RebekahsZ Posted May 23, 2013 Share Posted May 23, 2013 (edited) I have had 2 different R200 CLSDs that I put in my 240z with LS2 power. I did the 6-clutch mod. The first 3.90 CLSD I shimmed to a wet 65# breakaway torque and it made an intermittent banging noise, but was otherwise great. When I changed ratios, I built another R200 in a 3.54 case/R&P with a different CLSD carrier (out of a 3.70 CLSD); I did the 6 clutch mod, but didn't shim it resulting in 45# wet breakaway torque. The second diff made the same banging noise. I've heard of chatter, but I didn't think the intermittent banging noise was chatter. I have a new RT mount with a rubber bumper between the nose of the diff and the front crossmember keeping the diff nose from moving either up on accel or down on decel. The mustache bar has poly bushings. Can you guys watch the attached video link and help me understand what is happening? I'm new to LSDs. I put a goPro camera on my gas tank (sorry the fuel pump is so loud) and you can see the passenger side rear wheel, and axle. You can hear what must be chatter, tire chirp, and the occasional POP which sounds like a loud BANG inside the car. The maneuver I did to produce the symptoms was a slow turn to the right (it does it when turning to the left too), left-foot braking to keep the speed down and applying throttle to increase torque on the LSD. The banging seems to occur most often when I let up and straighten the wheel. The bang usually happens when turning to leaving a 4-way stop, when driving around in a parking lot or when tooling around the paddock at an autocross or drag race. It generally doesn't bang when in a straight line. I don't have any clunking when launching at the dragstrip from up to 4000 rpm. Perhaps this banging is normal and to be expected, but if I have a problem, I'd like to understand it and fix it. Go to youtube for it so you can watch it full-screen. All the smart guys please advise! Edited May 23, 2013 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted May 23, 2013 Share Posted May 23, 2013 Do use any kind of friction modifier in the oil?I used to use ford friction modifier with 90wt non-synth gear lube in mine-no noises.If you preload the clutch packs with the throttle while turning you are essentially locking the rear wheels together.You have alot of horsepower on tap so you have set up your clutch packs to grab .The clsd unit is a compromise-an all-gear gleason-torson unit would be smoother..If you use the car for drag strips then do any kind of road course/auto x the car set up will be a compromise-its a matter of personal taste. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 23, 2013 Author Share Posted May 23, 2013 Yeah, I used a tube of friction modifier. On the previous diff I used either two or three tubes. You can't hear the little chattery noise inside the car. It is the bang or pop that I want some insight into. I've got my eye on a helical but the current owner has to get his 8.8 swap done before I can buy it. I already have a vicious on the shelf. Just trying to learn something. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 23, 2013 Share Posted May 23, 2013 Every LSD is a compromise; the Torsen/Quaife/helical options sacrifice too much grip for comfort for my liking. A nicer CLSD would have friction material on the clutch disks and not have as much chatter. The popping noise happens when the clutch pack slips and the clutches slide past each other and then grab again. Add more friction modifier or reduce preload or both. I think overcoming the little bit of chatter you have there will not be difficult. Quote Link to comment Share on other sites More sharing options...
johnc Posted May 23, 2013 Share Posted May 23, 2013 "Its just the normal noises in here." http://www.youtube.com/watch?v=DwqqZPlAI7E OSG Super Lock will solve your problems. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 23, 2013 Author Share Posted May 23, 2013 Thank you. So is the banging likely to harm anything? I can live with it if this is "normal" and just part of having an CLSD. I have to induce the chatter and I have to use the brake to make it bang repeatedly like the video (the video exaggerates the frequency of the problem). It is just so startling when it bangs totally out of the blue when I'm tooling around daily driving or making the turn onto the return track at the dragstrip or turning into the paddock at the end of an autocross run. Subconsciously I also think "you just busted an axle!" Quote Link to comment Share on other sites More sharing options...
duragg Posted May 23, 2013 Share Posted May 23, 2013 Its funny as I shimmed mine for 60 or 70 lbs and never hear a peep from it. Used 1 bottle of FM. I just changed to a different juice and won't drive again till next season starts. The gears whine during light throttle, but that's about it. Guess they are all a little different. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 23, 2013 Author Share Posted May 23, 2013 Johnc-the audio you sent me says "Even the losers get lucky sometimes." I will try not to take it too personally. If you say it is normal and won't hurt anything, I'm gonna drive it and try to ignore it. I've got one of your units on my wish list, it just has a couple things ahead of it. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 23, 2013 Share Posted May 23, 2013 So is the banging likely to harm anything? I can live with it if this is "normal" and just part of having an CLSD. It shock loads the CVs and stubs, but you've got everything upgraded, so I don't think it's likely to harm anything. I know guys who didn't run friction modifier in their rock crawlers because they wanted their LSD to be more aggressive. Just put in another tube and your problem will be solved. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 23, 2013 Author Share Posted May 23, 2013 Yeah, it is actually a low-power phenomenon. I tried the extra FM on the prior diff to no avail but I will try it on this one too. I think you told me on the last one that I could go with as much as 3 tubes. I did the diff work myself so i can visualize the internals. What exactly is happening mechanically inside the diff on the big bangs? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 23, 2013 Share Posted May 23, 2013 The clutches are slipping and then grabbing again. It's just stiction. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 23, 2013 Author Share Posted May 23, 2013 Another tube of trans-x in my hand. Quote Link to comment Share on other sites More sharing options...
