RB25 gearbox in 32

[Sydneykid]

Hi drift_me_silly, you asked "q....if r33 auto diff fitted to r32 with r 25 box....would fifth at 100k's drop down to around 2ooorpm?..."

As far as I know the Auto R33 diff and the Manual R32 diff are the same ratio (4.363 to 1). So I don't understand the question...

The Series 1 R33 clutch (push type) is the same as the R32 clutch. The Series 11 R33 and R34 is different (pull type). We have used the same OS Giken twin plate in an R32 GTR, R32 GTST and S1 R33 GTST. Fits straight in. Hope that answered your question.

The Trust 6 speed has a close ratio set of gears whereas the R34 GTT has a wider ratio set. So not comparing apples with apples. Any car with any engine would be faster accelerating with the close ratio gearset than the wider ratio.

Hope that helps

[Cubes]

Isn't the RB20DET flywheel smaller though? Hence the clutch smaller? I have no idea..

[Duncan]

ummm, wot sydneykid said....

...or just use the spreadsheet;

www.hgeconsulting.com.au/carspeed.xls

[Cubes]

I am sure I was told that the RB20 Flywheel is smaller than the R33 Flywheel.

[Roy]

My R32 GTSt has a flywheel and clutch meant for an R32 GTR, so whatever the differences, they don't stop you fitting/switching.

... and as for fitting an Rb25 behind an RB20, im not having any trouble with my box at them moment. (im guessing i have between 135-150rwkws) At what sort of rear wheel power figures do they start having troubles. And what troubles surface first?

[Clint32]

Thanks Duncan, that was easier than doing it myself

[Ender]

Isn't the gtst clutch smaller than the GTR clutch...I was under the impression that they were not the same

Cheers

[Sydneykid]

Hi guys, the starter motor bolts up in the same spot, so the flywheels must be the same diameter. The bolt pattern on the crankshafts are the same. All the gearboxes have the same size and splined input shaft. So if you consider the package (flywheel, pressure and clutch plate), then all Skylines with the push type actuation are interchangeable.

RB20 flywheels are a bit lighter than RB25's and the clutch friction surface is smaller in diameter. So I don't think you could use an RB20 flywheel with an RB25 pressure and clutch plate, not without machining anyway.

Change the lot all together though and there are no problems.

Hope that clarifies further

[MrMayhem]

same fly size 32.33

[Cubes]

So its just the Pressure plate that is different.. Hence the bolt up for the pressure plate also.

[Sydneykid]

Hi Joel, if that's the case then drill and tap the holes, machine the friction surface and it will fit.

[MrMayhem]

Its teh same also

whats giving you the impression they are different

[Clint32]

I was looking at bot gearboxes today and i removed the speed sensor from the rb25 box and it was very long, about 4inces, then looking at the rb20 box the sensor is more towards the back of the box and i could not be any longer than about 2inches, i couldnt take it out as i would then have to replace the oil but i just wanted to know if there was any special trick to swaping them over as the rb25 one is long with a red gear on the end and it appears to be all in one piece.

[Dr_Drift]

??? I assumed they were the same as we have a RB25 box in a 32 here.... I'll check in further detail....

[Clint32]

Im told that a 32 gtr speed sensor is required as they are mechanical also.

[Cubes]

Interesting.. So 32 GTR Speed sensor it is...?!

[Clint32]

I will be checking tomorrow on my mates 32 gtr, but it would make sence, similar gearbox internals

[MrMayhem]

Clint the entire speedo cable R32 GTR

[Cubes]

If the boxes are the same size roughly (RB25DET & GTR) would it be possible to use the GTR Crossmember or due to the 4wd throw that idea out the window?

[Clint32]

No Joel they are heaps different, there is a huge bulge in the chassis where the transfer case is on a gtr and this is where out mount bolts on a gts