Finally Building It

HolyGhost

First Fill-Up (of many)
Spent some time reviewing the FSM's to work out the wiring of shoving the z31 ECU into the X. So far I think I can use the z31 ECU to trigger the X's fuel pump relay no issue. Also if you ever want to see a way to complicated fuel pump setup review the 300zx diagram uses two different ECU pins and a relay.

Looks like the gauge cluster doesn't use the ECU except for the tach which uses a signal from the ECU to give the tach output. The z31 uses an old style tach which uses the coil to get the reading. Did some searching lots of adapters to go from the ECU output to an old style tach but couldn't find anything to convert coil pickup to a 0-5v square wave the X cluster is looking for. Eventually found an adapter for a race logging box called the CoilX looks like I should be able to wire it up to the old z31 coil I am swapping over and it will give out a square wave.

CoilX Link
https://wiki.autosportlabs.com/CoilX

If anyone has any experience on something like this feel free to share.

What the X cluster is looking for from the FSM.
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HolyGhost

First Fill-Up (of many)
Well I ordered the CoilX part from autosports lab. I will update if it works or not but just to keep things documented here is my theory of how this will work.

From the FSM the distributor gives the input to the X's ECU then the X's ECU gives a output to the gauge computer. From the distributor it looks like for each ground of the coil a pulse is generated to the ECU then to the dash computer. If you look at the two different FSM pages the wave from the coil is directly translated to a square wave pulse that the dash computer is looking for. The dash is looking for a 0-5v input with different pulse frequency. Basically as the coil is grounded a pulse is created to the ECU translated to a square wave and then sent to the dash computer to display the RPM.

My theory is since each time the coil closes the computer sends a square wave the CoilX board does the same thing. I just need to wire the CoilX to the z31 coil and it will generate a square wave that will increase in frequency as the RPM increases giving the dash computer what it needs to display the RPM.

Distributor output to the X ECU.
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ECU output to the dash same amount of pulses as the ECU sees from the distributor just different wave form.
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The CoilX part shown on a oscilloscope. Each pulse is turned into a square wave. Increase in frequency when RPM increases the same as the X ECU.
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paulforeman02

Test Drive
So excited to see how this turns out. The amount of work you're putting in is awesome to see. I definitely want to see it run when it's all done. Makes me glad I just went with the supercharger and ECU swap from a wrecked X, haha. Good luck!
 

xEndlessfight503x

Bought an X
Impressive work figuring out the coil signal, I would of been lost ha.

I’m really excited to see how this turns out. Should make some good power with the meth too.
 

HolyGhost

First Fill-Up (of many)
So excited to see how this turns out. The amount of work you're putting in is awesome to see. I definitely want to see it run when it's all done. Makes me glad I just went with the supercharger and ECU swap from a wrecked X, haha. Good luck!

Some days I wish I would have went that route but wanted more power.

This is some next level shiat. I dig it.

Impressive work figuring out the coil signal, I would of been lost ha.

I’m really excited to see how this turns out. Should make some good power with the meth too.

Thanks guys hopefully my theory is right but it's fun trying to figure all this stuff out no matter how it plays out.

Not much updates been slow progress the past few weeks. Got the front diff out to make room for the oil pan drop. I am also going to switch to the z31 dipstick as it sits further back and won't interfere with where I want to mount the turbo. Installed the new motor mounts and they leave enough room for my external waste gate so it's slowly coming together.

Motor mounts old vs new.
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Installed
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oil drain drilled.
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HolyGhost

First Fill-Up (of many)
No real update on the project hopefully get some time next weekend to work on it. However I did find a sweet deal on Denver Craigslist. 2000 Xterra 144k on the clock but I'll let you guys guess what I was really after.

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HolyGhost

First Fill-Up (of many)
Finished the mock up of the crossover and driver side exhaust. Still need to get the up pipe mocked up then I can get it welded up. Had to massage the firewall to get the vbands to fit. Not a huge fan of how everything fits but have to make due with the space I have. Also built a connection to the up pipe from 1/2" plate. Cut a 2.5 inch hole with a hole saw took forever.


