I just started my install of a Tomei 1.5 LSD and decided to restack the clutches for a softer lockup. From what I've read and seen the Tomei locks up really hard at 100% and is probably too much for a relatively stock powered car on sticky street tires. Also I'm not too keen on having it chatter and skip like a madman on every parking lot.

Does anyone have experience with this diff and restacking the clutch plates? Any recommendations on what I should try as a first go with this lsd? I'm probably going to aim for 60% lockup, but would love to see what others think.

Car is still NA, no substantial power mods, just stiffer suspension. Tires are 265/275 Bridgestone RE71R.

 

Me. I swapped two plates on each side and am very happy with it. Been that way for 30k miles and it still feels identical to the day I did it. I will very very occasionally get a clunk on hard 1st gear acceleration in a tight turn, but otherwise it is silent even in parking lots and reverse.

 

That's very interesting to hear because that would suggest you have 10 contact surfaces vs the original configuration of 12 surfaces. Drawing on the left is factory configuration of the Tomei, drawing on the right would be yours based on my understanding:



I've seen a few threads about people complaining about just how loud LSDs like the Cusco or the Nismo are even configured at only 6 contact surfaces (60% or 6 out of 10 contact surfaces). So to hear that you have a relatively quiet experience with 10 contact surfaces vs those guys at 6 is surprising. What oil do you use? Are you using any oil additives? Friction modifiers?

I actually found an oooold Sports Compact Car article from when they ran Project 350z (only way to find it now is on the webarchive) and they installed a Kaaz LSD which also has 12 discs per side (and therefore 12 contact surfaces). They didn't get it to behave until they reduced the contact surfaces to only 4 AND added new sticky tires. So I was actually going to do the same, reduce it down to either 6 or 4 contact surfaces. I'm stuck on this decision. The configuration would look like one of these two:



I'm now leaning to 6 contact surfaces if you've had no issues at 10.

 

Found the article, actually not on the archive, still accessible:
https://www.motortrend.com/how-to/04...n-350z-part-2/

 

Excellent diagram.

I swapped two pairs of plates. Meaning that I have 8 contact plates. I run Motul gear 75w140. I have 285/30r18 Pilot sport 4S rear tires.

https://kaazusa.com/product/nissan-f...z-lsd-1-5-way/

This KAAZ diff is basically identical to the toemi setup. I used the 65% option.

 

Impressive. I've never taken apart a rear diff but want to learn. If mine fails I will open it up. My car came with a Nismo and it's VERY chatty on low-speed turns. I thought it might be a 2.0 but hard to tell outside of a track. I tried some turns during deceleration and it was similarly "violent."

I was hoping my threads would attract the attention of a prev owner here but nothing so far, so learning about the car with a wrench.

Don't mean to hijack: just giving you a +1 for an excellent conversation and hope you post an update.

 

no worries, I welcome the discussion. If you do ever take the nismo apart for a clutch re-stack I would love to hear about it.
I put the diff back together , unfortunately forgot to take pictures. I ended up taking the 6 contact face option per side and essentially putting the round discs into 3 groups (each group provides 2 contact surfaces, for a total of 6). The one difficulty I had was that getting the housing to slip onto all of the discs without them moving around and binding between the two housing halves (top and bottom) was tricky.

I'll try to pull the diff out of the car tomorrow or this weekend latest and do the swap. Hopefully I don't need any shims because I need this to be back together and tested before my track day later this month.

Really glad GreyZ chimed in with his experience with 8 contact surfaces as based just on that old Super Street article I was going to go with 4, but now I think I'll try the 6 first and if its still loud or a bit too ON/OFF at the track especially on long sweepers then I'll just add some friction modifiers or a different oil (Motul 90PA seems to be a favorite). I might actually go so far as to bring some friction modifier additive to the track later this month and add some in between sessions if the diff doesn't behave.

 

I actually used friction modifier the first couple of fluid changes on mine when I was using non lsd fluid.

Go get the ford performance lsd friction modifier. Thats the best stuff I have ever heard of and have used it in a few different applications. Its also cheap and every dealer has it typically.

 

I've run Sonoma 8 days in the 04 Touring (VLSD) and 2 in the Cayman (open diff, I think) but never in the prepped 03 Track. The LSD is fine on the street now that I'm used to it but I'll be taking it slow on track for the first time in a couple weeks. No idea what to expect on the turns. It will be interesting, though, using the same tires and pads I'm used to, but with the LSD and Brembos. I have a feeling it will be more fun.

 

Thanks for the tip! Will definitely get some. I presume this is the stuff you are referring to:

 

Thats the stuff.

 

ok, update time:
LSD install is done. Couple of neat things along the way.

Ended up installing a bunch of new hardware since all the old stuff including plugs and oil overflow were either rusted or not really usable anymore:


This included all new half shaft hardware. All my old bolts were rusted. Honestly the rust is one of the primary reasons I keep switching to titanium almost everywhere.


Old diff cover bolts were rusted and disgusting, so I replaced with titanium m10 1.25 bolts. These will never rust.


So apparently there is a gear oil specific gasket maker. Had no idea before, but used it and it seems to hold up fine:


Pressing on the new bearings was easy. You need about a 63mm flat disc to push them on:


I have a small harbor freight press at home that made this part easy. Absolutely no difficulties pressing the nissan bearings on:


Next came the ring gear bolts. A bit of blue loctite was used:


I don't have a vice, so what I did is bolted down one of the halfshafts to a plank of wood, placed the diff on top of the shaft, and then had zero difficulties getting the ring bolts to the right tourque spec.


