Rb25Det Swap

[Dylan454]

Hi guys this is just an idea at the moment not a serious plan but is it worth doing a rb25 swap into a r32 skyline. I have an rb20det at the moments which is fine for now but I was wanting to eventually get a rb25 and rebuild it and put it in my car but is it hard to do and what are some problems with doing it thanks.

[Exodus01]

I have had so many problems, it is so definitely not worth it. i still havent finished and ive been working on it for a while.. i changed it over caz my rb20 was hunting and i had the rb25 lying around so thought after reading it would be easy enough. I have plugs that dont fit, all the looms change. Dont reuse the rb20 loom, this does not work. I should of just fixed the rb20

I dont even want mine road registered so i havent worried about hooking up to body and making speedo or wipers work either.

[Exodus01]

We tried reusing the existing wiring and found the injectors we wired up correctly except one were the wiring colours reversed.

You lose VCT from the rb25det as the rb20 doesnt have it

The ECU fried when we tried using the rb20 ignitor box

Just whilst the engines out, change the loom straight to the Rb25det loom, injector loom, coil loom, ecu and ignitor box

youll need to figure out how to wire up the body harness and get the wipers, speedo, fuel pump etc all working.

Another issue i had was the injectors had seized from the engine sitting so long, had to hit them with 12v so they free'd up.

[Dylan454]

But is it worth spending a lot of money on a rb20det to make less power than a rb25det ??

[Exodus01]

what do you want to achieve out of it?

[Dylan454]

I'm not really sure yet but most likely a street/drag car I wouldn't drift it

[r32-25t]

The swap is very easy, but make sure you also get the wiring harness and ecu, then all you need to do is change the plug under the dash to r32 type and it all plugs in and works

[Exodus01]

the wiring colours dont match between loom and 32 plug so youll need to do lots of reading and checking wiring diagrams etc for that to just "plug in". I posted asking for some help on this and even asking someone if theyd do it if i paid and got no answers so it was go through all the wires and figure how they transition however i dont want my registered so i ran an individual power line to the fuel pump and bypassed all of that.

[Reaper576]

I'm trying to do it to my R32 at the moment and I agree with Exodus, unless you are aiming at making big power I would just stick with the 20 I know I wish I had

[r32-25t]

I not being a smart ass but I did the swap in 2 weekends going from a rb20 with a broken timing belt to a running rb25 using a series 2 rb25, wiring harness and ecu.

I used all the r32 alternator, starter, power steering pump, a/c compressor, engine mounts and harmonic balancer. So it bolted back in as if it was always there then modified the r33 harness using the 32 body plugs (in the cabin) and fired it up and never had an issue, it was my daily driver and everything worked as per factory

[Reaper576]

I'm at the point of just been completly stuck on mine now all becuase i let an auto sparky look at it

the wiring is the hard part the rest of the coversion is really easy

[Exodus01]

I Agree with Reaper, i read about how easy it was.. followed all of the tuts and pages on here and the wiring has been an absolute balls up..

[Reaper576]

For the money that I have spent trying to do this conversion now even wtih out all the wiring muck arounds I could have build a pretty mental rb20 and not have to worry about getting it enginereed

[Dylan454]

I have only ever heard of people saying the rb20 is not worth doing up because it just can make a lot of power but I have never actually seen a done up rb20det

[Exodus01]

if i did it again i would have dropped a V8 in it (since its for drifting and would have been a lot less effort).. TBH the rb25 and rb20 are not worth doing up, youd be better spending the money on a 32 GTR.

End of the day its your money and if your up for the hassles and cost then go for it.

[Dylan454]

Did you use a series one or series 2 rb25 when you did your conversion

[Exodus01]

Series 1, i got it running, idles a bit rough but no tune, injectors were seized and hit with 12v to free. need to hook up to ECU and tune.

I am now running all rb20 wiring with new AFM (stock, dont know if mine was causing a problem) and R33 ECU. Have the rb20 coil box still there as matches wiring.

[Dylan454]

So what you saying is you kept all the 20 wiring and used the 33 ecu do you have to change and wires

[Dylan454]

Woops I meant when using the 20 loom do you need to change any wires to use r33 ecu

[jiffo]

It's my opinion some people should not got down this path, they're simple not suited to the problems you invariably come across.

Makes no difference if you're swapping a 25 in place of 20 or going for a V8, you will have some dramas along the way.

With all the info available on the net these days, one would expect a straight Rb to Rb swap to be easy but that hasn't been my experience, you need patience and some clear headed pin out ability when it comes to the wiring.

Forget an auto sparky unless you have very deep pockets. Usually you're simply paying him to learn.

You also need to sift through the mass of mis-information given on the net, a LOT is simply rubbish.

Talk to the guys who have actually done the full hands-on swap, not the keyboard heroes.