Hi all,

I have a 2004 RX8 GT model with aftermarket springs, shocks and sway bars. I'm running Racing Beat springs coupled with Tokico D-Spec Adjustable shocks. Sway bars are Agency Racing Adjustables.

The rear end tends to bottom out on me frequently nowadays. Oddly enough even despite having stiffer springs and stiffer dampners to boot. I notice it sometimes when I'm by myself when there is a moderate bump on the road, and feel the front absorb the bump, then the rear just bounce off the bump stops. If I have people in the back, forget about it... It almost feels like it's riding on the bump stops depending the load.

I can't help but feel that something is wrong. I did have the opportunity to visit my sister who actually has a stock 2008 Anniversary model. Her car with a full load didn't bottom out like mine does, and sadly enough felt much stiffer! Visually comparing the ride height, they look the same, except my rear end looks a tad lower.

The suspension settings on the car are pretty mild. Sway bars are at the softest setting, D-Specs are halfway (5 turns from soft), and the alignment is set to factory specs. I do have aftermarket 18 staggard wheels, but I don't think they have much to do with the equation. I've had these components put in about the same time, and are less than 8 months old. I've had one track day with this setup, and the rest is regular driving.

I cranked up the stiffness in the rear to 7 turns towards stiff see if that helps out any. I'm going to have my buddy put it up on rack and inspect the rear suspension components and make sure nothing is out of the ordinary (loose bolts and what not). But I'd really be shocked if the shocks/springs are blown/worn.

Any thoughts, feedback, comments would be greatly appreciated.

 

Just measured the fender height between front and rear.

Unloaded:

Front - 27 inches
Rear - 25 1/2 inches

Loaded (rear passengers)

Front - 26 3/4 inches
Rear - 24 7/8 inches

The rear is definitely drooping more than it did before, or at least compared to stock suspension components.

 

Anyone? Anyone? Bueller? Bueller?

 

First try replacing your shocks. Could be as simple as that and you can never go wrong with putting new ones on.

 

So the cars seems level? measurements seem off to me. You measured from the fender to the ground? Any chance you got the wrong springs on the rear?

Just measured mine and unloaded the rears are at 26 1/4" and the fronts are at 26 1/2" from center fender to the ground. Weird because to the naked eye the front looks lower.


Something is very wrong because you are .75" lower than me in the rear and the racing beat springs should only be a .5" drop all around.

 

You can use fender heights for reference but don't use them to set ride height(s). Use hard points on the car like the bottom of the subframes.

OK---here's my guess. You have coil bind in the rear. Take a rear wheel off and put a jack underneath it. Raise the jack slowly. Watch what the suspension (and particularly the spring) does.

If you're running the rear of your car low, raise it up a few turns, drive it around and eval.

Happy rotoring.

 

Clarification: Put the jack on the bottom of the brake rotor and raise the rotor to raise the suspension. You can't hurt those big nasty things. Just make sure you've put the lugnuts back on so the rotor doesn't jump off the studs.

 

I was thinking it was initially the shocks. But what makes me think it's spring related is the low ride height since the springs are responsible for that. Both the RB Springs and D-Spec shocks were both bought new about 8 months ago, which in a worse case scenario I think I'd still be eligible to RMA them. Just would suck to have to pay for the labor of uninstalling and reinstalling.

I unfortunately don't have an extra set of shocks to try this out with. The OEM ones that came with the car (used) were blown beyond belief (had NF210 lowering springs on it). Right now I don't have the money to buy another set of D-Specs. But if I can isolate the problem (with everyone's help on the forum), I can make arrangements to get them replaced.

Regards,

 

Yeah I measured from the ground to the top of the inner fender. I know it's not the most accurate way to measure it, but the easiest (for a lazy **** like me anyways).

I remember when I first got these springs I was looking at them to make sure I got the right stuff (after reading on the forum about suspension issues in the rear). It looked a little low, but I thought that was normal and didn't think much of it. Everything looked right as far as I could tell. Granted I didn't do the install myself (my friends at a local shop had taken care of the install for me), I was there when they did the install. Is it possible to install other mazda springs on the rear?

It's definitely worse than it was before, now that I was able to compare mine with my sisters bone stock 08 model. I didn't measure the car when I first got the suspension installed, but do remember it had a tight 2 finger wheel gap (terrible measurement method I know), but now it's a tight 1 finger (just about to tuck the wheel). As a reference point, the front wheel gap (using the finger method) is a tight 3 finger gap. This makes the car look dramatic when I'm accelerating without really stepping on it. Maybe that's way everyone is trying to race me all the time?

 

Should I just rotate the spring in the perch? Just to clarify the springs/shock combo I have are non-height adjustable, but the shocks do have dampner adjustability. (Racing Beat Springs and Tokico D-Spec Adj Shocks.)

