: Has the GC Kit rear end clunk been solved yet?



Venomous-V
12-05-06, 05:32 PM
It's finally starting to bug me enough that i want to do something about it. Those of you who have the kit ,i'm sure you know what i;m talking about. Its a knock,bump,clunk, whatever you want to call it. It happens going over bumps only. Any body get theres fixed or diagnosed the problem and come up with a solution? I know this was slightly adressed a while back but i didnt hear of anything being resolved....!?!?!?!

Venomous-V
12-05-06, 09:50 PM
???anyone???

calicadi
12-05-06, 10:11 PM
I think what you're describing I've learned to accept as the new normal. I did run into an odd "chuff" sort of sound coming especially from the right rear. Turns out the lower shock bolt on that side backed out and eventually fell out somewhere on the road. Once I had that replaced and properly torqued, no more "chuff".

Is it front, back or all four corners making noise?
What spring rate are you running?
Have you checked the upper and lower shock mount torque?

Seattle CTS-V
12-05-06, 11:52 PM
I describe it as more of a solid sounding 'thump' as I come off the backside of a speed bump. I too accept this as the new 'normal'.

rand49er
12-06-06, 05:16 AM
I describe it as more of a solid sounding 'thump' as I come off the backside of a speed bump. I too accept this as the new 'normal'.Got it here, too. Annoying to say the least. Seems to be right rear (though my hearing sometimes plays tricks on me), but why would that be? Why not both sides if at all?

BTW, thanks for bringing this up.

Venomous-V
12-06-06, 08:28 AM
I'v found it is mostly right rear when it is cold out but sometimes both sides in rear in warmer weather. I recall WW or Dreamin had adressed this issue with a little success. This whole NEW NORM thing sucks.

cjones
12-06-06, 08:52 AM
I kind of assumed I was overpowering the FE4 shocks and that FG2 might help.

rand49er
12-06-06, 02:05 PM
I kind of assumed I was overpowering the FE4 shocks and that FG2 might help.Hmm-m, I was actually thinking the opposite ... that the FG2s would exacerbate it. But, I'll be the first to admit that I'm far from understanding exactly what's going on under there with this noise. :hmm:

Avejoe
12-06-06, 07:44 PM
I also have that sound ! I took the shock off and the rubber washer was eaten right through by the stock metal spacer. I put a leather washer on and installed the shock again. Much quieter now, but still noticeable on big bumps. I think if the neopreme spacer(GC) was 1/8 taller would solve the problem. As far as it being the right side,I find that most of the bumps in the road, are on the right. My spelling sucks

Dreamin
12-07-06, 02:20 AM
I'v found it is mostly right rear when it is cold out but sometimes both sides in rear in warmer weather. I recall WW or Dreamin had adressed this issue with a little success. This whole NEW NORM thing sucks.

I dont have and never had a rear clunk sound (w/FE4s)... :confused:

rand49er
12-07-06, 05:53 AM
I also have that sound ! I took the shock off and the rubber washer was eaten right through by the stock metal spacer. I put a leather washer on and installed the shock again. Much quieter now, but still noticeable on big bumps. I think if the neopreme spacer(GC) was 1/8 taller would solve the problem. As far as it being the right side,I find that most of the bumps in the road, are on the right. My spelling sucksGot any pics?

BTW, you spell "sucks" perfectly. :D

btraer
12-07-06, 07:51 AM
I have an 06 with 2500 miles and I have yet to experience any rear end problems, noise, etc.

Venomous-V
12-07-06, 08:22 AM
Has anyone tried calling GC? Since dreamin doesnt have noise,maybe they know something we dont. Or maybe they did something slightly different with his.

Dreamin: after seeing what is in the kit and how they are installed, do you see anything different then yours? Or did you not see what they did to your car?

Seattle CTS-V
12-07-06, 09:39 AM
I have an 06 with 2500 miles and I have yet to experience any rear end problems, noise, etc.


Do you even have the Ground Control kit we're talking about? That could explain why you don't have the GC clunk...

rand49er
12-07-06, 11:07 AM
Do you even have the Ground Control kit we're talking about? That could explain why you don't have the GC clunk...:histeric:




(Oh, sorry.)

cjones
12-07-06, 01:19 PM
My drivers front spring squeaks like crazy, anyone else have that problem? I can push down on the front of the car and hear it.

Venomous-V
12-07-06, 04:40 PM
I get the squeek in the fronts when it has rained or when theres a lot of moisture up there. It must be the bushings.

rand49er
12-07-06, 04:52 PM
I have occasionally gotten something from the front, too. Sounds like driver's side front as best I can determine. Reminds me of a loose bolt sound. I checked and did not see anything.

