RB25 Build

[trey21096]

Question, flame me if you must, but my problem is I keep hearing varying claims on what an rb25 can handle on stock internals. Now keep in mind I plan to have it fully tuned and I drive sensebly . My goal is somewhere in between 500 or 600 hp. I looked around and while I can find tons of info on the swap, there doesn't seem to be much in the way of building one. I guess what I'm getting at is has anyone built one to those levels and if so, what is the minimum needed parts wise?

[forum04pl]

im not too familiar with the rb25 motor, however, i can tell you what you will most likely need aside from some sort of motor setup.

be ready to invest in larger injectors and most likely a higher flowing fuel rail (around 800-1000cc for that power), some sort of engine management (most likely a standalone), upgraded turbo depending on what type of fuel you will be running to put that power down your turbo choices may vary (gt35 would be a nice choice if opting for race gas). then your usual ignition, intercooler, basic head work,and exhaust. you go go more crazy than what ive put here but i figured i would give a basic setup of what you should be looking at for the power range your looking for. the turbo choice will be mainly up to you depending on what you are specifically looking for. with more info i might be able to help you out with that.

as for rb specific motor parts you are going to have to look elsewhere. i have no experience with the motor so im not going to rambe off any facts. i have heard that the rb26 is capable of holding much more power than the 25 motors. if that is true then your most likey looking at a build bottom end and some other motor work.

[koukitype_x12]

i melted my no 1. ring land amd cracked 2 more !!!sooo... thats the weak point rebuild mine with 87mm wiseco, crower rods, w/ n1 water and oil, along with crank coller. i highly recommend

[Sileighty_85]

If your gonna go with new internals Wiseco Pistons and Eagle H Con-Rods are good while your at it you might as well get the Crank Balanced. Along with some Good Bearings like Nismo or Tomei from WWW.RHDJapan.com

[trey21096]

I'm trying to go as extreme as reliably possible on stock internals. Yes, I know I should probably invest my money in the internals first but I can only do one thing at a time. If the stock internals can hold like 400-450hp that would be great, but like I said, I can't get a straight answer on it.

[Sileighty_85]

well ive seen SR20's push 400WHP on stock internals So I think you would fine but at least rebuild the bottom end with OEM parts cuz ppl dog the shit out of those engines over there in Japan especially if an amercian owned it at one time.

[ECR33S14]

central florida turbo made 680 RWHP on stock internals with a P-trim T67 turbo 880cc injectors greddy manifold... yada yada yada. im going to be running basically the same setup they have except for forged internals. if your looking for big power id go ahead and get into the motor.

[pr0ject TRUENO]

Record numbers don't mean jack shit if your shooting for reliability. You may be able to push 800hp on stock internals, but the added stress of daily driving adds on to that. Not to mention differing mileages and any wear and tear on the motor. Heck, the record for KA-T on stock internals is about 500hp. But that doesn't mean it's gonna last being daily driven, nor does it mean every motors gonna be able to be pushed to those numbers without blowing. Better safe than sorry. If your shooting for at least 500-600hp, at least get stronger pistons and rings.

RB25's are known for their notoriously weak ring lands. On stock internals, I wouldn't push more than 350-400hp, especially if you're planning on it being your daily driver. If you're interested in knowing what mods you'll need to support your power goals PM me.

[trey21096]

thanks for the help. I plan on opening up the motor when I get it and actually I was planning to buy the swap set and then also buy another motor set that I can rebuild in the mean time. I have some money to spend but I'm trying to save as much as possible without cutting too many corners cause I'd also like to rebuild my KA thats in it now and drop it in a hatch. I'll keep the projects posted.

[TheWolf]

RPM is more of a killer on those engines than power is. I've seen more broken oil pumps than I'd like to mention.