Gtr Or Gts4 Differentials?

[MJTru]

Im in the process now of switching out all my parts from my gts 4 to my new gtr body I got. For all that don't know I crashed my gts4 that had a fully built rb26 motor for about 600 hp into my gts4 and now putting it into my new gtr r32 body. Im stock between a rock and a hard spot. I don't know based on my own personal experience what is the better setup, and it doesn't hurt to ask. Gts4 diff or gtr. ??? This car is only for drag racing. Thats it. The only street use will be, just to drive the car to the track. The most hp im looking to get is 800hp.

Things I want to know is.

Is the gts4 diff stronger than a gtrs (r32) from what ive heard the gts4 will shorten the gears and be better for drag racing, and is what lots of gtr users should use, but is it strong enough for 800hp ???

Next, I have a new gt42r turbo, is it too big for 800hp. Im planing on using that turbo in a 6Boost T4 twin scroll manifold with twin 44mm tial gates. Finally after all is done I will do the fuel system to suport that hp. Im working on it as we speak.

Thanks guys and please look at the attached photos for details

[MJTru]

Im working on painting the engine bay and assess the whole body. this body is so new I have a hard time believing its a 1992. Absolutely no rust no where at all, but tye rotors. Lol

[MJTru]

This is today before I tore it down today for paint. I will keep everyone posted.

[XKLABA]

I have 400hp at the wheels in my 32 and with 4.11 I have to be careful how I launch it cause it will want to turn around on me, I nearly ran over the Christmas tree once cause of it, 4.3s would only make that worse, also I'm near the top of 4th now so 4.3s would mean using 5th which is ok in a sequential but not ideal in a H pattern

[Griffin]

I have a front 4.3 diff / sump I would sell if interested.

[GTSBoy]

Marcus,

The diff is not the "gears" on the outside that set the ratio. The diff is the stuff inside the pumpkin. The GTR diff is a proper 2 way mechanical diff. Is good. The GTS4 diff is a shitpile viscous LSD. Is not good.

What you want is the gears off the GTS4 diff to give you a lower ratio for drag accel, and the centre from the GTR diffs. Disassemble both sets, sapw them over. Pay someone money to do it.

But what you really probably need is at least the rear GTR diff rebuilt, if not replaced with an aftermarket 2 way centre, and an upgrade for the front diff centre too (probably a Quaife).

There have been heaps of threads discussing this stuff on here. Read them.

[Ben C34]

Based on XKLABA ' s post 411 seems the eay to go.

[MJTru]

Marcus,

The diff is not the "gears" on the outside that set the ratio. The diff is the stuff inside the pumpkin. The GTR diff is a proper 2 way mechanical diff. Is good. The GTS4 diff is a shitpile viscous LSD. Is not good.

What you want is the gears off the GTS4 diff to give you a lower ratio for drag accel, and the centre from the GTR diffs. Disassemble both sets, sapw them over. Pay someone money to do it.

But what you really probably need is at least the rear GTR diff rebuilt, if not replaced with an aftermarket 2 way centre, and an upgrade for the front diff centre too (probably a Quaife).

There have been heaps of threads discussing this stuff on here. Read them.

Hmm

Thanks alot for the info. I can rebuild rear ends I understand how as I've done it for lots of trucks before, were talking about back lash and shiming to get the right wear patter with a bit of paint, or it can be very noisy if done wrong, one of my uncle is a pro at it. What I didnt know about was how you broke it down. I will invest in a LSD 2 way center for front and rear. But im just a little mix up here. You mean the crown and pinion gears from the gts4 is what your saying is what i need and get rid acual diff part and use the gtrs.

Which one is the 411 and 413?? I can't even sleep now lol, as all ill be doing is reading there differential threads.

Thanks guys I hope I understood you guys right.

[MJTru]

A little to late Griffen. I just got a new sump from Rob at RaceFab. Im got damaged in the accident.

