Hi everyone, new to the forum but have always found it helpful when browsing for problems.
I currently own a GS300 that I modified with Tein Flex Z coilovers, Megan Racing rear swaybar, and 18" Model 3 wheels wrapped in 245/40 Continental ECS02. My alignment is 1.9 degrees of camber with 0.02 toe-in F/R. The car has a ton of grip in the corners, but I am never quite satisfied with how the coilovers behave. I have the dampers set to 4 clicks from full stiff, and I feel that the car is jiggly but still ultimately underdamped. I run out of suspension travel (slam into the fenders?) when hitting bumps at speed, and it results in a really jarring bang sound.

For reference, my stock ND3 Miata Club does not do this, regardless of what speed I go over the same bumps at.

For my next suspension setup, I would like something that controls the body motions well without crashing over bumps. This car is my daily, and I would like "driver's car" driving dynamics without being overly stiff. I am willing to spend a good chunk more than the Teins to achieve improved handling. I did some brief research and it seems that Bilstein B8s paired with some lowering springs are a solid option. What springs would y'all recommend to go with the Bilsteins? I would also be open to coilovers with properly-valved dampers.

Here is a picture of my car as it sits. Thanks in advance!

That's interesting. How long have you had the flex-z's installed? I'm also running a set and close to full stiff. It feels planted and smooth over bumps. I also have sway bars, adjustable in the rear at full stiff, and strut bars. When you set up the coilovers did you make sure to set height with the bottom of the coilover body only? No compression of the springs? Some people mess that up and set height by squishing the springs. Makes for way too high spring rate and bumpy ride.

I have not messed with the preload, I've always adjusted height from the correct collar. To clarify, the car rides fine when driving normally, I'm more referring to aggressive driving. During aggressive maneuvers, the coilovers feel very travel-limited, and the springs too soft (at least for the height that I am at). Mid-corner bumps at speed result in bottoming out, and the car gets unsettled. On the bumpy canyon roads that I like to drive on, this results in me having to slow way down for certain larger bumps that I can just fly over in the Miata.

Another possibility is worn out bushings; I believe all my bushings are still factory units at 160k miles. I put the Teins on at around 130k.

There is also a possibility that I have too high expectations for this car, but I do feel like there is massive improvement to be had in the suspension of my GS. For around $800, I'd say that the Teins done their job for the price, but I think I'd like to try something else next time around.

Hmm, I'm afraid the trade off will be a stiffer ride all round to go with anything above the flex. But you need what you need. Sounds like you need a monotube set. I've run a lot of Tein's on a lot of vehicles and I have to say, the Flex is probably the most ideal street set I've ever run. It is the highest performing twin tube design I know of and the comfort is beyond comparison. You might benefit from a more track oriented set. Maybe look at BC. Even their entry level sets are monotube which should automatically resist compression better and respond with faster rebound. But that will transfer some more of the bumps into the vehicle. Still, maybe you will find that you can run a monotube at a lower dampening setting for comfort.

You'll definitely have to look at spring rates and shock compression/rebound rates and compare them to the flex to make sure you are getting something different.

hello there, I'm also new here and I know my question is not related to the thread but I just so happen to stumble upon. Anyways I looking to upgrade to Tein Flez Z in the near future and was wondering how you guys find the ride feeling compared to the stock shocks in terms of comfort (daily driving) and dampening of bumps and uneven surfaces, as I know they're meant to be more sporty. I just want to get some opinions based on experience. Thanks

All coilovers will be a drastic change from stock. However a good quality set is bearable and worth the performance. I am happy with the flex-z. But you might look at the "Street Advance" which is similar but more comfort oriented. The flex has a solid metal upper mount, the street advance uses a hard rubber compound to absorb more impact/vibrations. I was actually totally happy with the "Street Basis z" for years. I only upgraded because I started making big power and wasn't feeling planted under boost.

Thank you! ​​​

There isn't a ton of room above the front upper ball joints. So if you're pretty low or you are a little lower but compress the suspension really hard, the upper ball joints will hit the strut tower and the control arm will hit the reinforcement ridges.

