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Rear Crossmember

I have been wanting to change the rear cross member for some time. When I restored the car I never removed the part and cleaned or painted it. Now the parts are done in powdercoat texture black and it looks sharp.

I installed a camber/toe kit on the new unit so that I could make the rear adjustable also like the front of the car. I also installed a poly bushing kit on the assembly. Note the adjustment capabilities now with the kit. There is a 1.5 degree plus or minus adjustment for the camber and .75 degrees of adjustment for the toe. I guess now I get to pay the big bucks getting my car aligned, but hey when I go into the alignment place when the idiot says "Yea we will do a four wheel alignment" I wont get as upset as before because it is adjustable now.

I had to drill the stub axels to fit the new 1/2" studs I will be running. I also have bought Mcgard lug nuts from Summit Racing. The studs are morosso type and they seem to be the good quality I have always thought of regarding their products. This looks so killer, I dont think I will have any problems with loosing wheels with these studs and lug nuts. I also sent the stub axels out and had them shot peened just for my own peace of mind. I priced a set from Nismo and they wanted 600.00 for both axels. I had both of my axels done for 95.00 shipped to me, not to bad. One of the nice things about this upgrade is that the stock wheels can also fit the car still. The outer diameter of the lug nuts are the same as the stock lug nuts, so I can run my 205's if I want to also, I dont think I will because the convo's look really killer on the car, but still it is nice to have the option.

I also had to drill the rotors with larger holes to fit over the new studs. I was worried somewhat about getting the larger holes correctly drilled because I was starting with a hole already, but the drill located very nicely and the rotor fit right on the hub with no rotational play and I did not have to hit it on with a mattet.

One thing I also changed on the cross member was the rubber bushings on the ends of the part. The stock configuration on all the zx cars are basically a floating rear cross member. I was not happy with that and wanted my rear secure to the car. I designed a set of stainless steel fittings to go in place of the rubber ones. I used the old rubber bumpers on the ends and made the new parts a press fit. Now the cross member is secure to the car. Notice that the new part is on center and the old part was off center about .300 thousands. I effectivly moved the rear tires back to get them more center in the wheel wells. I never did understand why Nissan pushed the tires forward in the wheel wells. I will not have to modify the bolt that connects the differintal to the rear cover mount. I checked the difference in its position when I started installing the differential, and the rubber bushing was well within its tolerance to accomidate the differential sitting a little further to the rear of the car. I was happy I did not have to make changes in the bracket and the position of the bolt, that would have been a pain to remove and reposition.

I also took the cross member to my friends body shop and welded the cross member together where the spot welds had been done from the factory. The part is very solid now, and that makes me feel a little more secure about the part.

I also trashed the stock bolts holding the assembly to the car and got 14mm grade 10 allen bolts 140mm long and self locking nuts to hold the ends of the cross member to the car. Here is a picture of the rest of the hardware completed for the install. I had to drill the lower securing brackets to accomidate the 14mm bolt, as the stock bolt was 12mm on one end and 14mm on the other.

Here is a picture of the rest of the hardware used for the sway bar and the lower bracket. I also replaced the stock bolts for the bracket with stainless steel bolts and flare nuts.

Here is the finished assembly. I utilized stainless steel hardware every place I could, but Nissan used some non standard thread bolts in the shock mounts and the brake brackets and I could not get them in stainless steel. I think it looks so cool, and my wife did not mind to much me bringing it into the house to keep it warm. LOL No I just got some new carpet for the garage, the old stuff was looking a little bad with all the cars I have been working on lately. I like clean work spaces, and I really like the soft floor to lay on when I am working. I guess I am getting soft, but cement is not that comfortable to me anymore.

I will finish off the project with the brakes and steel braided lines from my old assembly and I'm in there. I have considered the vibration factor of a solid mounted unit, but I just cant have the rear of the car floating around like it is now. The movement affects the way the car does a burnout, and I want it going strait, not sidewayes.

