uglygun

Read the suspension FAQ and didn't see this one covered regarding UCAs.


Team Z upper control arm kit...

It's got the words "strip" in the title of the product description. YES, I would call that a significant hint.

But, are they worth anything to a guy wanting to build a car meant for carving corners?

I like the fact that there appear to be fully articulating spherical joints at both ends and that it looks well braced. Could putting these on with a set of fully articulating spherical ended MM XD lower control arms make for a very free to articulate solid axle?

Intuition leads me to suspect that the upper/lower combo would make for eliminating the binding issue quite nicely. With a panhard bar installed all the things should be doing is setting pinion angle anyhow.

What I am wondering is if their "corrected" geometry helps for anything other than launching at the drag strip. I can see the things almost becoming like that of a modern mustang's 3 link. I don't exactly have a problem with that.

I don't like the idea of a rear suspension that binds, in stock form, so one of my very first upgrades is to a MM panhard bar. Eventually the lower control arms are gone in favor of something along the lines of the MM XDs or maybe the Team Z(since they did get mentioned as preferred) if it's suitable for road course and not just strip.

Eventually I will be throwing a set of coil overs on all four corners as well as doing a Kmember/A-arm swap. But those things will be down the road quite a fair bit.


I have 3 tracks within an hour drive for me. Willow Springs, ButtonWillow, and Famoso. The intentions for the car are to have it do a bit of everything well including being a daily driver that can be fun on the back roads in the hills. Won't be the shining star of absolutely everything but it won't be a slouch at anything either.

The TEAM Z rear suspension package is within my budget and it looks ridiculously simple to install.

uberstang1

They should work well compared to stock because of the spherical joints, but the relocation and the adjustment for pinion angle only serves from launch purposes. I run them on the street with no issues, the hardest part of the install is pressing out the stock bushings on the ears on the rear end. You would need to finger out what to set the pinion angle at so its neutral from your purposes.

uglygun

Is the geometry change with the Team Z kit better for drag purposes only?

Or would it also be suitable for things like autocross? I could see where longer spherical upper control arms would be more suitable. However, I can see where angles would play a big component and could compensate for what look like shorter arms on the Team Z uppers.

uberstang1

Im not an autocrosses so i don't know, thats a question to ask a serious auto cross racer. but people in the autcross world never worry about instant centers and geometry so I highley doubt its any benefit to you.

Norm Peterson

The upper link inclination is what primarily determines the dragstrip benefit. This does not directly affect cornering considerations and is one of the nice things about 3-link arrangements in general.

The upper link length is partly responsible for determining how fast the anti-squat varies as the rear ride height varies. Generally, slower rates of change would be better for autocross, since the flip side of anti-squat is anti-lift (which has a couple of downstream consequences).

I have no idea how long the 3rd link you speak of happens to be. But the OE 3rd link on the 2008 S197 is pretty short as well (I'm getting just over 8-9/16"). In later years the OE UCA might be slightly longer, but not by much. At least one S197 aftermarket UCA is also slightly longer than the '08 UCA, but again not by very much.

At this year's Solo Nationals there were no other chassis at all entered in F-Stock (the joke running something like "D-Stock, E-Stock, Ford-Stock"). And in ESP, Terry Fair's overweight fully streetable and daily driven S197 placed 4th against much more fully developed stripped/lightened/trailered competition.

The good thing with the 3-link is that you can tune the anti-squat pretty much separately from axle roll steer and roll center height. There isn't anything terribly wrong about having a rear roll center that drops slightly on acceleration (corner exit), so it's mostly how the amount of squat permitted influences the rate of axle rollsteer (which also varies with ride height) that you might have to tweak when you're looking for a few hundredths of a second.


Norm

uglygun

I should note that this will be for a 95 Cobra.

It's gonna be dual upper control arms unlike the single UCA of the newer cars.

Page for what I am talking about is here,
http://www.teamzmotorsports.net/product_p/tzm-uca1.htm

Norm Peterson

I'm afraid that when I read post #1 and saw
and
without any link to the Team Z site or pictures that would have clarified what you're looking at - I assumed that you were planning to make a change from the converging/triangulated 4-link to a true 3-link + panhard bar setup. That's very close to what I'd do if I had a SN95 that I was looking to update (think 3-link + Watts link).


So I just watched the video on your new link . . .

The Team Z kit is first, last, and always intended as a dragstrip arrangement, as the shorter uppers provide a faster increase in the anti-squat even after you might increase the static A-S value with LCA relocating brackets (sometimes aka "anti-squat" brackets). The folks on the video don't even mention street driving, let alone corner-carving.

This kit does have some influence on cornering, in that the rate of axle roll steer goes up fractionally. and again this is courtesy of the shorter UCA length. You could probably tweak it to work at cornering fairly well, but I'm pretty sure that rod-ended standard length UCAs in the OE UCA pivot locations would always be better for cornering.

Generally with a triangulated 4-link suspension axle and the OE LCA settings, rear axle roll steer is already a bit on the high side. This starts noticeably getting in the way of good slalom performance at some point, so you don't want it increasing any faster than necessary. Axle roll steer also gets affected by any LCA relocation, so the end result depends on all of the details just like the anti-squat picture does.



A few words about "bind". As long as your axle is located by exactly four links that are attached by "friction-free" rod ends/Heim joints at all eight pivot points there is no "bind". But it's not just about having Heim joints to eliminate bind that's caused b y bushing stiffness, and I'll get to that with "geometric" bind.

Unfortunately with the Fox/SN95/NE rear suspensions, you still need to bind up the axle side connections of the LCAs so that the LCAs don't roll over and let the springs pop out of their seats. Therefore, the best you can do is 6 "friction-free" spherical pivots out of 8. Short of a proper coilover arrangement anyway (which opens up a whole 'nother can of worms).

