RB20DET or S13 SR20DET 5spd

[tonycharger72]

Hi Guys was wondering if anyone could help me with this conversion into a 280zx,

 

I have an 1982 280zx and want to install a 5spd Manual,

I was thinking of using an RB20DET or SR20DET 5spd (s13 box),

Anyone know what is involved to get this to mate to an L28 engine?

 

I know about swapping over the pedal box, adding a master & slave cylinders, hose's etc - and i know i can just unscrew the speedo and change it back to the mech unit suitable for the 280zx speedo cable,

 

But,

 

More interested in finding out what is required to mate the box to the L28,

What mods would be required to get the box to fit up - i know the bellhousings on these box's arent detachable (well not like the supra 5spd), so more is involved, but anyone know if its possible to remove the Nissan 5spd bellhousings and swap an L28 friendly bellhousing onto it?

 

Also - i know the L28 crossmember will bolt to the SR/RB box, but i dont know if it will line up correctly with the 280zx body trans mounts - anyone know if this is or isnt the case?

 

Also, kinda related to the above question - but does anyone know if the tailshaft needs lengthening or shortening???

Any info would be great,

[thehelix112]

I put a S14 SR20DET box onto my L28. Mate has put an S13 box on using identical procedure. Tutorial is at:

 

http://forums.hybridz.org/showthread.php?t=105982

 

Answers most of your questions I think.

 

Dave

[tonycharger72]

You are a legend mate

[tonycharger72]

oh...........this work with an S15 SR20 6spd???

[thehelix112]

Despite having one in the shed I'm afraid I can't help you there. Someone else I'm sure will though.

 

Dave

[tonycharger72]

I have just been told that the RB20 box is a much better fit, still use more or less the same process as you listed, but its a shorter gearbox than the SR20 box,

Still have to fabricate a crossmember for the box, but the tailshaft can remain the same length, make life a little bit easier,

[EMWHYR0HEN]

I beleive they have identical gear ratio, and they look exactly the same internal, and externally. I think it just has slightly different bell housing. same thing for strength if u ask me.

 

I Have an RB25DE, which has the same tranny as an RB20DET and the tranny bolted right up. The L28 was only like a half inch different in location than the RB.

 

I'd go with the RB tranny

[tonycharger72]

There is a mob in Australia - Stewart Wilkins - who will give you a good 2nd hand RB20DET tranmission with modified bellhousing to suit L24-26-28 engine for $850AUD, sounds like a pretty sweet deal, considering most places flog these boxes off for $500 for good used items,

[thehelix112]

Dude thats a really shithouse deal. One drill hole and 20 minutes worth of die grinding is not worth AUD350.

 

Dave

[z_cars_rule]

why are you wanting to use a different box? why not use the L28 manual box?

[thehelix112]

Strength. 71C gears are wider than 71A/B. Selector forks and shafts are also beefier.

 

Dave

[z_cars_rule]

fair enough, but if you are looking for strength, i would stay away from the RB20 box, 25 box sure, but the 20 is not too good at handling torque, which you will have a fair bit of with the L28.

[tonycharger72]

"Dude thats a really shithouse deal. One drill hole and 20 minutes worth of die grinding is not worth AUD350."

 

I will check to see if the box gets rebuild, but it probably dosent for that price,

 

Its just i dont have an L-Series bellhousing,

 

Just to save myself the hassle of tracking it down - unless i can find someone flogging off an old L-Series box (does the L16-18-20 boxes use the same bellhousing as the L24-26-28 boxes?),

 

Then it will work out cheaper,

 

I sold two used and old 260z boxes for $350/piece - if im paying this for a suitable L-Series bellhousing, then there is not much difference,

 

Im sure this is unlikely though and i should probably just stop being lazy ,

 

You got a spare L-Series bellhousing lying around???

[z_cars_rule]

where are you located ?

[tonycharger72]

Im in Canberra Mate,

 

I have a 280zx - im really interested in your,

 

"RB20DET powered 280ZX"

 

I think i may have already asked you questions about it though,

 

It was a really straight forward swap wasnt it? like used the 280zx crossmember and tailshaft,

You used the RB20 engine mounts and slotted the 280zx crossmember and that was it to get the engine into the car???

[z_cars_rule]

yes it was really straight forward. to be completly honest, that hardest part was the throttle setup.

 

I used the 280ZX drive shaft, skyline mounts, 280ZX crossmember, the part i 'slotted' was on the isolators from the skyline, the locating tabs on them are a tab about 1cm wide, where the 280 only had a locating pin as such, so i cut the locating tab so that it would fit in the hole of the 280zx crossmember.

 

add me on msn if you want further info, z_cars_rule[at]hotmail.com

 

i will be driving the car down to canberra in january if you would like to look at it, maybe even sooner if i take a holiday.

[tonycharger72]

That sounds good mate, really like to see that car, i have recently bought a turbo kit for the L28 and am still deciding whether or not to use it or just slap in an RB engine,

 

When i get home i will add you to me MSN mate,

 

Do you have any pics of the conversion???

[z_cars_rule]

i have a thread in the RB section on my convertion with a couple pics,

 

i have a few more pics on my computer, but now that i have done it i realise that i really should have taken more.

[col]

Hi Im from QLD im also concidering the same options for my everyday driver and possibly a project car with manual 4L lexus v8 maby we could get together sometime col

[NZeder]

fair enough, but if you are looking for strength, i would stay away from the RB20 box, 25 box sure, but the 20 is not too good at handling torque, which you will have a fair bit of with the L28.

Not all RB20 boxes are the same The RB20DET from a R32 GTST Type M is differnet to the RB20DE box. I believe the RB25DE and RB20DET boxes are the same - the RB25DET is a different box altogether it is not a FS5W71C like the S13/14/R31/R32/R33 types. You can only get these RB25DET boxes from GTST R33 and above as there were not RB25DET R32's from the factory.

 

Back to the FS5W71C boxes I believe there are a few different types - some have dual cone syncros on 2nd only others have these dual cones on 2nd and 3rd (the RB20DET is one that has both) also I believe most of the boxes have alloy selector forks however I am lead to believe the RB20DET/RB25DE boxes have steel selector = stonger again (I will tell you once I pull apart my RB20DET box that I have when I do the conversion to L6 bellhousing). I have also read that the RB box is shorter compaired to the SR/CA 71C box 845.5mm tail vs 795.5mm for the RB and that a 280zx auto mount can be used with only minor sloting of the bolt holes to mount the RB box to a 240/260z (again once I get hold I one I can tell you this also)

 

Re the statement about handling the torque well the RB30e fitted to the Aussie build VL commodore has good torque and used these FS5W71C boxes (I know they have the alloy forks) so again for the guys in Aussie/NZ another option is these units also - wow lots of FS5W71C to chose from, you can find them all over the place - not like the 240z/260z/280zx 71B boxes these days

 

EDIT: also a number of Japanese firms make close ratio gear sets for these 71C boxes ie OS Giken, Kameari, Holinger (Aussie) etc and these will handle more HP than most L6 can though at them ie 600+ HP. The standard 71C are good for about 400HP (the RB20DET ones that is)

 

Cheers