gramercyjam

Ok, I'm going to chime in, just so people don't get the idea that 150/250 somehow is a desireable setup. Maybe he ran those rates, but I don't think he was ever happy with that setup. He has run for at least the last two years 400/400 (on the advice of Vic Sais I believe) and Advance design shocks. He is satisfied with the setup, at least for now. Spring choice for a competition car can be a function of budget (it is for me) - 400 lb springs can't be controlled by budget shocks.

My wheels/tires are already under the top spring perch with a 240Z strut. I have about 1mm clearance between the rim and strut tube. I'm limited on tire diameter by rules (16"). So there doesn't seem to be a way to reduce scrub by either moving tires inward or going to larger tires. Increasing the angle between the spindle and the strut tube may be one possible way to do it.

I am not familar with 510's, but it sounds like a reasonable thing to do if the inner suspension joint arm was raised. As the control arm travels through an arc, if the T/C rod didn't travel through the similar arc starting at the same angle as the control arm, it would pull on the control arm. I can visualize how raising the control arms could increase the veritcal component of the forces at the inner control arm pivot during braking that could help counter act dive. I can't say how well it would work in practice.

I have 16X10 wheels, and the inside edge of the rim is as close to the coilover springs as possible. Maybe too close (1mm clearance)? I'll need to make some scrub measurements to see. I thought about the 280ZX possibly having better geometry than the 240 and did a visual comparison last night between the front 280ZX strut and a 240. There are definitely some major differences. Although the overall length is identical on both, the 240 spindle is much further away from the strut tube, there is a larger angle between the spindle and the strut tube, and the spindle is placed further up on the tube than the 280ZX. The 280ZX strut may have inherently less scrub, but with the spacers required to push the wheel out far enough to clear the springs, I don't see any advantages to using a 280ZX strut. Kick back is definitely a major issue with me. Not so much with bumps, but when the tires grab in transition during a low speed (40 mph) manuver such as when sliding on some gravel in a turn and then hitting a clean surface, and it started showing up when in search of more grip, I try lowering tire pressures to the 21-23 psi range, down from the 28 psi I was running. There may be no ideal solution, but I'd like to improve the situation if possible.

Anti progressive here. I haven't tried them, but I've seen Z cars with them on, and they did very poorly in autox.

That linkage doesn't appear to be complete yet in the picture.

I'm am there Dude! In my USAF days days I saw a number of Yanks make the trip over and pick up an older cherry yacht for some pacfic crusin'. It sure looks like the life. A few years back I almost had my wife talked into it. Then my brother told her how dangerous sailing is ...

I have urethane tranny crossmember bushings. I think I ordered them from VB but I don't think they help much. I plan on welding up the diff mount, tranny mount and motor mounts solid.

I have Webers with an unknown manifold brand. It didn't line up to the firewall bracket so I made a new one with a rod end and a piece of aluminum angle and put it where it was needed on the firewall. Then made up the rest of the linkage back to the stock bell crank using some threaded rod and couple of small heim joints.

Fly to England. Buy a nice sailboat. Sail it to Hawaii or Fiji.

You are radical dude! It might be easier to to just learn to drive drive backwards!

Gotta disagree here. Yes, I agree that it can be done in a weekend. But, most people will not do it in a weekend. In fact, many will just give up when they get to the part where the spindle pins need to be removed. I'd say plan for a "4" and hope it is a "2".

Glad to hear of a positive experience with Ackerman. I'm not sure how it would be accomplished - some modeling would need to be done. It is legal for prepared. You can move suspension mounting points, hubs and uprights are totally open. You can change cars with struts to double A arms but you can't mount shocks inboard. --John B

Regarding setting up chassis and steering on an prepared autox 240Z with massive lateral grip - beyond the typical discussions on springs and shocks, toe-in and bump steer, I have a serious need to know about ackerman, scrub radius and king pin inclination. I think there are a couple of different camps on these items - both pro and anti, theoretical static models VS real world dynamic effects. Any opinions or knowledge on the subject here as it relates to grip, handling, steering effort of the Z? --John B

I think you taillights are the same as every body elses that year. The center section with the logo is probably dealer installed or aftermarket. Check to see if your key will reach the hatch lock. It wouldn't on my '83 ZXT with the center piece that said "turbo". I can't imagine Nissan putting something out from the factory like that. --John B

FWIW - I run 16X10's on 16X10 3 piece wheels with 5" backspace and .5" rear spacers, .6" spacers in the front, 3" studs and coilovers on a 240. There is not enough clearance for the coil over springs or seats to extend below the top of the wheel. The wheel rubs on the springs or seats unless you move the perch high enough so the springs and seat stop above the top of the rim. The 3" studs are barely long enough with my wheels and spacers. Front tires fit in the stock fenders without fender rub with just a rolled lip. Rear tires require some rolling and flaring. The car is lowered so I have about 3.5" of ground clearance at the rocker pinch welds. YMMV. --John B

Thats huge. There should be no toe out at all. This is definitely at least one of your problems. You should not need camber bushings to correct it unless something is very bent back there. I would look very carefully at the lower A arms/transverse links and associated hardware. --John B.

I'd be looking at rear alignment and/or worn suspension bushings - When my '73 was a daily driver it was fine in the dry - but had the same problem in the wet. Changed out all the rear suspension bushings - problem gone.

I had one of those clunks on my '73. I checked all the bolts on the suspension and they were tight. Finally, with the car in gear while looking underneath it from the rear, I rocked it back and forth. It was immediately obvious that the diff was moving and although the 2 bolts holding it to the mustache bar were tight, they just weren't tight enough.

I don't think "hard" is the word. Could be tedious for some. I was a mechanical typewriter/calculator mechanic in a previous life so taking apart small stuff with lots of parts has never been a problem. I would just be careful not to lose stuff. Don't take it apart on the lawn, or over a sewer drain, in a gravel driveway, or on a shag rug, in plenty of light, etc. --John B

I went there, but it has been a while. Got my BSME there, and was sr computer guru for the engineering school for a few years after that. --John B

I've had the problem before too. In mine the contacts were burnt - filing the contacts with a points file may help. If they are way burnt, you can try putting a little dab of solder where contact point used to be. You may need to repeat this process every once and a while when they start acting up again. --John B

It does make a difference you can feel and quantify in competitive driving. On the street, well I certainly would never notice the difference there. I drive like an old lady on the street. Maybe my street car should be a low rider --John B

Ok. Simply put, corner weighting balances the car. Here is a popular link to the concept http://www.grmotorsports.com/cornerweight.html. But the easiest to understand explanation compares corner weights to a 4 legged chair with a leg that is a little long. The chair rocks on the diagonal legs. The length of the long leg (or the shorter legs) needs to be adjusted so the chair will sit flat. On a car, this translates into improved handling. --John B

That coilover FAQ leaves out the most important key advantage. Adjustable corner weights. --John B