Okay, I just bought my IP R200 Diff kit but I have a few questions:

(1) What models are compatible with the IP Kit?

(2) Does the internals of the R200 diff need to be modified to handle the extra power?

 

Hey mate,

Nissan R200 diffs are not mechanical and are viscous except some diffs from GTRs (not in all models). I think IP kit doesnt use GTR diff so it won't apply anyway. It's best to change the viscous diff to a mechanical 1-1.5 way because the diff from these cars are quite old now. Some will still work but if you plan to put decent torque through them you will spin one wheel.

Could you do me a favour?

I am planning to purchase a spare set of axles and CV's from inline pro but not sure if it will fit my setup. Just in case mine break.

Could you measure the distance between the end of the CV flange on the diff side (ie from the diff flange) to the cup of the out CV joints?

Thanks mate

 

What type of R200 diffs do IP retrofit? There is a big difference between them, basically what breaks are the output shafts. I used to own a S14 and then a GT-R before the S, and I remember people were always looking for diffs from the GT-R, the output shafts were stronger compared to the R200s that we got in our cars here, they also came with clutch LSD. People also swapped to the Q45 r200s becuase the output shafts were also very strong.

 

90-96 NA 300ZX

 

Well since I knew nothing about Viscous differentials I did some research and found the below which was helpful. Since I got a differential with the kit I think I will just get a geared differential. In the past I always used Eaton, on cars with more than 600Ftbl of torque and 295’s, I am going to check them out more.

I also got a tip from Geoff at Fullrace that the Q45’s do have a lower gear. I had been looking at options for a gear closer to 3.73:1 but I am not sure if it is really worth buying another differential.

When you spin one tire in your car because you don’t have a limited slip, the side and pinion gears inside the carrier, aka spider gears, are moving really fast to allow that one wheel peel to happen. THE MOST FREQUENT CAUSE OF FAILURE IN NISSAN DIFFS IS RELATED TO THE SPIDER GEARS.

On the Nissan diffs, ring gear size is given in mm.
R160 = 160mm or 6.29” in diameter
R180 = 180mm or 7.08” in diameter
R190 = 190mm or 7.48” in diameter
R200 = 200mm or 7.87” in diameter
R230 = 230mm or 9.05” in diameter


Here is a list of available diffs that you might (relatively) commonly find in a Z:

R160 - Originally came in 510s, Subarus. Lighter weight than stock Z diff
R180 - Came in 240, 260, 77-78 280Z automatic, and 280ZX automatic, among others. Also in the new WRX STi
R190 - Nissan Comp diff used in early 70's race cars and 432R's. Still some of these floating around.
Longnose R200 -weight 76 lbs - Came in 260Z 2+2, 280Z manual, 75-76 automatic and 2+2, S130, Z31, 200SXT
Shortnose R200 - weight 72 lbs - Later model 240SX, Q45 1989-1996, R32 Skyline, 300ZX NA, 350Z
Shortnose R230 - weight 114 lbs - 300ZXTT, Armada front diff

The torque capacity of the shortnose R200 should be equivalent to the R200 longnose, which means it can handle a lot of abuse. 400 lb/ft should not be a problem with the R200 shortnose, and it will probably hold a good amount more if the VLSD is used. There is apparently another model of the R200 shortnose which has 5 bolt output flanges on the sides of the diff. This model should be avoided, since the CV adapters we have available use the 6 bolt flanges.
R200’s come in a 4 pinion version only, but there are several different clutch packs. It appears that the Z31T diff from the 87-89 300ZX Turbo came with a large spacer to take the place of several of the clutches in the stack. With powerful engines and slicks this can lead to stripping the teeth off of the clutches, making the diff no better than an open diff. NISMO and Nissan Comp sell another version which has more clutch disks and no spacers that should be a lot stronger, but there is some ambiguity as to what you will get when you order one. At least one person has reported buying an LSD from Nissan Comp and getting the spacers. The better diff with the improved clutch packs also has more aggressive lockup. One way to tell the two apart is to look at the ramps and the cross pin shaft shape.
Power Brute - This LSD is the same as the Nissan unit, and is imported from Japan. Again which version of the R200 diff you’ll be receiving is somewhat ambiguous. Get the good clutch pack if you can.

Quaife - This is an entirely gear driven LSD. The way this works is that the side gears drive long pinion gears into the sides of the case. As long as there is traction to both wheels the pinion gears get driven into the case, and the friction from that action transfers the torque from one wheel to the other. This torque transfer can be measured and is frequently referred to as a torque bias ratio. The R diffs have a torque bias ratio of 5:1. Amazingly this diff is warranteed for life, even if the car is raced. The Quaife is a one way diff and does not lock up on decel.

OBX - Chinese knockoff of the Quaife. Some other car forums had reported manufacturing errors. Still in business?

PHANTOM GRIP - The Phantom Grip is an inexpensive part that converts an open diff to limited slip. The way this one works is it has two plates that slide in between the side gears of your open differential. In between the two plates are springs. The springs push against the side gears, and this makes it harder to rotate the side gears. The strength of the springs alone determines the amount of lockup, there is no torque sensing function in this one.

