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Want to change the Diff ratio on the R32 GTR what are the options

rev210
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rev210 Grand Master

rev210

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I am presently considering how to go about changing the diff ratio in the R32 GTR from the 4.11 to 4.375. Don't care for the top end or fuel ecconomy it's a work car.

I am aware that the front and rear diffs need to be swapped and I am wondering about the easiest way to go about getting it all happening.

I have heard that diff centers from various skylines are compatible I'd like to know from people exactly which ones are bolt in. Also from another angle how hard the ring and pinion are to change and what centres are compatible there.

blind_elk Grand Master

blind_elk

Posted
Posted
I am presently considering how to go about changing the diff ratio in the R32 GTR from the 4.11 to 4.375. Don't care for the top end or fuel ecconomy it's a work car.

I am aware that the front and rear diffs need to be swapped and I am wondering about the easiest way to go about getting it all happening.

I have heard that diff centers from various skylines are compatible I'd like to know from people exactly which ones are bolt in. Also from another angle how hard the ring and pinion are to change and what centres are compatible there.

The GTS4's diff (4.375) in the RB20 swapped straight over into the RB25DET Stagea engine I fitted.

The front suspension needs to be almost pulled apart, because you need to extract the RH drive shaft before you can remove the diff. (the LH is not quite as involved)

The torque setting on the pinion retaining nut is "VFT". You will need a BBIIGG socket and a LLOONNGG breaker bar to undo it.

Duncan Grand Master

Duncan

Posted
Posted

Front and rear diff centre from the r32 gtr are mechanical already, so just get the clutch packs tightened up. Put the gtr centres in an existing GTS4 front diff and rear diff and voila!

Any centre that fits the r32 gtr will fit an r32 gts4 :P

Cubes Grand Master

Cubes

Posted
Posted

Take note of the fuel economy difference Rev..

I am considering the swap from 4.363:1 to 4.11:1.

Fuel economy being a factor + the 3ltr tends to rev too quick through the gears when accelerating lightly, first being the biggest pain in the arse.

GTR32 Rising Star

GTR32

Posted
Posted

Hi Rev;

I trust you have done your homework on this and worked out speeds in gears etc. With an already short first gear in the GTR it's going to shorten it's legs further and for a work car - assume daily driven? - that might be annoying. I was actually considering going the other way to a taller final drive as an RB26 with minor mods prob has the grunt to cope. I understand Mercedes is going from 5 to 4 speed autos in thier big hitters because they have the torque to cope with it. No point changing gears unless you have to.

Just my 2c.

Regards.

R32-GTS Mentor

R32-GTS

Posted
Posted
Hi Rev;

I trust you have done your homework on this and worked out speeds in gears etc. With an already short first gear in the GTR it's going to shorten it's legs further and for a work car - assume daily driven? - that might be annoying. I was actually considering going the other way to a taller final drive as an RB26 with minor mods prob has the grunt to cope.  I understand Mercedes is going from 5 to 4 speed autos in thier big hitters because they have the torque to cope with it. No point changing gears unless you have to.  

Just my 2c.  

Regards.

GTR first short gear ?? They have a very tall first gear pulling over 60k;s out of first.

rev210 Grand Master

rev210

Posted
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Posted
Hi Rev;

I trust you have done your homework on this and worked out speeds in gears etc. With an already short first gear in the GTR it's going to shorten it's legs further and for a work car - assume daily driven? - that might be annoying. I was actually considering going the other way to a taller final drive as an RB26 with minor mods prob has the grunt to cope.  I understand Mercedes is going from 5 to 4 speed autos in thier big hitters because they have the torque to cope with it. No point changing gears unless you have to.  

Just my 2c.  

Regards.

Hi,

The first part of my post reffers to my care factor about the fuel ecconomy, thanks for the concern tho'.

When you own a GTR I think fuel ecconomy has to be very low on the priority. My car is used for work and does 30,000kms+/year but, it's expenses (inc. fuel) are paid by a car allowance. If I cared about fuel ecconmony I would have bought a scooter.

Cubes Grand Master

Cubes

Posted
Posted

Rev,

Just out of curiosity's sake would you mind taking note if it does indeed change the fuel economy for the better or worse?

A nice example of a higher diff ratio returning better fuel economy is the R13 Skyline's 3.7:1 vs the VL Commodore 3.45:1.

Around locally the R31 returns better fuel economy then on the open road the VL returns better.

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