Jump to content
SAU Community

A Road Legal R31 Rb25Det

mungy
 Share

Recommended Posts

mungy Experienced

mungy

Posted
Posted

This has been one of those "oh while im doing this I may aswell do this" build and one thing after another led to building one amazing R31.

I Know most people dont like R31's that much,but even you who dont will appreciate this car I promise.

The story starts a few months ago when a good friend rang me and asked if I wanted a cheap R31, I immediatley said yes as I have a secret love for the R31. I was told it had a blown trans but it was a regoable r31 with 120,000km on the dash and had been can sprayed in matte black, my original plan was simply to swap out the trans as I had one sitting there with 160,000km and just drive the car.

Well that didnt happen........

It arrived on the back of a green tow truck and was actually still drivable, looking at the usual fluids the oil was clean, trans was full of water and the radiator was full of trans oil so I had decided it needed new radiator in as well as the trans out from the 31 I had sitting there.

It dawned on me that the 31 I had (smashed of course) also had a brand new $1500 A/C system with a new condenser, compressor, lines and evap, so I thought I should put that in too and make my summer alot more comfy.

I quickly ripped out the radiator and condenser and thought to myself the radiator hoses are much nicer on the other 31 so ill change them too, while i was getting the newer hoses off the other R31 all the other ancillaries look much newer so I decided to swap it all over...............

This is when it went all pear shaped...........

Because I needed to rip out the dash to get the new evaporator in I though it would be much easier to get a manual conversion done while everything was out of the way, and it would be easier to swap trans and ancillaries if the motor and box was all out of the car.

Once its was all pulled out I looked at it and as a joke to myself thought "this would be a perfect time to put a 25 in"..........

A few phone calls later I had decided to go ahead and put a 25 in, I had one sitting there in a 40th anniversary R33 with low enough K's and decided to use that.

The motor I had was in an auto R33 but I was planning on using a full manual kit I had from another R31 I had purchased before. While installing the pedals and clutch components I thought "would be a perfect time to get an s13 front end on this" and immediatley pulled the front end apart..........

At this point it started to dawn on me that this car was nearly completley in bits and thought I better finish this off and pulled all the front panels off to look for the usual rust.

looking at it sitting there on jack stands basically a bare shell at the front and striped out interior I realised I was only going to change the trans and now the car is in bits...................and immediatley started to regret my choices.........................

BUT WHATS DONE IS DONE........LETS CONTINUE.......

So now the entire front end was off I thought I may as well take out the K frame and clean out the entire engine bay as well.

Right there I decided I may as well go all out and convert this to 5 stud and get this car legal with a 25, I got myself s14 hubs and ball joints, R33 turbo brakes and the EF/EL rear brake setup to get it all to legal specs.

I then started to get EVERYTHING sand blasted and cleaned, every part was taken back to bare metal and resprayed in annodised red.

I stared to reinstall every part off the front end once it all came back, it looked quite nice, all brand new and red.

This is about when I had decided that going all out ment not using the shitty 20 box and installing a 25 box, so I went and plucked a NEO box with 110,000KM to put in with the 40th ann RB25DET I had chosen.

Many days and swear words later I had the front end back together and the engine with the neo box bolted into the car, surprisingly the gearbox just bolted up perfectly, no plates or washers or any modification at all, just bolted right in and measured up EXACTLY the same length as the 30 manual box, all I had to do was take the manual tailshaft to Hardy Spicers to change the front of the shaft to suit the neo box.

I enlisted the services of a very good mate, most of you know him here by the name simon s14, to come wire up this car.

Being a 40th anniversary engine, it turned out even the wiring loom was different to the standard series 2 engines and was slightly harder to get all the wiring done than normal. Having the wiring done we tried to start it for the first time........for some reason the fuel pump had just stopped working in the month or so the car had been sitting there, very strange, I needed to change the fuel pump anyway so had decided to use the R34 NEO turbo fuel pump, in it went and the car fired up.

The car is now waiting to go to garage7 tomorow to get the rear end converted to the ford brakes and the 5 stud to be drilled into the hubs, Decklan is also making up a completley new exhaust system for it so when it goes for emmisions testing it should pass first go(fingers crossed)

Ill get some pics up as soon as I can of the car in its current state, and update the build once it comes back from Garage7.

Not long after this car will be going to regency for a full inspection.........................god I hope I did a good enough job.

Link to comment
https://www.sau.com.au/forums/topic/434932-a-road-legal-r31-rb25det/
Share on other sites
trustr32 Rising Star

trustr32

Posted
Posted

Very cool read man sounds like a more extensive version of my old 31 that I bought for a daily and when the motor blew ended up doing a full overhaul lol. Keen to see some pics if you've got any.

And don't worry about the haters 31's will always be old school cool.

mungy Experienced

mungy

Posted
  • Author
Posted

Well I own a jap wrecker so I have many....many parts available, ill get some pics up tonight.

Unfortunately because the business was pilfered by thieves not long ago ive been recovering from that loss and the cost of new security Ive put the project on hold for now, the car is so close to being done its really upsetting I cant just splurge more cash on it.