Leon Posted May 23, 2013 Share Posted May 23, 2013 Another tube of trans-x in my hand. Nothing of note to add to this discussion but I do like your user title. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 24, 2013 Author Share Posted May 24, 2013 Who's idea was it to make it impossible to add oil to the diff while it is installed in the car! To be continued in about a week...... Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 25, 2013 Author Share Posted May 25, 2013 (edited) Another tube of trans-x in the pumpkin. Used some 3/8" fuel hose to help get it in the fill hole. Edited June 1, 2013 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
Nigel Posted August 11, 2013 Share Posted August 11, 2013 How much modifier did you end up using? I seem to recall you had another post about this but I can't find it now. I finally got around to putting my extra group buy clutch discs in, and now I'm wishing I hadn't bothered. I didn't add any shims, so the breakaway is about 45 to 50lbs and I've got two bottles of modifier in it but it's still popping and binding way too much to my liking, even after 1500 miles of driving. It feels like someone is pounding on the diff with a hammer when turning at slow speed and it makes me cringe every time it happens. Driving in the rain is even worse. I could feel and hear it binding even at 35 to 40 mph on sweeping turns. Maneuvering in a wet parking lot is a miserable experience. I'm going to try one more bottle of modifier. But it seems rather ridiculous to have to run 20% of the diff fluid as friction modifier. Or is this typical. But if that doesn't minimize it to an acceptable level, as much as I hate the thought of tearing everything apart again, those extra discs are coming out. I know there are lots of other people using the group buy discs though, but I haven't seen much feedback from those people. If you're using them and haven't had any issues, what's yor secret? Nigel Quote Link to comment Share on other sites More sharing options...
duragg Posted August 11, 2013 Share Posted August 11, 2013 (edited) Funny I shimmed my stock 6 pack pretty high and it doesnt make a peep of noise at all. I changed fluid and have no modifier and still nothing. Maybe the material used in group buy is gummier steel or stainless? I wonder what your disk plates look like now. Plate galling? Edited August 11, 2013 by duragg Quote Link to comment Share on other sites More sharing options...
Nigel Posted August 11, 2013 Share Posted August 11, 2013 Funny I shimmed my stock 6 pack pretty high and it doesnt make a peep of noise at all. I changed fluid and have no modifier and still nothing. Maybe the material used in group buy is gummier steel or stainless? I wonder what your disk plates look like now. Plate galling? From what I recall, the material used for the new discs was matched to that of the OEM discs. Perhaps it has something to do with the surface finish? The OEM discs have rings machined into the surface, whereas the discs from the group buy do not. Nigel Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 11, 2013 Share Posted August 11, 2013 Some of the older Nissan LSD diffs which had more clutches didn't have the spirals, but yeah, the grooves are there to get oil between the plates. You might try a different base oil as well. You can see the roadster LSDs had no grooves, older R160 LSDs too, R180s, R190s: http://www.gordon-glasgow.org/lsd2.asp Quote Link to comment Share on other sites More sharing options...
Nigel Posted August 11, 2013 Share Posted August 11, 2013 It makes me feel a little better to know that not all OEM discs have grooves. Looking at some pictures I took of my clutch pieces when everything was apart, I noticed that the discs with the external fingers that go between the new discs have slots radiating out across the face. That should allow oil to get between the discs. However, from my pictures, I can't tell if the slots are on both sides of those discs. I've already tried changing brands of oil. I started with Lucas oil, which came with modifier in it. It was binding badly, so I added about 1/2 a bottle of modifier (spilled half of it on the floor!), and did a bunch of figure 8's. That helped, but not enough. I added a additional full tube of modifier and it improved more, but still not enough. I then drained it all and switched to Redline, with two full bottles of modifier. At first, I thought that did the trick, but the binding came back again. It doesn't do it all the time, but it's enough to be really irritating. Strangely, I can do figure 8's under power with no problem. But more often than not, it will happen maneuvering around a parking lot. It could be my imagination, but it seems to be worse after reversing out of a parking space. Just once I'd like to put something in my Z and have it work right the first time! Nigel Quote Link to comment Share on other sites More sharing options...
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