[EndlessCorners]

Current Setup:
Koni Sports
Eibach Springs (Pro Kit. 1.3 inch drop all around. Progressive rates, eibach wont tell me what they are)
Ride Height: Front L22 3/4 R22 1/2 Back L23 1/2 R23
15 inch Enkei wheels
205/50/R16 Toyo T-rs


The Symptoms
The car gets unstable when it hits bumps. When you hit a mediocre bump it feels like it bypasses the suspension and goes straight to the chassis. Smaller bumps aid the unpredictable feeling of traction. The car bottoms out quite easily, there are some speed bumps that I can't drive over with out scraping. Strangely enough if you bounce the corners of the car they don't feel all that stiff, my friends 2001 accord on stock suspension feels stiffer.

Some solutions ive tried
I decreased the tire pressure down to 30 psi in a stupid attempt to try and get a better wheel rate. I turned the shocks to full soft, again in an attempt to get as much compliance with the road as possible. I decided to try full stiff all around for the hell of it, the car pogo sticked front to back in a bad way.

Side info
I talked with Brandon Kraus of Roger Kraus Racing about my suspension. I was a bit early in the morning for me so I didn't catch everything, more specifically what he thought my ride heights out to be, and the range of spring rates I ought to consider. But he thought that my ride height could be about an inch too low. He suspects that im hitting the bump stops. His suggest was that I get FM springs and cut down the bump stops. Brandon also mentioned that if I track my car I should feel the Koni sports overheat in about 10 laps. I had brought a friends car by for an alignment so he was unable to see my car. I'm planning on bringing my car by and getting his opinion before I buy anything.

My Opinion
This all sounds good, before I walked in I thought that there was a lack of suspension travel. Wheel gap doesn't concern me, I don't care how much of it there is if the car handles better. The only thing I really care about is predictable traction, this is my only goal for the suspension.

So what do you guys think? What should my next action be?

 

[StepInTheMirror]

Tein Flex!

Hahaha... how I'd love to dish out all my money on those sweet, sweet coilovers.

Anyway, its a pretty well known problem that the Miata's suspension travel becomes very limited (especially in the rear) once you lower the car. So, there are a couple of parts suppliers that could help you out. For example you could consider the FM Shock Mounts to give you a bunch more suspension travel. There are also Fat Cat Motorsports shortened bump stops which I have heard great things about for increasing suspension travel...

But if you really don't care about the ride height then... you should just try to find some springs that sit higher. Or move your konis to the highest perch.

There are lots of ways to find more suspension travel.

 

[EndlessCorners]

Tein Flex!

Hahaha... how I'd love to dish out all my money on those sweet, sweet coilovers.

Anyway, its a pretty well known problem that the Miata's suspension travel becomes very limited (especially in the rear) once you lower the car. So, there are a couple of parts suppliers that could help you out. For example you could consider the FM Shock Mounts to give you a bunch more suspension travel. There are also Fat Cat Motorsports shortened bump stops which I have heard great things about for increasing suspension travel...

But if you really don't care about the ride height then... you should just try to find some springs that sit higher. Or move your konis to the highest perch.

There are lots of ways to find more suspension travel.

The Koni shocks for NBs don't have an adjustable spring perch. The FM shock mounts wont help me either. I want to say that I have enough travel in back because the ride height looks to be about an inch higher then in front. But I know this isn't true because whenever I hit a good undulation it feels like the back end gets launched.

 

[slutz4]

Im not a suspension expert but Im sure higher spring rates would help, have you ever thought about saving up and getting ground control?

 

[boogie van]

I have the same setup although on an NA. I have heard the koni/ground control combination is quite nice for the price, so Im considering upgrading to that someday.

I would have to agree that the eibach springs feel too soft, I get quite a bit more body roll than I would like to, but I have yet to experiment with adjusting my sway bars, which are currently on their softest settings. I look forward to toying around more with those and shock stiffness and tire pressures this spring

Do you have sway bars? Whats your alignment situation?