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

    • JC71
      new 1.5 LSD issues/concerns

      By JC71 · Posted

      sold listed as a Tomei LSD 1.5 Way For 1998+ Nissan Skyline ER34 25GT RB25DE w/Open R200 https://www.ebay.com/itm/174006114594?campid=5338967980&mkevt=1&mkcid=1&toolid=10050&customid=&mkrid=711-53200-19255-0&loc_physical_ms=108689&loc_interest_ms=&campid=5338967980&mkevt=1&mkcid=1&toolid=10050&customid=71883f2ccc571356e0a757bc7adfdde2&mkrid=710-53481-19255-0&loc_physical_ms=108689&loc_interest_ms= it went in like butter all gears, alignment, back lash etc, rotation and clearances correct, and if rolling all rotates smooth and free when coasting down road , clutch in or out over 10 mph smooth... its the binding, clunking and jerking from a stop that is most concerning, also seems like its going to tear the tires off in 10 miles of normal road driving. 
    • Kinkstaah
      new 1.5 LSD issues/concerns

      By Kinkstaah · Posted

      What 1.5 way? There's no such thing really as a 1.5 way, just different ways of explaining 2 ways with different ramp rates. HOWEVER. In any driving in a straight line your 1.5 or 2 or 1.7 way should have no clunking at all. With the clutch fully depressed the diff should be silent (unless it's welded but I'm assuming it's not). Something aint right here.
    • JC71
      new 1.5 LSD issues/concerns

      By JC71 · Posted

      Clutch is a spec brand, new clutch system,( PP, flywheel, friction disc, etc. pull type) installed 100 miles ago, with no problems.
    • JC71
      new 1.5 LSD issues/concerns

      By JC71 · Posted

      looking for some help and maybe some insight on others experience with a new LSD. R34 GT ran and drove beautifully, but always alot of grip loss due to the open R200 rear end, so I just installed a new 1.5 LSD way into the stock open R200 for a ER34. Simple. Everything seemed right. I test drove for the first time this weekend. as I started to back out the garage the first time slowly with tires straight it sounded and felt like I had a loose or half disconnected drive shaft...that was clucking around loose and shaking entire vehicle, and making it feel like the trans clutch was spontaneously slipping then grabbing very roughly while just letting out pedal slowly. I backed it out went to pull forward with the same noise, shake and slip grab feeling with hesitation, I turned the tires to back out more and then pulled ahead some same thing but worst because of added wheel resistance (which that I expected) puzzled … pulling it back in checking everything over and finding nothing wrong, I tried it the next day. same thing, couldn’t believe how it shook everything again making a terrible noise and making it feel like the trans clutch was slipping and grabbing, but I got it out of garage into the driveway, got it straight, drove forward and then reveres a few times in a straight line everything shaking , causing what felt like clutch slip and grab every time, sounded like right behind front driver tire and I could feel it in the floor board with my feet,... worst right when beginning to let clutch pedal out to engage slightly, shuttering and sounding terrible along the way…I managed to slowly get down the road, babying it the whole way, once I was rolling (out of 1st) seemed to be better and between shifts, then clutch felt closer to normal…not slip/ grab etc., but back down to any stop, straight road or turning, same thing. Made no difference if all tires were straight or if I was turning. All other gauge read out correct. with in 2 miles as planned I reached the empty parking lot and performed the break in procedure that came with lsd, essentially to drive in a figure 8 a bunch.  Did this, binding chattering, and shaking the car the whole way. I drove it back home seemed somewhat normal once I was in straight line and past 10 mph or so, and I know it will “bind” on corners and cause some tires squeal when turning especially from a stop, but when I begin to move it still causes what feels like the trans clutch to slip and jerk badly as well as shaking the entire car, and sounds terrible, that I didn’t expect. I used the fluid they supplied with LSD kit and did the breaking, planning to change fluid as they suggest after breaking, but wondering will it get smoother or less aggressive with use? maybe a 1.5 is just too aggressive for normal road driving?   I have a LSD that I put in my 71 cuda when I restored it, with amazing smooth , quite yet effective results. Different style LSD but that ones a joy to drive. maybe expecting too much from this R200?
    • Matt Z
      SAU NSW - Archies Flame Grille Meet & Cruise to Kurnell

      By Matt Z · Posted

      Join SAU NSW for a flame-grilled feed & flame-spitting cruise! Sunday 17th August 2025 3:30PM Meeting Archies Flame Grille Sylvania Waters 4:45PM Cruise Departure 5:15PM Arrival at Cape Solander Kurnell Meet Location: Archies Flame Grille Final Destination: Cape Solander Kurnell *Disclaimer* There will be a lead and follow car so no one should get lost. If you would like to attend or bring others along please put your name down and a +1 as numbers will be needed prior! This is NOT a race and we will all be adhering to all road rules. If this is what you want please come to one of our many track days. This is an official SAU:NSW event and will be run under a CAMS permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU NSW and thus, treat others accordingly. • Any misbehavior will not be tolerated and you will be asked to leave.
×
×
  • Create New...