2 RB25 quick questions

[Bryson]

Two questions,

One.. on an RB25, stock boost is 10 PSI or .7 bar yes?? and if thats the case, can the car handle maybe 14 without any additions to the fuel system or a larger turbo?

Second question,

what parts all would you need to make the RB25 into the 2.7 liter?

The rb26 crank and what else? If its not too parts extensive it migh tbe worth it to do it while the engine is out b4 the swap

[93RPS13]

i think you ahve to buy a RB26 stroker kit and bore out the RB25DET. correct me of i am wrong

[JonPowell]

I dont think you need to bore it out, I think the bore is the same but I believe that you are correct about the stroker kit. I think they also make a 2.8 L stroker kit if you are interested. I cant remember who they is, I think Jun makes the 2.7

[Bryson]

Well I was thinking more along the lines of a stock RB26 crank with some AMERICAN pistons, like JE or Arias, I was just wondering all that would need changing.. but I'm guessing if I have to ask its out of my league for now, thanks for the info though

[SHIFT_Lock]

bore is the same for the 25 and 26 . a 26 is a stroked 25.

[jiggyc1217]

ltrftp (long time reader first time poster)jon,

i believe the stroker kit you were referring to 2.8 stroker kit is produced by Greddy. Not sure if it would work for the rb25 engine, listed as an rb26 application.

[jiggyc1217]

jon,sorry about that previous post. it turns out that the 2.8K stroker kit is produced by HKS; Greddy makes the 2.7L stroker kit.

-jason

[meggala]

the rb 26 crank and rod fit in the rb 25 with out a problem and then you can bore it out a little to 87mm and yeah you will be pretty close to 2.7 but you will also have the strength and revability of the rb26 bottom end. its a very good move. meggala

[Bryson]

Hey meggala, thanks man thats just the info I was lookin' for.

I don't really understand all the ins and outs of some engine parts so if this is way off base let me know... but when you change the crank and rods, does that change which type of main and rod bearings you need to use??

[meggala]

I would use the rb26 but I'm not 100% certainas I'm not an engine builder sorry

[93RPS13]

i guess i was wrong.. thanks for the correction

[wmsadeq]

the rb 26 crank and rod fit in the rb 25 with out a problem and then you can bore it out a little to 87mm and yeah you will be pretty close to 2.7 but you will also have the strength and revability of the rb26 bottom end. its a very good move. meggala

Hey Meggala I have question for you. Could just the Rb26 Connecting rod be used with out the rb26 crank shaft? A related question: is there a different between the Rb25 rods and the Rb26 rods since the engines have the same stroke?

I am looking for a solution to what I heard as being the weakest point of the RB25 when pushing high hp and higher revs ... the connecting rods!?!? So what steps one could take to help the engine along before having to do a full engine rebuild (blanced crank, aftermarket rods & pistons, etc.)

Thanks

Wail

[TommyTheCat]

They dont have the same rods because they have different strokes!

They have the same bore, but different stroke.

[dreamsOfSkylines]

All rb26 stoker kits will work in an rb25, but you can't mix rods, crank, or pistons between the two. I imangine you would need different bearings buy not entirely sure. You can get the HKS 2.8L stroke kit for like $6000 (plus shipping) and it replaces crank, rods, pistons, rings with forged and balanced peices.

[Bryson]

**** man those Stroker kits are so damn expensive... I know you can just get some custom pistons made and pick up an unused Rb26 crank.