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making a 4wd into 2wd?


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#1 OZ001

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Posted 03 February 2009 - 12:40 PM

for example i was to fit a r34 gtr engine in my 280zx, could i use the gtr 6 speed gearbox and change it to 2wd onto my 280? or do i h ave to look further to find something thats out of a 2wd???

#2 Lurch ™

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Posted 03 February 2009 - 01:31 PM

Anh, your far better off just using a R33/R34 GTS RB25det manual front cut.
It'll cost FAR less & be nearly as quick.

If you really wish to go down the GTR path with the 6sp gearbox, you'll need to strip the back off the GTR gearbox, remove the Altessa centre clutch pack, cut the casting off the housing where the centre clutch back was & weld the hole up. This is NOT something someone without experience should attempt.
You may also find major problems with the ECU, when it can't find the sensors for the 4WD system.
Seems like a lot of work for when you add up the 10k+ purchase price for a BNR34 front cut...


#3 George

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Posted 03 February 2009 - 01:37 PM

sound advice. rb25det is a much better option.

#4 sco_aus

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Posted 03 February 2009 - 05:19 PM

I'll second George's suggestion..

#5 mtopxsecret6

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Posted 03 February 2009 - 09:49 PM

run the 26 with an adapter plate with an s15 box hanging off it.

#6 sco_aus

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Posted 03 February 2009 - 10:49 PM

Any reason for that mtopxsecret6? 
So why do you want to get a RB26?  They are a great engine, however, to me there isnt much choice in getting more than around 300-350rwhp becuase of the car being so light and traction difficulties, not to mention drive train etc.  Of course I am biased towards a RB25DET since I have one, but the cost difficulty of doing an RB26 conversion dont seem to out weigh an RB25.

Ok, now I have finished my advise, here is the practical info that may help your question.  The R32 GTR 5 speed was basically an RB25 5 speed gear box.  So to me it would make sense that you should only need a RB25 5 speed and the bell housing from an R32 GTR 5 speed, in theory this works, but it is an avenue you could explore to find out?

#7 RB26DETT

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Posted 04 February 2009 - 07:59 AM

run the 26 with an adapter plate with an s15 box hanging off it.


i dont think the S15 box will hold up for too long they are know to be weak behind an SR20DET already

#8 OZ001

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Posted 04 February 2009 - 08:45 AM

Any reason for that mtopxsecret6? 
So why do you want to get a RB26?  They are a great engine, however, to me there isnt much choice in getting more than around 300-350rwhp becuase of the car being so light and traction difficulties, not to mention drive train etc.  Of course I am biased towards a RB25DET since I have one, but the cost difficulty of doing an RB26 conversion dont seem to out weigh an RB25.

Ok, now I have finished my advise, here is the practical info that may help your question.  The R32 GTR 5 speed was basically an RB25 5 speed gear box.  So to me it would make sense that you should only need a RB25 5 speed and the bell housing from an R32 GTR 5 speed, in theory this works, but it is an avenue you could explore to find out?


im not getting the r32 gtr box, i was thinking of a r32 gtr but those engines to me are just prototype engines with all the oil problems, thats is why i purchased the R34 gtr half cut with a 6 speed. im trying to push my luck with a rb26 because im aiming for about 500hp+ i dont know whether the 5 speed can cope with all that power though :S

#9 sco_aus

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Posted 04 February 2009 - 11:34 AM

I think you will find the 6 speed even less likely to withstand that power, remember adding another gear only makes the gearbox 5 times more copmplex and 5 times more likely to fail.  Nissan rates its RB25DET gearbox as one of its strongest, but for 500+hp, all I can say is GOODLUCK. You will need new stronger gears in the box, clutch, diff, drive shafts, brakes etc.  Not trying to patronise, just it is going to be a long expensive road ahead.

