Nismo GT Pro LSD configurations

[tidi0x]

I have wasted too much time on this, more than I am willing to admit. I hope someone can set the record straight for me. 

I want to replace my Nismo (non GT pro, non GT) standard 2 way in my R33 GTST with a 1.5 way... Ideally I want to get an ATS 1.5 way Carbon LSD, but I don't want to reuse my 29 spline 5x1 axle stubs, and new 30 spline 5x1's are impossible to get a hold of ($$$), and I don't want to drop the cash on going to 6x1 stubs and axles ATM. Which leads me to the Nismo GT Pro 38420-RSS15-B5 or RSS20, as they come with new axle stubs meant for the diff, and is "Convertible" from a 2 way or 1.5 way to "Other ways", but that is where I am stuck as the documentation is a bit all over the place. 

To sum up what I have found I believe the all the Nismo GT Pro PN's are convertible from 2 way, 1.5 way, and 1 way; but Nismo sells 2 skus (2 & 1.5) so people do not have to disassemble to convert it. 

I found this thread on 350z but it left the question unanswered. https://my350z.com/forum/engine-and-drivetrain/620032-nismo-gt-pro-lsd-1-5-vs-2-way-and-torque.html 

Essentially the way I think it all works out is like follows... 
2 way 

1 way 

and 1.5 way would be the center pinion shaft in the 1 way block, but with the with the center flipped 180*. So the ramped side of the pinion would face the 1 way gate and act like a ramp. 

 

I can only get my hands on the 2 way in the states, and I am not trying to get stuffed on tariffs by ordering from Japan or anywhere else. I want to confirm that if I get the 2 way I can convert it to the 1.5. 

 

 

[MBS206]

Dose will be able to confirm this more, but a 1.5 way IS a 2 way. It's just not as aggressive on one of the ramps.

Changing from 2 to 1.5 I'm not sure how though.

[Dose Pipe Sutututu]

Oh I don't want to get into the details of the 1.5way, @Kinkstaah is the one that holds all the wealth.

 

[GTSBoy]

This would appear to be useful

 

Confirmation of OP's 1.5 way interpretation at ^:10 mark.

[tidi0x]

1 hour ago, MBS206 said:

Dose will be able to confirm this more, but a 1.5 way IS a 2 way. It's just not as aggressive on one of the ramps.

Changing from 2 to 1.5 I'm not sure how though.

I know and understand they are principally the same. They both cause lock under decel, but the 1.5 nomenclature implies "half" or less locking force, or it allows for more slip or a speed differential between both wheels. Right now the driving manners with the 2 way is pretty rough on transient to full off throttle in the backroads. In other words letting off the throttle too rough is not forgiving, great for drifting, tougher for controlled grip driving. 

 

17 minutes ago, GTSBoy said:

This would appear to be useful

 

Confirmation of OP's 1.5 way interpretation at ^:10 mark.

 

Yeah, I have watched that video a couple times, I am more so just looking for the confirmation that both part numbers offer the same ramp architecture and are just different settings from the factory.  

 

38420-RSS15-B5 

38420-RSS20-B5

[GTSBoy]

I would be very confident that they are the same parts (the 2 different SKUs). It seems very clear that you can drop the cam in the 2-way opening, or in the other opening. If you arrange it in the other opening in the same way that you see any other 1-way diff, ie, with the flat of the cam up against the 1° side of the opening, then it would work as a 1-way. It can only spread the ramps when driving forwards - cannot spread the ramps on overrun.

It would then appear obvious that if you put the cam into the opening "backwards", that you would get the angled flats of the cam working onto the "points" of the 1° side of the opening, which would give you ramp spread in both loading directions.

I do wonder if the forward direction of the 1.5-way config is equivalent to the forward direction of the 2-way, seeing as the cams are flipped and the angled surfaces on those would need to be the same on each side - AND - clearly when installed in either the 2-way or 1-1ay configuration they are not intended to work exactly the same (the ramp angles on the 2-way are 10° different between forward and backward, and the ramp doesn't exist in the 1-way config).

'twere me, I think I would rather actually have a set of rings that offered the 2-way with two different sets of ramp angles, say the 55/45 of the existing design and maybe a 45/37.5 combo for a less aggressive effect), AND another set of rings with a dedicated 1.5-way opening and a dedicated 1-way opening. The 1.5-way opening would actually have the steeper angle on the overdrive side that causes it to be less pushy than the forward drive angle, like you see in many other diffs. But really - if this Nismo thing is thought out properly and all those surfaces work on each other the way that they need to, who am I to argue?

[GTSBoy]

I would be very confident that they are the same parts (the 2 different SKUs). It seems very clear that you can drop the cam in the 2-way opening, or in the other opening. If you arrange it in the other opening in the same way that you see any other 1-way diff, ie, with the flat of the cam up against the 1° side of the opening, then it would work as a 1-way. It can only spread the ramps when driving forwards - cannot spread the ramps on overrun.

It would then appear obvious that if you put the cam into the opening "backwards", that you would get the angled flats of the cam working onto the "points" of the 1° side of the opening, which would give you ramp spread in both loading directions.

I do wonder if the forward direction of the 1.5-way config is equivalent to the forward direction of the 2-way, seeing as the cams are flipped and the angled surfaces on those would need to be the same on each side - AND - clearly when installed in either the 2-way or 1-1ay configuration they are not intended to work exactly the same (the ramp angles on the 2-way are 10° different between forward and backward, and the ramp doesn't exist in the 1-way config).

'twere me, I think I would rather actually have a set of rings that offered the 2-way with two different sets of ramp angles, say the 55/45 of the existing design and maybe a 45/37.5 combo for a less aggressive effect), AND another set of rings with a dedicated 1.5-way opening and a dedicated 1-way opening. The 1.5-way opening would actually have the steeper angle on the overdrive side that causes it to be less pushy than the forward drive angle, like you see in many other diffs. But really - if this Nismo thing is thought out properly and all those surfaces work on each other the way that they need to, who am I to argue?

[Kinkstaah]

I don't know if you can disassemble the thing and put it backwards for different ramp rates. They're both "2 ways" or both "1.5 ways" because well, 2 ways and 1.5 ways are the same 'thing'

I do not know for sure, but I believe the 38420-RSS15-B5 is the 1 way, and 38420-RSS20-B5 is the two way.

In other words, I predict Nissan considers this:

to be a 1.5 way.

No idea what actually happens when it arrives/you disassemble it. It would be an excellent question to ask Nismo directly! I somehow doubt you will get an answer though, I feel you would be the first person to document what you encounter when you open the box and the internet would be grateful.