Project VA WRX: Improving the Suspension With Tein Flex-Z Coilovers
Many of our MotoIQ Project Cars feature top of the line or even exotic suspension parts, exactly the kind of stuff you want to use in cars that see mixed track/street use with a heavy track bias. However, not all of our cars are set up like this, some of our cars are more street oriented and set up towards hassle free daily use.
We decided that Project VA WRX would take this route. Since track duty is the domain of the more powerful and expensive STI we will be building the VA WRX to be more street oriented. It will still perform pretty well but have less compromise in daily driver practicality.
For selecting a suspension, we decided that super trick two and 3 way adjustable dampers were not the way we wanted to go. We wanted a suspension that would work well yet be affordable and durable. After doing some research we decided to give the new Tein Flex Z a try.
The Flex Z is Tein's new lower priced but high performance line of coilovers designed to compete toe to toe price wise with the tons of crappy cheap coilover sold on Ebay and such that are flooding the market. Although the Flex Z suspension line is built from the ground up to be inexpensive, it doesn't mean it sacrifices performance or durability. Read on and let us show you how it does that and how well it works.
Read more about Project VA WRX here!
The Tein Flex Z is not a cheaply made in China re-labeled shock, but a high quality unit made in Yokohama Japan. It has a lower cost not so much due to using worse materials or shoddy construction, but rather due to Tein investing in OEM high volume assembly methods that reduce unit costs. The costs are mitigated by the use of a sealed damper unit that contains the rod and piston but is valved per application. The damper is adapted to various chassis with removable mounts. A WRX specific McPherson strut lower mount is used with the damper with a WRX specific camber plate for the front shock. The removable mounts also allow ride height adjustment independent of shock travel and spring preload. Since the damper is the same dimensions across many different applications, there is economy of scale and production costs are greatly reduced. 
The Flex Z is 16 way adjustable with close to equal linear adjustment steps. The adjustments mostly affect rebound damping although compression damping is affected slightly. The camber plate is made of lower cost powder coated steel which is not trick like anodized billet aluminum but perfectly fine for the job. The powder coating is a highly corrosion resistant 2 layer process. The damper unit itself is a twin tube design with a drawn tube and a non-rebuildable swedged and crimped top seal. This sort of manufacturing is much cheaper than a typical racing shock that is assembled with many machined parts. This is just like how stock replacement and OEM parts are made. The damper unit is gas pressurized to reduce foaming and cavitation in the valves. The innovative universal damper system allows Tein to make a high performing but durable low cost coil over. When the suspension needs to be serviced, just the inexpensive damper unit is replaced. Custom valved dampers can also be special ordered per application. 
Just because the camber plate is steel and cheaper doesn't mean it's not durable. High quality bearings are used and all steel hardware parts are highly corrosion resistant yellow chromate coated. The Type Z has a full length dust boot to keep dirt and water away from the seals. 
The rear shock is much like the front part. The lower ride height adjustable mount and the top mount are application specific. The threaded body of the dampers is coated with Tein's proprietary highly corrosion and wear resistant ZT coating. This coating greatly helps prevent the ride height and preload adjusters from becoming stuck to the shock body even in corrosive environments like winter salty roads.
8 comments
By chance do you have any content where you compared shock dynos of various coilovers for a specific application? Maybe showing say $500 up to $3500 offerings, comparing the linearity of their adjustment, etc. etc. I’m too much of a layman to make actually look at the dynos themselves and make the comparison, but it would be great to read your takeaways/insights from an expert like yourself.
Cheers.
That would be pretty expensive to do, costing about $1000 per set of shocks, and dyno’s don’t tell you everything. Especially with cheap shocks.
Regarding the coilover install, did you guys adjust preload or ran it how it came out of the box? And Are Rear LCA recommended.
Thank you!
We did some minor adjustments of the ride height but did not preload the suspension.
Regarding the install, did you guys adjust preload or ran it how it came out of the box? And Are Rear LCA recommended.
Thank you!
We don’t tune with preload, I don’t agree with that. Preload doesn’t increase the spring rate, it just increases the initial force to move the suspension.
Can you confirm that the new Flex Z’s are made in China. I just bought a set from an authorized dealer & i’m looking at the box & they say designed by Tein in Japan, Assembled by Tein China MFG. Which is odd since they’re advertised at the time of writing this as Made in Yokohama Japan.
Seems they do have factories in both Japan and China. Flex Z’s are majorly produced in China according to their blog page. (https://teinusa-blog.com/made-in-japan-or-china/)
I bought a set of Flex Z for AE100 for a surprisingly expensive price of >$1200 back in Oct 2021. “Made in Japan 日本製” was printed in big letters on the packaging.