280zx turbo engine on test stand with Air/Fuel

[Dave WM]

Just figured it was time for clean thread on this.

I used a NTK25572 single wire O2 sensor for the ECU

AEM wide band gauge and sensor for the read out

Stock ECU, PRW-2 for the ignition transistor (and the correct transistor as well for testing).

Aftermarket CAS (NTK) due to OE flaking out.

the rest is all stock (turbo/CHTS/Knock sensor, Idle air control (vacuum modulator to control it), EGR.

 

[cgsheen1]

Welcome to the club!

Sounds pretty good, I do think that idle is a little high - probably by a couple hundred RPM. The stock L28ET ECCS will "prime" the fuel system running the fuel pump for about 4 seconds at IGN ON. It'll then stop the fuel pump and not run it again until it gets the signal from the CAS that the engine is turning. It doesn't have to be fired, just a stable repeating signal from the CAS. Like I said before, the green LED will come on at IGN ON and will stay lit until the ECU gets that signal  from the CAS. You can watch for that too (if your ignition key wasn't on the opposite side.. 😝) Those AFR's look pretty standard for the stock engine management.

I'm impressed with your test stand and I think you've got a nice L28ET there. I'm probably more impressed that you have it running so well with the stock harness... Enjoy it! I do. Goldie is an uphill beast - the torque of the turbo motor is awesome even at stock boost. Stock boost is 1/2 Bar (~7ish pounds) and the stock over-pressure relief valve is set for something between 9 and 10 pounds. The intake manifold has a "blowoff valve" built in (that's not what Nissan calls it, but it performs the same function - dissipates the boost pressure if the throttle is suddenly closed so it doesn't slam back to the compressor wheel).

[Dave WM]

having fun with it. Yes the green LED does exactly what you described, After the engine warms up some the idle drops down to indicated 750-800 ish (I had to reset the tach, it was set up for a 4 banger). I like the way the fuel pump primes as well. I had a couple hurdles to overcome with odd stuff like the intermittent CAS, but over all so far so good. Biggest issue will be fitment into the S30 engine compartment for the AFM. would like to see what others have come up with on that. Most of the conversions seem to delete the AC compressor and/or use standalone aftermarket EFI, not requiring the AFM.

Edited March 25, 2023 by Dave WM

[cgsheen1]

I would NEVER delete my A/C compressor! 

🤪 It's the first thing I had working after my L28ET was running. But, my early 260Z frame had factory A/C so it wasn't a big deal. (My L28ET was a gift from my youngest son who knew once he gave it to me, I'd have to find an S30 to put it in. He was correct.)

Our first turbo swap was into my youngest son's '76 280Z. Mine was done a couple years later.  We both used the AFM in the beginning - then a MAF. I'll try to find some pics but all were mounted in or near the usual 280Z AFM location - not USING stock AFM mounts however. I think we cut his out and mine didn't have any mounts to begin with.  We did custom cold air from the AFM / MAF in front of radiator core support - not the stock air filter. He still uses the F31 (Infiniti M30) ECU (with Nistune) and MAF. I moved on and will be moving on again to an AEM Infinity 506 ECU. I just need to get the engine harness finished.

[cgsheen1]

No, this isn't Goldie, it's my son's 280Z. His original color was 304 Gold Metallic. The original color of my 260Z was Brown Metallic which was oversprayed single stage orange...

Nick's 280Z had been running with the L28ET for a couple of years when the above pic was taken. I bought the 260 frame in late 2007 and drove it for the first time in March of 2008.

Humble beginnings. 

Edited March 26, 2023 by cgsheen1

[Dave WM]

yep that seems to be the issue the mount. I may end up carefully drilling the spot welds so I can reintall it back to NA if I ever want to. So I take it there is enough flex in the rubber pipe to angle up the AFM (looks like it has to come up a bit from the stock ZX location.

[cgsheen1]

Yes, there's room and flexibility. And in both cases our A/C compressors and associated tubing / hoses are installed. There's a bit of manipulation involved in the liquid line going through the radiator core support to the condenser. It gets pretty tight in that area with the larger AFM and the cold air... 

[Dave WM]

One of the things I am looking at is to pull the AFM perch by drilling the spot welds and putting back some rivnuts (maybe covered this already) as a precursor to the swap. I am hesitant to make unreversable changes since my car is a survivor. With the rivnuts I can reinstall the perch with minimal changes if I ever go that way. From what I can see there are only a few spot welds and they seem to be pretty easy to get at. This way I can pull the perch, and then reinstall the perch with the NA setup, saving me time when I am ready to do the swap, I dont like having my car down even a couple of days. I still have to look into the wire harness (I want to run the engine from the car wiring, not the test stand ign switch) so test out my pump wiring and tach. once that is done i am pretty sure I can do the swap in a weekend by just removing the bolted on perch, and swapping the engine. The Air filter is another issue. I like using OE style filter housings, but I assume the NA would be too restrictive. So I either go with the cone type (fast) or invest some time into reengineering a ZX filter housing. Looks like some fab work to make that happen due to the lower core support hole for the pass thru. Again main goal is a swap that is reversible to NA to be able to preserve the survivor status. 

For now I am still playing with O2 sensors, I ordered a couple different brands just to see how well they work in closed loop. I have also been thinking about the stand alone again, and maybe even a later model ECU that has sequential port injection. OR make one of the kits, I have extensive soldering experience so not concerned about that as long as its all thru hole stuff. I presume the surface mount (if used) is preassembled. 

[Yarb]

Just recently removed my AFM bracket. No longer needed as I’m removing any brackets that will no longer be needed since I’m going to triple carbs. I had to sacrifice the bracket in order to drill out the spot welds. The configuration of the bracket won’t allow to get a spot weld cutter back in there unless you can find a long bit to clear the bracket. I can send pics if you like. Let me know.

[Dave WM]

35 minutes ago, Yarb said:

Just recently removed my AFM bracket. No longer needed as I’m removing any brackets that will no longer be needed since I’m going to triple carbs. I had to sacrifice the bracket in order to drill out the spot welds. The configuration of the bracket won’t allow to get a spot weld cutter back in there unless you can find a long bit to clear the bracket. I can send pics if you like. Let me know.

Yes please do Yarb, I want to know what I am in for.

[Dave WM]

here is a new video, I am testing narrow band sensors, trying different brands to see if there is any difference. this is the NTK.

I did fix the tach, it was set for a 4 banger on the previous video. Idle now is 750-800, idle up with AC vacuum about 1k.

 

Edited March 29, 2023 by Dave WM

[Dave WM]

hmmm, did some more testing, put the bosch narrow band in, car runs like poo (goes super lean) back the the NTK, good to go. Guess the bosch is not the right one OR some cheap counterfeit deal. It was very low cost like 13$ IIRC guess you get what you pay for. The NTK was more like about 40$. I have the denso on the way, more video and testing to come when it arrives.