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Triple Blowthrough Turbo


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2 hours ago, DuffyMahoney said:

You will love the Zcar brake setup.  


Yeah really looking forward to it, everyone I know locally who runs the setup only says good things. 


This AM I had to get under the car to unplug a few things so I performed a quick undercarriage inspection. 


All looks good and bone dry and it seems the RMS was the leak culprit. Hopefully it stays that way until the next major service




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2 hours ago, Zetsaz said:

You always seem a few steps ahead of me and with better attention to detail haha. That RMS is a job I'm hoping to do this summer. I have a leak in the same area. Same with the Z Car Garage brakes. 


I feel like I've had this vehicle long enough that I've stripped the car down to a shell and rebuilt it with all new components 3 or 4 times at this point 😂. Kinda like my buddy, his s30 is like an airframe that keeps getting stripped down and rebuilt. 


When you do the RMS make sure you use a RMS tool. I used to always knock them in by hand but the proper tool makes it so much easier and foolproof. Also inspect the side seals. 

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  • 2 weeks later...

It's been a hectic few weeks but I've been inspired to get back on the build this weekend. 


Yesterday I had the opportunity to go for a ride along with a skilled driver then test drive a 3.2 NA stroker car with triples and the brakes I'm waiting on. I must say I miss being able to rap the throttles NA but the 3.2 turbo just sucks you into the seat in boost. 


The plan this spring has changed a bit as I've been inspired to revamp the s30s suspension a bit more but this weekend I'm going to focus on getting the main harness out. 



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Today I got the dash pulled. I started tracing the damaged wire back from the fuel pump circuit.


It looks like the black/white stripe which if I recall correctly is 12v switched ignition. I was using this wire to feed the 12v ignition leg of the oil pressure sensor to trigger the 12v relay to the fuel pump once that circuit closed under pressure. Now that I'm thinking about it, I had one oil pressure sensor start failing almost new but it was due to an oil leak due to a manufacturing issue earlier in the build thread and not an electrical issue. 


Hopefully I can get the harness out and decide what to do from there. 




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Next week my schedule looks terrible again so I decided to press forward and get to a good stopping point. 


I finished unlooming the dash harness and found the extent of the ground and 12v ign wire melting stopped where they respectively tied into larger branches. I noticed also some damage in the harness where the previous owner had spliced into some areas back when the car was drawthrough turbo in the 80s for the boost gauge, water/meth injection, etc. 


Generally, this harness is actually one of the nicests 50 year old s30 harnesses I've worked on, not far gone enough to warrant replacing everything. 


So I think the strategy here will be to uprate and replace all of the ground and 12v ignition wires, along with the entire fuel pump circuit (green wire + ground is about it) on the body harness. I'll order some rolls of factory colored wires today and clean up the harness while I wait for materials to arrive. 


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This AM I assessed what needs to happen. 


I ordered 10AWG gxl wire for the fuel pump dedicated power and ground circuits, and 12-14AWG txl wire for the harness repair/uprating. For the walbro 255 I think the final 2 foot pigtail to the pump is like 14 or 16 AWG, so it's questionable what a 10 AWG dedicated feed/ground gets me, but at least there will be limited voltage drop and headroom to upgrade the pump later. 


Since I have this all torn apart and my 12v ign and a ground wire melted I have decided to pull all accessories off the harness and into a dedicated distribution panel to avoid this in the future. 


I currently have: (1) fuel pump trigger, (2) boost controller, (3) o2 sensor, (4) tachometer, (5)msd 6ald. There are several fused/relayed compact powersports solutions I'm eyeing for this. 


I'm also planning to swap in an early 280z voltmeter and built the charge light off of the alternator L circuit as my amp meter doesn't do much with the internally regulated alternator. 


This will also be an ideal time to fabricate the AC system but I also want to drive my car this spring so perhaps it'll have to wait until winter again. 


Hopefully I can get everything ordered today then as is usual it'll be a couple week wait for the parts. 


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After some research, I saw a lot of Z forum questions on how to get charge indicator lamps to work without many clear answers although it is a simple circuit and universal for many vehicles. I recall wiring in a few on motorcycles many years ago. 


I found a schematic I believe from a 280zx off atlanticz which shows the circuit. It seems the charge lamp will be between the L terminal (switched ground) on the alternator and 12v switched ignition. So if my understanding is correct, when the engine is off or a charging fault occurs, L will approach 0 providing the ground for the charging light to go on. 


Next I will need to research if it's better to have ring and/or spade terminals or if the set screw type terminals are acceptable for all of the stranded 12v ign wires I want to consolidate on the car. The set screw type power distribution solutions are generally more compact, but seeing as my car vibrates its fasteners loose regularly I'd be concerned wires can vibrate loose or fatigue and shear over time. 


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  • 2 weeks later...

Realized I haven't updated for a while but the build has been going on in the background. 


This past few weeks I was waiting on electrical parts so I fully stripped down the suspension as I have a new set of coilovers and brakes going on. 


Today my voltmeter finally showed up so I'll start gauge swapping later this weekend. 



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I had a few mins after lunch so I went ahead and swapped the gauge housings and rear mount brackets to test fit. 


So now the early 280z voltmeter bolts into where the ammeter used to go. 


Now that I've verified the fit I'll tear it apart for restoration and rewire it all to mate with the OE 240z harness. 




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Got some more wiring done while I'm waiting on other parts which have been trickling in.  


Not sure why but the shorter KA/SR trans yoke dust covers were NLA for years then they came back in stock recently so I ordered a few and they just came in from Japan. My current JDM SR trans is missing this so I'll tap it on later this spring.  


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  • 2 weeks later...
  • 2 weeks later...

It's crazy how quickly time flies when you're busy but this weekend I'm getting back into the build again. 


I've been pretty on/off due to personal commitments but things have been moving forward. I have some buddies coming by this weekend to swap parts which will be nice to clear out my space then it'll be a few days of prepping and bolting on new parts. 


I feel like I've rebuilt the car a few times at this point, but the nice thing is you can basically shell swap a s30 over a weekend if you had everything prepared. 


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