| Background: For around three years, I have been the proud owner of Powertrix Sport Street coilovers. Since I spent most of my time in college driving the relatively smooth streets of Georgia, I had few issues with the ride quality of the Powertrix units. I recently graduated from college and moved to TX for work. The main problem with North Texas streets is that they are paved with concrete instead of asphalt. The concrete separation joints became a huge inconvenience due to the linear nature of the PT Sport Street struts. Bone-jarring slamming was a common occurrence as I encountered 50+ nasty separation joints each day. The other main issue with my PT units was that the rear units would oscillate frequently. The rear of the car would bounce around 4 times after hitting a bump. I tried adjusting my preload, switching my rear springs, cutting my front bump stops, making tire pressure adjustments, and fiddling with the strut stiffness setting. Unfortunately, almost nothing solved these frustrating problems. Turning my rear dampers up to 4 remedied the bounciness but exacerbated the jarring feeling encountered when hitting separation joints.
I spoke with several people at last year’s Branson Z Fest and the typical recommendation was to revert to a progressive Eibach/KYB setup. After building my Z’s suspension for great handling performance, I couldn’t imagine switching to a progressive spring without adjustable height though. Instead, I looked at numerous coilover companies. None of the Asian companies produce dyno graphs or list intricate details on the manufacturing processes used on their struts. The 800 lb Gorilla in the room was KW, a German company well known for its coilover systems. The least expensive coilover KW offers is their V3 at $2400. While the V3 is a two way coilover, it uses cheap progressive springs. I also have doubts about its twin-tube setup. KW’s performance coilover is the Clubsport, however it retails for around $1000 more.
I then spoke with Vorshlag motorsports in Plano to get an idea of other solutions. Apparently, a high quality 2-way Moton setup runs around $3800 given it could be made to work for the Z32. Otherwise, Vorshlag recommended building a custom one-off coilover for up to $7000. There is no way that I could afford an exotic coilover system ($3000+), so my options were relatively limited. That was until I discovered Fortune Auto’s new generation of coilovers. The Solution: Fortune Auto is apparently fairly new to the coilover scene, however their factory is located in Virginia. Each strut is valved and matched specifically to each car. Apparently, Fortune Auto has been marketing their “digressive” strut designs as a way to combat poor quality tracks and roads for a few years. A digressive strut is designed to limit the amount of force produced at higher strut velocities (i.e. when hitting a nasty lifted concrete separation joint). I almost pulled the trigger on a set of their coilovers 2 years ago, however the units were simply not digressive enough to make much of a difference. With the release of generation 4 of their 510 series, FA could promise enough digressiveness to take a bite out of my separation joint/ broken concrete issue. I spoke with Terry at length and he assured me he would build a set of digressive 510-series coilovers specifically matched to the Z32 chassis. To provide Fortune Auto some data to start with, I shipped in my Powertrix SS coilovers for a strut dyno and measurement. His shock tech noted that the front Powertrix struts were probably 40-50% too stiff. The rears were also a bit too stiff. The icing on the cake for me was that their coilovers are actually built in Virginia. You can typically request an actual strut dyno sheet of your struts as well. Please note that I ordered 510’s instead of 500’s because I picture my Z as a road-carving sports car, not a super comfortable cruiser. I also have numerous “stiffening” suspension modifications. If you have a stock chassis with stock suspension components and stock wheels, you may experience even more comfort. Modifications as of testing are as follow: -Tension rods with heim joints, poly fucas, poly rear control arms, subframe spacers, poly lcas, Stillen sway bars, Aruba Dave's underbody brace, 18" wheels, etc. Product Inspection: Fortune Auto then built a strut valving profile for the 510’s based on the Powertrix SS’s I lent them. Within a week and a half, brand new 510’s were at my door! FA did an excellent job packing the coilovers in double boxes for shipment. Extensive foam and bubble wrap held the struts in place. An included zip-lock bag contained wrenches, strut dyno sheets, and a signed inspection/ quality control sheet. Beefy (aluminum!) mounting hardware holds the steel strut bodies in place. While I did not have a chance to weigh the coilover assemblies, the mounting hardware is probably a pound lighter than the Powertrix components. The strut bodies arrived with light oil on the threads, probably for additional corrosion resistance. The dust boots are made of a thicker, seemingly more durable material than that found on the Powertrix struts. I ended up installing 8k/6k Swift springs. The top adjusters on the FA’s have 24 clicks of adjustment, compared with Powertrix’s 16 clicks. As with Powertrix, making the struts stiffer has little effect until to you get to around 4-5 clicks from soft. The bottoms of the strut bodies are not welded shut so rebuilding is possible. Unfortunately, the downside of the 510’s high performance strut internals is that rebuilds are recommended every 2-3 years for optimal performance. Note that it would currently take around 10 years to equal the price of a KW V3 coilover set, even with all of these rebuilds. I also ordered and received Fortune Auto’s extended rear strut adjusters. I plan to cut these down and install them through my rear plastic panels for easy rear strut damping adjustment. The front and rear adjusters have a fairly high quality look.
