Suspension – Part 1 (Redux)

Posted: May 13, 2013 in 300ZX Build
Tags: , , , , , , ,


Hard to believe over a year has past since my first “Suspension – Part 1” post, but here we are. The good news is I’m back at it with the new Z (and a straight chassis this time). So this post is a little rehash of what was installed last year (on the white Z), with a bunch of new parts thrown into the mix.

If I’m honest, when I first picked up the red Z, I was a little disappointed with the car’s handling. All my previous Z32’s had been Twin Turbo versions with the factory adjustable suspension; I had never owned a 2+2 before (or an NA for that matter), so I assumed the lack luster handling had a lot to do with that. I was also concerned that the 2+2 chassis might somehow be less stiff than the 2+0, as the car really squeaked and rattled while driving around town.

Thankfully, 98% of that came from the very tired 132K mile factory suspension. With the new SPL, Ground Control, and Tokico parts installed, the car literally transformed into a tight corner carver with far less body roll and tendency to “push” through the turns. So follow along and see just how I did it.


First step was to get the Z in the garage and pull the wheels for a visual inspection. Even with 132K, parts like the ball joints, tie rods, etc. were in great shape with zero play. The car really led a babied life.


The same couldn’t be said for the factory tension rods. OEM bushings are made of rubber, filled with a viscus fluid (I’m assuming for noise / vibration dampening). Over time the bushings crack and the viscus goo leaks out (which is a common problem with many of the Z32’s bushings).

It doesn’t help that the angle of the lower control arm keeps the tension rod bushing under constant load. The arm travels in an arc, stopping the factory bushing from staying centered (as you can see in the pic above). Once the bushing fails, it allows the tension rod to slide around under cornering, acceleration, and breaking (changing caster) – giving the Z a vague feeling in the steering wheel, along with a nasty shimmy under breaking.


Thankfully, SPL came to the rescue. This is just a small portion of the SPL suspension that will eventually be installed on the Z. I’ve had a very large box filled with almost their entire Z32 catalogue for over a year now! It feels so good to be finally installing this stuff, instead of it collecting dust in the attic.


SPL tension rods are seriously beefy (and practically too pretty to install under the car). This is true race car technology. Some of the specs include – Low-friction Teflon lined articulating spherical bearings, large diameter (1 3/8″) billet T6061 CNC machined / gun-drilled body, Titanium hardware, and a hybrid adjuster. Sweet!


Of course, this still being a Z build and all, something had to go wrong… After 20 years of road exposure, the lower bolts that fastened the factory brake deflectors to the control arm refused to budge and ended up snapping. SPL provides bolts used in conjunction with the factory mounts (for their own brake deflectors), so I had hoped to remove the stripped bolt with an “easy out” drill bit.     


So much for that… the easy out failed to remove the stubborn bolt, and eventually sheared in half while trying. Do easy out’s ever work?? I’ve never had luck with them.


With no other option, I decided to just drill out the mounting point. The early Z32 cars don’t even have factory mounting points on the LCA (as brake deflectors were only added to later year Z’s), so this is a necessary step for those cars anyway (and a fine option for my situation). A trip to the local fastener store – Ven-Mar – (love this place, they have almost everything when it comes to nuts and bolts), secured the longer bolts I needed to fasten the deflectors. 


I took measurements off the OEM tension rod and set up the SPL ones to the same length. You could probably get away with this method alone if you were only changing the tension rods, but a full alignment is definitely recommended. I’m changing almost everything in the suspension, so an alignment is mandatory for me in the near future.


Here’s where the hybrid adjuster comes into play. Since you can basically uncouple the front joint from the rest of the arm by loosening the allen screw on the aluminum collar, you can perfectly center the helm joint after tightening the main nut. No more bind! This is a seriously slick option in my opinion. 


Final shot of the installed tension rod with brake deflector attached. A thing of beauty! 


Next up was the install of the Ground Control coilovers and Tokico Illumina (5 way) adjustable struts I picked up used a while back. I forgot to take pictures while installing the fronts, so the above pic is actually from the white Z install last year (but it’s basically the same).

(If you’re interested in seeing how the front coilovers come together, check out the original “Suspension – Part 1” post.)

