I'm getting some valving changes done to these shocks and will have more to say about these when I'm finished, but I figured I would post these up in the mean time just for the hell of it.

Zeal Function X coilovers for FD3S, factory valved for 11kg front, 8kg rear spring rates.

Here are the force vs absolute velocity (rebound open) plots, no offset.

Full stiff (1):


Medium (15):


Soft (30):

 

And here's force vs absolute velocity (rebound open), offset to zero.

Full stiff (1):


Medium (15):


Full soft (30):

 

And here's force vs displacement.

Full stiff (1):


Medium (15):


Full soft (30):

 

Thanks for posting, I always like to see shock dynos.

 

Can we get a translation?

 

Really cool, I have the exact same shocks with the exact spring rate.

Why the dampening changes?

 

These shocks are just entirely too soft. They felt pretty good when I initially installed them, as I was looking for a good dual-purpose coilover that isn't too harsh for street use. They do fulfill the latter requirement, and do so surprisingly well for a Japanese coilover. Thus I was initially impressed when just driving them around on the street, not pushing them all that much. At that time, I kept them below medium stiffness so I figured there was a lot more damping left.

I can certainly feel the difference in damping as I change the adjusters, and ride quality degrades proportionally to stiffness as it should. The dyno proves that the adjustments actually work and do so in a fairly linear fashion. These are single-adjustable, and both rebound and compression are affected by adjustment. The adjuster is a needle-type bleed orifice in the piston shaft.

The problem is that even when turned up to full stiff, while you can feel the harshness of the compression stiffness over bumps, rebound just isn't that strong. The car feels floaty and uncertain in transitions, and only marginally improves as you turn it up to full stiff. It's like the rebound adjustment range is just shifted down too low - it works, but it doesn't go high enough.

Zeal is revalving them to address my concerns. I've talked to one of their techs and they have a pretty good idea of what I want changed. I'm going to have them dynoed again afterwards so I can show a comparison. I'll explain what was changed when I can show the final results.

Based on the data, I believe these are good dampers and have excellent potential when valved correctly for the application. They produced far more consistent results than I expected, especially after a year of use. That's why I'm not just giving up on them.

That and I have nothing better to do on the car over the winter.

 

Well the basic issue I have is the lack of rebound stiffness. Looking at the graphs, rebound appears pretty weak, but you need to look at other shocks and feel them in the car to really see it.

One thing of note is the hysteresis shown at the stiffest setting. The shop that ran the dyno suggested trying a lower gas pressure. These shocks do have a gas valve on the bottom of the cartridge, so this may be worth experimenting with at some point after the valving changes are done. Changing gas pressure would be going pretty far with shocks like these!

 

Nice info! Looking forward to the update.

I have the older Zeal B6 coilovers 11k front, 10k rear which only have 6 settings on the needle screw. I have put them on the 4th stiffest setting and love them on the street, have yet to use them on the track though since I've probably only put 800 miles on them.

 

I too have the B6 shocks. I have used them on the track but I don't think I have enough experience to recognize exactly what is going on to such a degree. I'm good enough to dial in or our oversteer and understeer but nothing at this level. Still love reading about it though. :-)

 

This is great info.

I have should have shock dynos of all the FD applications in a drawer somewhere. I'm gonna pull em and see how they look. These were dynos of them when new.

Endless actually contacted me I as a result of your valving concerns. Based on your results it's very likely that this will become standard valving for all FD Coils.

They do ride amazing regardless.

Thanks a lot, Rishie

 

Hey i have been looking at Zeal Coilovers for my FD. Its used about 50/50 street and track. Any recommendations on the best Zeal setup?
chase

 

I bet wheel and tire weight has a huge impact on the valving required that no over the counter coilover can account for.

Some race classes may only allow lighter but stock size wheel and lighter race tires and so you end up with lighter than stock combo and some classes or street cars may end up w/ much, wider, taller and heavier wheels and or tires.

So, a quality company will be one that will work with you on the valving you need for your application!