Rb26dett Swap Questions

[Naughty God]

    Hey guys, so after taking the time to decide what engine i want in my baby, i decided
to think about dropping a rb26dett into it, since its just sitting in my back garage looking sad   , i have a 240 that i was going to put it into, but i like my s12 much more lol   .... so i was wondering if anyone had any info on this swap? and if so what tranny i can use, ie rb25 or sumpin like that and if it'll fit with some modifications. i understand there is going to be plenty of fabrication involved in this swap. i would just like to know if anyone has any first hand experience in doing this, i understand this is a relativly rare swap, i've only heard of it being done once, but i hope its been done more. once i get the ca18 outta the car im gonna try to dry fit the rb in there. (just drop it in without the tranny on). see how it looks and how much im gonna have to do, now i've heard from another s12 owner i know taht if i were to do the swap i would have to relocate the radiator about 2 inch's forward, and cut that brace its connected to to make room. so if anyone has even a little info on it i would appreciate it so much, and if u dont have any info on it but could think about what kind of problems i may run into speak up! I would just love to take my s12 down to the local raceway with a rb26dett under the hood and set people straight with nissan aggression.  

[TalkingGoats]

Prepare to be flamed, just ignore it. If you are rich do it! You will be the first on the forum. There is a picture of one in an engine bay, and one with a vG30dett... Lots and lots of custom fabrication to make engine and tranny fit. You should just get an RB25 though if you are serious. Go with the whole drivetrain. Look at 10k for it all, and thats if you have nice friends, with a nicer garage... lol

Good luck, It would be inspirational.

[@^*FeNdERbeNdeR*^@]

I'm loyal to the S12, but what a waste of an engine that would be. I just don't believe you would get the power to the ground with the limited setup options with suspension and the like unless you want to start forking out for S13 or S14 conversion parts, modifying your floorpan and subframes to fit them, in which case...

I'd put it in the 240, it's a common swap into S13s over here (I think we have more Skylines than Japan though) with a far better selection of upgrade parts... And you'd end up with a far more driveable car

Just my 2c though

[Julie]

i think its gonna upset the weight balance too much. the rb is a straight 6, so theres more weight placed forward in the car.

i love the tech aspect of making it work, but its just not practical enough to get youre moneys worth. i say do a vq35 w/ forced induction. i havent seen that yet in a s12... not to mention the parts are easier to get since the engine is usdm

[abunaiS12]

there are plenty of suspension solutions to make the car adequate with the trailing arm setup or solid axle just not bolt in idiot stuff. and not terrible custom fab either just simple things. everyone has seen plenty of muscle cars with neanderthal like suspensions and there still badass and put plenty of power to the ground and you can put an r200 clutchtype lsd or if you have r180 theres plenty for that too in the diff no problems so i dont see why everyone is doubting it so much, the s12 is very light and i think it would respond well to the straight six, thats bullshit about upsetting the weight balance just change spring rates to suit. i say do it i have seen one picture of it in an s12 but havent heard much else about it if you have the engine already then you want to do something with it your not going to get a whole different one just cuz people say you should put a whole other expensive engine in your s12 so i say try it. like i said before the s12 is light so it would really rip shit up and cutting the bracing in the front for the radiator to fit is no big deal at all. do you have SRA or IRS

[Julie]

stiffer springs wont make it lighter in the front end. THAT is bullshit. the weight balance will STILL be more forward then using a well built 4 banger or a v6. you have to physically reposition the engine if you want to alter its weight balance. springs are made of metal, not magical fairy dust that have the ability to rebalance a car. doing a swap like this is more about bragging rights since the s12 is capible of high output engines unless serious fabrication is in your agenda. bottom line: theres cheaper, more effective swaps u can do for the s12. this ones not worth the time or money

[Draconis]

so i was wondering if anyone had any info on this swap? and if so what tranny i can use, ie rb25 or sumpin like that and if it'll fit with some modifications. i understand there is going to be plenty of fabrication involved in this swap. i would just like to know if anyone has any first hand experience in doing this, i understand this is a relativly rare swap, i've only heard of it being done once, but i hope its been done more. once i get the ca18 outta the car im gonna try to dry fit the rb in there. now i've heard from another s12 owner i know taht if i were to do the swap i would have to relocate the radiator about 2 inch's forward, and cut that brace its connected to to make room.

Okay... for a running S12 that has been proven, as far as I am aware, no one has had a rb26dett successfully swapped in.... But I know a buddy of mine who is currently undergoing this in Australia.  As far as the tranny, you would want to use the RB25.  Everyone with a 26 uses the RB25 tranny... reason they are expensive... anyone with a RB wants the 25 tranny, myself included.  As for fabrication, there is a lot.  And no, pushing the rad. 2" forward is not it.  You got to do more to it.... From my understanding, with the dimensions from a 20 and 26, which are relatively the same, you dont really have to cut anything or push anything... just need to relocate and shit.  But in order to do that, you have to use the tranny and the engine connected to get the right placement.  PM me if you want more info.  I have the rb20det S12 and from that now know what to do with a rb25... the 26 is a bit of a different animal but a shop who I keep in contact with has let me know a bit of info and stuff to know the basics.

