R32 - Gts-t V Gtr Rear End, Knowledge Requested Please :)

[Victory]

Something else to think about is that the GTS-T is 4.3 and the GTR is 4.1 - what affect will the ratio change make to your car?

Another option is a GTS4 diff - this uses the GTR housing drive shafts etc with a 4.3 ratio but a viscous instead of mechanical LSD.

All of the suspension arms are interchangeable between GTR and GTS-T with the exception of the ball joint that attaches to the GTR alloy upright. The other difference is the oil seal on the GTR drive shaft is different to the GTS-T one which requires the GTR housing to be machined to fit GTS-T drive shafts oil seal.

Bottom line question - what is wrong with your current GTS-T diff and rear end? If it has not broken why change it and increase your unsprung weight?

We have spent the last 6 months playing with this exact issue with our R32 that is running a RB25de from a R33. We have settled for GTS-T cradle and diff, GTR uprights with GTS-T hubs and drive shafts. Net result will be minimum unsprung weight and overall weight and with the power that we will have we should not break anything.

[Beer Baron]

you wouldn't bother using a GTS4 diff or cradle etc. you just get the GTS4 crown wheel and pinion and fit them to your GTR centre and housing. the viscous diffs are rubbish.

also the GTS4 diffs are really a 4.4 not 4.3 (35:8 or 4.375:1 if you want to get accurate!).

the set-up you have sounds good, but may be worth putting an LSD centre in that GTST diff casing as the viscous centres are not so hot. their behaviour changes a lot too when overheated etc. a GTR mech 2 way centre is nice and predictable. or just get an aftermarket LSD that's suitable for your GTST housing.

[Marlin]

Yeah cheers Victory, there's nothing at all wrong with my setup, it feels great to me! lol I just see everyone else running around changing this and that and had to ask if I'm missing something?

Some guys say they change it to get the alloy hubs for lighter unsprung weight, but at what cost? More rotating mass? I know what I'd rather deal with, no prize for guessing the last thing an RB20 needs is more resistance to overcome.

And I certainly wouldn't want to have a taller ratio, although I know most people hunt down the GTS4 ratios to negate that.

I'll ask again, but does anyone know where the strength limit is for GTS-t rear end? And what breaks first?

[Roy]

They are tonka tough unless you are a drifter , in which case all the clutch kicking and backlash in the diff seems to take a tole on the occassional half shaft.

I have never broken one in the 9 years and 120,000kms i have owned my car

[Marlin]

Well, if it's good enough for Rapist Roy, it's good enough for me

[Sydneykid]

This is a good thread to ask a similar question that has had me thinking about which way to go for a while, so some expert input might help. This is what I have in the car;

1. R32GTST cradle with Noltec subframe bushes, Whiteline Pineapples, de-bracketed, lightened and with minor geometry changes.

2. R32GTST hubs with MCA shocks that suite (spherical bearing lower mount).

3. R32GTST 4.375 diff with unknown LSD, works well

4. Polyurethane bushes in the upper and lower control arms plus the diff

5. A brand new, one piece tail shaft (R33GTST gearbox to R32GTST diff)

7. Milled alloy HICAS elimination bracket with R32GTST steering arms and new tie rod ends

The problem is, with 600 rwhp or so, I am a bit concerned with the durability of the drive shafts plus the 4.375 dif ratio is a bit short for the RB31DET rpm range (7500 rpm at 275 kph). I’ll only get one run at the drags with the MT ET’s before they flick me for the circuit race roll cage and no parachute etc. So I want to get it right, first time. Other than that it’s circuit racing use only. I’d like to also retain the R32GTST cradles as it . I also have a Nismo R32GTR LSD, a standard R32GTR diff with 4.1 ratio, a set of R32GTR drive shafts and a pair of R32GTR hubs. So what I was contemplating;

A. Machine the alloy R32GTR hubs to take the R32GTST style lower shock mounts. That will get some unsprung weight out compared to the R32GTST hubs and I can still use the MCA shocks as is. I’ll also put the R32GTR lower ball joints onto the R32GTST lower control arms with some roll centre correction.

B. Slot the Nismo LSD into the R32GTR diff

C. Then use the R32GTR drive shafts, that will add back some sprung and unpsrung weight

D. Either modify the R32GTR diff to take the R32GTST drive shaft (universal) or modify the tailshaft to take the R32GTR style universal.

E. Sell off the unused bits, mainly the R32GTST diff with LSD, R32GTST drive shafts and R32GTST hubs.

The questions;

a. Will the weight saved in the hubs (100% unsprung) offset the weight gained in the drive shafts (50% sprung)?

b. Will the combination of R32GTST cradle, R32GTST control arms, R32GTR diff, R32GTR drive shafts and R32GTR hubs actually fit together?

c. Modify the R32GTR diff to take the R32GTST drive shaft (universal) or modify the tailshaft to take the R32GTR style universal?

d. Is my assumption that the pick up (pivot) points on the R32GTR hubs the same as the R32GTST correct?

Any and all inputs greatly appreciated.

Cheers

Gary

[Roy]

Your problem is you have an RB25 box and an RB30. Wouldnt need to worry about all that weight a strength if you stuck with the lighter RB20 drivetrain

[sav man]

isn't the reason the gtr hubs are fork vs the gtst mounts because the alloy isn't strong enough for the gtst mounts? or was it nissan just stopping people from swapping them.

The more i think about what i want to do, the cheap Nismo gtst diff + gtr hubs/ball joints seems pretty good. gives me a good diff, and i don't need to put the extra weight of the gtr driveline in. only cause there is a cheap nismo diff avalible, and tassie has a few gtr's that are being parted out due to rust.

are the gtst and gtr outer drive splines the same? if not can you just swap the outer part of the 1/2 shaft from the cv?

[PHaT MR30]

isn't the reason the gtr hubs are fork vs the gtst mounts because the alloy isn't strong enough for the gtst mounts? or was it nissan just stopping people from swapping them.

The more i think about what i want to do, the cheap Nismo gtst diff + gtr hubs/ball joints seems pretty good. gives me a good diff, and i don't need to put the extra weight of the gtr driveline in. only cause there is a cheap nismo diff avalible, and tassie has a few gtr's that are being parted out due to rust.

are the gtst and gtr outer drive splines the same? if not can you just swap the outer part of the 1/2 shaft from the cv?

No ben i struck this problem when I did the 5 stud on mine, some one inadvertantly sold me GTR hubs instead of GTSt and the difference is physically visiable not to mention 28 as opposed to 32 spline shafts. I don't believe without spending $$$ you could combine the two driveshafts either (thought about it).

I have a pair of GTR alloy hubs if anyone is interested

[IDR46]

most guys that have 'shimmed' the GTR diffs have just had it set with tighter with a spacer washers etc. the nismo kit replaces all the disks inside it. completely changes the way it works. you end up with more friction disks than you used to have and a higher initial breaking torque (and you can chose between 75 ft/lb or 45ft/lb). it works just exactly the same as a nismo 2 way LSD, in fact it is the same as the original competition nismo 2 way LSDs (now they have fancier ones with adjustment etc, but the basics are still the same). best $300 you can spend on a GTR just about.

cradle pick-up points are a little different I believe. obviously you get the LSD too (which with the $300 kit becomes excellent), and yes the alloy hubs and bigger driveshafts are good. especially for a rwd car having nice big rear shafts wont hurt. the obvious downside is changing shock mounts but it's not too big a deal.

sorry to bump a old thread, but i cant pm with less then 10 posts, i have a gtr diff that is currently doing one leggers and use it 100% for drag, where would i get my hands on a "nismo kit"

Shane