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I am installing a Nismo 1.5-way LSD in my 2008 350Z. I purchased the diff from Nengun, part # 38420-RSZ15-4A. I am having some trouble with the cams and the torque for the 10 drive gear bolts.
1.5/2-Way
My understanding is that the LSD can be set to 1.5- or 2-way by using the two different cams. I know the Nismo and Cusco RS/MZ LSDs are very similar (albeit also quite different), and I am finding contradicting information about the cams. I want to set it to 1.5-way.
This is pretty much everything I was able to find on the Nismo. Reading the Cusco documentation, I am getting even more confused:
And here's a photo of my diff, which I thought was set up as 1.5-way using the triangular cams:
Torque
The manual that came with my LSD says something like 74-83 Nm (approx., talking from memory) + 31-36 degrees + Loctite. I went with 79 Nm (58 lbft).
The FSM calls for 78.5 Nm (58 lbft) + 31-36 degrees + Loctite.
However, the Nismo GT Pro LSD PDF, from Nismo's official page, says 132-152 Nm / 98-112 lbft and no further tightening (+ Loctite).
Are both of these correct?
The cusco photos are incorrect. Those two options are 1 way and 2 way. I did not see a 1.5 way setup in any of those photos. The instructions with the nismo diff do show a correct 1.5 way. With the 1.5 way, you should have the pinion shaft in the housing against the two different ramps. If the ramps are the same, it is 2 way, if the ramps are different it is 1.5 way and if on of the ramps are flat, it is a 1 way.
Id go with the lower value
Bottom says "nismo differential case" Do you have that?
Wow, great catch! Indeed, the manual of my diff does not mention a Nismo case. I have manual no. TY-384-18, whereas the one I linked to above is TY-384-19.
The cusco photos are incorrect. Those two options are 1 way and 2 way. I did not see a 1.5 way setup in any of those photos. The instructions with the nismo diff do show a correct 1.5 way. With the 1.5 way, you should have the pinion shaft in the housing against the two different ramps. If the ramps are the same, it is 2 way, if the ramps are different it is 1.5 way and if on of the ramps are flat, it is a 1 way.
Thanks for the reply, mate.
Which Nismo instructions are you referring to: the MotoIQ photos or the forum thread?
I have always used the FSM torque procedure for the ring bolts and never had an issue.
http://www.cusco.co.jp/en/pdf/CUSCO_LSD_GUIDE.pdf...Page 10, Figure 12 illustration on the right shows the correct orientation for 1.5 way on the Cusco. Your diff is currently set to one way (by conventional standards). You need to move the cross shaft to the diamond shaped cam to set it to 1.5, like the MotoIQ article. I am surprised the Nismo instructions dont clarify...unless Nismo considers the preload from the cone plates the 0.5 in 1.5 way, which on a steel plate diff like this can definitely be aggressive. Also you arent the first to catch it https://my350z.com/forum/engine-and-...y-1-5-way.html
As you mentioned they are similar but different...the cam angles on the Nismo "1.5/2way" unit are more like what comes with the Cusco RS one/two way...so you can imagine the Nismo is naturally going to have more deceleration lockup than the Cusco in 1.5 way config because of the Nismo's higher ramp angle on the decel side of the cam. vs the Cusco which has a specific 1.5way cam profile. Maybe just a simple marketing discrepancy?
I have always used the FSM torque procedure for the ring bolts and never had an issue.
http://www.cusco.co.jp/en/pdf/CUSCO_LSD_GUIDE.pdf...Page 10, Figure 12 illustration on the right shows the correct orientation for 1.5 way on the Cusco. Your diff is currently set to one way (by conventional standards). You need to move the cross shaft to the diamond shaped cam to set it to 1.5, like the MotoIQ article. I am surprised the Nismo instructions dont clarify...unless Nismo considers the preload from the cone plates the 0.5 in 1.5 way, which on a steel plate diff like this can definitely be aggressive. Also you arent the first to catch it https://my350z.com/forum/engine-and-...y-1-5-way.html
As you mentioned they are similar but different...the cam angles on the Nismo "1.5/2way" unit are more like what comes with the Cusco RS one/two way...so you can imagine the Nismo is naturally going to have more deceleration lockup than the Cusco in 1.5 way config because of the Nismo's higher ramp angle on the decel side of the cam. vs the Cusco which has a specific 1.5way cam profile. Maybe just a simple marketing discrepancy?
The MotoIQ article is what prompted me to delve deeper into this and I ended up creating this thread.
What you're saying makes sense: the triangular profile limits the movement of the pin to one direction only.
Every web shop that I have seen says the Nismo LSD is "1.5-way upgradable to 2-way." This wording, along with your explanation, leads me to believe that one needs to purchase a second set of rings in order to make the diff 2-way. That would be disappointing.
I have read that the Nismo diff is considered aggressive (more so that, say, the Cusco). I am planning on running mine at 60% preload (via the adjuster bolt) and 80% lock (restacked according the Cusco manual).
This wording, along with your explanation, leads me to believe that one needs to purchase a second set of rings in order to make the diff 2-way. That would be disappointing.
I have read that the Nismo diff is considered aggressive (more so that, say, the Cusco). I am planning on running mine at 60% preload (via the adjuster bolt) and 80% lock (restacked according the Cusco manual).
The Nismo differential definitely locks 2 way out of the box, the misleading part is that they call it a "1.5/2 way" when by conventional standards, it appears to come as a One/Two way. It seems that their definition of a 1.5 way is different than most. So if you want 2 way just stack it in the diamond shaped cam and call it good, no need for extra parts.
The Nismo and Cusco RS are very similar units...the differences are: Nismo uses cone plates for preload, Cusco RS uses linear springs. They both use 10 clutch plates per side, only the Cusco RS plates are grooved for improved oil cross flow. Either one stacked to 80% is going to be super aggressive on the street, and there will be a lot of popping and locking going on. Music to be sure, but for a dual purpose vehicle you may want to think about dropping it to 60% engagement on the clutch stacks.
And unless you are running a really sticky tire 60% will perform just as well and allow the car to yaw easier. It was amazing when I switched from the Cusco RS to the OSG how much the front yaw rate increased. I had to change my turn in as a result...and also on-throttle corner exit push is definitely more pronounced on the Cusco RS. Another huge change I noticed going from one to the other. Some people do prefer a tighter rear end though, there is nothing like the confidence and predictability you get in high speed sweepers from a tight diff. The OSG is much more transparent, as will the Nismo unit stacked to a lower lock.
If you haven't already bought one, do not run this LSD without a Differential Cooler, preferably one with a temp switch. I also wouldn't recommend running this diff in the car if its your daily. It also should've been in the noted on RHD (that's where I purchased mine) to purchase a diff cooler. I'd also upgrade those stock liquid bushings if you haven't already to either poly or solid if dedicated track car. After hard runs, especially in the summer months, I've gotten the temps hot enough that it took quite a while (with the cooler running) to bring temps back down.
I'm wondering if one can buy the "2 way" diff and make it "1.5 way" or at-least less locking under decel for a street car
CZP has the 2 way for $200 less than the 1.5 right now... Also the nismo units come complete with seals bearings stub axles and fluid making them a good value.
07-30-2018, 07:34 AM
Nismo GT Pro LSD - 1.5- vs 2-way & Torque?
