Assessing plug-in G4X option for 300ZX against goals

[Scryptid]

Hello Link users. I’m fairly new to the world of standalone ECU’s but excited to be exploring new functionality and potential for my vehicles. 

I’m looking to use a G4X plug-in for my 1990 300ZX. It was originally an NA car, and has been converted to a TT. Unsure if it’s a swap or engine conversion. It’s got upgraded turbos and manifolds, full exhaust, bigger injectors, bigger ICs and piping, and a single pop-charger style air intake. Currently it’s run on a chipped original ECU with a Greddy e-boost controller. 

I have some support from professional tuners but will mostly be embarking on a journey to learn to tune myself, having some limited experience. I intend on using resources such as HPA and others, as well as personal connections to professional shops to learn. 

My primary goals are better idle control, better low speed drivability, boost by gear, engine monitoring and protection, and hopefully with fine-tuning the engine’s performance, increasing reliability and longevity (as much as is realistic with an older turbo car). I also intend on converting to a MAP setup, likely using the onboard MAP sensor and installing an IAT sensor. Eventually, down the road, I’d like to convert to DBW to further simplify idle control and gain some more flexibility. 

 

Before I commit to this engine management solution, I was hoping to get clarification on a few questions. 

- I know that the ECU can be modified with flying leads for the internal e-throttle controller to be accessible. I’ve seen in other posts that the main concern for a DBW conversion on this platform is having enough input and output. I’m unsure how to figure out what is required on the ECU side, and what all I will need as far as additional I/O. I know an additional external controller will be needed since there are dual TBs. How do I ensure the ECU has the I/O needed, and what other features do I need to be considering when determining if I need more in the long run? I/O is a bit of a new concept to me in this specific type of use. 

- With the dual lambda, do I still need two Link CAN lambda modules (or other compatible controller) for the wideband sensors? Or does the plug-in have onboard controllers?

- Is it recommended with a primarily street driven vehicle to upgrade to a crank trigger and cam sync setup? I’ve seen other posts about the issues with the stock CAS and timing. 

- Does this specific ECU sound like a good option, or will I be running into limitations using the PnP option? I don’t particularly consider myself experienced enough to build an entire wiring harness, though I’m capable of some more basic wiring jobs, repinning, and such. My hope would be to replace the wiring harness with an OEM style replacement and wire in the needed/new sensors or components as additions when I need to, potentially repurposing unused wires in the harness as I delete unnecessary systems (such as the MAF), or simply running new wires.

 

Any insight is gladly welcomed. I’m hoping to do enough research to make the right decision the first time. I’m happy to clarify anything or answer questions. Thank you. 

[DerekAE86]

With the number of mods your car already has and the sheer amount of custom stuff you want to do in the future I would HIGHLY recommend going to a wire-in ECU rather than plug-in. You are just limited far too much by the plug-in and expander loom style.

From my own experience I'd say creating an engine harness from scratch, although daunting at first, is actually easier than repurposing or expanding on an existing setup as it usually requires extensive knowledge of the car and factory wiring - and thinking outside of the box about how and where you can easily route or add in functions because you are so constrained by what's already there. Starting from scratch with all the provisions you want is much much easier to comprehend.

I would also buy the highest end ECU to support all your future functions rather than buying a simpler one now and relying on expansion add-ons to gain functionality like DBW or Lambda. Since it'll likely be cheaper in the long run to just get the better ECU first.

As far as the crank/cam trigger upgrade. Typically older cars have very rudimentary/low resolution setups so road driven or not upgrading to an aftermarket crank wheel trigger will be better - but it just comes down to if you can justify the cost for what probably wont be much of a power gain when doing a street tune yourself. 

[Scryptid]

I appreciate the reply. Was kinda what I was afraid I might hear. 

So out of curiosity, what is it that I’ve mentioned that the plug-in can’t support other than a second DBW throttle body? Which realistically, I’m not fully sold on doing anyway. I’m trying to explore options to simplify the idle controls on the car.

I see the merits of the wire-in but I’m also concerned that it’s almost overkill. As far as I can tell, currently the only things that would need to be added outside the factory harness are the IAT, and the widebands. The DBW conversion is more of a hopeful idea but so far, I’ve not found almost any successful instances of it happening on this platform (the Z32) with the factory manifold, so it may get scrapped. It seems like the main thing that pushes the requirements over the edge. Anything else seems like it’s supported by the plug-in, but I guess that’s the clarification I’m looking for. 
 

Because you’re right, I definitely want to make sure I have an ECU capable of what I need, but I’m also trying not to dive too far into the deep end and take on more than I’m capable of with my current level of ability.

[DerekAE86]

It's not that the plug-in's can't support it. 

My personal opinion is that the plug-in ECU's are suited for completely factory cars where all you want to do is change to an aftermarket ECU to easily control plug-in/bolt on things like larger injectors / turbos to squeeze out more power. As soon as you want to do anything beyond that they rapidly lose their convenience value and start to limit you.

The fact your car was NA and now you've gone to Turbo means potentially more engine protection in the form of oil pressures and exhaust temps. Plus the benefit of modern boost control that can be folded up into the ECU rather than using the Greddy or 30yo factory solenoids. Then the MAP and IAT additions you've mentioned.

That on it's own would be enough to push me over the line. Then if you're already considering the possibility of DBW and different Triggers, etc in the future...

Again I'm not saying the plug-in's cant support this with the addition of expander looms and external CAN devices. But it may turn into a bigger hassle than you realize.

If you're worried about building a full loom from scratch you could just go the route of cutting the factory ECU plug off and rewiring the required wires straight into the aftermarket plug. If you've got the pin-outs for the factory ECU then it's pretty easy to match them to the pin-out for the Link.

[Scryptid]

Thank you for the elaboration. 
I’ll definitely do some more research and see what I can come up with. Both local Link tuners have recommended using the plug-in, but I absolutely want to take more perspectives and knowledge into consideration. All the others I’ve managed to speak with are Haltech only. I’ll probably make a detailed list of everything that I’m attempting to do, and see how it compares to the various options. Thank you.

[DerekAE86]

You have to remember that unless you find someone who specializes in your chassis/engine many Tuners will recommend the plug-in ones because they know if the car can drive in on a factory ECU it's going to straight up work when they swap it over to a plug-in and load a base map. When you start doing wire-in, and especially doing the job yourself, Tuners may start to get ansy because there's a high possibity of something not being right and they'll have to spend extra time diagnosing and fault finding an aftermarket ECU install they didn't do in a chassis they're not fully familiar with.

But if you're willing to do it yourself and get the car up and running with the base tune, fiddle with the settings and learn along the way its a great exersise.

Then once you're happy that everything is working and the car drives pretty well then you can take it to a Tuner to tweak the ignition and fuel map with their  years of experience on the dyno.