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Everything posted by tholt

  1. Just curious how you plan to mount the front? Have you shared any designs yet? I assume a new crossmember with mounting arms reaching back? I am working on the same project myself and looking at other efforts I haven't seen a really strong solution yet. Tom
  2. I would pay $50 for the carb setup

    Please let me know



  3. Thanks guys! I still haven't pulled the trigger yet, but I'm leaning towards the 2 disk 5.5 Quartermaster with the "rally" friction disc. It's supposed to be a little more forgiving of some slipping... It will require the anular TB, but one thing I might do after I give it a try, is to swap the clutch MC to a smaller dia. to provide a little more pedal travel. My car tops out at about 20 in 1st, so the launch will probably be pretty painless once I get used to it. It's good to hear the flexplate setup is the lightest, especially on top of being the cheapest . ...and I remember you
  4. Hi gang, I am planning to upgrade the clutch on my dedicated autocross F Prepared 280Z and was looking for some experienced advice. I currently run the Nissan Motorpsort 11lb flywheel/Centerforce bi metal PP/solid bronze puck disk setup and it has been bulletproof for over 15 years. The downside is the complete assembly weighs 23 lbs and I considering the 5.5 or 7.25 multi disk assemblies that weigh a lot less. Is anyone running this type of setup and have any recommendations? Are you running the automatic flexplate or did you buy the custom flywheel? What about throwout bearings? D
  5. Wow! You've been as busy as I have! I went through a similar unsprung weight excercise, but took a different approach based on laziness. In the front, since I had the upright removed and left the rest of the control arm intact, I weighed the control arm on the car, resting the end of the arm on the scale. Since I have a heimed front end, friction was minimal so I figured it would be close. so my numbers were: Control arm with brake caliper - 16 lbs Wheel+ Hoosier slick - 36 lbs Upright + rotor - 30 Shock + spring - 8 /2 = 4lbs So - 86 lbs on each front corner In
  6. Has anyone calculated the motion ratio of the front and rear suspension on a 280Z and obtained an answer that you are have confidence in the accuracy? Using a tape measure in the rear I have calculated a .82 MR. Measuring from the pivot to the base of the strut and from the pivot to the hub face (assuming zero offset wheels). Using suspension analysis software (Mitchell's WinGeo), it shows a ratio of 1.142, which I assume is the inverse, so that would be .876 Does anyone have a good answer for comparison? How about a good sketch showing proper measurement and calculation? I n
  7. On to Phase 2: Okay... At first pass I'm not liking the forward toe link too much. The basic problem is the toe link really gets in the way of the sway bar link. I haven't figured out a good way to make that work yet other than ditch the sway bar or put the toe link at a bad angle. I did two iterations of this design. The simplest is shown below as LCA2-B (purple). It works the best of the forward link designs and mounts in the stock inner locations. It might be advisable to add one more bar from the inner bar to the toelink joint... but again no swaybar I tried another version using h
  8. Okay... trying to get caught up here and my brain is really starting to hurt. So, if I am understanding Dan's sketches and and the output of his spreadsheet, it says that if you have a 1 degree angle between the inner and outer control arm axis the amount of bind that will induce is about .025"... That would be 1 degree of toe per side.... that's a LOT... The most I would ever try and run in the rear is about 1/8" per side, that would be about .3 degrees ( I would really only run about half of that). Using that number in the spreadsheet it says that the induced bind is only about .
  9. I've definitely seen Johns control arms... My only gripe is there is no provision for toe adjustment. I think I am leaning more towards something like the Arizona steel tube arms with it's adjuster but add heims on the inner mounts... Tom
  10. You finally made sense to me on you last reply Jon... Good point, but I think the thing that has probably convinced me to ditch the plan is the fact that the forward joint (blue) is only held by 3 rotataing points. In other words, that forward triangle is not a triangle. It's a quadrangle with a short leg running through the blue piece. The only thing that will keep that joint from rotating fore and aft is the friction of the clevis bolts. It might be sufficient to do the job, but when it slips it's going to get real weird real fast. Maybe there is a reason that the car I saw this on is
  11. Like just about everyone else, I have an overwhelming compulsion to design and build my own rear control arms. My application is for an autocross only car, so keep that in mind as you pass judgement. It will never see the open road or >100mph... That said, this is pretty much a direct copy of a setup I have seen on a GT2 Z and it hasn't fallen to the ground yet after several years of competition. Only the sway bar link has been added. I really like the total on-car adjuastability. One of my main goals is to facilitate as much track width/camber adjustment as possible from the bottom. Sim
  12. Hey Mark, If you want to run Prepared with the 3.1... you can still run XP. You can turbo it, stroke it, V8 it, whatever! So long as it fits in front of the firewall, it's legal. (pretty much.) Don't spend too much time looking for sub 10" wide 16" slicks... they don't exist. There is no market for them, so no one makes them. That said the DOT-R's are not much of a step down. Especially if you are running on asphalt. For the slicks to REALLY show their strength you need some really grippy concrete or ultra grippy concrete (which is very rare). Many people in various prepared classes have beg
  13. That's the number one online question I get about my car. I wish I knew the answer. They were on the car when I bought it. I want to say they look like the ones Arizona Z car sold, but they got out of the fiberglas business. I think Motorsport Auto used to sell something very close also, but I don't see them anymore... So bottom line... I don't know. Sorry... Tom
  14. I don't think I want to tear into it that deep... I was planning to add heim mounts on the end links, but that is about as fancy as I plan to get for now... Tom
  15. Jon, I'll second what Pete says and recommend waiting until you are on the ground to make your final decision... That said, I have the 3" flares and I am running 16x10" wheels with 5" back space and have run the bigger 23.5x11.5x16 Hoosier slicks with no problems. I had about 1/4" clearance between the tire and the springs, and after running numerous events I did find a small black smudge on one rear spring from a minor rub. I couldn't find a mark on the tire, so it was a very minor kiss or two during extreme conditions (like when I would get on 2 wheels at mid turn over a nasty bump). I nev
  16. Sorry for dropping out for a few days guys... and Cary, I'm extra sorry I caused you to actually read the rules! Now that you have read them, I agree with your interpretations... The question of WHERE the wheelbase should be relative to the chassis is a whole other can of worms, since the drawings someone else posted in another thread dimension the wheelbase from the bumpers. So long as you have a wheelbase of 91.7" or less and the wheels look like they are where they are supposed to be, I can almost guarantee you will never have protest problems... Back to my car and what I am planning
  17. Thanks for the feedback guys! I can't believe I never realized how much info was on this forum... I've had a login here for years, I must have posted more than once before. Allright... so I think adding caster is a given. I will just have to sneak up on that to find the right amount. I am currently running bias ply slicks but I may try switching to the Hoosier radial slicks. That might play into how much I want. Looking at the difference in camber gain I may want to start low with the bias tires and add more if I want to try the radials. Jon, on the rollcenter and stiff springs com
  18. I've been reading all of the very good (and some very long) threads on suspension mods and was curious if there was any firm concensus on optimizing the suspension mounting points on a dedicated race car? Many of you are familiar with my car ( http://sth2.com/Z-car/ ), if not, it is a purpose built F Prepared 280Z autocross car and about the only area where the car is not fully optimized is in the suspension geometry. That is my project for this winter. I started by using some suspension analysis software and took my best shot at measuring the current setup. I think I did a prett
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