TORSEN - This LSD was available for a short time and there are just a few of these floating around, seems like most/all are for R200s. The Torsen diff is a gear driven LSD like the Quaife, but the one used in the Nissan diffs is designed in such a way that it is more like a 1.5 way and does provide some amount of lock up on decel. There have been reports of a new Subaru being fitted with a R200 torsen diff, and also it seems the S15 version of the 240SX has a Torsen as well, so we may be seeing more of these diffs hitting the market at good prices soon.

NISSAN VLSD - Viscous LSDs are commonly available in the shortnose R200 and R230. They did also make an appearance in the 88 SS version of the 300ZX Turbo. The limited slip mechanism is passive meaning that it is not doing anything to limit slip until one wheel "starts" to spin. A brief description of how it works is to compare it to a viscous coupling like that in a torque converter. The faster one side wants to spin, the more the viscous coupling locks the two wheels together. VLSD’s are not as grabby when they lock up and they aren’t as positively locked either. In road racing applications the fluid can overheat and cause slippage. The fluid used in the coupling is independent from the rest of the differential oil and it can be changed in viscosity to affect the aggressiveness of the unit.

KAAZ/CUSCO – These Japanese aftermarket parts manufacturers both make LSDs for the R diffs. They are commonly advertised for the 240SX which uses a shortnose R200, but the LSD can be used in a longnose R200 as well. If you purchase one of these diffs, make sure you get the replacement for 240SX with an OPEN DIFF. This will have the correct spline count for stock side stub shafts or Z31T CV shafts. Both KAAZ and CUSCO produce LSD’s in 1.5 way and 2 way variations. The 1.5 way doesn’t lock the rear wheels together as hard under deceleration as it does under acceleration. This makes the car easier to handle when on the brakes hard. The clutch packs on these diffs are very impressive. They have a lot more and a lot larger clutch disks in them than the Nissan diffs so they should be extremely durable.

ARB Air Locker - ARB makes a selectable locker for the R180 and R200. This is an air powered unit that turns the diff from completely open to fully locked at the flip of a switch. The lockers have been around for a long time and are very popular with the rock crawling crowd. This means that they should be extremely strong, and this differential would be an EXCELLENT choice for a street/drag car, because it could be driven around town with the open differential and then locked solid for the track, and then switched back.

Reference
http://forums.hybridz.org/showthread.php?t=114798


The viscous type is generally simpler because it relies on hydrodynamic friction from fluids with high viscosity. Silicone-based oils are often used. Here, a cylindrical chamber of fluid filled with a stack of perforated discs rotates with the normal motion of the output shafts. The inside surface of the chamber is coupled to one of the driveshafts, and the outside coupled to the differential carrier. Half of the discs are connected to the inner, the other half to the outer, alternating inner/outer in the stack. Differential motion forces the interleaved discs to move through the fluid against each other. In some viscous couplings when speed is maintained the fluid will accumulate heat due to friction. This heat will cause the fluid to expand, and expand the coupler causing the discs to be pulled together resulting in a non-viscous plate to plate friction and a dramatic drop in speed difference. This is known as the hump phenomenon and it allows the side of the coupler to gently lock. In contrast to the mechanical type, the limiting action is much softer and more proportional to the slip, and so is easier to cope with for the average driver. New Process Gear used a viscous coupling of the Ferguson style in several of their transfer cases including those used in the AMC Eagle.
Viscous LSDs are less efficient than mechanical types, that is, they "lose" some power. They do not stand up well to abuse. In particular, any sustained load which overheats the silicone results in sudden permanent loss of the differential effect.[5] They do have the virtue of failing gracefully, reverting to semi-open differential behaviour. Typically a visco-differential that has covered 60,000 miles (97,000 km) or more will be functioning largely as an open differential; this is a known weakness of the original Mazda MX-5 (a.k.a. Miata) sports car. The silicone oil is factory sealed in a separate chamber from the gear oil surrounding the rest of the differential. This is not serviceable and when the differential's behavior deteriorates, the VLSD centre is replaced.

 

Why 3.7 and not something higher?

I have a ~4.39:1 diff and it was a bit tall for the 2L. With the 2.5L its just right I think....yet to test it out on the track.

 

I would like something a bit easier for the street and my tires. Curenly the diff has a 4.08:1 which should be undecernable compaired to the factory. However runing RE010's with my Greddy kit a 12 PSI I had no problems breaking the tires loose. With my new setup I am not quite sure how I am going to keep the power to the ground. I hope to be putting 350-400Ftlb at the wheels, I probably should have a set of 275's or larger.

I am have not made up my mind yet I still have to build an acceleration map with the availible gears and look at my spool vs cruzing RPM.

Of course that is all assuming that I can get the car moving under it's own power again.

 

Of the diffs you've mentioned I have ran the Quaife before and was extremely happy with it.

Yeah get the car running already and stop turning this car into the never ending story. LOL. I'd try what you got and go from there if it's that much of a problem down the line.

 

At $1,500 it better be bullet proof, it is a shame I could buy Eaton's or Thorsen's for $400 all day long on my domestics and my Vette had a bullet proof Dana from the factory.

The Cusco clutch type are a bit cheaper at about $1,000

 

Stickier tyres or progressive boost control.

Stick with what you got. Dont go backward with the diff ratio