HELP! 32GTR diff into 34GTR

[Hardwork]

Hello ladies and gents!

After any advice as to what is needed to make a 32 diff fit into a 34 gtr. I have removed my stock A-LSD and driveshafts, and have purchased a 32 diff with 32/33 non vspec shafts. I did some reading and read some accounts of spacers being required, new bolts different lengths etc.

anyone with first hand experience able it’s shed some light?

 

cheers!

 

[KiwiRS4T]

Not going to work. Your front and rear diffs are 3.54:1 and the R32 diff is 4.1

[Hardwork]

17 minutes ago, KiwiRS4T said:

Not going to work. Your front and rear diffs are 3.54:1 and the R32 diff is 4.1

Sorry forget mention I have a 4.11 front diff ready to go in, will be just disconnecting the front shaft till I swap sumps.

[KiwiRS4T]

Ok but you do realise that there will be a significant increase in your revs at highway speeds and your six speed box will be operating over a much smaller speed range. Have you looked hard for a non A-LSD rear diff?

[Hardwork]

2 hours ago, KiwiRS4T said:

Ok but you do realise that there will be a significant increase in your revs at highway speeds and your six speed box will be operating over a much smaller speed range. Have you looked hard for a non A-LSD rear diff?

Yes mate I’m well aware. The shorter ratio is precisely why I went to a 4.11 as I wanted a closer ratio setup, the fact it’s a mechanical LSD is a bonus. This is very common in 32 GTR’s when people swap the getrag into them and retain the factory diff ratios. It’s also not that bad, using my current tyre size I’ve roughly calculated my new cruising RPM at 110km/h is 2800, which I can live with. 

[niZmO_Man]

No idea if Supra Getrag uses longer gears, but could be handy to swap out 6th to a taller ratio.

[WHITEBEAST]

16 hours ago, Hardwork said:

Sorry forget mention I have a 4.11 front diff ready to go in, will be just disconnecting the front shaft till I swap sumps.

Could this cause any trouble with your transfer case? I know it doesn't hurt the R32 box much, (something to do with preload on front drive shafts with R33, R34). Good luck with it all.

[GTSBoy]

You'd have to bleed out the transfer case (which is well documented and simple enough) to run a 33/4 GTR without front drive.

[BK]

3 hours ago, WHITEBEAST said:

Could this cause any trouble with your transfer case? I know it doesn't hurt the R32 box much, (something to do with preload on front drive shafts with R33, R34). Good luck with it all.

He said he's going to remove the front tailshaft until sump is swapped, so transfer will not be physically connected to anything so it's not going to damage anything. I've done this and drove 3000km and back to Adelaide with no front tailshaft connected and Attesa fuse pulled in the 33, and the 34 has the same 2nd failsafe solenoid (which causes the transfer preload in a 33/34. 32 only has one solenoid) as the 33. That's how you rear wheel dyno one without depressurising Attesa.

Also regarding the Getrag with the 4.11 drive, remember what I wrote in the GTR box upgrade thread.

On 25/04/2019 at 11:07 AM, BK said:

Short ratio does not mean close ratio. Quaife, PPG, OS Giken 5 speeds have a really tall 1st gear compared to standard, then 2nd and 3rd are changed taller too to make 1st - 4th closer together.  Ratios are:

Standard 5 speed - 3.214, 1.925, 1.302, 1.000, 0.752
OS giken 5 speed - 2.695, 1.703, 1.236, 1.000, 0.826  (can have std 0.752 5th)

final drive 4.111

Now have a look at R34 Getrag:

3.827, 2.360, 1.685, 1.312, 1.000, 0.793
final drive 3.545

Ignoring 1st, 2nd to 6th gears it's similar ratios to a Giken 5 speed. May aswell not have the 1st in it with 4.11, so what's the point of using a Getrag 6 speed in an 32 / 33 unless you want a very short 50km/h Motorkhana gear ?

6th isn't the problem, as crusing rpm only increases a bees dick. The Getrag has a stupidly short first, but ignoring that 2nd - 6th is very, very close to having OS giken ratios 1st - 5th in a 5 speed. So as above Getrag 1st behind a 4.11 drive is essentially a motorkhana gear. You'd be probably taking off under normal conditions in 2nd, although 2nd is a bit taller again than an OS 1st. It'll be ok as most of the time will be between 2nd and 6th, 1st will rarely be used.

This isn't a problem, just pointing out that it's going to have a very, very short first.

[Hardwork]

1 hour ago, BK said:

He said he's going to remove the front tailshaft until sump is swapped, so transfer will not be physically connected to anything so it's not going to damage anything. I've done this and drove 3000km and back to Adelaide with no front tailshaft connected and Attesa fuse pulled in the 33, and the 34 has the same 2nd failsafe solenoid (which causes the transfer preload in a 33/34. 32 only has one solenoid) as the 33. That's how you rear wheel dyno one without depressurising Attesa.

Also regarding the Getrag with the 4.11 drive, remember what I wrote in the GTR box upgrade thread.

6th isn't the problem, as crusing rpm only increases a bees dick. The Getrag has a stupidly short first, but ignoring that 2nd - 6th is very, very close to having OS giken ratios 1st - 5th in a 5 speed. So as above Getrag 1st behind a 4.11 drive is essentially a motorkhana gear. You'd be probably taking off under normal conditions in 2nd, although 2nd is a bit taller again than an OS 1st. It'll be ok as most of the time will be between 2nd and 6th, 1st will rarely be used.

This isn't a problem, just pointing out that it's going to have a very, very short first.

Apologies, mistake on my part. They are all effectively shorter, not closer after the ratio swap. Potato moment! 

Agreed, 1st is already very short. But like you said, it’s 2-5 is what matters (to me anyway). I’ve driven a friends 34 GTR with 4.11 final ratio’s, and I fell inlove with it. Hence why I’m not concerned over anyone’s uncertainty of the usability.

2 hours ago, GTSBoy said:

You'd have to bleed out the transfer case (which is well documented and simple enough) to run a 33/4 GTR without front drive.

And as stated above, removing the front drive shaft will void any need to bleed out the attessa system. I’ll need to bleed it again anyway as I removed the feed line to the old A-LSD which shares the same fluid,  but many shops dyno GTR’s in RWD with the front shaft removed.