Yancy

iTrader: (5)

Mods. I'm posting this here because I believe I will get the best results because the FI crowd are the ones largely using the carbon dif and taxing the rear end of their Z's and G's.

As most of you know, my engine was rebuilt by Forged, tuned with the F-Con, and makes crazy power on Sharif's dyno (632rwhp). My Z has the DSS stage 2 half axles and the Carbonetics carbon dif.

A few weeks after getting my car back, I noticed a very small leak coming from my rear end (a drop here, a drop there). The front seal where the drive shaft goes in is the one leaking. Sharif sent me 3 new seals for the rear end, but I haven't put them in yet because I have not been able to find a local shop that I trust to do the work (I had a horrible experience with Tuning Factory when they were still in business - btw, they are the ones that installed the 1/2 axles and carbon dif).

Anyway, the leak has progressively got worse (but not horrible). It may leak 1/3 a pint to 1/2 a pint every 3 days. I do however, jack the car up and fill the pumpkin with fluid every other day just to be safe (plus I haven't driven my car much at all in the last 3 months due to winter here in MI).

Anyway, I think I may have finally found a decent guy to do this work locally for me. So, here's the questions:

(1) My rear end has always had a wine to it after the install of the carbon dif, but I don't know if that is something common to the carbon dif or if I may need a new ring and pinion or what? Can people with the carbonetics carbon dif chime in here please?

(2) Also, since the rear end is going to be dropped and taken apart, do you think I should just go ahead and replace the ring and pinion and all the bearings just because?

(3) Is there anything else that I should replace in the rear end while it is out of the car?

Thanks guys for your thoughts.

G3po

iTrader: (8)

I have about 10k miles on my Carbon diff. After the break in procedure , I have aways noticed that this diff whines significantly more than the OEM VLSD under "leading" throttle. I have tried ATS lube, Motul and RP. None seem to make it either better or worse. I always note a sginificant amount of carbon and metallic sludge upon changing. I have been concerned that this sludge has been wearing on the ring, pinion and bearings. I am basically playing it by "ear" for now , pun intended.

XKR

iTrader: (1)

Well....we have around the same whp and I also have the same carbon diff. I get the same whining sound from the diff...and was told that thats normal.

I road race my car...so I feel that the stock final gear works best for me. Some of the drag racers feel that its best to get good sticky tires than to change the gear.

I guess the only thing left if you dont have it already is the Level 5 Drive Shaft. I had no choice...I had to get them

rcdash

iTrader: (18)

did u break an axle XKR?

Yancy

iTrader: (5)

XKR. I have Drive Shaft Shop stage 2 half axles. I'm just trying to gauge how many carbonetics carbon dif owners experience the whining sound to see if its nornal (or if my ring and pinion is messed up).

The rear end needs to be dropped out to replace the seals, so I was curious if I should also replace the ring and pinion while the rear end is out of the car (keeping the same 3.5 gears - but just new or slightly used ones). I'm not sure (until more people chim in) if its normal dif noise or a messed up ring and pinion.

If the majority of carbonetics carbon dif owners say they also have the whining noise, then I'll likely keep my ring and pinion and just put in the new seals and bearings.

Would there be any other items you typically change in a rear end when its out of the car as a matter of course?

eagletanggreen

iTrader: (40)

Hey Yancy!

I also have the Carbon dif and have 8K on it (hard miles). My Dif whines like a worn out *****. It just plain annoying ALL the time. Its one of the reasons I took my stereo out. I am going with a 3.3 FD here soon. My car is just plain useless with 675lbs of torque. The dif works great but like you whines alot, I think if I knew how loud it was I would not have bought it. Unless your a sponsored driver, driving to win $$$$ it's over kill. Yes their is a diffrence in stock and this dif big difference, but again if your doing 2 or 4 track events a year you can live with a stock lsd, With the power going even higher on my car there is no way I can drive the car with a 3.5 ......No way!
If the 3.3 cannot handle it then I just might move on to a different platform...Maybe GTR35????? We'll see ... Sorry for the rant

XKR

iTrader: (1)

No Raj.....but Sharif feels that with the amount of power he is now adding to the car I will break the stock ones for sure. Matter of fact he though he had already upgraded them

I had a friend get stranded because of a broken axle.... trying to prevent the same.

XKR

iTrader: (1)

There is nothing else that I would change.I am going to say you have the entire kit

Sharif@Forged

iTrader: (92)

There is a lot of whining going on here...bunch of babies.
j/k

The diff fluid is supposed to be changed out every 3000 miles or less, which most people...myself included...don't do. It's a great diff, but requires more frequent oil changes.

