Tag Archives: MonoFlex

2017+ 86 & BRZ FLEX Z, FLEX A, & MONO SPORT Coilover Testing

Posted on by

We just finished up some testing on the 2017 Subaru BRZ (and which would of course affect the 2017 Toyota 86). While the vehicles aren’t drastically different compared to 2012-2016 model years of the aforementioned vehicles (the 86 previously named the Scion FR-S), there are some small changes in suspension that affect how our existing coilovers feel.

TEIN Japan currently sells part numbers VSTD8-C1SS4 for the FLEX Z line, VSTD-D1SS4 for the FLEX A line, & GSTD8-71SS4 for the MONO SPORT line for their market.

Stateside, we currently sell the VSQ54-C1SS4 for FLEX Z and GSQ54-71SS1 for the MONO SPORT line. For the FLEX A, we previously sold the VSQ54-D1SS4 model number. Now we sell the VSTD8-D1SS4. For the MONO SPORT line, we’re looking to start selling TEIN Japan’s GSTD8-71SS1, since there isn’t much variation between the U.S. and JDM spec.

Phew, that’s a lot of part numbers…..

So, why the change to FLEX A part number VSTD8-D1SS4?

The reason is that there are a lot of similarities between the U.S. part numbers for FLEX A and FLEX Z. If you’re not familiar with either, we’ll just say that the FLEX A includes our proprietary Hydraulic Bump Stop (H.B.S.) and is also a serviceable damper (can be rebuilt/revalved). In terms of cost, the FLEX A is $210 more.

Since the features are really the only noticeable difference, we had to look at damping force between the JDM and US kits to see what would work best for our market. The U.S.-spec FLEX A and FLEX Z both had very similar damping characteristics. Aside from the H.B.S. setup in the FLEX A’s, they feel nearly identical.

With that said, we wanted there to be difference between the two kits. Something that will help differentiate the two when a customer decides what they’ll be using the kit for.

So, we recently started offering the newer part number of FLEX A, the JDM version, part number VSTD8-D1SS4. These actually have a difference in damping, being more aggressive. We feel this may end up being a better option for the more-than-occasional track driven car owner. Being a serviceable damper, this also will allow owners the ability to revalve the dampers for different spring rates, if necessary. Along with being slightly more aggressive, the damping adjustment range is shifted up slightly, giving the end-user a higher range of tuning flexibility at the track.

That’s not to say that the FLEX Z isn’t at all capable of track use. However, we wanted this setup to offer greater compliance for a daily commuter, while still having an available adjustment range that allows for much more sportier handling characteristics. Comfort was just more of our aim for this kit, and it is greatly noticeable on larger bumps as high-speed compression is softer and more forgiving.

 

FLEX Z and FLEX A coilovers will look nearly identical. But, as mentioned in this blog, there are some features that FLEX A has over the Z line: Hydraulic Bump Stop, serviceable dampers (rebuild/revalve), and slightly more aggressive valving out of the box.

 

So, as far as a total breakdown of each suspension offering we have for the FR-S/86/BRZ:

STREET BASIS Z (GSQ54-8USS2)– perfect for daily driver not looking to sacrifice OE ride feel but improve handling performance, while being ride height adjustable.

FLEX Z (VSQ54-C1SS4)– high performance street kit, with 16-click damping adjustment and included upper mounts (camber adjustable for front).

FLEX A (VSTD8-D1SS4)– higher performance street kit/occasional track kit with aggressive damper valving, but with a greater adjustment range for ease of tuning. Included Hydraulic Bump Stop (H.B.S.) providing greater control and damping stability against repulsive compression force. Includes upper mounts as well (camber adjustable for front).

MONO SPORT (GSTD8-71SS1)– entry-level race setup with single adjustable damping. Monotube internal structure with greater oil capacity for better endurance and performance for long track stints. Also utilizes are Micro Speed Valve (M.S.V.) to improve low-speed damping curve. Includes upper mounts as well (camber adjustable for front).

SUPER RACING (DSQ54-81LS1)– 2-way damping adjustable setup for dedicated track cars, suitable for cars with R-compound or softer tires. Lightweight (full aluminum rear damper assembly), and included duralumin upper mounts (camber & caster adjustable for front) and camber washers for front.

Hopefully this info helps. If not, you’re more than welcome to give us a call to discuss your suspension options!

Preloading It Up

Posted on by

Full-length adjustable coilover spring tension is an area which many consumers aren’t too knowledgeable about. Details that  “more preload is best” or “no preload is best” have always been a talked about subject. In general, the function of the spring tension on a full length adjustable coilover is for a more fine tuning of the suspension if used competitively. Such preload adjustments for regular street driven vehicles, which seldom see a track event, aren’t really need. That’s not to say that you can not use the preload on the street. It’s just that there would not be much of an advantage unless you are looking to achieve a desired ride height or ride feel.

Preloading will change the characteristics of the spring, but not the spring rate.  As the spring is a linear in rate, the rate will not change under preload, but the spring’s reaction will be affected. With the spring compressed,  its natural instinct would be to push back to its original shape. Thus, the force already exerted when compressed will creating a more aggressive ride quality. The drawbacks to having too much preload will be spring bind or, in worst case scenarios,  a broken piston rod or damper component. Spring bind can create a loud tapping from the springs during normal use of the vehicle, not to mention terrible ride feel since spring stroke is all but eliminated. The continuous spring binding creates a kind of solid state to the coilover assembly which will transmit the road vibrations and shock over to other damper components, eventually causing it fail.The broken piston rod or component can be caused by the excess spring tension, as well.

Preload.rev

Relieving preload from the spring or creating “negative preload” would change the ride height of the vehicle along with the dampers’ piston stroke. The drawbacks to excessive negative preload would be a loss of piston stroke, noise from the spring, poor ride quality, and eventually damper failure. The piston stroke loss would allow for the damper to bottom out, which in turn would create a poor ride quality as the dampers’ upper springs seat or mount would be riding against the bump rubber. With the constant bombardments, the bump rubber will eventually break down causing some of the rubber material to fall in between the seal which can then cause the seal to fail. This can also create noise caused by the spring’s loose condition, which will shift back and forth on the damper assembly when the damper is extended and compressed. This occurrence is most common over uneven road surfaces such as driveways, dips, or at times freeway expansion joints. This could cause damage to the damper body threads, spring seat, and upper mount.

Preload.2.rev

If you are uncertain as to the preload of your full-length adjustable coilovers, the best recommendation is to set the spring seats to the installation manual’s suggested position. This position will offer the optimal damper stroke and adjustability.

EDFC Motor Extension Kit?

Posted on by

That’s right!! TEIN Japan is currently in the works designing an extension component for the EDFC motors and is called the EDFC Motor Extension Kit. This kit would allow the adaptability of  EDFC and EDFC Active to those kits which may not have enough room or space in the engine compartment or rear trunk/ bulk head area.

P1070198 (Small)

 

Although this extension kit will allow for fitment for those hard to fit areas, keep in mind that some kits even though not EDFC compatible may have other reasons as to why they would not be compatible. The best suggestion would be to either reference my previous blog post “EDFC Fitment Check” to determine  initial compatibility or contact us direct to assist you in determining the compatibility.

This kit seems to be an excellent option even if you have sufficient space in the mounting area. It would tidy up space as well as add a more compact look to the coilover. We will follow up later in the year with an expected release date for the kit, until then you can periodically check both our main website and our blog for any news.