'93 Miata with 1.8 swap and GT2560 Turbo

[Gadgethm]

Hi everyone!

I've got myself a 1993 miata with a 1.8 swap + turbo build. This thing has been fun as hell to build! I got it about 2 years ago off of CL already converted to MS1 with a WRX turbo and no intercooler. Thing burned oil like crazy cause the turbo was on its last legs. Pretty quickly I got a Speeduino thrown in there and I've been making it better ever since!

Quick list of mods:

• Engine rebuild before I bought it with ARP head studs, cometic head gasket, and titanium valve springs

• Short throw shifter from MiataRoadster

• Cobalt Stainless Steel Exhaust with Flyin' Miata catalytic converter

• DIYAutoTune's upgraded timing wheel for NA miata CAS

• Flow Force 640cc Injectors

• Supermiata crossflow radiator and coolant re-route kit

• Silicone coolant hose upgrades (Heater core, lower + upper hoses as part of re-route)

• ATI Super damper + 36-2 timing wheel (sensor not installed yet, still using the old CAS + nissan timing disc)

• Garrett GT2560 turbo with custom built manifold & downpipe

• BEGI intercooler piping kit

• Completely overhauled the interior: New carpets, leather wrapped the dash, gauges, Sparco seats, etc

Here's some potato-quality photos from my potato-quality phone:

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IMG_20220717_194650.jpg (2.67 MiB) Viewed 3562 times

IMG_20220717_194638.jpg (2.58 MiB) Viewed 3562 times

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I'm a sucker for open source projects and the build-it-yourself vibe. I've been tuning this car on the street myself and while it runs okay for now, there's a few things here and there that I wish my speeduino PNP could do such as full sequential injection + ignition, knock detection, check engine light, MAF support, etc.

Enter rusEFI! I'm particularly interested in getting MAF support working with this build. Enough that I actually set up my piping with a MAF in mind, including a bypass valve and routing the valve cover vent line to the intake tube before the turbo. Part of this started when I read (this thread), and the thought of it has just stuck since. It would also be neat to mess with some of the code to see if one could get a blending of the two systems; though thats mostly just the programmer in me getting all excited...

I'm planning to purchase a board from @beermoneymotorsports (great job by the way, these ECU's look awesome!), but I really wish the gerbers were available for the community to make it a completely open source package... I'm half tempted to try my hand at making one using the Hellen scripts and then posting the KiCAD files. Maybe a future project?

Anyway, happy to be here and let me know your thoughts on the MAF stuff above! Am I crazy, or is this something actually worth trying to make work for my setup?

[mck1117]

Welcome to the party!

MAF should be functional enough to do what you want! Simon (Simon@FutureProof) tested it recently and found it maybe better than speed density on his car. One interesting option is to run a post-turbo MAF: between the intercooler and intake. That should theoretically give the best response/accuracy, but nobody here has tried it yet. Not really a temperature concern if your intercooler is doing its job.

[Gadgethm]

I had thought of that! I do worry about oil contamination from both the turbo and the valve cover vent, so I was planning to go the same route as OEM and do pre-turbo. Does make me wonder what the response would look like though!

[Simon@FutureProof]

Yep, good timing as Matt said I recently switched my e30 over to the MAF algorithm and I have been really surprised by just how well it works, in 3 or 4 logging drives I have managed to get it running as well if not better than the SD tune I had on there before.
Though my e30 is NA and a boosted MAF setup has not yet been tried, we think boost will be fine as the system calculates cylinder filling so it should account for the boost as greater cylinder filling which is exactly what you want.

A hot wire MAF system should respond to both the increase in density a turbo creates and the temperature so there is no reason a blow through system can't be made to work well on RE as long as the IAT is somewhere near the MAF sensor to be able to make some small corrections to the fueling.

Regarding the oil, I'm not sure it will be that much of an issue unless your spewing oil into the intake.
The hot wire is hot enough to burn off most contamination so unless it's really bad it should be OK. If it really is that bad then your bigger problem is that oil entering the cylinders where it will greatly reduce your knock resistance.

There are some open source boards if you were really set on that side, given you want to make lots of changes and play around with extra features the proteus may be a good option for you. It has a lot more IO than the miata hellen and means you can hook up a lot more sensors to it.
The PNP boards have been semi closed source as a way to fund the development of rusefi, which is why there are no gerbers available. The more feature complete rusEFI gets the greater the costs of maintaining everything and developing the next big feature.

I do agree a blended strategy would be interesting to try out, I'm not sure exactly what form it would take but I would like to consider something where we use MAF and compensate for intake and exhaust pressure differential.