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Hey all! Does anyone on here have any experience with T3's upper (or lower) trailing arms?
I understand that the watts linkage combined with the stock four link can bind up under large amounts of articulation. Would swapping to heim joints on the upper trailing arms reduce the amount of binding during cornering?
I figure the drawbacks would be increased noise, but if it reduces binding and allows for pinion angle adjustment on my newly lowered car (just installed BC coilovers), is it worth it?
What I took away from that... and assuming that you aren't modifying the chassis.. panhard bar brackets etc... is to replace the upper and watts link hardware with new OEM. And I have the T3 hardware for the lower.
I think the idea is that the new OEM upper and watts link restore the bushings to new, more compliant rubber.
But this was before T3 came out with the adapter that is mentioned above.
Oh interesting, I didn't realize they updated the upper links with the option to make it parallel. I assume they're just using the stock mounting locations just putting in a longer bolt so it mounts on the outboard side of the stock location. Does anyone have pictures of that? As always I wish T3 would include pictures of their parts mounted on the car.
What's to gain then from running their upper links with the parallel mounting? Less binding with adjustable pinion angle?
I like T3 but they really need to put a disclaimer on their upper links, not to use them without mounting the front "outboard" of the original location. I mounted both the upper and lower and the rear end would barely move (car on jack stands, springs removed). I called and they told me to move the fronts outward *. Now a month later they offer the hardware but still don't state not to use in original location. Hmmm.
The upper links move in a short outward-pointing arc. Looking at it from the top, or rear, the distance between the links' rear mounting points (on the axle) needs to change as the axle twists. Not much, but it has to be able to move. Also as one wheel moves more than the other, like if you jacked one wheel up to change brakes, this puts a twisting force on the axle because the short upper links are at different points in their arcs. The OE rubbers absorb this force, but the rod ends will not. I put new OE links on top, with the T3 lowers, and I can now move the axle through its range without binding. I should note that I also replaced the watts links with rod ends so they don't get any binding. As your rear goes up the shorter top links make the pinion rotate down. This puts a twist in the watts links' rubber ends. Not much, but it's one of those "bind" points, so I eliminated it.
*Before moving the upper links outward, pull your cargo boxes and inspect the body where the links mount. This spot is famous for rust, so I wouldn't want to put extra stress on it without checking it first. I was surprised to find mine was rusty, and that's why I didnt use the T3 links mounted out there, putting extra stress on a weakened area.
All good info. I like the idea of the solid links on the watts, where did you source that? or was that a custom situation?
And as for sourcing OEM suspension parts. Is that even possible these days? I’ve only been able to find the Energy Suspension poly bushings to replace the rubber for both the trailing arms and the watts linkage.
I wouldn't use poly bushings anywhere on the rear suspension except maybe the lower links, since they have the straightest arcs / least twist. The "binding" everyone talks about is when the rubber bushings can't twist anymore and well,... "bind". Putting hard poly bushings in there will just make it bind sooner.
I think. Haven't tried poly bushings on this car. If the links all swung straight and smooth on their bolts then poly would do its job. But the rear suspension bushings on our cars NEED to have that squish in them.
I got the new upper links from Mazdatrix. Or Mazda, not sure. My T3 upper links are for spare parts now.
That is great feedback. Especially running that cantilevered upper mount 'extension' on an original, almost 40 year old chassis.
And for reference, all our OEM suspension links, watts link bracket, and even most of the bolts are all available from any Mazda dealer. Just grab the part numbers out of the Parts Catalog and bring the list to your dealership parts guy. Once he finds out its all for an old Rx7 he will understand.
This is one of my google docs from a parts order I put into the local dealership. The misc hardware that I quoted below that is for new metric hardware, sourced from Belmetric, not worth reusing old hardware.... if it comes out in one piece to begin with.
Last edited by tommyeflight89; 04-07-20 at 04:32 PM.
I’ve got all the poly stuff ready to go into my car. I know it’s not going to be ideal but the rubber I pulled out was beyond rotted. The Energy suspension stuff seems fairly decent, but I guess I won’t find out until I put it to the test. I know I’ll be finding another solution at some point in the future.
I understand that you already bought the new poly bushings, but understand that they will give worse handling than stock. They will exaggerate the binding issues inherent to the rear suspension.
Poly isnt tooooo bad if you have stiffer springs at least.
i have done the articulation test with the axle on trolley jacks with the springs and shocks out, the poly bushes do distort and squish admirably on full flex, (its actually ludicrous how much they have to squish on full flex), but then again, i have torn the mounts off my diff once, but that was on a turbo setup on semi slicks so not sure what conclusions to draw there. Ive never actually experience the binding issue affecting handling as far as my dullard senses can tell.
you can drill the upper polies in a bind (pun intended? I dont even know any more) for more squish.
this was all with "superpro" brand bushes.
saying that i might still invest in some oem uppers at some stage for a sanity check.