As far as calling GC, it actually did occur to me to do that, but I figured that they'd tell me to check for loose bolts in the front or, for the rear say, "Are you sure you put it together properly?" :ill:

Venomous-V
12-08-06, 10:32 AM
Wasnt there also someone who was going to bring their car to the GC shop to see if they could figure out the issue? Was that done? Or was that Velose?Anyone?

Dreamin
12-08-06, 12:28 PM
Has anyone tried calling GC? Since dreamin doesnt have noise,maybe they know something we dont. Or maybe they did something slightly different with his.

Dreamin: after seeing what is in the kit and how they are installed, do you see anything different then yours? Or did you not see what they did to your car?

V: I have the prototype kit on my car... not the "GA" kit. The only difference's I know of are:
* I dont have the sleeves installed up front
* I have needle bearings up front, that were deemed unneccesary and deleted in the production kit
* I'm using the WW spacers in the back; not the GC spacers.
Hmmm... Maybe their spacers are clucking?

Venomous-V
12-08-06, 07:52 PM
Are WW spacers all that much different? Is it a different material? Different size? I'm not worried bout the fronts, just that damn clunk in the rear.

I wonder if WW has any more spacers. maybe i could get a set and compare and try. or maybe just see a picture of the difference.

First Class Motoring
12-08-06, 11:28 PM
it's not the spacers,i tryed both.it's something alse.

rand49er
12-09-06, 05:14 AM
Seems to me that enough of us here (though not all) seem to be experiencing some kind of noise ("clunking") problem that something is definitely going on. Probably no one there today (Saturday), but I will call them on Monday.

Venomous-V
12-10-06, 01:01 PM
Good move RAND. Keep us all updated on what you find out. I got some info from WW that he had a noise as well but it ended up being a loose control arm socket or something. He said he retorqued everything and noise went away. Moral of the story i guess is to check all bolts everywhere! Hope we get some good info and answers generated within the next week. Is anyone near their shop that has the kit and the problem that could stop by there and get it looked at?

rand49er
12-11-06, 05:40 PM
I got Jay at Ground Control on the line a few minutes ago. As I should have known :thepan: , he suggested that I re-check everything, ESPECIALLY on the side that seems to be the culprit. Unfortunately, it ain't gonna be this week ... too busy with Christmas buying, relatives coming, yadda, yadda. I WILL report back, though. :thumbsup:

lunarx
12-11-06, 07:45 PM
As I have a set of FG2 w/GC, soon to be put on my car, I anxiously await news of a fix.
I really don't want to further add to the clunkiness of my V.

BTW - I have 600/650 springs.
I fear they may be too stiff for comfort.
Any user feedback on these spring rates?

rand49er
12-11-06, 08:44 PM
... BTW - I have 600/650 springs.
I fear they may be too stiff for comfort.
Any user feedback on these spring rates?If you want to trade for my 550R/500F setup, let me know. :thumbsup: I probably got 500 miles on 'em, if that.

lunarx
12-11-06, 09:20 PM
If you want to trade for my 550R/500F setup, let me know. :thumbsup: I probably got 500 miles on 'em, if that.
Sounds good to me. :D
As my kit is not installed yet, I can send you the springs in advance to make the swap easier for you.
email me (GC@eluna.info) and we can work out the details.

Feffman
02-11-07, 08:51 PM
Gents:

Installed the GC rears today (not enough time to do the fronts - next weekend) and the clunk is absolute crap. It's not loud, but it will drive me batty knowing it's there. It just can't be right.

Thinking about this, I noticed a gap between the plastic cover/housing for the rear shock and the rubber washer supplied by GC. The plastic housing (top part of the stock shock) houses the bump stop. Could the clunk be the bump stop hitting the top of the shock? Mabe a thicker rubber/urethane washer to fill this gap????

Can we take the shock back to the stock configuration and run the different springs? My guess is IF (notice big IF) we can do this, the clunk goes away.
Thoughts!

Mark "Feff" Pfeffer
www.MVPTrackTime.com

lunarx
02-11-07, 09:51 PM
What is the solve guys?
I have not installed my GC's yet for fear of the dreaded clunk.

I would think the clunk would have to be comming from the springs and/or spring perches.

Perhaps some additional preload on the springs will keep things from clunking.

I also wonder if the springs are not coil-binding on compression.

How feasible would it be to run the next length spring?
It would be 2" longer and might keep things held together tighter.

Is there 2" of range on the threaded collar to compensate for a longer spring?

Another solve might be some urethane or delrin insulator disks on each end of the spring.

Just tossing out some ideas for the experienced guys to comment on.

rand49er
02-12-07, 06:14 AM
Sounds like this "clunk" is more common than I thought.

Mine has done it since day one. Seems to always be in the right rear only for some reason. :confused: Once this arctic weather moves back north, I'll be checking this out.

