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RB25 Z32 swap, trany questions.


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#1 Guest_rx7636_*

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Posted 25 January 2007 - 02:42 PM

I bought at 90 300zx non-turbo for a school project. I will be doing a RB25DET swap. I had a few questions and wanted to confirm some info before I buy anyother components. First off are the nonturbo and turbo transmission the same. Can I use the nonturbo transmission for the hybrid setup. I ask because for a extra $75 I can get the nonturbo trany when I pick the car up tomorrow. As for the hyrbid tranny the Rb and Z32 tranny have the same internals correct. Just different bellhouing, input shaft, output shaft length and tail housing. So do setup the hyrbid z32 trany I just need a RB25det rwd bell housing and input shaft. Then I was told I could either use the rb clutch or a non-turbo 300zx clutch. With the hybrid tranny it allows you to run all the stock z32 trany sensors, trany mount and driveshft. I appriciate the help and I will be posting plenty of pics as the swap and cage move alone. Thanks, also once I get the Z32 tomorrow I will be ordering the engine and tranny. I found a deal for a RB25DET clip 5-spd(rwd) for $2,600 shipped with complete suspension, brakes, dash and all underhood components, but no body panels. Has 56k miles verified by gauge cluster which is included. Just wondering seems like a great deal to me and I will be able to sell tons of left over parts. Thanks again

#2 Z U L8R

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Posted 25 January 2007 - 03:12 PM

i'm pretty sure the clutch kit should work, the starters definately are not the same, you might want to see if you can use the z32 flywheel once you get it apart just in case the spacing is different between the flywheel and the starter gear, shimming would be almost impossible.

the driveshaft is the big nissan yoke as is the 25 tranny, depending on how you convert it you may or may not have to lengthen/shorten the overall length of it.

if your z32 won't bolt up to the 25's block i would (in your shoes) probably just use the 25's tranny, look into swapping the speed sensors, then cross the bridge of a custom transmount/driveshaft fabrication if it presents the need.

i'm not sure 100% sure about the n/a vs TT trannies being different gearing, but i wanna say i believe they are, as far as the rear ends go, the TT came with a tall ~3.6 viscous lsd, where as the n/a's should be a 4.11 viscous lsd, which'll be good great for getting out of the hole.

all in all it shouldn't be too hard of a swap. you got a great deal on the whole clip. keep us posted & good luck, i love 25's

#3 Guest_rx7636_*

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Posted 25 January 2007 - 03:19 PM

Thanks for the info. I know the Z32 bell housing wont bolt up to the RB. But getting a driveshaft made will be around $500 so I prefer to not have to. If anyone can confirm the z32 transmission with rb bell housing and input shaft will work. I am 99% sure that is how it is done when other say" hybrid z32 tranmission used". Then again the stock driveshaft, all the sensors and brace can be used. So for the starter sense I will use the rb bell housing and most likely clutch setup. I dont see why the rb starter wouldnt work fine. Thanks

#4 Z U L8R

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Posted 25 January 2007 - 03:39 PM

oh i c what you're saying. RB front bellhousing with Z32 rear, and mixmatching the guts

the z32 starter is goofy lookin like a hexagon that bolts to the side of the z32 front bellhousing where as the rb's has an ear at the top and an ear at the bottom which the bolts go through the block then back towards the rear of the car and through the rb's front housing then into the starter and thread in. that's why you'll have to use the rb's starter, but there's only 2 wires going to it, the thick one that goes to the battery and the small blade connector that gets the start signal. the only problem you might run into is clearances, but that's why they make dead blow hammers and welders LOL.

#5 Guest_rx7636_*

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Posted 25 January 2007 - 03:44 PM

Yep, just looking for a confirmation so I can either get the na transmission tomorrow or order a tt one. Thanks

#6 RB26powered74zcar

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Posted 25 January 2007 - 03:44 PM

I bought at 90 300zx non-turbo for a school project. I will be doing a RB25DET swap. I had a few questions and wanted to confirm some info before I buy anyother components. First off are the nonturbo and turbo transmission the same.

