going from rb25 to rb26

[platez808]

As much as I try my best to AVOID posting threads asking questions, I feel like I've done a lot of research and I just need some confirmation and clarification, so bear with me here. I guess it's important to view this post within the context that I live in Hawaii where shipping is expensive and parts/shops are very limited.

I currently have a mostly stock rb25det sII in my s13 that i finally got running well.

But I came across a really good deal to get a complete rb26dett (minus the trans) shipped. It's good enough of a deal where I'm thinking (after a lot of research) that if I were to sell my current setup locally and go with the rb26, that I can break even or even make a few bucks. I know it sounds crazy, but man does it sound good to me.

So here's the plan as it currently stands. I actually have a friend who is already willing to buy the rb25 and is looking to put it in his s14. The deal was for him to get the complete motor setup (including the mckinney mounts, splitfires, harness, fmic, etc) minus the rb25 transmission, radiator, and fans. I would be the one to convert my s13 rb25det wiring harness to work with s14. I know it won't be easy but I'm confident about figuring it out.

He prefers not getting the rb25 trans so we wouldnt have to source another rb25 trans and custom driveshaft. So I know the next best thing would be to get an rb20det/rb25de transmission, but even those are hard to come by. So right now we're leaning towards using the s14 ka trans, because I have read/heard that it'll be a bolt on affair (minus a few trans bolts), but at the same time I've heard different. I know either way that I would need a different transmission mount. So the questions are:

***Is there anyone that knows for a FACT that a KA bellhousing/trans will bolt on to an rb25 and will drop into a s14 using stock driveshaft and shifter hole location without modification?
***What starter needs to be used if we were to use either the rb20 or ka trannys?

So for the rb26dett, I'm not even sure if it comes with the stock flywheel and clutch, but trust that I will find out everything (compression test numbers, etc) I need before I even think of spending any money. But if everything checks out fine, the plan is to get a mckinney mount kit, mckinney downpipes, and rb25 oil pan. Then I would modify my mckinney fmic kit for rb25 with greddy mani and use the rb25det trans, custom ds, GTR radiator, and dual FAL pullers. In terms of the wiring, I'm planning on doing it on my own, but will probably just go by experience with the rb25 wiring and using what ever wiring diagrams and ecu pinouts since i haven't really found any write ups for it. My questions about the rb26 are:

***Will I be able to use my exedy hypersingle clutch and flywheel from my rb25 on the rb26? Even if I could, would I be better off getting another clutch since I plan on making at least 400whp?
***What if my motor doesn't come with trans bolts? What would be my options?
***Do the turbo lines need to be modded in anyway to clear the steering shaft?
***Any other modifications that I have overlooked?

I know this was ridiculously long for a post and thanks to those who stuck through it. i just want to be prepared and thorough. Please let me know what you guys think and any insight would be much appreciated.

[SullivanRacing06]

are you kidding me with all these damm questions

no with the ka bell housing. go rb25 transmission and be done
the rb starter
yes you need to use you rb25 flywheel/clutch/transmission/transmission/flywheel bolts
why would the motor not come with transmission bolts?
nope
holy fuc& this cant be a serious question????? hope you have at least 10k if you dont have a transmission, maybe 8500-9000 if ya got a 25 transmission

stick with a 25 if you cant figure all this out.... you can get similar pwr numbers on equally modded 25 n 26s

[FinkenS14]

rb25-to-rb26-conversion-t492949.html

[disrupt]

what they said.

you will need from your rb25 setup for your rb26:

rb25 power steering pump to get rid of hicas rb26 pump.
therefore will also need the rb25 harmonic balancer
rb25 starter
rb25 flywheel/clutch/bolts
rb25 transmission

there is probably a few other minor items.

best of luck

[disrupt]

the turbo lines are fine. you need a mckinney downpipe to clear the steer shaft or modify an rb26 dp.

use a modded rb26 pan (cut the diff off and weld up the two shaft holes) instead of an rb25 pan.

[julio]

You can use the 26 power steering pump and crank pulley, but you just have to de-vane one the pumps and Tee that side of the pump back to the resevoir.

[disrupt]

This is true. personally i went with the rb25 power steering pump and crank pulley because it buys you another 1/2" between the pulley and radiator.

[julio]

That is also true, lol. Ah, the perils and tribulations of cooling with an rb powered s-chassis.