Feffman
02-12-07, 06:39 AM
Gents:

How about a set of springs with stock 3.5 inch inside diameter, slightly shorter height (stock height uncompressed is 13 inches) with the same spring rates as the GC kit? Mounted using the stock mounting hardware as a simple replacement. Use all the stock components, just swapping springs. I know Eibach and H&R make kits, but they lower the car around 1.25-1.7 inches. I only want about 1/2 inch drop in the rear. This seems simple or am I overstating this? Thoughts?

Feff

lunarx
02-12-07, 07:35 AM
Gents:

How about a set of springs with stock 3.5 inch inside diameter, slightly shorter height (stock height uncompressed is 13 inches) with the same spring rates as the GC kit? Mounted using the stock mounting hardware as a simple replacement. Use all the stock components, just swapping springs. I know Eibach and H&R make kits, but they lower the car around 1.25-1.7 inches. I only want about 1/2 inch drop in the rear. This seems simple or am I overstating this? Thoughts?

Feff

There are Barrel Springs with 3.5" diamater on one side.
http://carrerashocks.com/springs.pdf
(see page 4)

This might let you retain the stock lower mount and use the GC threaded upper spring perch.
Best of both worlds perhaps?

rand49er
02-12-07, 09:39 AM
Gents:

How about a set of springs with stock 3.5 inch inside diameter, slightly shorter height (stock height uncompressed is 13 inches) with the same spring rates as the GC kit? Mounted using the stock mounting hardware as a simple replacement. Use all the stock components, just swapping springs. I know Eibach and H&R make kits, but they lower the car around 1.25-1.7 inches. I only want about 1/2 inch drop in the rear. This seems simple or am I overstating this? Thoughts?

FeffMark, what do think is going on under there? Are you assuming that maybe the GC spring is not staying in contact with the perch? Then, when it re-encounters the perch during a sufficiently high amplitude jounce/rebound cycle, it makes that "clunk" sound? And, by putting a bit longer spring (uncompressed length), it would stay in contact with the perch at all times?

I'd love to have the capability to put a mini-camera under there and record both the video of this contact point simultaneously with the amplitude of the road surface height as a function of time.

Feffman
02-12-07, 10:54 AM
Mark, what do think is going on under there? Are you assuming that maybe the GC spring is not staying in contact with the perch? Then, when it re-encounters the perch during a sufficiently high amplitude jounce/rebound cycle, it makes that "clunk" sound? And, by putting a bit longer spring (uncompressed length), it would stay in contact with the perch at all times?

Randy:

That's precisely what I think is happening. I'm not sure lengthening the spring will alleviate the problem either. A spring with constant load, may do the trick, but we'd lose a lot of height adjustability. Also the idea of some type of heavy rubber dampener (like the stock ones on the bottom and top) would eliminate the metal on metal (at the top) contact on the Ground Control set up. I've sent GC an e-mail this morning and hopefully will hear back from them today.

Here's hoping!

Mark "Feff" Pfeffer
www.MVPTrackTime.com

Venomous-V
02-12-07, 10:56 AM
Thank god this thread got revived! I am sick of this f*cking clunk and passengers asking iin a dopy voice,"whats that noise". anyone live around their shop??

rand49er
02-12-07, 11:03 AM
Maybe WW will chime in. He'd be an excellent source of info. Also, ronr has the kit, has installed it a couple of times, and authored the FAQ instructions.

12race
02-12-07, 02:18 PM
I have an 06' with about 3800 miles, had 2500 on it when I bought as a program car. Took it in for pesky leaky rear diff, dealer replaced complete diff....nice.

However, just last Friday noticed a low speed clunk, funky noise and feel coming from right rear, especially when turning. Called dealer, taking in first thing tomorrow morining.

Thanks for posting this, gives me some potential root causes to suggest to service advisor.

06' V - Platinum/Black, B&B

04CTSVFLA
02-12-07, 02:35 PM
12race, they are talking about people with ground control coilovers installed.....also what dealership do you take it to in GA - are they very friendly....reason I ask, is the current dealer I use, likes to fix things instead of replace them - not to my liking.....does the georgia dealer like replacing things instead of fixing them....lol.....may of found a new dealer.

Feffman
02-12-07, 02:40 PM
Just spoke to Stan at Ground Control. Jay is out today but Stan assures me they will get on it tomorrow to figure what the "clunk" is and how to rectify it.

Feff
www.MVPTrackTime.com

Venomous-V
02-12-07, 04:54 PM
Just spoke to Stan at Ground Control. Jay is out today but Stan assures me they will get on it tomorrow to figure what the "clunk" is and how to rectify it.