Installation When I first installed the 510’s, I realized that the upper rear top hats/ mounts did not seat completely onto the chassis. I gave Fortune Auto feedback and they had new, compatible units designed and built. Aside from this issue, the rest of the install went effortlessly. I used my Powertrix top hats temporarily. One thing to note: the 510 rear strut bodies are a little on the short side. I can only get my car up to around 25.5” between the ground and the top of the rear wheel wells without spring preload (around 1.5 finger spaces). The fronts provide ample adjustment either way. YMMV on final height. Ride Quality/ Handling Analysis: Once I got ride height adjusted and my car on the road, I drove on the roads that used to give me trouble with my Powertrix coilovers. The struts did an excellent job absorbing all of the nasty separation joints that used to unsettle my chassis with my 7k/5k Powertrix SS coilovers. These were little more than a minor inconvenience with the Fortune Autos. I am comparing both coilovers at the softest setting by the way. Since low speed damping was increased compared to the Powertrix units though, these “prototype” 510’s tended to bounce violently over low-speed changes in the road. I ended up shipping my 510’s back to Fortune Auto and we recruited a gentleman in Virginia to lend his 300zx to the company for a couple days of testing. Fortune Auto then installed my struts on his car and spent two days collecting data and dialed in the valving further. In the end, Fortune Auto took a massive chunk of high speed damping force out when compared with the Powertrix SS struts. Please see the attached dyno graphs for an idea of the change in damping. For the most part, FA maintained the low speed damping of my Powertrix struts while dropping the high speed damping significantly. Theoretically, this should maintain the roll control of the Powertrix units while improving compliance.
Anyway, when I received the re-valved 510’s I began testing them on the road. The forceful bouncing over low-speed road changes has been reduced while high speed compliance is even more improved. --I would argue that “street-valved” 510’s with 8k/6k Swift springs are less bouncy over rolling, wavy road surfaces while simultaneously MUCH more compliant over broken road surfaces (high speed changes) than my old Powertrix SS’s with 7k/5k springs.-- The 510’s blow Megan street coilovers out of the water. To give a better idea of the comfort improvement of the new 510’s, I can drive over concrete slabs that have separated 1” or more at 40mph without unsettling the chassis. Essentially, these units provide ride quality somewhat similar to an Eibach/ Tokico spring and strut combo with the roll control of track-built coilovers. Don’t expect luxury comfort however. Certain nasty low-speed bumps can cause some bounciness. Fortune Auto can valve their struts for better track performance or even more street comfort though. Unfortunately, I have not tested roll control enough to deliver a final verdict. On the softest setting, the 510’s with this street valving provide about as much control as the Powertrix SS Coilovers with 7k/5k springs. I am betting that stiffer settings will yield similar results. When I get time, I will post an update on roll control with stiffer strut settings. Fortune Auto 510 Coilover Review Summary: Pros -Excellent ride compliance for a track-oriented coilover
-Good price (msrp as of writing $1699.99). You can typically find 510’s for less than msrp though.
-Great roll control even when valved for the street (about as much as a Powertrix SS strut set)
-Light but beefy mounting and adjusting components
-Rebuildable strut bodies
-Built in the USA Cons -Current strut bodies are somewhat short in the rear. Shouldn’t be much of an issue unless you aim to keep a stock-like ride height.
-The struts should be rebuilt ever 2-3 years for optimal performance (an unfortunate tradeoff typically associated with high-performance internals)
-Some bounciness on poor quality roads with significant low-speed surface changes (wavy concrete for example). These struts are not as bouncy as Powertrix SS’s for me though. 9/10 Conclusion: I feel that Fortune Auto built an excellent set of coilovers for the Z32 community. I am proud to have provided them with the parts and feedback required to really dial-in their struts for our chassis. The 510’s are apparently the only (moderately-priced) modern, ultra-digressive coilovers built for the Z32 chassis with extensive real-world testing. If you have any questions, feel free to send me a pm. I also had a great experience dealing with FA over the phone. P.S. The lines on the struts dyno sheets corresponding to struts not labeled with “Powertrix” are the Fortune Auto 510 struts. The “Powertrix” struts are PT SS Coilover Struts built around 2010. 
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Fortune Auto 510 Street-Valved Coilovers Review - 
