RB25 TO RB26 LONGBLOCK ????? CAS

[virus77]

I'm tossing around the idea of getting an RB26 block and head and swapping it into my current setup. I want to be able to use my nistune ecu, intake manifold, injectors, mafs, and wiring harness, etc....... so i have a few questions

I believe Raw brokerage sells an adapter plate for mounting ITB's on a 25 so I guess I could mount my 25 manifold on the 26 head (how much does this cost?). This would take care of the manifold, injectors and most of my wiring concern. Ill use my Z32 mafs instead of the 26 ones, maybe even a dummy z32 mafs for big horsepower options if I decide to go twins... movin on

Does the CAS on the 25 and 26 interchange...... if not do they read the same signal pretty much so I can wire a new plug into my harness and run a rb26 cas on my nistune ecu?

Am I missing any obvious issues which I may run into while doing this swap which I have overlooked like a douch-er

[Cjmartz2k]

To answer your question, RB20/25/26 CAS's are all the same. I think just the plastic Neo ones or an R34 RB26 might be different.

Now, I don't think the adapter plate would work both ways, just by looking at my 26 ITB to RB25 head adapter. Could be wrong, but I'd have to think about it. Their are two plates in the adapter with sunk in holes to mate the two, and I don't think it's just a matter of flipping it around or something simple like that. Not sure though. Besides that, the RB25 head casting flows the same as an RB26 casting. The only real difference is the solid lifters, and you can get those for an RB25 head anyways.

Bottom line, there is no real big advantage to going to an RB26 that couldn't be done cheaper by just building your 25. The displacement is negligible, and the head can be built just as well. You can even run a 26 intake/ITB's on a 25, but I don't think they are that much of an improvement anyways, and you already have a greddy intake, so there really would be no point. What were you hoping to gain by going 26?

[virus77]

I was thinking a more stout bottom end, better head and the 8k redline. Is the difference in the head only the lifters? cams, ports, flow...nothing else.

Honestly sometimes I get ideas in my head and I like to think them through. I got my motorset for a grand with trans so I figure I would get a RB26 block, swap it in, sell mine longblock and have a decent upgrade to an RB26 motor without much cost. Ive also considered swapping in a NEO head for the lifters but im not sure if the VTC works differently so im not sure if my ecu would control it properly.

What is it in the RB26 that give it the 8k redline, technically speaking the NEO rb25 has the same bottom end and solid lifters... is the stock turbo the only limiting factor which led nissan to set the redline 1k lower?

[PorkChopExpress]

ive always thought of the 26 as marketing and hype. pistons are still cast and the rods dont look any more beefy. the name across the valve cover is what makes it much more expensive.

[eh?]

ive always thought of the 26 as marketing and hype. pistons are still cast and the rods dont look any more beefy. the name across the valve cover is what makes it much more expensive.

The RB26 rods are much more beefy vs R33 RB25 rods. Something like 40 grams heavier.

[Shocker]

The RB26 rods are much more beefy vs R33 RB25 rods. Something like 40 grams heavier.

Also the Rb26 head port wise, and combustion chamber is very close to the same as the RB25 head, however having the solid valvetrain (solid bucket, with shim) is the advantage in my eyes. When you get above 8k rpm I'd prefer solid components. Then there is the .1L displacement bump.

[virus77]

I mean in stock form the ITB's and twin turbos have a definite advantage over the RB25 but in my case I guess its not really worth it since I have an manifold and a new t3/t4 I could slap on the 25 and call it a day. I sorta regret not getting a 26 from day one but I found a good deal so I went with it.

edit:

Just checked tomei's website, looks like the rb26 stock has nearly 1mm more lift on the intake cam and .5mm on exhaust compared to the rb25

The neo head has nearly the same as the RB26 intake and even more lift on the exhaust cam.

Anyone know if the vtc on the neo is all that different than the standard rb25... I might just swap in that head, looks like it will give me all the things I was looking for. Already has solid lifters and over 1mm more lift on both cams
Modified by virus77 at 9:47 PM 11/18/2009

[Cjmartz2k]

26/Neo rods are much beefier than standard 25 rods. The ports and overall castings between the heads are the same flow wise. Yes, the 26/Neo cams are bigger. Just buy bigger cams. Neo VCT is not an on/off switch like the standard RB25. It's ecu controlled, and a moot point anyways if you get big cams. If you want the .1L of displacement, get a 26 rotating assembly and put it in the 25 block. Not worth it IMHO. What turbo are you running? You probably have no need to rev you motor to 8k anyways, especially with stock cams and an un-ported head. 26 pistons do appear considerably stronger just by looking at them.

It sounds to me like you are getting caught up in the idea of having a neo or 26. Spend your money on forged rods/pistons, cams, and a bigger turbo and you be much better off. When you find yourself with an honest need to rev to 8k+, then look at a solid lifter conversion by tomei. Also might want to think about the crank collar oil drive at that point too.

[virus77]

I'm just thinking out loud. I have a perfectly good running car but I just want the best for my baby man, no harm in having a better motor is there

Seriously though I have modest goals but I like having an efficient setup. If I could have a better powerband at lower boost levels at the horsepower and more reliability im all game. By the time I get into my rb25 and swap out internals or build it, get cams and do a solid lifter conversion ill be knee deep in receipts compared to swapping in a longblock, be it NEO or 26.

I'm probably just going to leave it alone for now, I have a t3/t4 50 trim .63 which I got a good deal on and I'm sure it will be plenty fast in my Z but I like to keep my options open. God forbid something goes wrong with my current motor I'll look further into this.

P.S. any idea if a r33 vtc solenoid can be used on the neo head to run it like the old on/off style (could ditch it realistically but I'm curious). I wouldn't ask so many damn questions about this but I don't have the luxury of having these motors at my disposal to compare... just a bunch of rb25s lol