Expert: Dan Liddy - 6/10/2008

Question
Dan,

I emailed you a few months ago about turing my 280zx into a raod racing car. After readingwhat you had to say about the suspension we still went ahead and pursued the endeavor. After a weekend of running at Barbers Motor speedway here in Alabama, I see what you were talking about with the susension. I put coilovers on all four corners. Obeviously the spring rates were not stiff enough. The front is 350 and the rear is 250. i bought this through ground control and they really were of no help with the spring rates. They also sent me 8" springs. My Question is to you could you please give me some Idea as to what I might do or a direction I might go. I dont want to bother you but your credentials seem to be the best I can find when it comes to these era cars. I did my first NASA event this weekend and Saturday ran 4 sessions. On Sunday I got in 2 sessions before we had a front right shock to fail at the bolt in point. It completely sheared the threaded stud off and proceded to shear the to bottom shock tube bolts off and the wheel assembly ripped from underneath the car. Any more insight would help. thanks for your time it is nice to use your knowledge and experience. Also do you know of anyone who may have a 240z or that era car already built that might want to sell it.

I love these cars!!!!

Matthew

Answer
Hi again Matthew.

I don't mind questions about real race cars.   I love them ! just don't want to be bothered with stupid questions about street racers.

Well, I think you should have gotten 10" springs, and my friend that has been racing a 240 Z for at least 20 years, says 275 fronts and 250 rears, you mimght want to soften both of those by 10 Lbs. just for personal comfort.  Spring perches should be 7 " from the bottom of the strut tube measured from cast part of the spindle where the tube seats.  The tube itself should be shortened to the length of the shock body plus clearance for the nut plus a big washer or two. Shock body should fit solidly with no play.

I believe the reason you had the catastrophic failure was due to the short springs bottoming, the cars are better than that.

BUT, you should get something well beyond a stock front sway bar. Try finding AFCO on the net, and see what they have- - -they're in the $200 range and pretty good stuff.

There should be plenty of Z's around B'ham, Decatur, and Atlanta, try E-Bay, and just google "datsun z cars"

Do feel free to write again.

Dan Liddy