The OE arrangement approximates "friction-free" pivots with rubber blocks that at least do not develop large forces in reaction to being distorted. Hence you're starting to get a little bind, the amount dependent on how "stiff" the rubber is.

Poly bushings get a whole lot worse at adding "bind", since the high stiffness that helps in one direction hurts in at least two other directions. Even worse material choices are possible, but I won't go there. Poly is bad enough.

The above cases of "bind" involve the end connections offering significant moment resistance (think in terms of bending the links here).


Worse than bind due to bushing material is "geometric bind", which is caused when you add a fifth locating element such as a PHB to a triangulated 4-link. Here, the geometry is fighting with itself, and ultimately something has to give else the suspension won't let the car roll without bending or tearing something (think torque boxes here).

This PHB/triangulated 4-link thing has been done, sometimes even with fair success. But you have to be very careful about the height at which you install the PHB - and on the bushing material used particularly in the converging UCAs. The devil is truly in the details here, and the sacrifices that you have to make to get this to work as good as it possibly can will ultimately get in the way of either pinion angle control or drama-free cornering. Personally, I don't see it being worth the trouble to work up something that still has to be significantly compromised in some way or other.

A fully rod ended set of LCAs and UCAs plus a rod ended PHB installed at the wrong height is going to develop as much "bind" in roll as 5 links could possibly cause.


Norm

UPRSharad

The relocation kit is not designed to handle cornering forces.

This is more appropriate for your '95 Cobra:

http://www.uprproducts.com/mustang-c...trol-arms.html

http://www.uprproducts.com/mustang-b...gs-8-inch.html

uglygun

Talk about that can of worms because a coil over set up is being heavily considered.

I'm about a month or so away from having the entire rear axle rebuilt(going from stock 3.08 to either 3.73 or 4.10) to include new axles.

When the axle is dropped that's when the upper control arms, lower control arms, and the panhard bar are going in. And I'm damned tempted to throw coil overs on at the same time just to have the rear end 90% towards "done" with tuning and remainder of setup to come down the road when the front end gets redone.


Completely understandable.

About the only reason I'm seeing poly and rubber being an option are with regards to ride harshness as well as a bit of shock absorption with less maintenance. I can see spherical heims being a bitch to maintain as well as potentially causing some harm in regular every day driving to the torque boxes through fatigue and sheering forces.



I've read the parts about how MM only sells LCAs and if a panhard bar is to be used then the UCA's be kept as rubber insert UCAs. I can fathom why they say that and what they are trying to avoid.

I can also see how if triangulation is being done by a pair of upper control arms that a panhard bar kinda winds up begging the question or could work against the job of the triangulated UCAs.

First time I looked under an 05 GT I saw the benefit to the 3 link with PHB, made perfect sense. However I'm kinda stuck with the current 4 link situation unless there's a relatively pain free way of converting to 3 link with PHB. If there is please provide me with that information.

As for a torque arm, I'm sorta considering it but not ready to go that route just yet. Kinda a one last final piece thing.

Norm Peterson

Mainly the issues are structural in nature, as the existing shock mount locations aren't really up to the task of withstanding the spring loads in addition to the damper (shock) loads. That's before you start running the spring rates consistent with a corner-carving toy and the increased amounts of damping to suit that.

Combining those loads concentrates them over the small areas of the upper shock mount bushings (ultimately on areas only a little bigger than the shaft nut ends and the washer seats on the shafts), which were designed for OE shock loads only. People who have run air shocks with the OE springs still in place have occasionally discovered this when a shock shaft tears through its mount and punches its way into the trunk.

So you'll want to do a bit of structural reinforcement, in a way that provides a good load path from the shock mounts to main chassis structure.



What happens is the OE lowers and uppers define one geometric roll center, while the LCAs and the PHB define a separate one. Together they form sort of a "virtual rear stabilizer bar" of unknown stiffness (that can be quite large, depending on the details - which is exactly where the devil in this-all resides).

One of those details is how closely you can match the PHB-defined RC to the tri-4link RC. While it is possible to match the static RC's "exactly", roll centers do move about as the car's ride height varies, and these two will not stay "in step".

The next detail involves bushing stiffnesses. You either keep the UCA bushings soft to mostly take them out of the lateral force equation and put up with a lower amount of pinion angle and wheel hop control - or make the PHB bushings soft so that the PHB only limits the axle from moving too far laterally (in which case, why bother with a PHB in the first place?).

The same concerns apply if you were going to use a Watts link instead of a PHB. Note that the WL is better geometrically (and that should you choose that instead there are two different WL designs to choose from).


Up until a few years ago, there was a true 3-link replacement for your chassis. Unfortunately, they are not in business any longer and the tooling/jigs to fab it up were never to my knowledge sold off. But you might be able to either find one used to rebuild or enough information online to fab up something similar. Evolution Motorsports "Tri-link", and they also offered a Watts link. Short of serious dragstrip abuse involving 600+ power & torque and pretty big grip (and perhaps other case-specific issues), it seemed to be a decent enough product.

I have also seen a prototype of a 3-link that was intended for converting the '78-'87 GM A/G body cars from a triangulated 4-link arrangement that was very similar to the Fox/SN95. Don't think anything came of it, probably due to the A/G body folks of a few years ago being nearly 100% drag-race oriented and content to work with what was already available for that activity.

I suggest that if you do decide to move away from the triangulated 4-link that you make a clear choice between a 3-link and any torque arm up front. There are some differences in weight, unsprung weight, and static and dynamic geometry, and in the ability to tune the suspension properties of anti-squat/anti-lift and axle roll steer. There probably isn't a single universally "better" choice between the two . . .


Norm