Daily Archives: December 12, 2019

ENDURAPRO Shock Absorber Testing on S550 Mustang GT (w/ Performance Package)

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This past week we had a 2018 Ford Mustang GT (S550 chassis) come in for testing. This particular one has the Performance Package. This package looks to include “heavy-duty” front springs and a thicker rear sway bar. Our guess is that the factory shock absorbers and rear springs have also changed from earlier S550’s Performance Package, with the shocks being a tad big more aggressive in valving, and so far we can say that we feel these differences.

ENDURAPRO PLUS (damping adjustable) for S550 Mustang shown

You can say it is a much sportier ride now. However, for some of us older fellows at TEIN USA, it was a bit too uncomfortable, whether it was street or highway driving. Personally I don’t really like how overly sensitive the steering was. Felt like I could accidentally loose control should my reflexes overreact. It just felt very twitchy and unstable.

Anyway, we wanted to test our upcoming STREET BASIS Z coilovers for this vehicle. BUT, it was also an opportunity to test our ENDURAPRO shock absorbers on this car, and it was definitely an improvement from our point of view!

As mentioned, the new GT Performance Package offers factory upgraded suspension. It was a far cry from how the first S550 GT we tested felt (when we were developing our FLEX Z coilover kit).

With the ENDURAPRO shock absorbers, ride quality was much more bearable for a daily drive. Much of the harshness we feel from the factory suspension is gone (however we can feel a difference with the stiffer front spring). Turn-in hasn’t changed dramatically, which we can possibly attribute to both the front springs and the larger rear sway bar.

Front ENDURAPRO strut compared to OEM strut.
Rear ENDURAPRO shock absorber compared to OEM shock.

How this compares to earlier S550 GT suspension is quite different, however. Again, with the current Performance Package suspension being more aggressive, the ENDURAPRO shock absorbers now make the car feel more compliant (not soft, not boaty, just better comfort). On an earlier S550 much of the sportiness is still there. But in both cases, the included Hydraulic Bump Stopper of our ENDURAPRO shock absorbers adds a much smoother ride quality under heavy loading. Over very large bumps, like expansion joints or overpasses on a freeway, this Hydraulic Bump Stopper really helps suppress upward jolts and smooths out the rebound. Given that the Mustang has relatively short suspension stroke, this pays huge dividends to providing comfort!

ENDURAPRO shock absorbers for the S550 Mustang are in stock and ready to ship!

Part numbers:
Front- VSGC0-A1MS2-L (left side)
VSGC0-A1MS2-R (right side)
Rear- VSGC1-A1MS2

Also available in ENDURAPRO PLUS (16-click damping adjustable)!

Front- VSGC0-B1MS2-L (left side)
VSGC0-B1MS2-R (right side)
Rear- VSGC1-B1MS2





TEIN Hydraulic Bump Stopper Technology

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Lately one of our greatest developments to hit the mainstream in TEIN suspension kits is our Hydraulic Bump Stopper (H.B.S.) system.

This technology isn’t anything new. However, the current derivative is a much more affordable design, and has now made its way into coilovers like our FLEX A and FLEX AVS kits, and now our ENDURAPRO & ENDURAPRO PLUS shock absorber lines.

Why are we creating so much buzz about this system? Mainly because a comparable Hydraulic Bump Stop system isn’t typically found in passenger vehicles, outside of trucks where you’d have to opt for something like an externally mounted bump kit.

Even our current Hydraulic Bump Stopper system used in our FLEX A, FLEX AVS, & EnduraPro/EnduraPro Plus shock absorbers differs from systems used in rally suspension, which are typically much more expensive units and require rebuild. Our current system is more affordable to make and doesn’t require servicing (FLEX A and FLEX AVS dampers are rebuildable, but the H.B.S. system doesn’t need to be rebuilt, per se).

Still, all this hype we’re making about a Hydraulic Bump Stopper doesn’t mean much if you don’t know what it does. So, picture this: You’re in a fully loaded vehicle (max occupancy) and have the trunk fully loaded. Already you can picture the suspension starting to sag. Then, while driving, you hit a big speed bump. On any normal suspension, chances are you’re hitting the bump stops, which will do a great job of preventing the shocks from bottoming out. However, the consequence of hitting the bump stop is a harsh impact and resulting bouncy or wallowing feeling.

Now, a Hydraulic Bump Stopper eliminates this bouncy/wallowing feeling. It does so by creating more damping force towards the end of the damper stroke.

Typically our dampers are valved to offer a digressive feel, meaning that as piston speed (of the shock absorber) increases, it will only increase damping force to a certain extent, then it actually does not increase in force if piston speed is even higher. That is typically fine, but when this high piston speed is towards the end of the shock’s stroke length, it will have that harsh feeling (remember that bump stop?) we’re mentioning about.

Honestly, a damper with progressive or linear rate damping can still hit a bump stop and cause that harsh feeling.

But why does creating more damping force with the Hydraulic Bump Stopper help? Essentially it’s slowing down the piston of the damper. It gradually builds up this damping force so that the end result is a smoother absorption of force, while letting the damper rebound normally without oscillation.

When you see Stadium Trucks or Baja Trucks take on a massive jump, what you see on its landing is actually quite impressive. The suspension fully compresses, but as the suspension extends again, it’s nice and smooth. No crazy up and down oscillation. That’s what our H.B.S. system does, but for a smaller scale (shorter stroke length than Stadium or Baja Trucks, obviously).

Or, another example: Using lowering springs on OEM or replacement shock absorbers. While this setup is common place, and most work relatively well, some lowering springs might be too low of a ride height or too stiff a spring rate for the OEM valved shocks. A premium replacement like our EnduraPro line is a better match. Valved to offer a beneficial increase in performance, the added Hydraulic Bump Stopper is a nice addition because of the lowered ride height with lowering springs.

While our EnduraPro/EnduraPro Plus shock absorber line is a match in terms of overall length (compared to OEM), they offer larger internal capacity and more damping oil, and improved damping characteristics. So from a performance standpoint, these are a great upgrade for your lowering spring. Again, these include our H.B.S. system, and when lowering a car using OEM/standard replacement shocks, reducing that stroke length can mean exacerbated issues with ride quality and more chances of hitting that dreaded stock bump stop. You’d end up with similar ride issues in a fully loaded vehicle. Now we can resolve this potential issue by using the increased damping force the H.B.S. system creates further down the shock absorber’s stroke length!

It really is an ingenious system, and one that we’re glad to bring into mass-production. The fact that we can adapt this product into our replacement shock absorber line means that this feature is available to all consumers, whether their budget allows for just our premium shock absorber replacements only, or for those looking for greater handling performance (like our FLEX A or FLEX AVS coilover kit). We’re hoping to add this to many more of our products in the near future!