Suspension.

Re-valved Koni Sport shocks,
Koni Thredded perches for 2.25� ID springs,
Hypercoil springs (550# front 6� long, 300# rear 7� long)
Home made shock tops made from M2 shock tops.
Racing Beat Hollow front bar
Racing Beat Rear Bar
Racing Beat End Links
Super Pro urethane suspension bushings.

After closely studying the design of the Miata suspension I decided it needs more bump travel particularly if lowered. Also I saw no good reason to have the shock rubber mounted in a way that prevents it from acting directly. Spherical ball mounting was in order. I studied both the M1 and M2 designs below and came up with my own design shown below.


One thing I noted as I studied the Koni shocks is the rear shock still has over an inch of shock rod sticking out the top when the rod bottoms out in the body. This is a good thing to know if you�re just planning on cutting down a bump stop or using a very soft one. It won�t take much to make the bump stop ineffective as the shock will bottom before the bump stop has a chance to be effective. The shock tops I designed allow the shock rod to extend up further than the top of the bump stop so this is not an issue. The front Koni shocks compress further on the other hand.

The shock tops are made from the metal part of an M2 shock top plus these parts.
1.25 OD 4130 steel tubing machined ID to 1� with circlip ring grove.
1� OD �� ID Wide series Teflon lined Spherical Bearing.
1� Circlip snap ring.
1� tubing used as a spacer.

The steel top cup was cut off the NB top mount and the machined 1.25� piece was welded on. Everything pressed together and held in by the circlip later I added Permatex sleeve retainer as well to securely hold the bearing from moving in the housing.

The shock rod slips trough the hole in the bottom with clearance and the shoulder stops against the spherical bearing.

The rear assembly. I used the bump stops from an NB and added an Energy Suspension urethane spring seat to keep things from creaking on the top side. Originally I had a 6� rear spring. Warning a 6� rear spring will not work. It won�t have enough travel and will coil bind. The rear spring needs to be 7� to have enough travel.

The Front assembly. I had to ad a �� rubber and a plastic spacer to the bump stop and it seems to be just enough to keep a 225/45/15 Avon Tech R from rubbing hard metal to metal on the top of the fender. Now I just polish it a little. I use all the available travel up there without moving metal out of the way though. The splash guards were already rubbed out of the way.

Front and rear assembled. I painted them blue because that�s the color paint I had on hand. Another benefit from this design is that since the top of the shock rod extends up further the excess shock travel you end up with from going to the much stiffer springs is used up. This makes it so the springs don�t come flopping loose when you jack the car up. There is right at zero preload in them when they are un-loaded as it should be. Note also that for the NB bump stops the rear one is both shorter and softer than the front.

installed pictures.