I did have the car on the rack for an oil change not too long ago. I always make it a point to look around especially before I go on a long trip and what not. Last time I looked I didn't notice anything out of the ordinary. Then again I haven't seen a coil bind before.

Thanks for the suggestion Eric, I'll give this a shot.

Regards,

 

Good luck bro

 

a) you need to disconnect the swaybar first otherwise trying to jack up one side is an exercise in futility

b) these aren't coilover shocks i.e. there's no way to raise it up a few turns

 

I have the same problems, I got mazdaspeed springs with koni shocks and racing beat sways before, and after a while the springs felt soft and bottoming out, so I adjust the shocks to stiffer setting and felt better, but it did not solve the problem of bottoming out, so I brought a set of Progress Technology Auto-X Springs because I want a higher spring rate than mazdaspeed with out going to coilover. After the installation and max out my shocks setting it felt night and day, it never bottom out or felt bouncy over bunps. The thing is that springs should not sag more then 1/4", anything more then 1/4" it call for new springs..

 

I'm going to guess that the front springs somehow are on the rear of the car. It's really hard to mix it up since the spring perches are different but it's easy to get confused when the springs are off the car because people typically think the shorter springs go on the rear of the car when it's actually the opposite.

I would verify that the proper springs are on the rear. The way to tell is the rear springs taper at the bottom to rest on the much smaller spring perch while the fronts are about the same diameter all the way down.

Else you may have the rear sway bar installed upside down. It won't explain your low rear ride height but it would explain the clunking and bottoming out feeling. The curve of the blades on the rear bar should be curved downward towards the ground. not up towards the body of the car.

Also take pictures of the underside of your rear suspension and post them up so people can take a look at your setup. You can just crawl underneath the car.

 

Pretty much the same story on my end thinking back. Initially they felt great then the rear just felt like it was sagging. If anything I hope I can RMA these if they are bad. The thing that really surprised me was (seemingly) how much stiffer the OEM shocks felt on my sisters car versus mine. Hauling 4 people was no problem compared to mine bottoming out.

Regards,

 

Unfortunately I don't have access to a camera (other than my iphone) at the moment, but will take some shots when I can. However I do have some photos of the springs/shocks when I first got them installed that I can post now. They haven't been removed since the installation. Aside from the sag and dirt now they're still in the same position they were.

Here's a photo of one side partially installed:


Another rear shock pending installation:


Based on the photos they "look" right. But then again they also look very similiar with the biggest difference being the rears were slightly longer.

Here's the front shock:




I had the springs/shocks and sway bars installed all at the same time. I remember my buddy was having a problem with the rear sway bar install. Initially it looked upside down, but felt we got it right after rereading the instructions. Though definitely worthwhile to have everything rechecked to confirm.

Another buddy who owns a shop has a lift, so I'll see about getting the car up on there and taking a few snap shots as well as confirming the part numbers for front and rear. On paper at least, I know I got the right part numbers.

Thanks everyone for responding to my post, I'll keep you guys posted!

Regards,

 

Found a recent picture that has a good view of the suspension from the rear:



Nothing's changed since this photo suspension wise...

shaunv74: Does the sway bar look upside down? Granted the car is on a lift, it seems to be pointing in the right direction?

 

Thanks for the pics. The right springs are on the right side of the car.

Also the swaybar is oriented correctly.

I would definitely check and retorque everything. Especially sway bar endlink bolts.

 

Everything "looks" okay. Weird.

 

Agreed. I would go with Eric's suggestion and check the suspension travel by measuring it on the ground and then relaxed in the air. Also try jacking up the suspension until it lifts the car to see where you are getting contact. Also I would check for evidence of rubbing on the springs and sway bars to see if you can figure out where it's bottoming out.

 

Thanks for checking the post and all the suggestions guys. I'll take it into my buddy's shop and see if I can re-torque everything on the rear.

Seeing that everything thus far looks like it's installed correctly, I guess the next step is to see about getting the parts RMA'd. If not maybe it's time to consider going with another brand...

I'll keep you guys posted, thanks again everyone!

 

I sort of skimmed through 80% of this but...did you happen to cut the bump stops about 1 inch? If not that is your problem.

 

I haven't cut the bump stops... But then again I had the springs/shocks installed by a friend who owns a shop. Just curious, by cutting the bump stops what benefit do you gain besides added suspension travel?

 

I don't see how cutting the bumps tops would matter? It would just mean you would hit them earlier if they were not cut. Doesn't explain the sagging.

 

If you are bottoming out on the bump stops and cut them you may not bottom out on them. I'm having a hard time believing the the Racing Beat springs would be bad. It's a good quality brand and tons of people on the forum have them with the Tokico's with good results. It's conceivable that you got a bad set but not likely a design problem.