Jump to content
SAU Community

Recommended Posts

I just bought a NVCS RB25DE and im going to bolt on all my RB20DET stuff...

my question to all the knowledgable gents out there in skyline land is:

What size are the stock side feed injectors and will my shit run lean if i use a RB20det computer with stock injectors?

also any helpful hints and tips you guys might have RE installing said motor.

CHEERS, ANDYLAUREL

Link to comment
https://www.sau.com.au/forums/topic/135068-rb25de-t/
Share on other sites

People in forums often take issue with NA+T. You'll find I'll arc up each time and say how wonderful it is!

I wouldn't run stock ECU mind you, especially with the massive change in displacement.

I would also use a turbo more suited to an RB25.

Besides that, no reason why you can't hammer out a good 12-14psi on a good tune. You'll see some good power from that and good response with the high comp.

Link to comment
https://www.sau.com.au/forums/topic/135068-rb25de-t/#findComment-2513433
Share on other sites

its been done. stock 25det computer and turbo. use the det injectors. the oil suply for the turbo needs to be taken of the oil pressue switch via a t peice.

the oil return is ok. just fit the turbo drain in the block (theres a bung.

the wiring is abit diferant. to what extent i dont know. but its defenatly diferant

ohh ok. the injectors are gonna be way to small.

Link to comment
https://www.sau.com.au/forums/topic/135068-rb25de-t/#findComment-2513981
Share on other sites

I've got a set of RB25DET injectors if you want them.

Oh, and a RB25DET Factory ECU

Maybe install those injectors and ECU, and you're good to go..

let me know.

oh, and you'll definately need a new fuelpump.

Edited by The Mafia
Link to comment
https://www.sau.com.au/forums/topic/135068-rb25de-t/#findComment-2514985
Share on other sites

i had a performance shop offer to install one of these into my car for $2100 (including swapping everything over and remapping my stock ecu) which i thought sounded pretty decent, but i was only expecting 6 or 7 psi because the compression is pretty high already. Without replacing anything bottom end to decrease compression, what sort of power would you be looking at with your setup? You can pm me if you like, i dun wana get your thread off topic.

Link to comment
https://www.sau.com.au/forums/topic/135068-rb25de-t/#findComment-2515169
Share on other sites

What size are the stock side feed injectors and will my shit run lean if i use a RB20det computer with stock injectors?

Again, I am saying NO to the RB20DET computer with stock injectors on that block. How on earth are its maps going to be correct on a 2.5L engine.

You need what The Mafia is offering if you don't want an after market ECU.

Edited by psybic
Link to comment
https://www.sau.com.au/forums/topic/135068-rb25de-t/#findComment-2516482
Share on other sites

wtf? You can't hook up a RB20 ECU to a RB25 motor...

my god..

Easiest fix - Install RB25 ECU, and injectors. Car would probably start fist go. And won't need to be re mapped...

anyway, don't say I didn't warn you.

Also, wouldn't the RB20 wiring loom be different to the RB25 loom?

Link to comment
https://www.sau.com.au/forums/topic/135068-rb25de-t/#findComment-2518735
Share on other sites

or just remap the stock RB20det ecu to cope with the extra demands :(

I'd do the same thing too...an rb25det ecu would probably allow you to run the car but i think the ignition timing maps might be too aggressive for the de+t...

Edited by limpus
Link to comment
https://www.sau.com.au/forums/topic/135068-rb25de-t/#findComment-2518831
Share on other sites

i was thinking that the stock RB20 ecu will be perfect to run the RB25DE because i will be using an RB20 AFM and the RB25de injectors are the same size as 20DET injectors...

hence when the engine is running, the AFM is metering a larger amount of air going into the engine (becasue its 2.5ltrs) and will add fuel accordingly... hence mixtures will be fine (at idle)

before you knock my block off, i understand that anywhere on boost, the 260ccs will not be able to supply sufficient fuel, but i think my metering hypothesis is correct...

Link to comment
https://www.sau.com.au/forums/topic/135068-rb25de-t/#findComment-2521943
Share on other sites

I've tried to use an rb20 ecu on my rb25. I was looking to do a remap. The rb20 ecu had the rb25 maps loaded onto it.

IT just wouldn't run. It idled like shit even with the rb25 maps. I remember reading somewhere before in the pfc threads that the ecus have slightly different wiring and require some modification.

Link to comment
https://www.sau.com.au/forums/topic/135068-rb25de-t/#findComment-2521962
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • I'm back from the dyno - again! I went looking for someone who knew LS's and had a roller dyno, to see how it shaped up compared to everything else and confirm the powerband really is peaking where Mr Mamo says it should. TLDR: The dyno result I got this time definitely had the shape of how it feels on the road and finally 'makes sense'. Also we had a bit more time to play with timing on the dyno, it turns out the common practice in LS is to lower the timing around peak torque and restore it to max after. So given a car was on the dyno and mostly dialled in already, it was time for tweaking. Luis at APS is definitely knowledgable when it came to this and had overlays ready to go and was happy to share. If you map out your cylinder airmass you start seeing graphs that look a LOT like the engine's torque curve. The good thing also is if you map out your timing curve when you're avoiding knock... this curve very much looks like the inverse of the airmass curve. The result? Well it's another 10.7kw/14hp kw from where I drove it in at. Pretty much everywhere, too. As to how much this car actually makes in Hub Dyno numbers, American Dyno numbers, or Mainline dyno numbers, I say I don't know and it's gone up ~25kw since I started tinkering lol. It IS interesting how the shorter ratio gears I have aren't scaled right on this dyno - 6840RPM is 199KMH, not 175KMH. I have also seen other printouts here with cars with less mods at much higher "kmh" for their RPM due Commodores having 3.45's or longer (!) rear diff ratios maxing out 4th gear which is the 1:1 gear on the T56. Does this matter? No, not really. The real answer is go to the strip and see what it traps, but: I guess I should have gone last Sunday...
    • 310mm rotors will be avilable from Australia, Japan, and probably a few other places. Nothing for the front can be put on the back.
    • The filter only filters down to a specific size. Add to that, the filter is AFTER the pump. So it means everything starts breaking your pump even if its being filtered out.
    • Just like in being 14mm too small (296mm) makes it not fit, being 14mm too big (324mm) it also won't fit. You want to find the correct rotor.
    • @GTSBoy Ok so that was the shops problem...they showed R33 rotors on R34 page and i did not know 296 do not fit(and are for R33) Yes i bought "kit" with rotors and pads. Pads are ok(i have GTT calipers front and rear). They have some 324mm but no 310mm. So i dont know if they would fit. I have 17inch LMGT4s So another question. Can i fit those in the rear or they are just "too" big for that?
×
×
  • Create New...