85 RX-7 Race suspension help?
 

Hello all,

I am in the middle of re-building almost all my RX-7 and right now I have all the suspension off the car. I am building it to be a track car mostly with a few short trips on the street here and there. I have been reading up on some of the different suspension setups available but honestly nothing really seems to be "race" designed. Sure the Racing Beat suspension package is a step in the right direction but the shocks that are still available are not really designed for racing. I am NOT looking for 30 way adjustable or crazy high dollar but I am a bit lost of what is available out there that is more track than street setup.

I might add that I have removed A LOT of weight out of the car and before when I had the car on the ground it looked like a rally car due to the weight being out (almost like pulling then engine) and I have removed more weight after that (think anything not necessary) and I am worried that if I bought the Racing Beat 1 inch drop lowering springs it would still be very high due to it being designed for a "full weight" RX-7. I'm fairly new to RX-7 race car setups ect but have an understanding and would like to hear what other racers might suggest.

I am curious what everyone these days run on the track due to lots of production getting scarce.


https://cimg1.ibsrv.net/gimg/www.rx7...0464839e9b.jpg

If you want a real race suspension setup go with Anze suspension or Motion Control suspension. Both of them make real race care suspension setups.

Like with all race cars, the answer depends on regulations and budgets. In my case I'm building an FIA Group 2 car which is nearly standard except for sprinsg and dampers, brakes, engine and gearbox internals.

On the front you need to ditch the Mazda struts due to stub axle weakness. In my case I used near-identical Corolla AE86 uprights with 40mm Bilstein coil-over tubes, alloy hubs for Ford studs and standard top mounts. Rose joints for TCAs and tension struts, standard steering rods and ends completes the front.

On the rear I also used AE86 Bilstein dampers and slightly heavier springs in the original location. I'm in the process of rose-jointing the 6-link rods, building a roller-bearing Watts link and remounting the top radius arms to be parallel to eliminate binding in roll.

For the track, the front strut tubes need to 'pass through' the upright with separate steering arm mounts welded below them so you retain roll centers and damper travel while lowering ride height.

That sounds like a good set up. MR2 struts also fit in the front if you are keeping the FB strut housings.

What do you mean by Strut housing? The MR2 upright (cast steel bit welded to the bottom of the strut that caliper and hub attach to) has the 'pass-through' hub for the driveshaft and no stub axle so not suitable for FB.

My setup is going to end up being an Anze Suspension configuration w/ FC Front Subframe, Roll Center Correction Kits, S4 LCA, Stock ABS Knuckles w/ Speed Sensors, and my custom rear 4-link that I've documented.

Angelo Zarra of Anze is great to work with... Legendary.

Making my top links parallel will not completely solve the binding problem since shorter arms will subscribe a greater arc for the same suspension travel and therefore torque the axle but until I get in on the chassis stand and jack up one side of the axle to simulate roll I won't know how much of a practical effect it will have. It might be that I end up retaining rubber on just two ends of the radius arms rather than the factory eight.

Forgive the state of this car, it's my parts, development and test mule and otherwise rusty old hack.

With all 8 radius arm ends rose-jointed the suspension bound solid at 3" of compression and 3" of droop in roll.

This is allot for a race car but rally and rallycross cars depend on rear end traction in poor conditions for speed so more would be better. With the top link mounted as in the pictures an extra inch each side in roll is possible but the top radius arm really needs to be longer for more.

I plan to fit a longer top arm and weld a tube mount through the inner wheel arch and support it back to the body floor on the inside.

https://cimg6.ibsrv.net/gimg/www.rx7...0b6c758102.jpg
https://cimg7.ibsrv.net/gimg/www.rx7...ee419914ed.jpg
https://cimg9.ibsrv.net/gimg/www.rx7...a88ef7616d.jpg
https://cimg2.ibsrv.net/gimg/www.rx7...553d056feb.jpg

I run an MCS suspension on my first gen. If your looking to just have a little fun look at the technotoytuning. Ground control still offers first gen stuff. I guess stance does also but I don't know much about them. I assume your just looking for a fun track day car so the above 3 are affordable and good enough to get you most of the performance of the expensive stuff.

The radius arms in my pics above are from Techno toy. Unless you want to experience accident-inspiring solid suspension bind, do not use techno toy rose jointed radius arms. You would be much better off with standard Mazda arms and new, soft rubber bushes. As always, good shocks and new bushes will make more of a difference that most drivers could use.

I meant shocks and spring setups. The other stuff isn't of a ton of interest. The lower rear links are an ok deal, you can't make them yourself much cheaper unless you have materials already or if their rod ends are junk I suppose.

Depends on how far op wants to take the car I guess.

Your glasses front end may end up being your nemesis. Trailering, curbs, tire changing at the track.
Also mounting things up there is harder I imagine.

Also bear in mind that Toyota Corolla AE86 rear dampers and front struts will fit and are probably more widely available.

Sorry guys I completly forgot about this thread some how. Yes my main focus of my car is track days, hill climbs, and auto x mainly because I don't think my car follows some rules for wheel to wheel racing but it will be mostly a built for fun track car and a bit of street driving. I guess when you look at it 1K for coilover setup isn't breaking the bank when others out there are way more expensive. And thank you for pointing out ground control making parts still as I have yet to see that come up on my searches. And Greg wow your car is going to be wicked when you get it all dialed in! Thanks for sharing your pictures :)

If you can fabricate follow along with some of my threads and I show everything you need to have much better suspension than most of the bolt on aftermarket stuff out there for much less money. Standard struts converted to use Bilstein strut inserts, Ground Control camber plates with cheap eBay coil-over sleeves, and 1.25 sway bar in the front. Third link with Panhard bar in the rear, 5-inch circle track springs fit in the stock perches, Bilstein shocks, no rear sway bar. With this setup my car was one of the fastest cars on track, set fast times of the day and win races overall.

https://www.rx7club.com/1st-generati.../#post12115201