FWIW I am slammed yet rarely feel unstable.

I run 30 psi on the street, currently the shocks are at 1.25 turns from soft in the front, .5 turn from soft in the rear.

 

[EndlessCorners]

I can't really complain about body roll, its not very significant. I think my Eibachs might be progressive. Would the ground control kit work with my current Konis, or would I have to buy different ones?

Stock swaybars

This is how my alignment looks:

Front Left Right
Camber -1 -1 Deg.
Caster 6.1 6.3 Deg.
Toe 0.00 0.00 Inch
SAI 11.9 9.1 Deg.
Incld Angl 10.9 8.1 Deg

Rear
Camber -1.5 -1.5 Deg.
Toe .04 .05 Inch
Total Toe 0.09 Inch
Thrust Angle -0.02

At 30psi I wore out the outside edges of my ties. There is also scuff marks on the sidewalls, so I Was rolling over on them too. Initially when I ran higher pressure the car felt nervous. Now im running those same pressures and the car feels better. So I guess my driving ability has progressed some.

 

[boogie van]

have you tried disconnecting your rear sway bar? its a free mod...or un mod? Its common for people to do to decrease oversteer if you have a problem with that.

http://forum.miata.net/vb/showthread.php?t=173025&highlight=disconnect+sway+bar

is that toe out in the rear or toe in? toe out could be causing your car to feel a little uneasy.

I wish someone more knowledgable then myself would chime in here.

Plus re-reading your post...Im not even addressing the issue you are having with the feeling like the rear is bottoming out. FCM bumpstops might be the fix you are looking for there. They are known to provide needed suspension travel in the rear.

http://www.fatcatmotorsports.com/FCMstops.htm

To be honest, there is probably more useful information on miata.net as probably most handling discussions have been beat to death there.

 

[EndlessCorners]

Alright I found out what springs I have an updated above.

I'm going to go pose my question on M.net and see what I get.

 

[Agent935]

Are you measuring your ride height from the hub or from the ground?

I had a similar feeling setup to what you are describing with my LE with RB Springs and My Stock Bilsteins. I cured it with Tein Flexes.

If you don't want to make such a drastic step, I hear the Fat Cat bumpstops can help. Not as much with an NB as with an NA but I hear they can help.

 

[EndlessCorners]

I'm measuring my height from the fender to ground. At the request of M.net I ran outside and took some quick fender to hub measurements.

11.75" in the front and 12.5" in back.

A guy over there said that If I was in that range I would have an inch of suspension travel and be on the bump stops all day. I don't know if he was thinking about an NA or NB.

Linky: http://forum.miata.net/vb/showthread.php?t=215826

 

[StepInTheMirror]

Yeah, hes probably right, you are sitting pretty low.

Did you cut your bumpstops when you installed your new springs or are they full size stockies?

I'd be looking into either a spacer to raise the suspension up a bit, smaller bumpstops, or a new setup with stiffer springs.

 

[minime]

LOL! Enless, you posted the same thing over on miataforums! You will get better feedback on the MF. I don't consider posting anything performance related on this forum, but all the eye candy is over here

 

[EndlessCorners]

I have no idea what the PO did when he installed the suspension, but more then likely the bump stops are stock.

I'm leaning toward the ground control setup but the FM springs also have my interest.

More then anything I want these Eibachs off my car. I'm tempted to try and resell them but I think I will do everybody a favor and destroy them with a torch. O

 

[asianrice02]

might want to look at fatcatmotorsports. he a sponser at m.net and seems to be more familar w/ miata and shock travel

 

[clshrckr]

also fat cat motorsports is local to the bay area so if you buy anything from him you can locally pick up/pay cash

 

[EndlessCorners]

I'm reading through there site right now.

 

[white91base]

I have the FCM bumpstops with NB eibachs and AGXs and the ride quality is definently improved, as is my ability to put power down on less than smooth surfaces. The car is less sketchy on rougher roads now for sure. It feels more stable in higher speed corners now too. Basically I'm saying that for $60 you can't go wrong.