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

    • GoHashiriya
      From Japan and back to Europe, my sh*tbox R34 GTT

      By GoHashiriya · Posted

      I got back to Japan in January and was keen to get back on track as quickly as possible. Europe is god-awful for track accessibility (by comparison), so I picked up a first-gen GT86 in December just to have something I could jump into right away. The Skyline came over in a container this time and landed in early January. It was a bit battered after Europe, though—I refused to do anything beyond essential upkeep while it was over there. The clutch master cylinder gave out, and so did the power steering. I didn’t even bother changing the oil; it was the same stuff that went in just before I left Japan the first time. Naughty. Power steering parts would’ve cost double with shipping and taxes, so knowing I’d be heading back to Japan, I just postponed it and powered through the arm workout. It took a solid three months to get the car back on the road. Registration was a nightmare this time around. There were a bunch of BS fees to navigate, and sourcing parts was a headache. I needed stock seats for shaken, mistakenly blew 34k JPY on some ENR34 seats—which, of course, didn’t fit—then ended up having the car’s technical sheet amended to register it as a two-seater with the Brides. Then there’s the GT86. Amazing car. Does everything I want it to do. Parts are cheap, easy to find, and I don’t care what anyone says—it’s super rewarding to drive. I’ve done a few basic mods: diff ratio, coilovers, discs, pads, seat, etc. It already had a new exhaust manifold and the 180kph limiter removed, so I assume it’s running some kind of map. I’ve just been thrashing it at the track non-stop—mostly Fuji Speedway now, since I need something with higher speed after all that autobahn time. The wheels on the R34 always pissed me off—too big, and it was a nightmare getting tires to fit properly under the arches. So I threw in the towel and bought something that fits better. Looks way cleaner too (at least to me)—less hotboy, less attention-seeking. Still an R34, though. Now for future plans. There are a few things still outstanding with the car. First up, the rear subframe needs an overhaul—that’s priority one. Next, I need to figure out an engine rebuild plan. No timeline yet, but I want to keep it economical—not cutting corners, just not throwing tens of thousands at a mechanic I can barely communicate with. And finally, paint. Plus a bit of tidying up here and there.  
    • The Bogan
      NC MX5

      By The Bogan · Posted

      Nope, needed to clearance under the bar a little with a heat gun, a 1/2" extension as the "clearancer", and big hammer, I was aware of this from the onset, they fit a 2.0 with this intake no problems, but, the 2.5 is around 15mm taller than a 2.0, so "clearancing" was required  It "just" touched when test fitting, now, I have about 10mm of clearance  You cannot see where it was done, and so far, there's no contact when giving it the beans Happy days
    • GoHashiriya
      From Japan and back to Europe, my sh*tbox R34 GTT

      By GoHashiriya · Posted

      It's been a while since I've updated this thread. The last year (and some) has been very hectic. In the second-half of 2024 I took the R34 on a trip through Germany, Italy, France and Switzerland - it was f*cking great. I got a little annoyed with the attention the car was getting around Europe and really didn't drive it that much. I could barely work on the car since I was living in an inner-city apartment (with underground parking). During the trip, the car lost power steering in France - split hose - and I ended up driving around 4,000kms with no power steering.  There were a few Nurburgring trips here and there, but in total the R34 amassed just shy of 7,000kms on European roads. Long story short, I broke up with the reason I was transferred to Europe for and requested to be moved back to Japan. The E90, loved it. It was a sunk cost of around EUR 10,000 and I sold it to a friend for EUR 1,500 just to get rid of it quickly. Trust me, moving countries f*cking sucks and I could not be bothered to be as methodical as I was the first time around.
    • MBS206
      NC MX5

      By MBS206 · Posted

      I assume clearances were all a-okay?
    • The Bogan
      NC MX5

      By The Bogan · Posted

      Shock tower brace is in +5Kw....LOL  
×
×
  • Create New...