Mock up on the 300zx engine out of the car.
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turbo flange need to round the edges.
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HolyGhost

First Fill-Up (of many)
Looking good, my man! are you going to hard pipe the heater hoses that run above the cross over? I'm glad to see it progressing.

Thanks! right now the plan is to wrap the crossover in header wrap and to sleeve the water lines in heat shielding. Actually from how tight everything is around the exhaust I will be spending quite a bit in heat sleeves for all the wiring.

After thinking about how to get the oil cooler fitted for this build I have ran into a snag. Does anyone know of a sandwich plate that would fit the X's oil filter location for a cooler? My fall back plan if I can't find one is to swap the oil filter housing from the 300zx and run both filters. The 300zx filter housing fits on the passenger side of the motor and has a built on sandwich plate for the cooler. The 300zx filter housing also has the benefit of being free.

I am traveling for work these next few weeks but trying to get some work in on the X on the weekends. I did call around looking for 98/2 welding gas for the stainless welding but the cheapest I found it local for a rental bottle was 270$. Current plan is to have a local welder tig the stainless together for me. Should cost less than the gas bottle for me to do it.
 

Prime

Shut up Baby, I know it!
Admin
Location
Denver Adjacent
No real update on the project hopefully get some time next weekend to work on it. However I did find a sweet deal on Denver Craigslist. 2000 Xterra 144k on the clock but I'll let you guys guess what I was really after.

FKxAgfq.jpg


jKTEXtu.jpg
I saw thst listing. I thought about it.
 

xEndlessfight503x

Bought an X
Thanks! right now the plan is to wrap the crossover in header wrap and to sleeve the water lines in heat shielding. Actually from how tight everything is around the exhaust I will be spending quite a bit in heat sleeves for all the wiring.

After thinking about how to get the oil cooler fitted for this build I have ran into a snag. Does anyone know of a sandwich plate that would fit the X's oil filter location for a cooler? My fall back plan if I can't find one is to swap the oil filter housing from the 300zx and run both filters. The 300zx filter housing fits on the passenger side of the motor and has a built on sandwich plate for the cooler. The 300zx filter housing also has the benefit of being free.



Ah, glad to hear you had that all figured out.


I think you may be able to run the late pathfinder oil filter adapter,
21305-4w00a.
 

HolyGhost

First Fill-Up (of many)
I saw thst listing. I thought about it.

Yeah with dual arb lockers and calmini transfer case gears it was a sweet buy. I was going to get at least the rear locker and transfer case gears anyways since the turbo might kill low end power. I plan to just swap the whole rear and front diffs from the silver one along with the transfer case.

My friend who helped with the rear bumper said he would by the rig from me after I am done with it. He has a dana 44 for the front and he is deciding if he wants to keep the nissan drivetrain or go chevy.

I think you may be able to run the late pathfinder oil filter adapter,
21305-4w00a.

Thanks looked it up if I buy the adapter new it's pretty pricey. I am also have one hell of time telling where it mounts. Do you have any idea how they mounted that adapter? I see it is for the VQ series engine with the dual cams.
 

HolyGhost

First Fill-Up (of many)
Thought I would throw this out there to the community. I am in the planning stages of building a custom roof rack inspired by the Gobi Ranger rack. Love the look of the rack and hate the cost. I think I should be able to knock one out for less than 500$. 1" steel tube with an expanded metal floor and 1" movable cross bars. I plan to follow the contour of the X's roof for a cleaner look. I am sourcing steel local and have a shop lined up to cut and bend the brackets that bolt to the roof.

Just wanted to see if any of the members in Colorado/Utah would be interested in one? I was hoping to build 5 including my own so if anyone is interested send me a PM. Right now I would prefer to keep it local and not ship. This isn't a sales advertisement just figured it would be easy to repeat the process for multiple racks while I was building mine.

Probably get started in April and have mine ready by May. Let me know if you have any interest.

Also got my first piece welded by the local welder. 2.5" thin wall aluminum for the charge pipe going off the turbo. You can see the vband mount for the BOV. Looks like good work, same guy will be TIGing my exhaust manifolds together since the cost of gas is more than paying him to weld it.

