Getting this installed today (too busy to do it myself)…it comes as a 2-way 100%lock, so I switched it last night to a 1.5 way, 80% lock. The manual that came with it was in all Japanese, and while I’m ½ Japanese, I don’t come close to understanding the written language…luckily there were pictures with #’s (like 100% / 80%/ 60%, or 1-way, 1.5-way, 2-way) – so it wasn’t too hard to figure out what to do.

Lock %:
The plates that have notches on the outside lock onto the housing, the plates w/ notch on the inside lock onto the gear portion. These 2 types of plates have grooved surfaces that are opposed to each other. (so by alternating them, you get the most amount of friction – 100% lock….by coupling some of the same type of plates together, you can get less friction  80% or 60%)

1, 1.5, 2 way:
The gear portion in the middle of the housing can be switched around to work as different types…it was fairly easy to look at the manual’s pictures and set it up to be a 1.5 way.


Here’s some pics (I always like to see lots of pics before I do a project...so here's all of mine!)









After opening the case, the internals just slide out.


The 2 different plates





















Making sure it’s correct

 

Nice!

 

cool

 

i know it made me nervous when i took it apart...i may have to do it again to increase the lock from 60-80%.

 

Nice pics, it's nice to see the difference between the cusco and my nismo unit. The Cusco Ramps are slightly steeper than the nismos.

Your last picture there shows it as a 2 way. Assuming you didn't take the picture of the final 1.5 way assembled.

As long as you have it apart, you might want to consider sending your plates off for WPC treatment. It is cheap and will make the diff silent.

Look for one of my old thread for more info.

 

yeah - the pics are out of order...the 2nd to last pic is how it came (2-way).

it's getting installed as I type, so it's too late to do the coating.

How much was the coating?

 

Excellent writeup on both threads. Do you have any further findings on the Cusco RS 1.5 at 80% lock? Really interested to hear any more results / concerns.

Also curious about the treatment mentioned which would reduce chatter. I'm trying to decide between the Cusco RS 1.5 set at 80% vs. an OS Giken 1.5.


Thanks in advance...

Stanford

 

I took daveh's advice, and got my Cusco unit WPC treated. I never experienced it without the treatment, but my RS unit is silent. So, I assume it did it's job, and it did it well.

I too have mine set at 1.5 way 80%, and it seems to work well. Daveh also recommended Motul 90PA, which I am also very happy compared to the Valvoline Diff fluid I had in there previously.

 

How was it working with Izumi-san?

What made you decide to treat it? I haven't had a stock RS chatter (unlike the MZ) in stock configuration.

I probably would have WPC treated the LSD regardless as well, but just wondering your reasoning.


For anyone else, the stock RS shouldn't chatter, and WPC treatment is an amazing product/process that I would recommend for anything ranging from bearings (main and crank), cams, cylinder walls, pistons, clutches, you name it.

 

The only thing I remember about dealing with Izumi-san was that he was courteous, and it was a little hard to understand him due to language, IIRC.

What made me decide to treat it was because I heard daveh's Nismo unit chatter a lot before the WPC treatment. And, it was quiet after the treatment. For about $110, I thought it was worth getting it done, especially since I didn't want to pay someone another $300+ to remove and reinstall the diff plates. There was no rhyme or reason other than that. At worst, I wasted $110. At best, I saved myself $300+.

 

Nice

 

Gotta love the Japanese-only instructions that come with Cusco products.

 

so what did you think of it, getting one in the spring

 

For those looking into this or any LSD, I would recommend a 1.5-way and for the RS, I wouldn't go anything below 80% lockup. I really like 100% lockup and prefer that setting.

 

can someone explain the 60,80,100% lock up to me. What is the % actual mean.

 

what is WPC coating?

 

http://www.wpctreatment.com/

It is similar to shot-peening but at a much finer level (plus the benefits of heat treating the material). It creates micro-dimples on the surface of the metal that knocks down all the stress-risers and uneven 'landscape' of metal. That combined with the micro-dimple's abilities to hold oil -both greatly reduce friction.

For brake rotors, clutch plates, and LSD plates, this treatment strengthens the part and reduces 'chattering' due to uneven deposits and "hot spots" on the friction surface, while keeping the surface smooth and consistent.

 

Rotors too? Not sure if I'd do the rotors since you're transferring pad material onto the rotors, and need the friction and heat for that process.

 

Same principle as clutch and lsd.

At the moment WPC only treats rotors for select race applications. They have had success overseas with treating the rotors and we are currently testing a crack-prone rotor application to see the longevity improvement over untreated. In terms of performance, initial bite, pad transfer, etc... are so-far the same as untreated (at the moment, maybe even more consistent pad deposits, but more time will tell).


-0.02

 

Interesting...keep us in the loop re:the results of your testing!