If its whining, there isnt much if anything you can do about it.

XKR

iTrader: (1)

You got to be kidding Then please change my diff oil Sharif....matter of fact trans also....thx

rookie

iTrader: (10)

I have this diff as well. The whining didn't happen at first, but after not doing the fluid changes as suggested the whining started. Replaced all the bearings and the whining went away. I think the bearings are getting fubar'd by the sludge if the fluid is not changed often.

eagletanggreen

iTrader: (40)

Hum!

Thats what happen to mine, no noise then it started whining and has never stopped. I have changed the fluid 2 times already??

Yancy

iTrader: (5)

Hmm...interesting. I'm going to have the new seals and new bearings installed and make sure I change the fluid every 3000 miles or so.

G3po

iTrader: (8)

Not to be a "whiner" , but I have have changed fluid more than 4 times in less than 10k miles and followed the break instructions religiously. Even at 2k miles , the sludge has been notably significant. I would not be incline do replace the bearing sonly to have them whine again in a few k miles.

If the black sludge is in fact degrading the bearings at such an increased rate , I think it would be good to hear from Carbonetics directly.
I mean this was one expensive diff.

rookie

iTrader: (10)

I used the ATS fluid to break it in, than used Motul afterwards. Not sure if the whining started with the Motul or the extra miles I went. After replacing the bearings, I used Motul again and it was quiet. Had a show in Vegas so my friend drove my FX out there. On the way back clunking noises were coming from the diff. Took it to Technosquare since they replaced the bearings for me and the Motul was pretty burnt up, it was boiling out the breather.

Technosquare than put in some Redline fluid, (forgot the weight) but it's been good since.

G3po

iTrader: (8)

Hmm.
From the ATS/CN description:

"More than 70 times the service life of metal LSDs
*Virtually noiseless performance"

I guess these statments should be clarifed with:

"and more than 20 times Less service life on bearings".
*Virtually noiseless performance except for an ear piercing bearing noise"

Sorry to be sarcastic, I'll admit that with most performance upgrades have a downside. But to be honest , I ihaven't heard an acceptable response from Carbonetics, yet.

" this is normal statement is a bit-o-BS"

Z1 Performance

iTrader: (564)

just reading through this...how many miles did everyones car have on them when they changed diffs? What parts did you replace (if any) when you did the diff? How many have also changed ring and pinions to lower ratios? Among these, what else was changed with the ring and pinion?

As for fluid there are a few that were deemed acceptable by ATS/Carbonetics for their diffs. Here is an excerpt from an email I got when I asked

"There are other oils which ATS found acceptable. BP 9140S 80w-140 and New Tech UW76 75w-140." Problem is I don't think either is carried in the US.

I've asked them about Motul, and they said they had no data on it so could not say. I didn't ask about Redline, since we don't carry it.

When I asked about the wrong oil being used, they said this:

"Basically if an oil does not fit, it usually is aggresive and causes more particles generated from both carbon chips and metal plates. As the time goes by, those particles are accumulated and changes the backlush. Then you will have a strange noise in the differential section and have to change the fianl gear and pinion. "

They also recommended a diff cooler for those doing lots of track days, but this is recommended even on a stock viscous (those who have done a hard track day on r compounds on even a stock VLSD know what I mean....the stock diff likes to burp at the track, and make a mess!)

Remember, the LSD is a direct replacement, but it's not a matter of old diff out, new diff in. You still have to measure backlash to the pinion gear. Failure to set the right backlash can easily lead to a very harsh whine within only a couple thousand miles, and no oil change is going to fix it unfortunatley. The whine comes as a result of the edges of the pinion becoming rounded off

G3po

iTrader: (8)

-Replace VLSD with ATS after 10k miles.
-original ring and pinion. No gear change
-all new bearings and seals.
-Nismo diff cooler
-BL set to OEM spec
-breakin with ATS synth fluid . changed 3 times within 5k mile.
- never seen any large chips , just lots of black sludge.
- no whine unit the about 4k.
- then tried Motul, did not help , actually made it pretty grabby at low speed, then RP_Max no help with noise but much smoother.


IMO , this diff serves it's "specific" purpose very well at the track (both cicuit and Drag).

"but given the "ultra high maintenance and cost , I would not recommend it for DD street cars."
I'll be changing to 3.3 , and then I prolly go with a Cusco RS, this time around.

rookie

iTrader: (10)

Can a vendor have pity on us and hook us up on replacement Cuscos?

thawk408

iTrader: (16)

You should get rid of the 19s and street tires. I think that would help your traction issues a lot, lol.