I also marked them up with a 0 deg, 45 deg, 90 deg marks on the bolts after torqueing down. This way I can get the last 33-45 degrees the FSM calls for with my impact gun:


The last ~45 deg of rotation to properly secure the ring bolts:


old ring bolts look good, but per FSM, these are done:


I checked all of my measurements including backlash and runout. Unfortunately my backlash was a bit out (~0.009"). Factory calls for ~0.004-0.005 if memory serves, but with my track day coming up I have no time to get the shims needed to get it right. The goon news is the runout was perfect, but the backlash, will have to stay as is for now. The even better news is despite my backlash beighn out the diff made less noise than the stock install aside from the usual clutch type popping.




After installing I took it for a drive and it immediately popped (engaging/disengaging of the clutch plates) around tight turns. So I came back in and added the Ford friction modifier. This made things a bit better and then I drove for a little while to do some "running in " Overall I would say that 6 plates on either side seems still aggressive (certainly for street use, but maybe not so for track use). I am getting popping around tight turns. However this is on day one after installation. I have no clue how things will be after breaking the diff in and most importantly I have no idea how it will behave at lime rock later this month. So the plan is to leave it as is and see how the behavior is later this week at the track. My hope is that with a bit of break in the diff will be a bit more quiet and also behave as expected. I am also entertaining the use of a different gear oil since I'm using the tomei stuff right now. I will update once I have some track time later this week as any feedback I can give from street use is a bit irrelevant unless I want to go onto on-ramps with speeds that will place my life at risk.

 

Looks good! I love the look of new hardware. First thing I did with my 03 teardown was use up a half dozen cans of degreaser. I don't understand people who ignore sludge and rust. Or it could be a sign that they paid a shop to do the mechanical work.

 

Couldn't agree more, especially now that this platform is transitioning into classic car territory (20+ years from earliest production) there are a lot of pieces that really need to be replaced due to rust and damage. I do a little bit every time I work on the car and in recent years have been transitioning to using almost exclusively titanium hardware when putting things back together. This has saved me soooo much time on any components particularly prone to rust such as exhaust hardware. Its so nice when the bolts come apart same as the day you put them together. I highly recommend it especially if you buy titanium hardware in bulk through sites like aliexpress to keep the costs down. I have to restock a bit actually:

 

My 04 is a CA car that was never driven hard afaict. It was easy to get started on it. Will be selling it soon. It was easy. My 03 was a FL car and doesn't have rust-belt corrosion but there's a def difference between the two. This one WAS driven hard per the replaced diff and trans. It's been more challenging to clean up & work on. When I was younger, I had a 68 Mustang coupe, and just spending 2 years in Ohio caused devastating rust across the whole lower unibody and all hardware. Required a complete restoration. It's really a shame that salt is still used in the east when minerals are available. It's more expensive but how much do people lose when their cars fall apart?

 

Have you done the figure 8 break in process? Its really important to do it for a while to make sure there is sufficient fluid in between all of the plates. When doing the break in, it is important to make sure you are either clutched in or in neutral for the turning portion because you need the diff to be unlocked and slipping.

 

No I haven't done the figure 8 procedure, just a bit of street and highway driving. How long should I do the figure 8s for?

 

These are the instructions in the tomei manual. :

Break-in after installation:
Like engine brake pads, LSDs require break-in. To ensure operating performance and durability Please be sure to carry it out. If you do not run in, it may cause LSD burn-in or abnormal noise. It also significantly shortens the service life. [Plate and disc break-in procedure] (1) Repeat turning left and right for 30 minutes with the minimum turning radius (full steering angle of the steering wheel). At this time, drive the straight part and coast when turning. ① After that, drive about 100km at a speed of 60km / h or less. ・ After the break-in, change the oil. ・ Please change the oil regularly (3000km). ・ If the abnormal noise (chattering noise) becomes loud, change the oil. ・ If you feel any abnormality during use (extreme abnormal noise, vibration, damage), immediately stop using the product and inspect each part. please give me. If you continue to drive as it is, it may lead to a vehicle breakdown or an accident, which is dangerous.

 

thanks!
I found a dealer of motul 90pa near me so I’ll do the break in and oil swap tonight.

 

ok, so figure-8 procedure done and motul 90pa is in. So the results:
weeeeeeeeeell. It's definitely a little better. The pops are noticeably "softer", but did they disappear? Nope, hell no, definitely still there and veeeery noticeable especially in tight turns on light throttle in first gear (intersection slow turn left or right from a stop).
I'm coming to the conclusion based on my understanding of how a clutch diff works that the strength of the pops of engagement/disengagement of individual plates is also related to the pre-tension of the bevel springs on either side of the clutch pack and on this LSD there is no way to adjust that ....well there is one way, but more on that later.
So these are the thoughts related to the street manners of this LSD. As for spirited driving....oh yea, you can easily tell there is a difference, the rear end without a doubt has more corner exit grip and I will expand on that after Thursday's Lime Rock event. So for now I can't really say too much about how this thing behaves other than street driving and as far as that goes although the motul 90pa makes a difference as did the figure 8s, its still clearly a function-first type of diff. Not for the folks that want a nice and quiet ride.

I have also thought about removing one disc from the stack on either side of the LSD (so set it up with 11 per side instead of 12 reducing the stack thickness on either side by about 1.5mm). Obviously that would place less tension on the bevel spring and make those engagement/disengagements softer (think feathering your clutch), but first, I'll see how this thing behaves on track and also see if it mellows out a bit after a bit more street driving and breaking-in and another oil change after the track day.