which mod fixes the rear end the most?
would a watts with spherical bushings and a tri link pretty much take care of it?
i've searched but never really read which one fixes it better (if better makes sense)

 

This may not seem relevant to you, but I feel the need to post that Mazda could have gone with a panhard bar but they would've had to make it 75mm longer, so the lazy asses didn't.

 

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If you are talking about the G-Force Engineering bits you really NEED to do both. One with out the other it may make the whole thing worse. I know that Mr. Susko states that you need both. He doesn't just say that to try and make more money. When he designed the system he made the two work together.

If you are making your own or using some other brand (I don't know of any) it may be possible to make it work with just one component. I'm not sure what you would need it to look like though.

 

Mazdaspeed Motorsports makes a kit for the rear end of 1st gens that uses "2 new modified lower trailing links. Rubber bushings are replaced with spherical bearings. helping to eliminate 'binding' problem in rear end." It's less money that the G-force kit, which I very interested in, but I don't want something I have to weld in. I am planning to buy Jim Susko's book though, but the RX-7 project is on hold for a month or so since I just had to replace the rear subframe on my Protege5 autox car/daily driver.

 

The way the tri-link mounts to the rear end I don't think there is room for the watts link. The tri-link is the piece that fixes the binding problem, the lower links from M'speed don't. The binding occurs because of the upper links.

 

I would have to disagree that you don't NEED the trilink and the panhard rod. Installing just Panhard will lower rear roll center, eliminate bind caused by unequal length Watts link.

Trilink takes care of additional issues that need to be addressed. It is complimentary.

Your car will not self destruct if you just install the Panhard Rod. When I installed a panhard (and kept stock 4 links), I immediatelly noticed less bind, less roll stiffness, less roll steer and I can get on the gas earlier when exiting a turn.

sjd, the MM kit is just stock lower links replaced with spherical bearings instead of rubber. I have an early version of that kit installed, and I can say it did reduce oversteer a tad. I liked it. Keep in mind those bearings are solid metal and are loud, and stiff. NO GIVE in any direction, yet very easy to rotate vertically which reduces bind. Not sure I'd use it on the street. Lastly, that kit is not a complete solution to the rear suspension issues, does not even come close. Add Tri link and a better lateral axel locater for a complete solution.

All things equal, when designed properly (unlike stock 1st gen), a Watts link is a better, more efficient way to laterlly locate a solid axel. Less lateral movement than Panhard rod. But more expensive, more weight, and difficult to install. Long and short of it, Panhard works fine for our application.

 

I was talking about not being able to keep the stock watts link set-up with a tri-link. I think they try to occupy some of the same space above the rear. And the stock watts link actually works pretty well in design, its just puts the roll center in the wrong spot. The rear moves pretty straight up and down through most of its range. So a panhard bar would be a good first step because it lowers the roll center. But a tri-link will solve more of the problem and to do that you need a panhard bar.

 

I think jgrewe and I were thinking along the same lines. I was assuming that the tri-link would be the first step because it solves a bigger portion of the problem. It doesn't work with the watts link though.

I didn't intend to make it sound like the car would self-destruct. I was just thinking that the problems with geometry and packaging get tougher unless you do it as a whole package. Of course I hadn't considered using a panhard with the stock 4 link setup. That would work and will probably help but it isn't the whole package.

Also, I'll state it again. It may be possible to make a tri-link to work with the stock watts link. With the G-Force setup though it won't work.

We are all on the same page now.

 

Cool beans.

 

rats is the panhard hard to install, i can weld but i havent found any instructions and im werry to buy the setup and be lost.

 

the RWD 626 which share the same floor pan as well as many other RX-7 components has a pan-hard bar. I have never tried it, but I would wager to say that the entire 626 3rd member would swap into the RX-7 with custom trailing arms, and proper mounting of the chassis pan-hard mount.

I have all the parts to do this from a 626 I took apart... I am saving them for the RX-3 to get rid of the leaf spring, once and for all.