[RB25sx - SLPR]

If you do it, use an RB20det transmission since it will actually fit the transmission tunnel on the S12. Also, I suggest changing over to S13 spec front suspension to compensate for weight, and to use the S13 crossmember which most RB conversion mounts are made for (or make your own), the S12 steering rack will still sit in the proper position.

This is a face first endeavor, and it will cost > 8000$ EASILY. I suggest if you dont already know, learn how to weld, and get a mig welder+gas.

Check out my thread in this forum called "Project RB in S12 begins" (Something like that). Gives you an idea of what is needed, I will be updating it this weekend...

Goodluck.

-Dan

[sam31183]

I actually agree with julie, and let me tell you why.

Springs, shocks, tires, and tire pressure can only do so much. If you put a rocket on a donkeys back it has a huge power to weight, but in the end, it is still a jack ass with a huge motor strapped to its back.

[Draconis]

If you do it, use an RB20det transmission since it will actually fit the transmission tunnel on the S12. Also, I suggest changing over to S13 spec front suspension to compensate for weight, and to use the S13 crossmember which most RB conversion mounts are made for (or make your own), the S12 steering rack will still sit in the proper position.

This is a face first endeavor, and it will cost > 8000$ EASILY. I suggest if you dont already know, learn how to weld, and get a mig welder+gas.

Check out my thread in this forum called "Project RB in S12 begins" (Something like that). Gives you an idea of what is needed, I will be updating it this weekend...

Goodluck.

-Dan

First of all, DO NOT USE the RB20 tranny with the RB26.  That is the most stupid thing I have ever heard when it comes to a RB26 swap.  EVER.  The RB25 tranny can fit in the S12, it just takes a bit more work than the RB20 tranny.  We have a RB25 tranny in the shop and have looked at it compared to the RB20 tranny when I did my swap.  It will work, but the key is the position of the engine and tranny.  That is why I was able to put the RB20 in without changing ANYTHING of the S12, including core support or firewall.  Nothing was changed.  Do not get use the R32 crossmember.  Make your own or let me know and I'll see what I can do to make one for you.  If you use the R32 crossmember, first it doesnt like up in the S12 like it does in the S13 and positions it in the wrong place creating a situation where you have to cut/bang/etc. shit out of your way.  Yes the S12 rack will work just fine.  For that, you will need to stiffen chassis and yes, I would advise a S13 suspension system in both front and rear.  The RB20 is about the limits of what the S12 can do... or the SE S12 can do, which makes sense since the SE S12 is basically a Z31 in a S12 body and in Japan, the Z31 came with a RB20 stock.

[RB25sx - SLPR]

I dont know how far forward you would intend on slinging the motor in order to fit the RB block, but it will not fit the tunnel. Perhaps the transmission tunnel varies from SE to XE (I've got a CA20 notch), but it was most definetly not going to fit in mine. The speed sensor was crushed before it was even halfway in.

As for the RB20 tranny not being capable: That is just internet car forum garbage. The RB20 transmission will handle the stock torque output of the RB26 for at least a few years. It is essentially a KA tranny with a different bellhousing. Track racing? Maybe not so well.. But at the cost of the RB25 transmission + your floor pan it might be worth it.

Do what you will, but any way you cut it it's not going to be cheap.

-Dan

[Draconis]

As for the RB20 tranny not being capable: That is just internet car forum garbage.

It is not internet car forum garbage.  I am not an internet mechanic.  I personally know the difference between the RB20 and RB25 tranny.  The gear ratio in the RB25 is better and it is built stronger than the RB20 tranny.  Yes, the RB20 tranny may bolt up to the RB26, but it's  a waste of money and time.  If the RB20 tranny was so great, then everyone would be using it in addition to the RB25 tranny when building their 26.  But that's not how it is.  If you daily drive your 26, then maybe, but if you spend all that money on a 26, then why waste it?  Do yourself a favor and get the 25 tranny, and yes it will fit.  Not only do I know this from personal experience, but so do the Australians, and they did not get the SE S12.  Gerry's FJ S12 that clocked 9.12 seconds in the quarter mile used a RB25 tranny for a bit and when I talked to Fantasy (club s12 and aus12) about building a 500+hp FJ S12, he said also use a RB25 tranny and that it works.  It comes down to who is working on your car and how able they are.

[RB25sx - SLPR]

May I just point out that both of those engines are 4 cylinders. Given this, they would have been given the option of moving the engine forward. As i'm sure you already know, an RB brushes both the firewall and is but a few inches from the radiator crossmember, at this position, the transmission will not fit. AND it is only with the combination of RB block (mainly RB25) and RB25 transmission of which I speak. I believe myself to be a competent mechanic, as are both the people who are helping me on my project, and if I still had my piece of transmission tunnel I would show you.

-Dan