not be able to twist around?
 
Does anyone have a pic of the stock UCA swung all the way up? I'd like to see how much clearance is around the balljoint area in the fender pocket. I miss being able to head out to the garage and answer questions like this myself.
Do you need with or without suspension installed? My 2g is literally sitting with only the UCA's installed in the front suspension, so I can push it up and take measurements / take pictures, but if you need it based on the limits of suspension travel, then I'll be a few days away from that.
 
Do you need with or without suspension installed? My 2g is literally sitting with only the UCA's installed in the front suspension, so I can push it up and take measurements / take pictures, but if you need it based on the limits of suspension travel, then I'll be a few days away from that.
Without suspension attached, please. I just need to see a few shots of what it looks like with the UCA pushed all the way up as far as it will go. I really just need to see how much room is around the balljoint end.
 
I have a dumb question... Are heim joints necessary on the inboard pickups? Don't we want the arm to move up and down only, and not be able to twist around?
Honestly, I hadn't considered not running heims on them. A heim would offer a more fluid motion and better resistance to corrosion at the pivot point than something like a clevis attachment. That and when adjusting caster, if you didn't have a heim, you'd have to loosen all 4 nuts on the posts going though the strut towers to allow them to slightly pivot.

I guess it could work though. I just don't know if there's any benefits to ditching the heims other than maybe a small amount of money.
 
Honestly, I hadn't considered not running heims on them. A heim would offer a more fluid motion and better resistance to corrosion at the pivot point than something like a clevis attachment. That and when adjusting caster, if you didn't have a heim, you'd have to loosen all 4 nuts on the posts going though the strut towers to allow them to slightly pivot.

I guess it could work though. I just don't know if there's any benefits to ditching the heims other than maybe a small amount of money.


Just thinking out loud, Paul. I'm not an engineer by any means. Adjusting caster without any additional steps is reason enough to use heims for me.
 
Exciting stuff!


I have a dumb question... Are heim joints necessary on the inboard pickups? Don't we want the arm to move up and down only, and not be able to twist around?

With three pick up points the arm cannot actually twist. The spherical bearings are also a really good idea because they allow from some misalignment without binding but zero unwanted movement. It's pretty much a given that there will be misalignment since the inboard eyebolts (clevis in Pauls setup) go into no indexed holes. With poly or rubber it does not matter that much but if you put in standard bearings or hard delrin things will not be good.
 
Does anyone have a pic of the stock UCA swung all the way up? I'd like to see how much clearance is around the balljoint area in the fender pocket. I miss being able to head out to the garage and answer questions like this myself.
I can get you that pic once I get back home ;) love your parts bro. Once my 2g is ready I'm buying everything you sell for them haha :)
 
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My only suggestion is all clevis designs I've seen have looked like the below, with some more detailed posts saying this was the optimal shape based on FEA. I could look to find more info if this is of any interest, but I was just excited when this was linked to me and was the first thought that jumped to me to offer. I would have assumed you have seen these before, so if your prototypes were just proof of concepts, please disregard.

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Sorry for being MIA. I took a mini vacation down to Kentucky this past weekend and upon arriving home, I laid my Hayabusa down on the interstate on the way to work Monday morning. Messed my shoulder up well enough that I haven't been able to lay down or sleep much since. I haven't felt like doing much of anything since.
 
Paul, thanks again for taking the initiative and developing something new!

I apologize if my assumptions & questions below move this discussion a step backwards but hopefully it serves to further align those who read this threads thinking, allowing us to create a set of min. and max. goals for this community project.

Assumptions:
1.) These will be used in conjunction with Paul's front LCA's.
2.) The user will have coilers or some other means of controlling ride height.
3.) These UCA's are intended for autoX or road racers looking to correct suspension geometry from lowering vehicles ride height.

Questions:
1.) What is the min. amount (inches) the inner pick-up points need to raised in order to for new control arms to be effective?
-It would be a real shame to put all this work in only to determine after the fact, that the major benefit is steering feel due of the switch to heims and not see significant increase in corner speeds.
2.) What off the shelf components are available (A&A Manufacturing, Speedwaymotors, etc...) that would make this easier to manufacture and service?
3.) Should we consider abandoning the factory inboard mounting location in favor of a bolted/welded in bracket, so that a more traditional upper A arm style can be used?
-This is bit of a stretch but when brainstorming there are no bad ideas, right?
4.) What are the suspension settings this kit will help users achieve?
-I think this is one of the most important points to establish as


Please feel free to push back on the above or expand upon it.
 
Sorry for being MIA. I took a mini vacation down to Kentucky this past weekend and upon arriving home, I laid my Hayabusa down on the interstate on the way to work Monday morning. Messed my shoulder up well enough that I haven't been able to lay down or sleep much since. I haven't felt like doing much of anything since.

Sorry to hear. Feel better, dude.
 
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