its more of a rattle at this poinnt. turn your speakers up a bit and you will hear it. its throughout the whole thing. it might be hard to hear because it barely stops. its like bummmm bad dum bumm. i have sound clips that are better as well, but not on youtube.

If it's a constant rattle then I don't think it's The spring mount. You should have someone bounce inside your hatch and look underneath your z.

i wouldn't count on it just being an installation issue. it can well be a manufacturing defect. if it's not the endlinks i would check the rear spring orientation (some springs rub against the carrier unless positioned a certain way), pillow mounts could make noise too if worn, but it's too new so i would consider it a defect if it turns out the noise goes away when you use stock mounts.

i have bounced in the hatch, and the noise happens. i'm gonna take the wheel off and see if i can't find any issues right now.

id be funny if it was something loose (like a wheel lock key or wrench) rolling around in the spare area or under the trunk liner... (hint hint) :D

haha i wish it was, i've checked all of that :shakes head:

Jeff make sure when you take your wheels off you don't apply too much pressure and scratch the lug hole area. I've done it on previous wheels and it's a horrible way to start an already frustrating job. You should ask if bc is willing to warranty them. Put on stock struts and springs and wait for new coils. If not, then see if the shop u installed them at will take them off and re-install them (they should warranty their work) to see if you can reproduce the noise. Also the installer said the preload was maxed out but people make mistakes, kindly ask him to double check.

i wrap my sockets with masking tape or use my griot's wheel lug socket. either way works just fine without scratching the lug bores.

You could have bc replace...you have one year warranty with them tell them you had it check they will replace it. I had bc anything that could go wrong with it did I had one of my arms replace under my warranty because the nob wasn't working. It took less than a week for me to get my replacement.

You should just jack up the rear end of the car and take a snap shot of the rear spring and shock unloaded. I dont know what it means when the mechanic said it is at max preload, because from what I hear it is a straight linear spring. Like is the mechanic saying that the spring is maxed out at the top portion of the threaded body of the perch??

I think he meant the strut was maxed out.. Correct me if I'm wrong.

i asked them about everything several times. he said the thing with having the wrong preload, and not leaving the isolation ring there are all amateur mistakes. i checked everythingand everything is tight.
yea i'm very careful, thanks for the heads up!
good idea!
Not sure how i want to deal with it. if it is in fact a bad shock, i would expect a replacement, and money to cover the reinstallation cost. However, if a shock went bad in 2 weeks, not sure why i would really want to accept having replacments, and i'd want my money back to buy something else.

i did that and took pics and i'm gonna send them tomorrow. i'm rpetty sure the installation is all good. I checked EVERYTHING they said and any mistakes that could have been made during installation were not made
nah its basically the threads on top of the spring perch, if the rings are all the way at the bottom of the threads, then its maxed out, thats pretty much where they are.

Jeff, 25 years ago I had an internally broken Koni strut. It made a similar noise but I can not say for sure that it was identical to your noise, but it sounds familiar. If you can isolate the sound by reinstalling the stock coil over. Perhaps you can just remove the right rear and jump up and down in the trunk, listening. The later may not be the correct method. I am putting on coil overs soon so I will be sure to keep my old ones, just in case I need to follow my own advice. Good luck.

^Thanks man, i'm hoping its not that, and trying to rule out everything else with some help from the guys at BC. I must say they are being really helpful.

Here is one of the pictures i took and sent to BC. They are saying that this gap between the nylon rings (Below the gold ring) shouldn't be there and that he is pretty sure that's causing the noise. i'm gonna have to compare it to the left side spring to see if its different. Any thoughts?
http://www.the370z.com/attachments/b...rs-low-res.jpg
http://www.the370z.com/attachments/b...25-low-res.jpg
http://www.the370z.com/attachments/b...15-low-res.jpg

with preload of the car i dont think that gap is open... try putting a slit of rubber or plastic in there as a gasket, duct tape it temporarily and drive around if that eliminates the noise.

i dont think it will... you would have to be like em dukes of hazard making jumps to get that gap to open up while driving.

thats what i said. I explained that when i jacked up the bucket under the spring (as if there were some load on the car) , the gap went away right away. but Mike from BC said that the gap shouldn't be there even when theres no load on the car.

yah, well Mike from BC must know wat he's talking about then. :icon14:

not sure what you mean by that :confused:

if the left side looks different, then i would imagine that could be causing the sound. if it the same, and the sound is only from the right, then it obviously isn't.

i would swap the springs left/right and see. are they oriented left/right differently?

i'm swapping wheels for winter tonight. so i guess i will find out. the only thing bugging me is that if this were an install problem, the sound would have happened right away so i'm still :confused:

also check for scrape marks on the springs when you do your work tonight. should be a sign if it is the spring.

while you're at it, why not swap out the shock top mount to stock if it fits? it could mean that the pillow mount itself was the problem or the piston nut wansn't tightened down well enough and it backed out a little causing rattle.

