Rb25 Gearbox Into R32

[lwboosted]

hey guys, in answer to most of the questions...

1. Drive shaft, i used the r32 one and got the r33 yoke welded on the end from a driveshaft place..in keysbourough victoria.. costed me $100...i had the box in first to get the exact length needed.. i am putting a rb30det in my car in the following weeks so i can get a measurement if needed.

2. you use the r33 slave sylinder bolts straight up. r32/33 use same flywheel,clutch etc...

3. speedo!! i have used a nissan navara pinion assembly the one with 17 teeth as you cant get the 21 tooth one anymore i think it was $50 i then used the red 20tooth cog off the r33 speedo drive i have explained before what exactly needs to be done.. the cog is $50 if you break it like i did the first time.. the reason mine failed is because i didnt put the locator slot in the opposite side and it wore out!!! now that i have fixed it my speedo is spot on 100% with 18 inch wheels on.. and stock gear ratio..

3. crossmember. holes dont line up by about 50mm so i welded a new plate on the bottom and re drilled the holes.. i have a spare crossmember so if anyone is interested i will mod that and sell it for $100 pm me if you are keen..

dont get disenheartened with this conversion it is very easy do, and worth while!!! especialy if you want more than 200rwkw..

i dont look at this thread much anymore so if u have any questions pm me.

do you guys want me do write up a DIY guied???

cheers leigh.

Edited August 23, 2007 by lwboosted

[mr_rbman]

hey guys, in answer to most of the questions...

1. Drive shaft, i used the r32 one and got the r33 yoke welded on the end from a driveshaft place..in keysbourough victoria.. costed me $100...i had the box in first to get the exact length needed.. i am putting a rb30det in my car in the following weeks so i can get a measurement if needed.

2. you use the r33 slave sylinder bolts straight up. r32/33 use same flywheel,clutch etc...

3. speedo!! i have used a nissan navara pinion assembly the one with 17 teeth as you cant get the 21 tooth one anymore i think it was $50 i then used the red 20tooth cog off the r33 speedo drive i have explained before what exactly needs to be done.. the cog is $50 if you break it like i did the first time.. the reason mine failed is because i didnt put the locator slot in the opposite side and it wore out!!! now that i have fixed it my speedo is spot on 100% with 18 inch wheels on.. and stock gear ratio..

3. crossmember. holes dont line up by about 50mm so i welded a new plate on the bottom and re drilled the holes.. i have a spare crossmember so if anyone is interested i will mod that and sell it for $100 pm me if you are keen..

dont get disenheartened with this conversion it is very easy do, and worth while!!! especialy if you want more than 200rwkw..

i dont look at this thread much anymore so if u have any questions pm me.

do you guys want me do write up a DIY guied???

cheers leigh.

sounds good to me!

[Cubes]

DIY guide would be great.

GoT PiCs?

I currently treasure every WOT in third the box survives with 268rwkw behind the rb30. Its only a matter of time.

[Craved]

3. speedo!! i have used a nissan navara pinion assembly the one with 17 teeth as you cant get the 21 tooth one anymore i think it was $50 i then used the red 20tooth cog off the r33 speedo drive i have explained before what exactly needs to be done.. the cog is $50 if you break it like i did the first time.. the reason mine failed is because i didnt put the locator slot in the opposite side and it wore out!!! now that i have fixed it my speedo is spot on 100% with 18 inch wheels on.. and stock gear ratio..

can you buy the r33 cog seperate still?

is it part no. 32743 - 30P20 ??

[lwboosted]

yeah i bought one about a month ago.. costed around $50..

i can take pics of everything i will take them when i am putting the rb30 in my car.. about 4 weeks away.. cant wait!! 350 rwkw here i come.. hahaha

i blew 3rd 3 times with my 20 box and with only 200rwkw on the lil rb20.. lol

[Roy]

What fluid were you running in your RB20 box , also which clutch. Also what year model is your car. i find it interesting that i know of certain cars that have for god knows what reason had great reliability out of the std boxes, even when behind RB25 and RB26s...

