# rb20 tranny



## CrimsonKnight (Feb 13, 2005)

Hello im new at this. so forgive me. Do you have to swap the tranny if your doin an rb20 swap on an s13? Ive heard of the rb25 tranny with the rb26 engine. but what about the rb20? thank you .


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## CrimsonKnight (Feb 13, 2005)

Hello.. what transmition do i need for an rb20.. any help pleaseeeee?????somebody please. just give any kind of answer.


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## bridrive55 (Aug 26, 2004)

The RB20 transmission and block are completely different than any of the S13 stuff. Think about what cars the stuff came on: RB20 came on the R32 GTS-t and the Laurel, but not on any car with an S13 chassis. Basically, any of the S13 stuff will be pretty much interchangeable, but when you cross boundaries like that, you need to take more and more from the donor car.
If you're planning on doing an RB20 swap, you need to have the whole engine with transmission.
If you need any help, OPIUM works at a swap shop and drives an RB20DET powered 240SX.


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## OPIUM (Aug 18, 2002)

CrimsonKnight said:


> Hello.. what transmition do i need for an rb20.. any help pleaseeeee?????somebody please. just give any kind of answer.


You can use either the RB20 or the RB25 transmission with any RB series motor. However you can also use the guts of the stock KA24 transmission in an RB trans shell. Certain parts have to be modified, but it still works and has been done before.


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## DaCheat (Nov 4, 2004)

OPIUM said:


> You can use either the RB20 or the RB25 transmission with any RB series motor. However you can also use the guts of the stock KA24 transmission in an RB trans shell. Certain parts have to be modified, but it still works and has been done before.


Any idea what is the better Transmission? The RB20 or RB25 RWD setup?
or are they exactly the same? :cheers:


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## OPIUM (Aug 18, 2002)

RB25 is much beefier... Here is a few pictures of the side by side comparison of the 25 vs. the 20 that I took before I installed it into my friends ride..















































As you can see the RB25 trans is much larger and can hold much more power. Do a search for this transmission info by Nizmodore. He's had some good in depth info on it. It used to be a sticky.. don't know what happened to it


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## DaCheat (Nov 4, 2004)

OPIUM said:


> RB25 is much beefier... Here is a few pictures of the side by side comparison of the 25 vs. the 20 that I took before I installed it into my friends ride..
> As you can see the RB25 trans is much larger and can hold much more power. Do a search for this transmission info by Nizmodore. He's had some good in depth info on it. It used to be a sticky.. don't know what happened to it


So, Basically when I swap out the KA24DE in my car for the RB20DET I am better off going with the RB25 Tranny because it is Beefier and holds more power? Or can I put the RB25 Tranny in without making some sort of adaptor plate?
Also will the RB25 Tranny mount up the same? Mounts and will I still be able to use the Stock 240 Driveshaft like I would with the RB20 system?


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## bridrive55 (Aug 26, 2004)

DaCheat said:


> So, Basically when I swap out the KA24DE in my car for the RB20DET I am better off going with the RB25 Tranny because it is Beefier and holds more power? Or can I put the RB25 Tranny in without making some sort of adaptor plate?
> Also will the RB25 Tranny mount up the same? Mounts and will I still be able to use the Stock 240 Driveshaft like I would with the RB20 system?


Yeah, the RB25 tranny is a direct replacement for the RB20 trans, same mounts. The only principal difference is the synchronization. I personally don't think some extra mesh is worth the bank if you're not pushing over 350rwhp. But if you want to be really unique, gopher it.


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## DaCheat (Nov 4, 2004)

bridrive55 said:


> Yeah, the RB25 tranny is a direct replacement for the RB20 trans, same mounts. The only principal difference is the synchronization. I personally don't think some extra mesh is worth the bank if you're not pushing over 350rwhp. But if you want to be really unique, gopher it.


Yeah i'm probally going to match the RB25 Transmission to the RB20 Engine is I can get one for a good price.
It only makes sense to have a beefier Tranny, it can handle more power much more efficiently!


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## DaCheat (Nov 4, 2004)

OPIUM said:


> You can use either the RB20 or the RB25 transmission with any RB series motor. However you can also use the guts of the stock KA24 transmission in an RB trans shell. Certain parts have to be modified, but it still works and has been done before.


Can you get Prices on the RB20 or RB25 Tranny's?
How much would each cost? American $ is fine, I can Transfer it to Canadian funds so I know the exact cost.

Thanks!


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## bridrive55 (Aug 26, 2004)

DaCheat said:


> Can you get Prices on the RB20 or RB25 Tranny's?
> How much would each cost? American $ is fine, I can Transfer it to Canadian funds so I know the exact cost.
> 
> Thanks!


Yikes, I haven't seen them for under $500. And the shipping would also be ridiculous. I highly doubt that this would be worth it... The RB20DET transmission is a great trans, I don't think the added "beefiness" of the 25 is worth an $800 premium. Stock it up! They're both great transmissions. In fact, the RB20DET transmission is lighter.


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