Dorifto

Hey all - I've been trying to come up with a nifty design for a competition coilover suspension setup for my Z, as I'd like to enter her in Formula D sometime within the next 2-3 years. My idea was to use an existing coilover kit - like Tein, or Eibach - originally designed for another vehicle (preferrably a Nissan). I know there are complications with this - for instance, the suspension setup I would be modifying wouldn't be specifically designed for the car in question, which causes problems - however, I'm not too worried about it.

Now for my questions.

-What is the spring rate for stock 2+2 springs?
-Amount of total suspension movement (compression and extension / rebound)?
-Length of strut / spring assembly for front and rear? (I would go measure on my car, but stuff is all taken apart, and bad bushings make everything all sloppy.)
-Average amount of weight on front and rear axles (gross front axle weight and gross rear axle weight)?

I can't think of any other factors that would play a large role in suspension stuffs for right now. If I have the time, I'll do a little playing around with numbers and designs, and let you know what I figure out.

Any help and/or comments are much appreciated, in advance.

-Dave-O

Heat Rave R

I'd be real interested in hearing about what you come up with for installing another car's suspension, too.

Dorifto

Well, just looking at what I have to work with, it doesn't look as hard as numbers and sketches might lead me to think ... while the ZX has a very simplistic yet effective suspension setup stock, there are problems I might end up facing. For instance, up front, there's a strut cartridge used instead of a basic coil-over setup like the rear. The camber and caster is wildly effected by minute changes with the location / direction of the mounting area for the cartridge, whereas the rear camber / caster is dependent upon the ride height.

For my purposes, lower is better, as my Z probably won't see the street much again (unless she'll pass inspection in competition trim!), so the rear camber will be slightly negative by 1-2 degrees - a good thing, since I plan to drift. Up front, the lower I go means the less room I can use to mount the suspension goodies. Some creative cutting and welding to the cartridge holder might be in order if some of my designs won't fit or aren't feasible.

After a good amount of research, and a few emails to Tein, I've decided to use an RPS13 (1989-1993 Nissan 240SX Fastback) D1/street/competition coil-over setup, with the EDFC (electronic damping force control) option. This is where numbers work against me - the running total for a setup like this could escalate past $2500, if I get it wrong! That leads me to financial problems, and seeing as though I don't make much right now (and am buying a '91 Rx7, no less), the actual test-fit part of the project won't become of itself until a good few months later.

I'll get under the car with a tape measure and ruler tomorrow and whip up some sketches of what I have in mind - I'll be sure to post them for you all.

Again, any ideas, questions, comments, or beligerant insults are welcome!
-Dave-O

Heat Rave R

I think icice9 once posted a 280ZX that had a rear suspension out of a Skyline or Z32 or something. Maybe looking into that might help things.

Dorifto

I remember that car - it was the gold 2-seater at the Z convention in Cali not too long ago. That particular car had an RB26, custom flares, and R32 (?) rear suspension and subframe. That car - believe it or not - was what inspired me to follow up on my ideas. Perhaps I'll just custom-fab tubular A-arms for the front and rear, as well as new mount points. That should make retrofitting a 240SX suspension kit that much easier!

Hmm ... good idea, Heat! Thanks for the inspiration. Now I have more ideas in my head! SWEET!

Heat Rave R

While at my friend's shop, I asked one of the guys if I could use the rear diff of the S14 (considering an SR20). He told me that the whole rear of the S14 was part of a subframe that just completely drops off the car, and could possibly replace my rear end suspension with some work. Considering you're already getting the Silva coilovers, perhaps you might want to check on the S14 subframe rear suspension thing.

Hehe, isn't this some good brainstorming/sharing of ideas? Now THIS is what a tech forum's all about!

Dorifto

By George, Watson, you've done it yet again!

I should look into that ... then I'll just go ahead and drop an RB25 into her, and have a custom driveshaft built. Do you suppose the RPS13 (240 fastback) has this same basic subframe setup? There's a couple of them sitting in a junkyard not too far from my place, with most of the suspension still intact.

I think I may end up completely rebuilding the front of my Z with 304 stainless tubing or something like that. I could build a double-wishbone setup using S13 or S14 hubs, or mimic the Silvia's front suspension, accomodating for changes in width, location, etc. for the Z. Then just ZipTie the fenders and bumpers to it!
You dang skippy! I like this forum because of this type of feedback. I don't get that anywhere else besides here and wanganmidnight.com. On a side note, I've seen Bleach post there!

Thanks for the ideas and comments, Heat ... I appreciate it much!:bling: :bling:

Dorifto

Hey, this just got me to thinking ... I could use the S13/S14 brake setup! I could see the Z with a set of 14" cross-drilled and slotted rotors up front, with 12" slotted rears, and 4-piston calipers! I could also convert to the 5-bolt S14 setup! This would allow me to run a near unlimited selection of wheels/tires!

I love brainstorming ...

Heat Rave R

Don't forget pictures for a write-up! The guy I was talking to did seem kind of specific when he talked about the S14 rear suspension subframe, so I get the impression the RPS13 isn't the same. Couldn't hurt to double check though.