[Cubes]

My guess it has a lot to do with the clutch they run.

[Gts-t]

hey cubes/roy

how are u guys going with this conversion

Im still not sure how im going to get the speedo drive to work in mine, pretty much waiting till u guys sort it and can tell me exactly what is needed. Sk must be busy i pmed him a week or two ago about it buyt havent heard back.

thanks guys

[Cubes]

Hey Buddy,

The box is in; pick up the tailshaft on Wednesday/Tomorrow.

My only problem at the moment is the mounting height of the rb25 gearbox. With the std crossmember bolted up the top shifter section of the gearbox fouls with the tunnel. What I really need is for some one with their rb20t gearbox to measure the height from the gearbox yoke dustshield to the floor pan so I can work out exactly what I need to space it down by.

I've been told the shifter hole sits ~10mm below the floorpan which is ~35mm lower than what mine is currently sitting. Mine sits ~25mm above the floor pan. :S

Another mate has told me his rb20t box shifter hole sits approx flush with the floor pan.

Knowing that doesn't help me a great deal though as the thickness or shifter hole relative to the gearbox's mount maybe different to the rb20.

I really need to know the measurement from the dustshield to floorpan to make my life easier.

The gearbox mount isn't an issue as I'm going to use a little bit of plate to space the box down and provide the support for the standard xmember.

Either way I can't see the box needing to be dropped 25-35mm so the shifter will feel a little taller; if it bothers me I'll throw a nismo short shifter in to it.

Your rb20t box wouldn't still be in the car would it????

The speedo drive is super easy and cheap to sort; I've written a guide in the tutorial section.

[Gts-t]

oh awesome, ill have to look for it

my rb20 box is still in, so i should be able to take the measurement for you in the next day or two

thanks cubes

Hey Buddy,

The box is in; pick up the tailshaft on Wednesday/Tomorrow.

My only problem at the moment is the mounting height of the rb25 gearbox. With the std crossmember bolted up the top shifter section of the gearbox fouls with the tunnel. What I really need is for some one with their rb20t gearbox to measure the height from the gearbox yoke dustshield to the floor pan so I can work out exactly what I need to space it down by.

I've been told the shifter hole sits ~10mm below the floorpan which is ~35mm lower than what mine is currently sitting. Mine sits ~25mm above the floor pan. :S

Another mate has told me his rb20t box shifter hole sits approx flush with the floor pan.

Knowing that doesn't help me a great deal though as the thickness or shifter hole relative to the gearbox's mount maybe different to the rb20.

I really need to know the measurement from the dustshield to floorpan to make my life easier.

The gearbox mount isn't an issue as I'm going to use a little bit of plate to space the box down and provide the support for the standard xmember.

Either way I can't see the box needing to be dropped 25-35mm so the shifter will feel a little taller; if it bothers me I'll throw a nismo short shifter in to it.

Your rb20t box wouldn't still be in the car would it????

The speedo drive is super easy and cheap to sort; I've written a guide in the tutorial section.

[Cubes]

I want it running tomorrow night. I've had enough of waiting.

But yeah if you could grab a measurement that would be great as I can always tidy it up later.

Are you familiar with the measurement I need? I can take a couple of pics if you wish.

I'll take some pics of what I do with the gearbox crossmember mount. Basically just go out and buy the required thickness plate, drill a couple of holes, grab another couple of bolts and bolt it all up.

Then the tailshaft, no need to shorten as when they remove the old yoke they trim 1/2 an inch off anyway which is pretty much perfect from my measurements. To reweld the new yoke on to the existing tailshaft and then balance it costs $160 from adelaide tailshaft services.

Get a couple done and were having the price nocked down to $140 which I'm happy with.

[Gts-t]

No worries joel, i think im familiar with the measurement u need but send me some pics anyway to make sure

i have the whole r33 tailshaft, when i do mine ill shorten the r32 one a little and add the 33 yoke

[Cubes]

Here's a pic..

Basically the red dot on the dust shield depicts the highest point of the dust shield; measure from there to the floor pan directly above it.

The yoke shown is the std rb20det yoke.