#10 mtopxsecret6

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Posted 04 February 2009 - 09:24 PM

i agree sco_aus.. getting any skyline box to handle that power.. and last is a big ask. Running dog box internals would work though. The 32 gtr engine is not in any diffiecency to the 33 or 34, it was built tough from the word go. do a 30/26.. oe 30/25 with a 25 box.. the easiest and strongest setup i would suggest.

if you already have the 34 front cut.. you obviously have the money to trans plant the whole running gear into the datsun.. full gtr datsun.. now that's different.

#11 sco_aus

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Posted 04 February 2009 - 09:27 PM

aww yeh, do that.

#12 Scando

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Posted 04 February 2009 - 09:55 PM

Why did you want the R34 GTR box, strength or because it's a 6 speed?  If you're happy to go for a 5 speed then the RB25 box should do the trick fine unless you're going to do crazy things to it.  The thing to remember is that in a light car like a Z it's much easier on the gearbox than in a heavier car like an R33/R34.

#13 chris240

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Posted 05 February 2009 - 07:15 AM

there is a magnificent write-up in this months Fast Fours & rotaries magazine about the top 10 current jap engines...pros & cons.
I think they rated the RB25det number 4.
Im not sure if well get into trouble if I scan it and post it up though  ???

#14 Lurch ™

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Posted 05 February 2009 - 08:54 AM

Scan & post away Chris! ;D

#15 stevo_gj

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Posted 05 February 2009 - 10:11 AM

I would love to see that! Please post :)

#16 Kent

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Posted 11 February 2009 - 09:35 PM

The R32 GTR 5 speed was basically an RB25 5 speed gear box.  So to me it would make sense that you should only need a RB25 5 speed and the bell housing from an R32 GTR 5 speed, in theory this works, but it is an avenue you could explore to find out?


Just for reference, an RB25DET 5 speed gearbox will bolt straight up to an RB26DETT, as will an RB25DET flywheel and clutch.. use all the original rb25 or rb26 bolts etc. to mount the box whatever you have.

#17 sco_aus

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Posted 12 February 2009 - 04:45 AM

I was of the understanding the clutches were different, ie. Pull vs push etc.  From what I have seen the RB20 is very similar to the RB26 (designed at the same time) and the RB25 very similar to the SR20 (also designed at the same time as eash other).  I am not saying you are wrong, but I have never heard of it happening is all. 

#18 zedevan

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Posted 12 February 2009 - 08:09 AM

I think differnt yr 25 are different, some are push, some are pull, atleast from reading stuff on hybridz it's the impression I get, a fair few ppl have put 25 gearbox's onto 26's, and it's what I hope to do when I can justify wasting the cash

#19 Kent

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Posted 12 February 2009 - 08:33 AM

i know i am right, i have done it recently :)

The R34 RB25DET gearbox is different though (pull i think), and the RB26DETT gearbox changed between push and pull between R32 and R33 models.

The RB20DET gearbox is not strong, it is same as the RB25DE box, and similar to the VL turbo gearbox. The RB25DET gearbox is strong, and so is the RB26DETT (though 3rd gear would some times go, it happened in my old R33 GTR). The RB26DETT gearbox has to be strong.. there are a lot of high power modded GT-R's out there on their original gearbox (the front shafts were prone to snapping on clutch dumps though)

it doesn't matter to the engine if you have a push/pull gearbox.. as long as you get the correct clutch for the gearbox (that fits the engine of course).

i think i have some pics somewhere from when i put my gearbox on

#20 Lurch ™

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Posted 12 February 2009 - 09:59 AM

/Lurch puts his pedantic hat on ;D

The RB20DET gearbox is not strong, it is same as the RB25DE box, and similar to the VL turbo gearbox.


RB20det/RB25de/S13/S14/R31 and VL RB30e are all 71C series gearbox's.
VL Turbo is the MX7 which is the early development of the R33 RB25det gearbox.
The only main difference is that the MX7 doesn't have the double scynro's like the R33 box.




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