Ecu... Is This Possible?

[Jinman]

I have a R32 with an RB20DET in it and was tinkering around with things under the dash and pulled my ECU out. Its got RB25DET written on the side of it!

So I'm wondering if its possible to run an RB20DET with a standard RB25DET ecu?

I haven't owned the car too long and I'm hoping its the cause of a few of my running issues at the moment. miss on idle, goes nowhere above about 4,500-5000 to red line fair bit of black smoke. Thought maybe it could be a quick and asy fix with the ecu. Otherwise I'm going to spend some quality time with my coil packs cleaning them up.

Edited June 22, 2008 by Jinman

[madevo3]

um i dont think you can use it it will miss like a pig and maybe wouldnt even start either. yeah get another ecu rb20det one and it will run fine i have got one for sale if ya wanna buy it just pm me if you want it

[W0rp3D]

the fact that rb25det's have variable valve timing and the rb20 does not would be one major issue.

[infamous_t]

Problems you explained are what I'd expect running an rb25 ecu on an rb20.

The ecu's are virtually interchangeable except for the VVT, but the tune will be vastly different, hence you car running like shit.

Just go get the ecu its supposed to have, as the previous owner most probably had an aftermarket ecu, which he kept and put in the closest thing that worked(or didn't).

[QWK32]

what is the numbers on the ecu? or can you post up a picture of the sticker on the ecu. the 10 digit number and MEC -XXXX number.

[SKiT_R31]

does it have an safc?

rb25det ecu's are tuned for 370cc injectors, so unless its got different injectors or an SAFC it will be running lean as

if it has an safc, adjusting the mixture ~ 37% to get it to run, it would probably make it rich and retard off sfa power

the engines are very similar, as far as cams etc are concerned, and with a plain rb20 long motor on an rb25det ecu with all the rb25det sensors and electrics, you'd find it would run pretty well (should be fine on boost). But with the rb20 sensors and all the other crap along with it, it makes sense it would be pretty average. VCT shouldn't be a big deal, as unplugged on an rb25det it still runs fine...

So more info, what turbo do you have? what injectors? any piggyback devices? fuel pressure regulator?

[QWK32]

also from what i can tell injector outputs 4 and 6 are swaped around on the rb25det ecu compared to the rb20det ecu.

[Jinman]

No the car looks pretty standard engine wise. I'll take some photos of the actual ecu and see what you guys think.

[Bennett]

I thought they had more different pin-outs than just the injectors... but maybe im wrong. I put my 33 ecu in my mates 32 and it didnt even start.