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HolyGhost

First Fill-Up (of many)
Awww yeah! It's finally getting there. Final fitment tomorrow. Everything is so tight in the engine bay but it looks like it's all going to work.

Down pipe almost done just need the stub for the waste gate.
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paulforeman02

Test Drive
No real update on the project hopefully get some time next weekend to work on it. However I did find a sweet deal on Denver Craigslist. 2000 Xterra 144k on the clock but I'll let you guys guess what I was really after.

So funny. I saw this and kicked around the idea as well. By time I had decided to go ahead and pull the trigger on it and swap the diffs/t-case into my Frontier, I called the guy up, and he goes "yeah, some other guy came and got it yesterday." I was actually curious at the time if it was you... now I know! Glad it's going to a good project.
 

paulforeman02

Test Drive
Thought I would throw this out there to the community. I am in the planning stages of building a custom roof rack inspired by the Gobi Ranger rack. Love the look of the rack and hate the cost. I think I should be able to knock one out for less than 500$. 1" steel tube with an expanded metal floor and 1" movable cross bars. I plan to follow the contour of the X's roof for a cleaner look. I am sourcing steel local and have a shop lined up to cut and bend the brackets that bolt to the roof.

Just wanted to see if any of the members in Colorado/Utah would be interested in one? I was hoping to build 5 including my own so if anyone is interested send me a PM. Right now I would prefer to keep it local and not ship. This isn't a sales advertisement just figured it would be easy to repeat the process for multiple racks while I was building mine.

As far as this goes, you could post/check with NORAC 4x4 and Colorado Xterra Club on facebook?

https://www.facebook.com/groups/norac/
https://www.facebook.com/groups/769625289824853/
 

HolyGhost

First Fill-Up (of many)
So funny. I saw this and kicked around the idea as well. By time I had decided to go ahead and pull the trigger on it and swap the diffs/t-case into my Frontier, I called the guy up, and he goes "yeah, some other guy came and got it yesterday." I was actually curious at the time if it was you... now I know! Glad it's going to a good project.

That's pretty funny. I figured I would just go for it and hopefully I have time to swap everything by summer. Really just want to enjoy the rig rather than work on it all summer. We should do some wheeling this summer not much first gen guys around so we need to stick together. I read your thread on expo overland sweet build.

As far as this goes, you could post/check with NORAC 4x4 and Colorado Xterra Club on facebook?

https://www.facebook.com/groups/norac/
https://www.facebook.com/groups/769625289824853/

I don't have a facebook but my friend who helped me with my bumper does so maybe I'll make him help me out.

Little project update. Spent all day working on getting the ECU harness out of the car. I don't know what satanist works at Nissan engineering department but I have the whole dash out and still need to get the full mode door box and heater box out to get the harness out. Pulling the heater box and mode door are not even covered in the FSM as far as I can tell. Once I get this harness out I need to figure out how to shoehorn the 300zx harness in.

I'll upload some picture tomorrow.
 

Prime

Shut up Baby, I know it!
Admin
Location
Denver Adjacent
I don't facebook either. But am still a NORAC member and participate as much as I can. I can let you know when and where the next meeting is when I find out. If you're interested.

Btw, coming to GONE this year? You should be.
 

HolyGhost

First Fill-Up (of many)
I don't facebook either. But am still a NORAC member and participate as much as I can. I can let you know when and where the next meeting is when I find out. If you're interested.

Btw, coming to GONE this year? You should be.

Found the NORAC website looks like a cool organization. GONE is on the list but I am not signing up till I hear this thing run.

Finally got the engine harness out two days of fighting this thing out. Had to pull out the AC evap to pull the harness out. Next step is to start working with the 300zx harness to see how it is going to wire it up. Going to leave the dash out so I can start wiring up my gauges and locker switches.