Solutions other than raising the car include:

-shortened knuckles, paired with lower ball joint spacers aka roll center adjusters*
-aftermarket FUCAs with more clearance front thinner ball joints, like Serial Nine.
-pocketing the strut tower for more clearance.
-stiffer springs, with damping to suit

*roll center adjusters are nice for these cars in general, when you lower them. But they do move the upper control arm even closer to the strut tower, unless the knuckle is shortened.

You could also start by going full-stiff with your current dampers to see how much closer that gets you. That's a free thing you can try.

I’ve tried full stiff on my current dampers, and it feels like filling up the dampers with sand, without a whole lot more body control… not great in my experience.

Thank you for the suggestions, I am not very familiar with RCAs and FUCAs. How do they affect the handling on a lowered car?

Also, just curious: What suspension setup do you run on your own car? Based on your current/past setups, what would you recommend and what have your experiences been like with different setups?

I chose my setup in order to achieve a certain look, made functional. So with that context, I can share what I've done and plan to do, and maybe it will provide some insights that will help.
After using Tanabe DF210 springs on stock-style KYB shocks, a setup I was really happy to daily drive, I installed Fortune Auto 500-series coilovers with Swift 14k front and 12k rear springs. I also installed 17mm front RCAs, TRD Sportivo sway bars with shortened end links, and SuperNow tie rod ends with bump steer correction. I also have poly LCA bushings.

I chose those coilovers because I didn't want something extremely stiff, but it does take a decent amount of spring rate to not bottom out all the time at the ride height I want. The front upper control arms do hit the strut tower before the strut is bottomed out, on abrupt bumps. I haven't had any issues with this at autocross, even under heavy braking or rapid side-to-side movements. I get the feeling that more compression damping could help with, but ultimately the biggest problem is simply the reduced travel for the Front Upper Control Arm and the terrible condition of the roads where I live.

The RCAs space the outer ends of the lower control arms down, relative to the knuckle. This helps correct the roll center. Unfortunately, this also moves the outer end of the upper control arm closer to the strut tower.

What I would/will change: I would like to install shortened front knuckles, and thicker RCAs. The RCAs can correct the lower control arm angle, and the shortened knuckles regain upper control arm clearance.

I also just noticed that you said you have stock bushings with high mileage. That's definitely something worth looking at replacing. Even just new OEM style bushings would be an improvement.

Thanks for your detailed reply; How are the FA500 dampers in autocross settings? The 14k/12k setup would be a logical next step for me (Teins are 12k/10k). I'm also curious as to how a coilover setup like your FA/Swift would compare to a lowering spring + sport shock combo (ex. Tanabe DF210 + Bilstein B8), since the DF210 has a way lower spring rate.

Your modifications to correct suspension geometry seem to be useful; I'll definitely look into that. Also, I will be sure to address all of the relevant bushings the next time I change up the suspension, I'm confident this will also improve handling feel substantially.

Well, I'm not very good at autocross and neither is the car. But the dampers certainly aren't holding me back. My tires are not sticky enough to take full advantage of the additional spring rate under heavy loads, but the car does not dive, squat, pitch, and roll like the land barge it started life as. I did have to turn the damping to almost the stiffest setting in the rear because it was bouncing a bit, but that could also be attributed to the age of the dampers- I bought them second hand. Since doing so, no issues.

The DF210 feels how the car should have come from the factory, IMO. It never felt like a "lowered car" and the standard KYB GR2 (aka Excel G) struts were not taxed. I would expect the Bilsteins to be even better.

You should try changing your coil over settings to the softest settings and leave them there for several days and then adjust them stiffer slowly. A common misunderstanding with coil overs is that they have to be in the firm position to get good handling, and this incorrect. Obviously it depends on how you drive and the road conditions etc. but most coil overs, even in their softest setting, are much stiffer than the factory setup. And if they are to stiff the tires can’t traction like this. Try going for the softest then adjust them slowly and get the front and rear set accordingly.