Livable Suspension Setup?
Fortune Auto 500. A household name when it comes to aftermarket coilover suspension upgrade options. My experience with them hasn't been so stellar, but perhaps it's not as much due to the suspension itself as I previously thought. There are a few different factors influencing my perception here.
- Stiffness / Damping Performance
- Ride Height / Rubbing
Overview
#1 and #2 are closely related here. Read along and you'll see how
Ride Height / Rubbing
The hella-tight yo low ride height at which I found the setup was too low for comfortable driving. Exhaust scrapes were not uncommon and the worst symptom was rubbing, albeit only on the front wheels as the 10.5" rears still camber in cleanly under compression and avoid the fender. To mitigate this, I promptly raised the ride height at the front and rear ends of the car.
However raising the height setting on these coilovers is quite concerning, mainly because I don't know how high they can possibly go. It seems like these coilovers were designed to run slammed. I've raised the There is plenty (say several inches) of the threaded sleeve exposed and it's not clear how much further they will go. There's an obvious way to find out which is unthreading or 'raising' height all the way until the sleeve pops out, but there's no guarantee that it will go back together while being mounted. I'm not particularly interested in completely uninstalling the coilover just to find out how far it can be adjusted.
So I run the ride height a little lower than I would prefer to ideally.
Stiffness / Damping Performance
Since the ride height is low, during performance driving (e.g. autocross session) it's quite common to face rubbing when changing direction while the suspension is under compression. This is also not a symptom of these coilovers in particular but for any slammed/tyte ride height setup, It's just not designed for really driving the car hard... unless you run suspension so stiff that it simply doesn't compress enough to allow the fender to reach the tire.
That's not an actual solution though, it's just a bandaid. One that I had applied many moons ago and to reduce rubbing I set the coilovers to somewhere between medium and full stiff. This reduced (but didn't eliminate) the rubbing but at a premium. The ride quality turned into a jarring experience on the highway with several road transitions requiring bracing myself on approach as the norm.
Worse yet, at some point I forgot about the setting adjustment, decided the design was inadequate and resolved to replace the coils at the earliest possibility with a new S set from HKS.
Months later, I had the thought cross my mind to check the setting on all 4 corners and lower it if at all possible as a last resort to regain some road manners in the short term. Turned out they were still set to the mid range! The rear adjustment is not particularly easy on the Z34 as it requires removing the interior trim panels in the hatch. These dont exactly pop off so easily and more or less requires removing a lot of the interior including carpet, sub, spare tire, and the panel by the taillights in order to properly remove the panels covering either rear coilover. With some finicking, the side panels can be 'snuck behind' to make an adjustment, but it still requires moving some things around and popping a few clips out at least.
Reflections
That simple adjustment of lowering the coilover stiffness from about halfway (say 15 clicks out of 30) to the minimum stiffness setting has surprisingly made a world of difference in the driveability and road manners of the suspension setup! The car finally drives like a normal coilover setup ought to. Especially coming from a set of HKS Hipermax GT's on the S2000, the expectation for a coilover suspension setup is that it doesn't ride worse than my Megan Street coilovers did back in the 240 days. In fact the Hipermax GT's were an upgrade from the factory 120k mile suspension on the S2K and that was simply a mind boggling concept. Fast forward to the Z, reducing the stiffness settings to the minimum has finally resulted in a setup that dare I say approaches the road manners of the Hipermax GT coils.
Drawbacks
The drawbacks of the current setup is that rubbing is still an issue. The car is currently setting at a funky negative rake angle. The front ride height / fender gap is higher than the rear and both ends have so much threaded sleeve exposed that I'm not sure there will be enough sleeve remaining should I attempt to raise the heights any further. The front fender gap is about 1/2" and the rear gap much less than that.
Next Steps
Find the limits of the Fortune 500 coilover highest height setting or ditch them entirely and switch over to a set of HKS Hipermax S which I assume and expect will naturally support the desired range of height adjustability
Conclusion
The stiffness issue shows that the full soft setting on this coilover is actually quite decent. But perhaps the adjustment is not linear because the half stiff setting is quite harsh.
When it comes to the height adjustment, the biggest drawback here is that there's no indication of the limits of height adjustment. Regardless of any indication of such limits, the threaded portion is so long that the car would be impossible to drive if the coilover were lowered to the lowest settings on the threaded sleeve. Thus these Fortune 500 coilovers are not designed specifically with the height adjustment range of the Z34 in mind.
If I go to adjust the height up higher and find ample threaded portion remaining I may feel differently, but at this point it seems the height adjustment range just happens to work a little for this car but was definitely not designed for it.