After I installed the upgraded assembly I got to take the car on a long drive. The car feels like it is running on rails now. I did note I was able to hear the noise from the differential under heavy loads like 15psi of boost going up a 6% grade. I dont like the noise the differential makes to much under heavy load. I know the LSD is bullet proof, but it sure sounds like it is going to break sometimes.

installed suspension and Quaife differential

Here is a picture of the Quaife differential installed, Aint it purdy? I was for the most part happy with the Nissan LSD clutch pack type differential. I did have problems at times with one tire spinning on surfaces in a turn like cobble stones, and some parking lots, but the differential hooked up well. The biggest thing that prompted me to change it out and install the Quaife was its torque limitation. I spoke to the Nismo guys and was told that the diff was rated for about 300 foot pounds of torque. Then I got to talking to David at Malvern Racing and found out that the clutch packs were susceptible to failure under high torque loads over time. Considering the cost to repair the differential and the cost of a replacement I decided to buy the Quaife unit. No more clutch packs to adjust no more clutch packs to replace. The Quaife is a total gear setup, the unit is guaranteed for any torque load even under race conditions. True it did set me back about 1800.00 to buy and get setup, but I think it will pay off in the long run. I have not had any problems with wheels spinning in turns, and the most attractive aspect of the differential is that it is a torque-sensing unit. The differential will transfer the torque to the opposite tire in the event that one loses traction. That sounds good to me, in fact all of the stuff sounds good to me so I bought it and installed it. I finished up the differential with the NISMO LSD cover. This Nismo cover holds a little more oil then the stock Nissan cover, and believe it or not, it was cheaper then the stock Nissan part.

Here is the rear suspension I have setup in the car. For the most part is performs well, but let me clarify something here. I have built the stock suspension the best it is going to get, in no way am I comparing this setup to what I would design for full on racing, because it simply does not meet my requirements for a "race car" so with that here is what I built.
The shocks are the Tokico adjustable units, and as I understand it, they are no longer available. I first set the shocks to a setting of 4, and after Clark started tuning the car he was having some problems with wheel hop. I went down for another reason, and he told me about it. I set the adjuster to a setting of 5 and again Clark made the comment that it was "a different car" so they do perform like advertised. I think a good set of KYB race shocks will do the same as the adjustable units myself, but have never installed as set to find out. The springs are suspension techniques and they are the higher rated spring. That are also the non variable rate spring. I prefer these type springs over the variable rate springs. I ran a set of variable rate springs from NAPA, and they were good springs as well, so if you want the variable rate parts I would suggest getting a set of the NAPA parts and save yourself some money paying for a name. The rear sway bar is a 7/8" part and that also improved the rear problem the zx has of lifting the inboard side of the car in a hard turn significantly. So the spring/shock and sway bar combination has improved the rear characteristics of the car two fold. The adjusters were a Godsend for my car. I have had a toe problem with the car ever since I bought the thing. The problem was the rubber bushings were warn, and I was not prepared to take the control arm apart to replace them. When I did replace the bushings, they were very hard to remove, the press fit had to be at least .002 fit. Needless to say it took a big press to remove them. I realize there are other ways to remove the bushings, but I wanted to make sure there was no chance of the part failing because I nicked it with a saw blade or something like that.
The adjusters will move the caster, at least on my car, about 1.7 degrees and the toe about the same. The kit did repair my problem, but you will take note that the kit does not adjust camber and toe independent of each other. The kit is drilled off center and the bolt is off center, so when you adjust the camber you also adjust the toe. The very best kit you can get would be a kit that adjusts the toe and camber independent of each other. I have not found such a kit myself. I have considered designing such a kit. I have been known to design my own parts on occasion LOL, but this was not required. The car sits at about .3 camber and zero toe. My ideal adjustment would be zero toe and about 1-degree of camber to aid in the cornering. Again, not the very best design, but very workable.
So this is about the best it is going to get for the stock ZX rear suspension, if someone wants anything better, and there are better setups, then you will have to scrap the whole rear suspension of the car and start all over to get the full race application on the car.