You can see how the tail shaft is fairly spot on with its length. Pull 10mm off it (which is done when removing the old yoke anyway) and it lines up perfectly.

[BHDave]

i found that making sure the box was mounted at the same level in relation to the bolt holes on the tunnel worked for me. I used 5mm plate to modify the crossmember so the box/mount was effectively spaced down 5mm, then spaced it back up 5mm with some plate between the rubber mount and the crossmember.

I had some vibration issues at about 130-140km/h with the single piece shaft prior to spacing the box back up, and ultimately spacing it up by 5mm fixed it.

I bent the tunnel up to clear the top of the box too.

[Cubes]

Dave was yours a manual from factory or auto as they have slightly different mounting positions.

How was the shifter position? Thats my biggest hassle. I don't like it looking like a 4wd + the leather boot doesn't fit.

[BHDave]

factory manual, hence the modded cross member. AFAIK the auto r32 shell allows a straight bolt up with a manual cross member. That would have been nice.

Shifter position is fine, not a great deal different to when i had the 20 box. Some clown decided to mod the shifter on my box by chopping some of the thread off it (left about a cm) but otherwise its stock. Doesn't stick out above the gear boot or anything odd like that.

From memory the top of the shifter hole still sat below the level of the hole in the body work on mine, even before i mangled it for extra clearance.

Out of interest, did you lower your engine to fit the rb30 under the r32 bonnet? could the lower front half be messing with the back half? I just don't know how you can have the thing sitting that high at the back without it fouling on the tunnel further forward.

Edited October 10, 2007 by BHDave

[Cubes]

Cheers Dave.

I am a doofus.

The shifter does sit slightly higher but the problem is with the leather boots plastic top ring that slides over the shifter. My r32 one appears to be too long so it prevents the gearknob from screwing down. I can't compare it to my r32 rb20 shifter as the box is now gone but its almost as if the 25t shifter has its thread closer to the section that flares out so preventing the gear knob from screwing down.

I may still get a nismo short shifter at a later date if the longer throw gets on my nerves. I'm starting to think maybe the rb20t box either has a shorter throw or the box I was using had a short shifter already on it.

Has any one compared the length of the 20t and 25t shifters?

I have lowered the motor slightly which may be causing the back of the box to sit up slightly; I've currently dropped it 8mm; there's no vibrations or funny things going on; I need to make up a better xmember bracket/plate so I'll grab some 6mm plate instead of the 8mm I'm currently using.

Apart from that I picked up a bargain. This box with yoke, shifter and slave cyl cost me $950 but I had to remove it from a smashed R33 which was an huge hassle. The box is quiet and isn't notchy when cold. :D

The Exedy GTR 4puk solid button clutch is interesting to drive lol. Almost stalled it once but its not too bad; a tad difficult to drive clean if there's a police officer sitting behind.

I am very glad I decided not to cut down the tail shaft as the bare minimum was taken off so that the 25t yoke could be welded on. The gearbox and yokes dust shield only just lines up. Its pretty much perfect. If it were shortened any more it would have been too short.

[Simon-S14]

25 shifters are a lot longer then a 20 shifter... i find it quite annoying acctually and i'll prob fit a 20 shifter back in to my car, Too many mis shifts from 2nd to 3rd while drifting on the track... im not THAT retarded but the shifter makes me feel like a doofus every time! lol

Im very surprised you didnt have to reduce the tailshaft length... mine simply would not fit! oh well its in now lol

[Cubes]

Simon..

Was it a manual tail shaft you had or the old auto one??

Definitely strange how a few don't need shortening yet yours and others have.

So the 20t shifter does bolt up? I might try and track one down with a good boot.

The 25t gearbox with its longer throw gives it that VLT 5speed feel.

[Simon-S14]

another strange fact for you, as i have no idea whats going on with mine, but my motor, in comparison to showza's, sits way further back in the engine bay, the intake plenium is millimeters away from my clutch master, theres no room behind the head for heater hoses really... and my gbox cross member doesnt line up unlike showza's who used the same one i did and all 4 bolt holes line up.

cant work out why tho!