supposdly its no big deal to swap the strut, i'm kinda nervous about it tho. sucks that i have to do this in my garage. i paid enough money for the coils and install, and now i'm here in my garage working on the car myself to try and figure out what the problem is.

actually that's a shock (damper), not a strut in the back. :icon17:

Jeff man I know it sucks but whenever I work on my car I get this sense of empowerment! Unless of course I mess something up :-/. Just take your time and be patient. It helps!

i get that too. i'm always comfortable doing something AFTER i've done it. before i do it, i'm nervous. Which i guess is the way of the DIYer. First time i changed my oil i was like :ugh:, now its no big deal, same thing with swapping wheels and stuff, first time i was nervous having the car on jack stands etc. i'm sure this will be the same, but the more moving parts involved, the more i get nervous hah.

you're not a car guy until you can wrench on it. :D

If you're just taking the rear damper and spring off it should be a pretty simple process. Good luck buddy.

+1

uhhh.... someone go check on jeff...

Long story:
basically, the 2 rings on top of the spring, they were practically as LOW as they posible could be. there was like 1 thread left. when the suspension hung loose, there was a gap between the spring and the ring. On the left side there wasn't. i took everything out of the spring assembly. turned the collars enough to get out that to the very last thread, and put everything back. so essentially i have the most preload possible, however, the spring still has a little gap when hanging loose. ii fully expected to not have fixed anything. basically it seems like theres not enough threads on the spring perch, even though i'm lowered .75 inches, it seems like my car is too high or w/e to get enough preload. so anyways, i adjusted that ring maybe HALF a turn. all finished, i expected the sound to be there and was totally surprised that it wasn't.

i honestly think the installer put as much preload as they could, i just put a miniscule amount more, literally i could not possibly pput anymore preload because of the amount of threading on the spring perch. i remember the guys at the shop even saying it was at max preload and complaining how they wanted to add more but couldn't. so i dunno, i think BC might need to modify the design . maybe the sound only presented itself because i'm not lowered that much in the rear. Mike from BC said i'm almost at max height, which doesn't seem to make sense but w/e i'm gonna talk to them tomorrow and explain. i now have this really slight creeking sound but its not all the time, maybe a loose interior panel or something... i dunno, but its not really that bothersome, nowhere nera as bad as that goddamn rumble rattle.

Short story:

It appears as though, based on my ride height (.75" lower than stock, which is not that low), and the fact that i have 210mm springs, i have to max out the preload. However, there really isn't enough threading to do so.

It is my opinion that this was neither installer error, nor was it a defective product. it was just a matter of my ride height and the maximum amount of preload that can be put on the spring based on the amount of threading and the length of the spring. The solution: BC Racing is going to send me 230mm rear springs or spring spacers, whichever i want. i am most likely going to go with the 230mm rear springs. After my little escapade last night, i feel totally comfortable swapping them.

A major rep goes to Mike and BC Racing for talking to me on the phone for god knows how long explaining everything and sending me pictures of how to make any adjustments. Also, i'd like to thank Performance Motorsport for helping out diagnose the problem. they DID do the install correctly, and these are not defective shocks. i just happen to have my ride height set pretty high in the back. that is all. after adding what miniscule amount of preload i could, the noise went away. But with the longer springs, i can move the rings way up higher and have more preload to play with.

SOO if you do get these coilovers, which i really do enjoy, and you plan to only do a mild drop, ask for 230mm rear springs. If you drop any more than .75" in the rear you should be fine with the 210mm springs

ok so that wasn't very short, but i feel much more comfortable working on suspension now :tup:

Even though it isn't typical install practice there is a workaround. If you reinstall the top rubber spring perch and flip the spring and height adjuster you gain about 0.5 inches of adjustment. Downside it is a bit of a pain to adjust the collars because they are sitting in the pan of the lower control arm, however the control arm has an opening on the inside which allows lateral access.

interesting. well i have the noise gone now and i'm getting longer springs, but that's a cool workaround.

:yawn:

:tup:

things to buy: a GOOD low profile floor jack

harborfreight's racing jack is pretty good. ive been using one for several yrs with no issue. cheap too. i have 2 in my garage.

Yep that's what I have, works great.

i can haz? :tiphat:

really though, is this it?
http://www.harborfreight.com/3000-lb...ack-91039.html

my car is lowered an inch i want to make sure it would be low enough to clear under the car.

Just spoke to Mike from BC Racing. They are sending me 230mm springs free of charge. I must say, they have amazing customer service. within 20 minutes of me calling them and leaving a message, they had called me back and were helping me out. Spent probably at total of 1.5 hours on the phone with Mike and he helped me out with isolating the problem and now they are sending me what i need to make things work for my ride height. :happydance:

yep, i think that's the exact one i have. just get two. makes it easier get it under the car to the lift point especially on the front.

you know wat, most stores like customers that actually work on the car and show effort in trying to fix the problem. some customers are paper pushers where they just whine and :crying: and dont get off their lazy fat arse and just start blabbering off pointing fingers at everyone.

so good job on your part too. :tup: