Jump to content
SAU Community

Monster R31 Conversion

-scooter-

By -scooter-,
in Engines & Forced Induction

 Share

Recommended Posts

-scooter- Contributor

-scooter-

Posted
Posted

Hello peoples...

I own an R31 2 door skyline and the red top nics motor is getting old and worn. So i am thinking of doing an rb25det transplant.

I have many questions that i want to ask but for now i would just like to know if the rb25 gearbox will fit without modifaction or not, as i dont think the rb20 box will last long at all. I have benn told the 25 box is longer then the 20 box and a new tail shaft is needed..... what truth is in this???????

Any help will be great

thanks guys

:D :D :D

Link to comment
https://www.sau.com.au/forums/topic/32424-monster-r31-conversion/
Share on other sites
sky^rkt Proficient

sky^rkt

Posted
Posted

hey mate, im doing the conevrsion myself to my r31, and im using the rb20det box for now til i can afford a 25 box, as for ur question, yes u wil need a new tailshaft due to the different length of the 25 box, if you have anymore question do not hesitate to pm me or email me on [email protected]

-scooter- Contributor

-scooter-

Posted
  • Author
Posted

I'm at the stage of shopping for the engine at the mo. i rang a place called ALL JAP at virginia and the can do an rb25det with uncut loom,computer and gearbox all complete for $2750. That is good rite????

Also wat is the the cost of a tailshaft made to specifaction these days, im sure it is expencive though.

Cheers

Dan

:headspin: :headspin:

-scooter- Contributor

-scooter-

Posted
  • Author
Posted

Well thats good news, i was expecting to pay 600 to 1000 dollars.

so is that the only prob with the 25 box into R31 convert????

Sorry bout asking again but i just wanna make sure that everything is peachey before i go converting and find probs that i dont wanna find, if u know wat i mean.

i also heard that the speedo on a 25 box is electronic and 31 box is cable. Is this true???????

Cheers

Dan

:Bang: :Bang:

Skyrine-Dave Mentor

Skyrine-Dave

Posted
Posted
i also heard that the speedo on a 25 box is electronic and 31 box is cable. Is this true???????

true... You will need to source yourself an R32 GTR Speedo drive as they are mechanical. And then i think you use the RB25 sender on the end of this to fit the gearbox. This should get it all linked up to the R31

you also have a PM

-scooter- Contributor

-scooter-

Posted
  • Author
Posted

alrite then sounds like the gearbox is sorted.

so wat bout the engine and computer, is it pretty much a direct swap for the motor thats in there now

EG: ecu for ecu

motor for motor

any major problems with this????????

i think i might sit down and think hard and write a list of things that might need to be changed and post that, and c wat people think.

-scooter- Contributor

-scooter-

Posted
  • Author
Posted

well i made a list of questions to ask this forum, so here goes.....

1. Can i use the rb20 radiator i have now or use an rb25 one in its place?

2. Will my power steering and aircon pumps bolt straight on the the 25 block?

3. Can i still use my stock inter cooler (as i wont be able to aford a FMIC rite away)

4. Any engine mount modifaction required for fitment.

5. Any braking or suspension mods required.

6. Will i need an rb25 dump pipe or will rb20 be alrite.

7. Will the diff be ok for the power increase.

thanks in advance for any help.

cheers

Dan

:slap: :) :wassup: :Bang: :flamed: :):)

Skyrine-Dave Mentor

Skyrine-Dave

Posted
Posted

1. Rb20 radiator should be fine

2. yes they should mount to the same place on teh rb25 engine

3. dont run more than 12psi and ya should be ok, factory cooler sucks

4. no will fit original RB mounts

5. it would be wise to upgrade the brakes, even to R32 calipers/discs/ and hubs (5 stud)

6. yes

7. if its LSD... yesm

-scooter- Contributor

-scooter-

Posted
  • Author
Posted

cool cool.

Which would be cheaper in the long run??

to buy the motor and get some one to put it in for me (as im not experienced enough to put it in my self)

OR

find a place in bris that will do drive in with rb20 and a week later drive away with rb25 kinda package??????

Is there any places in brisbane that do this conversion at all?????

Cheers

Dan

:rolleyes::):)

sky^rkt Proficient

sky^rkt

Posted
Posted

1. i wouldnt advise using the rb20 radiator as it is pretty small, i would advise going to a wreckers and geting a 3 litre radiator as i have done.

2. the power steering pump wil go on yes, but u will need to put a biger belt most likely. i had to put a new belt on mine due to my car having hicas. the aircon will bolt straight on.

3.you can use your intercooler, but i would sugest trying top source a stock rb25 cooler.

4. the engine wil be a straight bolt in.

5. if you got the stock suspension in your r31 coupe i would sugest upgrading, because the stock setup is utter crap, shop around for a good deal. as for brakes they import brakes r a decent size, i would put on better brake pads. and if you can afford later on try get r32 calipers onto it. or even put slotted/cross drilled discs.

6. yes

7. the diff should habdle the power ok, u would have the r200 diff and they r a bloody good diff!, just hope u got lsd =]

hope this all helps

-scooter- Contributor

-scooter-

Posted
  • Author
Posted

Hmmmmm

i agree with u about the sus it is bloody crap.

It all gets me thinking, it would be so much cheaper to just buy an R31 with an b25 in it already. That way i can spend all my money on mods!!!!

they are in the trading post every now and then.

OR

could do the sus first, then brakes and so on, and leave the engine till last. Will take longer to do (because i will have to save money for a little while). But the convert will be mine and the way i want it done....

Decisions, decisions......