Pics of today's hell.
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The day did end on a good note. All the exhaust checks out and is fitted on the test engine.
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HolyGhost

First Fill-Up (of many)
Dropped the manifolds off with the welder. Should have some parts to verify fitment after welding this week. Plan is to have him weld in segments to verify fitment along the way. Not a proper race car unless you put it together and pull it apart multiple times during the build :)

Going to start wiring the 300zx EFI harness this week. Freaking nightmare of reverse engineering two cars into one but starting to figure it out. I will post my notes just in case anyone is crazy enough to follow my swap. (pro tip, just supercharge it)
 

HolyGhost

First Fill-Up (of many)
Passenger side done. Big shout out to Koza Customs in Cedaredge, CO great work and reasonable on the price. Going through him for all my technical welding.

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HolyGhost

First Fill-Up (of many)
Little update. Got the diver side, passenger and crossover all welded up. Next step is to have the machine shop deck them back flat as the flange warped with the welding.

I did mock up the water routing for the turbo and throttle body. I used super high heat silicone water hose but I don't like the blue so I sleeved them in black heat shield. I also got the lower intake fully bolted in. Making it the first thing in months I have bolted in without the intention to remove it for mock up. Going to try and get the harness connected this weekend and once I get my exhaust finished get this thing started. Only two months behind schedule.

Hose routing.
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sleeving much better.
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Lower finally bolted in.
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HolyGhost

First Fill-Up (of many)
Worked on getting the 300zx harness in. Still working out the pins to connect to the Xterra main harness but I am getting there. Drilled a 2.5" hole in the firewall for the new harness since the Xterra location was such a pain to get the harness out. With this location I should be able to get the harness out without having to remove the dash.

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HolyGhost

First Fill-Up (of many)
Back at this after work.

Got the oil feed done, used an adapter to keep the stock oil pressure sensor for the idiot light. Also started working the harness to fit the X looks like a rats nest right now.

Still working out the drain for the turbo oil feed but getting there. The manifolds ended up being way far from flat and the machinist suggested heating them while bolted to a flat plate to see if they would level out more. Going to try and build a jig tomorrow to see if it works. He suggested 3 inch plate to bolt them to... like I just have 3" plate laying around. Going to double up some scrap 1/2" to make due.

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HolyGhost

First Fill-Up (of many)
Tested out the jig with the passenger side, 3/4 and 1/2 plate sandwiched together. Heated the manifold and torqued to 38lbs. Letting cool overnight before I pull it apart and check to see if it got any flatter. Also stared working out where things are fitting in the engine. Current mock up as I work out the wiring. Looks like it's all going to fit.

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Prime

Shut up Baby, I know it!
Admin
Location
Denver Adjacent
Tested out the jig with the passenger side, 3/4 and 1/2 plate sandwiched together. Heated the manifold and torqued to 38lbs. Letting cool overnight before I pull it apart and check to see if it got any flatter. Also stared working out where things are fitting in the engine. Current mock up as I work out the wiring. Looks like it's all going to fit.

qkmT4Mj.jpg


GFyRXCj.jpg
That's hot
 

HolyGhost

First Fill-Up (of many)
Oil pan bolted on went a different route on the oil return. It's going to be a -10 to 1/2NPT. I just have 1/2 plug in there now while I wait for the last fitting. Working on the exhaust pipe routing and hangers. Wiring is being terminated this weekend hopefully I can get the fuel pump to turn on with the 300zx ecu this weekend I will call that a success.

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HolyGhost

First Fill-Up (of many)
that valve cover is sick. that'll need to be polished with color matching accents.

You mean the engine cover? The valve covers are all stock X stuff for now might switch to the red 300zx covers though as I like the looks.

Got the 300zx computer to turn the fuel pump on. I think I have all the wires identified and ready to be permanently connected. Right now they are just temp wired.

I know this doesn't look like much and I still have to adjust the pressure but it's been hours and hours reading and analyzing the FSM for both cars to see this and I feel so excited about it.

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HolyGhost

First Fill-Up (of many)
Worked on getting the engine bay wiring cleaned up and swapped the temp sensor connector, A/C switch and power steering switch over from the X harness. 300zx uses the same ohm curve on the temp sensor so I can use the X's sensor and connector. A/C and power steering are just switches to control the idle up. Swapped everything and worked the harness into it's "final" location.

What's left of the X harness so far.
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Starting the cleanup.
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More or less the final product.
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