Suspension Knock
 

Ok, been fighting this one for a while, and all my focus has gone towards the endlinks, but it sounds like I could be going down the wrong path, because no matter what I have done so far, the sound is back ....

http://www.youtube.com/watch?v=p1W5NM6xO2Y

This is me violently rocking hte car back and forth....

I will have to get my gf down there to see if she can pinpoint where the noise is coming from.....

not sure wtf happened with the video quality

Loose sway bar bracket?

I'm assuming you've checked to make sure all your endlinks are tight based on what you said in your post.

yep, i took the endlinks up to 55ftlb, and the brackets are at factory spec 35ftlb in the front, 19 in the rear.

Weird... all the control arms/shock towers/etc all tightened down good?

Pretty sure of it. There was absolutely no play when I had the car jacked up just now. FYI here is the other thread

https://www.rx8club.com/series-ii-wheels-tires-brakes-suspension-165/s2-oem-wheel-frushhnesss-222741/

Hmmm....Loose Strut Bar or maybe even a Strut?

Just noticed you have coilovers, maybe not enough preload on a spring?

Resolved. Chalk this one up to an endlink issue. Thanks guys.

yeah i had that happen to me too...except i had to buy a new endlink cause i screwed mine up while installing the coilovers.

Ouch, glad that didn't happen to me :(, but yea, basically i would measure the endlink length by lining up the holes ... but i forgot that as you tighten the bolts, the optimal length of the endlink changes as the angle in the endlink starts to slightly change. I found that, although length X would fit the holes without issue and show roughly 90 degrees between the endlink bolt and the ball joint, length X + 3to4 turns would be the best to maintain proper 90 degree angle once the bolts are fully tightened. ... hope that makes sense.

None at all ... how was that responsible for the noise?

Well to be quite honest with you, I believe that the endlinks were binding a bit, or the preloaded tension was causing knocks. I really dont know and that is due to my lack of proper experience with suspension tuning.

basically what i notice was happening was that although when i lined up the bolts and the holes it looked like the bolt was going to enter in straight which would leave it at about 90 degrees to the endlink body, as I tightened up the nut, it actually started to deflect to about 110 degrees to the endlink body (shooting numbers from left field, just trying to get an image in your head). I suspect that because of this, some binding was occurring as I was rolling on soft repetitive bumps which is when the swaybars are moving up and down the most.

Long story short, I had the endlinks too short.

Once I lengthened them a bit, all noise went away. I honestly wish I had access to a lift so that I could 100% diagnose and document what was happening

You might be missing some washers. That happened to me and it made the exact same sound.

paimon, do you hear this sound only when turning?

Well I dont really get the noise much anymore, or at least not as loud as before once I fixed the endlinks, but no, I would get the noise over very subtle bumps in the road, like driving slowly through a parking lot. Constant "cla-clunk cla-clunk thunk thunk" noise ... very embarassing lol.

As far as the washer comment, I know that they are common when using heim joints, but even for the steel ball joint endlinks? Or does that not matter.

I was noticing clanking noises from my suspension after installing Racing Beat front and rear sway bars with the front end links. The first case, where the noise was quite severe, turned out to be a loose right end link. However, after that was fixed, I continue(d) to hear a subtle noise when going over broken pavement (which is really bad and everywhere here in mid-Michigan). After having it to the dealer and the shop that did the install twice, the guy at the shop went for a drive with me, and we figured it out: The level sensor is clanking against the control arm (driver's side). It's likely more frequent or noticeable now due to the much firmer suspension when one side experiences bumps the other side does not, rattling the thing like crazy. Now that I know it's not a safety issue, it can ignore it (it's pretty subtle most of the time).