I decided not to install the Stillen Gen 2 adjustable upper control arms pictured above, as I only plan to lower the car 1″ – the 300 Degree Camber Kit should provide enough camber correction by itself. I didn’t feel like wrestling with installing the camber kit while the motor was still in the car (since the rear of the upper control arm bracket bolts are sandwiched between the strut tower and the engine), so I opted to install the kit later when I pull the motor for the twin turbo swap. But If you’re curious now, you can also view its install in the original suspension post above.


Nissan engineers really outdid themselves when designing the rear interior of a 2+2 Z32. Every panel interlocks in some way with the one next to it. Basically the entire rear interior had to be removed to access the rear strut tops. While the panels were out, I drilled small holes to allow access to the adjustment screw at the top of the strut.


I ran into two issues while installing the rear coilovers. One – you can see how a large gap is left between the spring and the perch when the Ground Control setup is installed on the strut (a regular Eibach spring is pictured on the strut above for reference). I’m not sure if this is really critical (as I imagine GC wouldn’t have designed it like that if it was), but I really didn’t like the idea of the spring coming unseated if the suspension ever fully unloaded. 


Two – the rear lock nut was frozen on it’s collar. The allen screw had become fused to the nut somehow. Thankfully, Ground Control stepped up yet again and shipped out a new locking nut to me ASAP (for a small fee). They instructed me to just cut the bolt through the slit – freeing the nut and allowing reuse of the collar. There was actually a mix up at GC, and they ended up sending me two locking nuts by accident. When I called to let them know, they told me to just hang on to it as a spare! Great customer service.


To remedy issue #1 – I found a set of helper springs – made by Powertrix – used (but new) in the classifieds. The helper springs are designed to take up the extra space between the spring and perch, and collapse when the suspension is loaded. A little clearance with a file was required on the spring to allow the helper springs to seat properly.


Shot of the installed rear Ground Control / Powertrix hybrid coilover.


To finish up part 1 of the suspension install, I swapped out the stock 2+2 NA rear sway bar for the larger 2+0 twin turbo version from the white Z. The larger rear bar helps limit body roll and dial in a little more oversteer to counteract the Z’s tendency to understeer or “push” while cornering.


It wasn’t easy getting the bar installed without removing the exhaust, but after a few minutes of maneuvering it popped into place (I removed the end links during install to limit any additional clearance issues). In the future I plan to toss the mushy OEM rubber end links and go with fully adjustable spherical bearing links (for both the front and rear). Fun fact – Sean over at SPL told me that the factory Nissan sway bars actually have the most torsional strength when tested against aftermarket options available. 


After a few days of driving (and about 50 miles of seat time), I couldn’t be happier with the way the car feels so far. The squeaks and rattles are gone, and the chassis feels tight as a drum riding on the Ground Control / Tokico Illumina combination. After some experimentation, I found I liked the Illuminas best set a little softer in the front (at 3), with a setting of 4 in the back.

The SPL tension rods vastly improve steering response and turn in feel (as well as eliminate the shimmy under breaking). And the larger Twin Turbo sway bar really tamps down excessive body roll and gives the car a touch of some much needed oversteer. It’s also worth mentioning that all this was achieved without destroying the ride quality of the car during regular use.

Remember, the car is still an NA-Automatic at the moment. Before, this heavy underpowered pig of a Z would just understeer and body roll as soon as I tried to push hard into a turn; now, it’s a completely different animal. She even tries to break the tail loose when I push her too hard! That says a lot for what suspension alone can do to change the characteristics of a car. I can’t wait till I have the rest of the SPL rear suspension installed and all 450 twin turbo ponies under my foot.

I’ve been working the past week on final assembly of the VG30DETT (just waiting on a few small parts), so stay tuned for a “Twin Turbo Swap Part 1” post coming soon! Follow us on Facebook if you’re interested in keeping up to date on the Z build (and documentary film) progress – I tend to update Facebook much more frequently as things happen:



  1. Fuergrissa says:

    By 5-way adjustable, you mean to say that the tokiko’s have 5 levels of adjustment right? I had lost track of your progress recently, glad to see you are back on track!

  2. Thanks! Yes, the Tokico’s have a soft to firm adjustment of 1-5 (5 being the stiffest). It’s a compression / rebound simultaneous adjustment (increase one – increase the other).

    Some of the fancier coilovers allow you to adjust compression and rebound separately. I’m not that advanced of a suspension tuner, so I think these will work well to get me started on the track.

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