Feff
www.MVPTrackTime.com (http://www.MVPTrackTime.com)

Woohooo!:thumbsup: Lets hope for a definitive fix.

wildwhl
02-12-07, 08:57 PM
I have the GC kit, but use the WW spacers on the FG2 shocks.

No clunk. When I originally pointed to the GC kit for clunking, after a couple of months, I figured out it was the front mount of the trailing arm not torqued down properly.

If you are running the GC kit at close to stock ride height (as some are) then there is no reason to modify the Nivomat shock...only if you are lowering the car.

Here's a thought, and something I tried which made me realize I needed to dig deeper. Remove the rear shocks entirely. IF the noise goes away - then it is the shocks. IF, like me it doesn't, look further. I then removed the springs and hand cut a 1/4" rubber spacer top and bottom. Still clunked.

Turned out to be (see above).

Good luck gents. Guess I should mention I pulled the GC kit off my car yesterday...have the Lotus now so the V doesn't need to be my firm riding biatch daily :suspect:

WW

rand49er
02-12-07, 09:13 PM
I have the GC kit, but use the WW spacers on the FG2 shocks.

No clunk. ...So, the WW spacers are the key here? Regardless of shocks used? :confused:

I'm one of those people that has one heck of a time with riddles. :thepan:

Got5onit
09-24-07, 08:36 AM
I've got a pretty hard clunk from the right rear and I just lowered with Eibachs using the WW spacers. I thought it was the bump stop bottoming out on the "harder" bumps. I guess I'll get under it and try retorquing everything.

I was thinking since the cradle/body mounting bolts were all that I removed during the install, to at least attempt to torque them down under load, without jacking it up, on a flat surface. Has anyone tried this? Hell, I don't even know if it can be done without taking the wheels off?

:(:confused:

gauge hp
09-27-07, 03:11 PM
I am very glad I found this thread, I was sure I installed the kit incorrectly, Ground control told me there should not be any banging or clunking from the rear end and to check my installation, well I have wasted several hours of my time now removing and reinstalling! I am anxious to hear what they have to say next. I like how the kit performs but it makes the as# end sound like a peice of sh@# now. I hav the same systoms as most, right rear mostly occasionally both sides.

RunningOnEMT
09-27-07, 03:19 PM
I'm gonna torque these down when i put in my pinion brace and see if that helps at all

rand49er
09-27-07, 05:02 PM
I am very glad I found this thread, I was sure I installed the kit incorrectly, Ground control told me there should not be any banging or clunking from the rear end and to check my installation, well I have wasted several hours of my time now removing and reinstalling! I am anxious to hear what they have to say next. I like how the kit performs but it makes the as# end sound like a peice of sh@# now. I hav the same systoms as most, right rear mostly occasionally both sides.With only two posts, you may one of those guys who never comes back here again, but if you do, just put a couple washers under the nut on the top side ... Voila! ... no more clunk!!!

tweeter81
09-27-07, 05:18 PM
With only two posts, you may one of those guys who never comes back here again, but if you do, just put a couple washers under the nut on the top side ... Voila! ... no more clunk!!!

I need some clarification for future reference. Here comes the stupid questions. Can you just remove the rear seat, take off the top shock nut, and add the couple of washers (how thick???how many???) to the top of the shock from the top? There won't be any pressure on the top shock nut, right--it can just come right off and be put back on top of the added washers? :bonkers::hmm:then:cloud9:

rand49er
09-27-07, 09:37 PM
Yup.

The biggest PITA is getting the seat out of your way. Once that's done, take the nut off (and a spacer, I think?) and put two normal-size washers (on each shock), put the spacer back on, and then the nut. The washers were mentioned somewhere in this thread (?) to be 5/8" I believe, but I'm pretty sure I had to use 3/4" ones; worst case it's another trip back to the hardware (don't ask how I know :thehand:). I sorted through the ones they had at the hardware and chose four of the thicker ones but more importantly make sure they're all about the same thickness as washers vary in thickness. Since there's no load on the shock, don't worry about messin' something up.

When you're done, it's like magic! My car went from being an embarrassment back to a $50k car for under a buck ... AMAZING difference!!! :thumbsup:

Venomous-V
09-27-07, 09:39 PM
guess i just need more spacers. added two on both sides as noted earlier and didnt change. got used to the clunk bang sound. maybe ill tackle it again

gauge hp
10-04-07, 10:16 AM
Thanks!

gauge hp
10-04-07, 10:30 AM
With only two posts, you may one of those guys who never comes back here again, but if you do, just put a couple washers under the nut on the top side ... Voila! ... no more clunk!!!

Thanks for the help... p.s. with only dial up available at home , limited time at work,and more questions than answers I tend to read more than I write, nonetheless I appreciate the help!