Oh what about the turbo setup guys

Do I need a new turbo or a gt42r will do the job. Im planing on getting a 6 boost manifold from Kyle (6boost)

Thinking T4 twin scroll with dual 44mm tial gates. See I already have a gt42r on a rb25 its way to big for the car a laggy like crazy, but its brand new and only drove the car one. But if I have to ill buy another turbo. Thanks again. Opps I should have made a new thread sorry:unsure:

[blind_elk]

I would have said use the GTS4 crown wheel and pinion. They have a ratio of 4.375:1, and will be slightly better for acceleration than the GT-R ratio 4.111:1.

However, I would expect 600hp can more than compensate for the GT-R ratio.

[MJTru]

I have 400hp at the wheels in my 32 and with 4.11 I have to be careful how I launch it cause it will want to turn around on me, I nearly ran over the Christmas tree once cause of it, 4.3s would only make that worse, also I'm near the top of 4th now so 4.3s would mean using 5th which is ok in a sequential but not ideal in a H pattern

Hi mate after reading up on this topic. And from what your saying you are running your stock gears r32 gtr (4.1) gears and using a gts4 gears 4.3 would be worst, I'm guessing cause your meaning ill have to run through more gears. What I can't understand is with 400hp your on the top of 4th gear using stock differential from a r32 gtr. Hmmm what rpms is the motor running. Its hard for me to imagine your on the top of 4th. I understand your point though mate. Hmmm. I hate these kinds of decisions. But like Gtsboy said, guys are doing the gts4 gears and using the gtrs center (crown and pinion gears from gts4) some even claim the mines gtr of do a similar set up. Thanks and I hope you would elaborate a bit more.

[MJTru]

I would have said use the GTS4 crown wheel and pinion. They have a ratio of 4.375:1, and will be slightly better for acceleration than the GT-R ratio 4.111:1.

However, I would expect 600hp can more than compensate for the GT-R ratio.

Hmmm I just saw this. I was thinking 600hp would compensate for it to mate. Im just trying to figure out whats best here. This is a very good point.

Has anyone done or tried both setups at this hp goal for drag use only. I can see 4.3 being nice for time attack car.

I have enough parts to give both setup a try. Just woud like to save some time.

[Ben C34]

Look at what mph you intend to run and what the engine will rev to and work back from there.

There are online gearing calculators to help you.

[KiwiRS4T]

I vote for the 4.1

4.3 helps compensate for lack of power but you would just be spinning all four. Rips kept the stock 4.1 in his 9 second Stagea. Psymins Stagea with a mere 550awkw was wheelspinning al the way down the 1/4 mile (although it wasn't set up for dragging) with GTR 4.1 diffs.

[XKLABA]

There is a few thing you need to work out first like

what RPMs you plan on running too,

what gear set you will have in the box,

what kind of box you will use,

what size tyres you want to race on,

These will all need to be accounted for when choosing a final drive, my 32 has trapped at 125mph which is near enough top of 4th, 7000+rpm

While your in gear acceleration will be faster with the 4.3s you have to be able to put it on the ground and these will make that harder especially with 6-800hp so while they might get you a higher mph they will do so at the cost of ET with a H pattern box

while I was working with the BSM GTR team we had this discussion when they wanted to go to 4.3s from 4.11s and after a lot of debating from me the decision was made to go a custom set of 3.9s which netted a consistent 2 seconds around EC and 8kmph faster down the main straight becuase Dave could put the power down sooner, hold gears longer and actually make use of the extra torque the worked motor was making, while I know this is a circiut car what is circiut racing but a series of drag races broken up with corners

The strength difference between 4.11s and 4.3s crown and pinion gears is neither here nor there, the difference in diff strength between the GTS-4 and the early 32 and the late 32 on the other hand is substantial, but mostly to do with output shafts, late 32 diffs have 31spline output shafts, the 31 spline is the one you want, if yours is a 92 model then 31 spline is what you should have

Personally I would drop you motor and box in and use the stock diff gears and take it from there