They are the same trans. The only difference is the front bellhousing. The turbo model is slightly larger ( larger flywheel) and the starter location/ hook up is different

Can I use the nonturbo transmission for the hybrid setup. I ask because for a extra $75 I can get the nonturbo trany when I pick the car up tomorrow. As for the hyrbid tranny the Rb and Z32 tranny have the same internals correct. Just different bellhouing, input shaft, output shaft length and tail housing.

They are the same as far as what you need it for. Input/output all the same.

So do setup the hyrbid z32 trany I just need a RB25det rwd bell housing and input shaft. Then I was told I could either use the rb clutch or a non-turbo 300zx clutch. With the hybrid tranny it allows you to run all the stock z32 trany sensors, trany mount and driveshft.

A rb26 or rb25 front bell will work the same. Then you can use the larger flywheel clutch.


I appriciate the help and I will be posting plenty of pics as the swap and cage move alone. Thanks, also once I get the Z32 tomorrow I will be ordering the engine and tranny. I found a deal for a RB25DET clip 5-spd(rwd) for $2,600 shipped with complete suspension, brakes, dash and all underhood components, but no body panels. Has 56k miles verified by gauge cluster which is included. Just wondering seems like a great deal to me and I will be able to sell tons of left over parts. Thanks again



joel

#7 Guest_rx7636_*

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Posted 25 January 2007 - 04:05 PM

double post, sorry.

#8 Guest_rx7636_*

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Posted 25 January 2007 - 04:08 PM

So I can use the non turbo transmission, which is great. Then I will need the larger clutch setup and rb bellhousing I will get with the rb clip. But will I still need to run the rb output shaft also. Besides the bellhousing and output shaft differnece is the only other diff to the z32 transmission besides sensor the output shaft length and tail housing. If so is the reason the output shaft is longer so for the AWD applications a different tail housing can be used. Thanks for the help. Also when I need a clutch I could either use a Z32 tt or Rb clutch sense they are both the larger style and the same. Thanks for the help

#9 Guest_rx7636_*

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Posted 25 January 2007 - 07:13 PM

bump

#10 Booztd 3

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Posted 25 January 2007 - 07:59 PM

Joel is not correct on the input/output shaft.

The main input shaft is a few inches longer on the RB transmission, so you need to swap that as well as the bell housing out. You'll also need to source a slave cylinder for the rb trans.

I am not 100% on the clutch that you'd use, but I know that an NA clutch will work, however I dont see why you wouldnt just clearance the RB bell housing to fit a 300ZX clutch, considering theres ~1cm difference in the diameter of the flywheel/clutch assembly.

To answer your question, the TT and NA Z32 trans are different, but ONLY in bell housing diameter. Either way, youll be using the RB bell housing, so you might as well just save some coin and buy the NA tranny. I have both sitting in my garage right now (NA and TT tranny's ) if you'd like some pics

#11 Guest_rx7636_*

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Posted 25 January 2007 - 08:14 PM

That makes more sense to me, I thought the input shaft was longer for the rb. I will be getting a r33 clip so it will come with the slave cylinder with it. You said I can clearance the rb bell housing to fit a 300zx tt clutch setup. So does the z32 tt use a larger flywheel and clutch setup than the rb does or the same and the non turbo is the same size as the rb.

#12 RB26powered74zcar

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Posted 25 January 2007 - 09:53 PM

Joel is not correct on the input/output shaft.

The main input shaft is a few inches longer on the RB transmission, so you need to swap that as well as the bell housing out. You'll also need to source a slave cylinder for the rb trans.

I am not 100% on the clutch that you'd use, but I know that an NA clutch will work, however I dont see why you wouldnt just clearance the RB bell housing to fit a 300ZX clutch, considering theres ~1cm difference in the diameter of the flywheel/clutch assembly.

