Rb20det to Rb25det(s2)?? Help me out here

[supersayianjim]

so ive recently took the plunge and got a rb25det. already got the harness sent off. going to use my rb20det tranny. build log can be seen here.

http://www.240sxforums.com/forums/rb-tech/118679-project-s-rb.html

so what should i know, iam new to the rb25 game. even though thier sister engines. what should i know?? iam planning on using my rb20 injectors with a ffim freddy manifold and a top feed fuel rail. iam going to use rb20/ka single cam injector plugs.

what else?? since this has vct can i get adjustable cam gears? or i don't need them??

[Skym]

Stock manifolds are good for 400whp, don't need to change them. Run a return flow intercooler (Blitz, etc) if you have to. Or stock R34GTT SMIC if you can find one.

Keep engine loom, R33 ECU, stock injectors (370cc), etc.

As far as I know (limited knowledge on the subject) you change plug under dash (where R33 loom plugs to loom in car under dash) to plug from RB20DET loom (have to know the pinouts) so it plugs in under dash. You'll need wiring diagrams for both engines to see which pinouts to put wires into on plug.

To adjust, keep VCT you use a modified internally 300zx ECU (Nistune installed with image for that engine conversion) that plugs into stock loom with 300zx MAF + 300zx plug wired in + retune. Or run stock R33 ECU if engine is close to stock.

[jumpei]

If you run a stock RB25 S2 turbo, they are pretty weak. some says even 0.8bar could blow the stock turbo.

[nick-nismo]

Take a look at this http://forums.gtrcanada.com/gts-tech...feed-rb25.html
I'm running a similar set up. I ran into some big problems using rb20 injectors with that ebay manifold and fuel rail it comes with.
Feel free to pm me with any questions

[supersayianjim]

thanks for the responses guys. iam having my harness/wiring done professionally, the same guy that did my 20 one so no headaches there. i will liik into that fuel rail issue,

[supersayianjim]

Take a look at this http://forums.gtrcanada.com/gts-tech...feed-rb25.html
I'm running a similar set up. I ran into some big problems using rb20 injectors with that ebay manifold and fuel rail it comes with.
Feel free to pm me with any questions

so how long have you been driving around now?? and has there been any further issues???

[nick-nismo]

About a month now probably 3000 Km's , no further issues after using the stock rail.

[supersayianjim]

so when i wire in the injector plugs. do i match the white lines?? and does that inch on each side have to be angled?? what if i get a straight piece welded on instead of using a bolt in the stock location??

[nick-nismo]

I'm not sure about the wiring because I used my rb20 harness and only lengthened the injectors plugs so it was pretty strait foreword. It does have to be fairly aligned. But just so the injectors sit at the correct angle into the intake manifold. Ya you could weld on 2 plates, one on each stock mounting tab on the rail, then mount from there.

I did it my way so I could pivot the rail and move it around untill I had the best angle then I tightened everything down if that makes sense.

[supersayianjim]

so wait!!! the rb20 injector harness plugs into the rb25 harness??? wtf!!!!

[garetth]

If you plan on making more power you should look into the RB25 transmission so you won't have to replace it later.

[nick-nismo]

I'm using a full rb20 engine harness with rb20 injectors on the rb25

[supersayianjim]

^^what wait??? i thought you needed a totally different harness?? do you have a s1 or s2 engine???

and in terms of tranny, iam just aiming for 400whp. i hear the 20 trans will last that much.

[supersayianjim]

now iam going to look for a z31 tranny. and i just acquired a holset hx35w turbo, so were getting ready to roll.