Well so the way I'm looking at it right now is, I already have the poly, and I don't have the money right now to buy new OEM stuff. Like I said, I know I'll be replacing the poly at some point in the future. In the mean time I just want to get my car back on the ground and drive it. I have a rear axle and rear brakes to rebuild still, and the rest of my BC coilover set to install. getting by suspension dialed will come later.
Hey Heebee, I wasn't trying to bust on your ride. Just my opinion. 10 years ago the big thing was drilling holes in the rear link bushings, to soften them. Anyway ,..
First pic below is with T3 Upper and Lower links...
I had T3 make them for me. I have a ford 8.8 rear end and the watts linkage doesnt end up in the same spot as original (because the diff is wider). I had the OE watts shortened/lengthened to fit by a local welder but the results were unusable. So I sent T3 the lengths I needed and they made them for me. If you know the right size ends you could have any rod-end shop make them for you, but I'm constantly disappointed with local welders and mechanics, so I had T3 do it. They were working on an order for me at the time.
me and Fungus Mungus made our own watts links. figured out what the lengths are and he had the spacers made.
if you want the funny; i cleaned out my car and i have a set of stock watts links and a set of rod end watts links, so i have no clue what is actually installed under the car!
Whatever you do, DO NOT polybush the radius arms. You will lock the axle solid in roll. RWD cars need roll for traction. You will load up the outside tyre until it passes its grip limit and the rear end will break away suddenly and uncontrollably.
The reason I used the TT parts the way I did was to meet period Gp2 FIA regs that did not allow body or bracket changes. It worked perfectly allowing max axle articulation. Happy to see someone at TT was paying attention 'after the fact'.
What is also needed for max traction is roller-bearing watts link with rose-jointed rods. I'm working on that now. If anyone dons of off-shelf roller bearing watts links please PM me.
I asked T3 if they were planning on doing a rod end link kit for the factory watts setup for the SA/FB's and they said they weren't planning on it. But if enough of us asked for it maybe they would consider making it. I would certainly prefer a nice watts linkage setup over their "some custom work required" bolt-in panhard.
A twin roller-bearing housing that could press into the standard watts link instead of the rubber bush would be ideal.
Originally Posted by heebeegeebee
I asked T3 if they were planning on doing a rod end link kit for the factory watts setup for the SA/FB's and they said they weren't planning on it. But if enough of us asked for it maybe they would consider making it. I would certainly prefer a nice watts linkage setup over their "some custom work required" bolt-in panhard.
Greg, what do you mean by twin roller bearing housing? Replace the main center bushing with a TRB? That point has side loading when in a strong turn but is it worth the trouble for the 1/8" non-deflection? That's not where the binding is in the watts.
By using rod ends on the watts links the binding caused by axle rotation is eliminated (binding in the watts links bushings).
Yes, replace the watts link rubber bush with twin roller bearings or even needle-roller bearings.. The only rotation possible in the standard link is by rubber deflection of that bush. And yes, rose joints on both ends of all 6 axle links helps allot.
Originally Posted by Maxwedge
Greg, what do you mean by twin roller bearing housing? Replace the main center bushing with a TRB? That point has side loading when in a strong turn but is it worth the trouble for the 1/8" non-deflection? That's not where the binding is in the watts.
By using rod ends on the watts links the binding caused by axle rotation is eliminated (binding in the watts links bushings).
It should be possible to find a metric spherical bearing that fits the Watts Stud that is welded to the rear axle. From there you would need a bearing holder that would be welded to center link to replace the rubber bushing. That said, doing this will be adding allot of extra load to the watts stud that is in single shear from the factory. Support brackets that made this a double shear mount used to be available because cars on 13" DOT racing tires have caused these things to crack/fail. And that was with rubber bushings every where - Pro 7 racecars.
In the end, I think you guys are spending allot of effort and money to "improve" on a bad design. Yes a watts link is superior to a panhard rod but the factory watts location is too high and the fact that it has unequal length arms and is off set dramatically creates binding at travel. A simple panhard rod using 1/2" or 5/8" rod ends that is located at the same level as the lower shock mount would work allot better. The 4-link suspension in the second post on this thread has an extremely long panhard rod and as a complete package, that suspension worked better than any thing you can do with the OE suspension/watts link.
As far as panhard rods, I am not referring to the T-3 panhard rod setup. You need to fab a couple of mounts and run a proper straight panhard rod. Some of you have done at least that much work already
04-06-20, 11:59 AM