Any advice on which way to go????? PROS & CONS

cheers

Dan

:Bang: :Bang:

sky^rkt Proficient

sky^rkt

Posted
Posted

i would sugest u change ur suspension first. then upgrade your brakes. then off u go to get a new engine. yes it might end up costing abit more doing the conversion rather than buyin a car with one already in it, but it all comes down to personal choice. i personaly feel better that i got a rb25det instaled in my car rather than go out and find a aussi model with an rb25det, but anyways good luck with it, just research the prices etc and decide what your going to do

-scooter- Contributor

-scooter-

Posted
  • Author
Posted

Another question

alittle while ago i went hunting for some wheels for my car but came up with only 3 or so different types of wheels that will fit due to the super large 4 stud pattern.

So im thinking maybe it is possible to fit r32 brakes (5 stud) to the front end and either a whole 32 diff in the rear or just the brake set up to my diff???????

is this all possible, as there is a much much larger range of wheels for 5 stud r32 wheels.

Dan

:D :Oops: :D :wassup: :bs!: :flamed: :(

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      R33 Fuel Pump & Brakes after alarm swap

      By GTSBoy · Posted

      Power is fed to the ECU when the ignition switch is switched to IGN, at terminal 58. That same wire also connects to the ECCS relay to provide both the coil power and the contact side. When the ECU sees power at 58 it switches 16 to earth, which pulls the ECCS relay on, which feeds main power into the ECU and also to a bunch of other things. None of this is directly involved in the fuel pump - it just has to happen first. The ECU will pull terminal 18 to earth when it wants the fuel pump to run. This allows the fuel pump relay to pull in, which switches power on into the rest of the fuel pump control equipment. The fuel pump control regulator is controlled from terminal 104 on the ECU and is switched high or low depending on whether the ECU thinks the pump needs to run high or low. (I don't know which way around that is, and it really doesn't matter right now). The fuel pump control reg is really just a resistor that controls how the power through the pump goes to earth. Either straight to earth, or via the resistor. This part doesn't matter much to us today. The power to the fuel pump relay comes from one of the switched wires from the IGN switch and fusebox that is not shown off to the left of this page. That power runs the fuel pump relay coil and a number of other engine peripherals. Those peripherals don't really matter. All that matters is that there should be power available at the relay when the key is in the right position. At least - I think it's switched. If it's not switched, then power will be there all the time. Either way, if you don't have power there when you need it (ie, key on) then it won't work. The input-output switching side of the relay gains its power from a line similar (but not the same as) the one that feeds the ECU. SO I presume that is switched. Again, if there is not power there when you need it, then you have to look upstream. And... the upshot of all that? There is no "ground" at the fuel pump relay. Where you say: and say that pin 1 Black/Pink is ground, that is not true. The ECU trigger is AF73, is black/pink, and is the "ground". When the ECU says it is. The Blue/White wire is the "constant" 12V to power the relay's coil. And when I say "constant", I mean it may well only be on when the key is on. As I said above. So, when the ECU says not to be running the pump (which is any time after about 3s of switching on, with no crank signal or engine speed yet), then you should see 12V at both 1 and 2. Because the 12V will be all the way up to the ECU terminal 18, waiting to be switched to ground. When the ECU switches the fuel pump on, then AF73 should go to ~0V, having been switched to ground and the voltage drop now occurring over the relay coil. 3 & 5 are easy. 5 is the other "constant" 12V, that may or may not be constant but will very much want to be there when the key is on. Same as above. 3 goes to the pump. There should never be 12V visible at 3 unless the relay is pulled in. As to where the immobiliser might have been spliced into all this.... It will either have to be on wire AF70 or AF71, whichever is most accessible near the alarm. Given that all those wires run from the engine bay fusebox or the ECU, via the driver's area to the rear of the car, it could really be either. AF70 will be the same colour from the appropriate fuse all the way to the pump. If it has been cut and is dangling, you should be able to see that  in that area somewhere. Same with AF71.   You really should be able to force the pump to run. Just jump 12V onto AF72 and it should go. That will prove that the pump itself is willing to go along with you when you sort out the upstream. You really should be able to force the fuel pump relay on. Just short AF73 to earth when the key is on. If the pump runs, then the relay is fine, and all the power up to both inputs on the relay is fine. If it doesn't run (and given that you checked the relay itself actually works) then one or both of AF70 and AF71 are not bringing power to the game.
    • Kinkstaah
      My BMW E39 528i touring

      By Kinkstaah · Posted

      @PranK can you elaborate further on the Colorlock Dye? The website has a lot of options. I'm sure you've done all the research. I have old genuine leather seats that I have bought various refurbing creams and such, but never a dye. Any info on how long it lasts? Does it wash out? Is it a hassle? What product do I actually need? Am I just buying this kit and following the steps the page advises or something else? https://www.colourlockaustralia.com.au/colourlock-leather-repair-kit-dye.html
    • GTSBoy
      My BMW E39 528i touring

      By GTSBoy · Posted

      These going to fit over the big brakes? I'd be reeeeeeeeaaaall hesitant to believe so.
    • PranK
      My BMW E39 528i touring

      By PranK · Posted

      The leather work properly stunned me. Again, I am thankful that the leather was in such good condition. I'm not sure what the indent is at the top of the passenger seat. Like somebody was sitting in it with a golf ball between their shoulders. The wheels are more grey than silver now and missing a lot of gloss.  Here's one with nice silver wheels.
    • soviet_merlin
      My BMW E39 528i touring

      By soviet_merlin · Posted

      It's amazing how well the works on the leather seats. Looks mint. Looking forward to see how you go with the wheels. They do suit the car! Gutter rash is easy to fix, but I'm curious about getting the colour done.
×
×
  • Create New...