To answer your question, the TT and NA Z32 trans are different, but ONLY in bell housing diameter. Either way, youll be using the RB bell housing, so you might as well just save some coin and buy the NA tranny. I have both sitting in my garage right now (NA and TT tranny's ) if you'd like some pics



oh well.... even the best make mistakes... :tongue: I have a spare RB25det trans, and a Z32 trans also, so what do I measure thats different? the splined shaft the clutch slides on??

#13 Careless

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Posted 25 January 2007 - 10:14 PM

oh well.... even the best make mistakes...


lol. bastard
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1976 Datsun 280z (given to the Crombies)


#14 RB26powered74zcar

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Posted 25 January 2007 - 11:01 PM

lol. bastard



haha.... you liked that, huh? :tongue:

#15 Careless

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Posted 25 January 2007 - 11:22 PM

haha.... you liked that, huh? :tongue:

like?
i use the word "like" only for people who donate parts =)
*nudge nudge*
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#16 Booztd 3

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Posted 26 January 2007 - 06:07 AM

You said I can clearance the rb bell housing to fit a 300zx tt clutch setup. So does the z32 tt use a larger flywheel and clutch setup than the rb does or the same and the non turbo is the same size as the rb.



From the research I have done, the NA clutch is the same size as the RB, but it just doesnt make much sense to me why nissan would put a 'smaller' clutch in a more demanding application (i'd consider an AWD platform to be more stressed than a RWD - making the same power) I'm going to do what I can to get the TT clutch to work, cuz I'd really like to run a Carbon-Carbon, but at the same time, I may just end up switching out to a TH400 or something automatic since I do alot of drag racing.

Guys have been running NA transmission with TT clutch/flywheel combos for years. All you need to do is take a grinder and start shaving off material on the inside of the bell housing, thus increasing the inside diameter to fit the larger diameter flywheel/clutch. 5mm on each side will do it.....pretty simple to me, I may try it with the RB25 bell housing

#17 Booztd 3

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Posted 26 January 2007 - 06:08 AM

oh well.... even the best make mistakes... :tongue: I have a spare RB25det trans, and a Z32 trans also, so what do I measure thats different? the splined shaft the clutch slides on??



I will be upfront with you on this, I have no idea right now. Initial inclination would tell me that the splined shaft is the longer counterpart, considering the internals of the RB and Z32 trans are identical.

PS - How the hell does one get an 'extra' RB25 trans, I searched for weeks and ended up shelling about 800 for one, and all I needed was the bell housing and input shaft! LOL

#18 stony

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Posted 26 January 2007 - 06:45 AM

:x i think he has me to thank for that one... well actually UPS
RB26DETT, T88-34D, 30 PSI, JUN head, 280 Cams W/ 10.30 lift, 1.2mm cometic Metal head gasket, custom intercooler, AEM series 2, 2 speed powerglide, Fully built Ford 8.8, 4:56 gears/spool, 4 link suspension. Go here to see the build: http://forums.hybrid...iration-part-3/

#19 RB26powered74zcar

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Posted 26 January 2007 - 07:49 AM

:x i think he has me to thank for that one... well actually UPS



Actually Stony, that trans I bought from you that got damaged, has long been "gone".
I have purchased several since that time, re-selling one of them, then keeping the two I have.

I also bought a couple Z32 trans, just to have for spare internals, and I even picked up a 88-89 Z31 turbo trans, which looks exactly like the rb25det trans. Thats another trans the internals are the same on...

#20 Booztd 3

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Posted 26 January 2007 - 08:58 AM

Actually Stony, that trans I bought from you that got damaged, has long been "gone".
I have purchased several since that time, re-selling one of them, then keeping the two I have.

I also bought a couple Z32 trans, just to have for spare internals, and I even picked up a 88-89 Z31 turbo trans, which looks exactly like the rb25det trans. Thats another trans the internals are the same on...



Aye, my RB trans cost me 925 shipped, however i score Z trannies for like 200 bucks typically.....probably why i have 3 of them in my garage now, lol




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