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Ok, so last night I started this journey by actually ordering some things. If you're not into details, skip this post and come back once I start putting pictures up.

I have an ECU on the way. Speeduino UA4C from WTMtronics in Michigan.

It's a Speeduino board designed by Weaver Markel and Josh Stewart. Josh is the mastemind behind the whole Speeduino thing and Weaver started making boards and distributes in the USA, as Josh is in New Zealand(or is it Australia?). They teamed up to design this one. As it is an open-source project, all schematics, code, and circuit board designs are available to anyone, anywhere, for free. Or you can donate if you choose.

The Speeduino boards are mostly designed to replace a factory ECU and re-use the case, to make it seem as if nothing has been changed underhood. This doesn't lend itself to ease-of-use by people like me that are starting from scratch. There are several versions of PNP(plug and play) boards already in a case for Miatas to illustrate my point.

So, the UA4C. It's a standalone with a 22 pin and a 24 pin header on the end for a total of 46 input/output pins. It comes with board-mounted connectors and loose connectors and pins for making up your own harness.

It has 4 ignition outputs and 4 injector outputs so full-sequential is possible in the future. Right now I'll do batch-fire(actually semi-sequential) injectors, 2 at a time. And I'll do wasted spark with that same VW Golf coilpack that Mike used, 2 cylinders fire at a time, one after compression stroke like normal and the other in-between. This is how MANY OE manufacturers did spark since the late 80s until recently. Now they do coil-on-plug which isn't really possible on a VW.

This the same way I've been running since 2008 with my Megajolt. Crank-fire(VR sensor) and wasted spark Ford coilpack. I built that from a kit of parts, and hand-assembled and soldered the through-hole components. This system has been 100% bulletproof so far.

The Speeduino board uses SMT(surface mount technology) and tiny components, so the board is basically finished and pre-soldered when you receive it. I added a bluetooth board for MSDroid(cell phone app to tweak and log on the fly). I added a signal conditioner to enable the VR sensor on my crank to be used as-is. I also added a stepper idle-air valve controller for possible future use(not planning to use at this time, but for $3.50 well-worth it).

The UA4C board includes both an on-board MAP sensor(Manifold Air Pressure or in my case: vacuum) and a barometric sensor for on-the-fly altitude  mixture compensation.

I also got the Arduino Mega that attaches to this board and is the brain of the operation here. And a nice aluminum case and custom pre-cut end plates for the case.

$187 including shipping so far.

I also ordered a new 3 pin connector from Mario at thedubshop for my existing VR sensor. $13 shipped.

Next up, I'll get some wire in multiple colors to build the harness. I already have extra shielded wire for the VR sensor.

I'm about to order some new injectors and an intake air and temperature sensors from CB Performance. That way they'll surely fit my CB throttle bodies and fuel rails.

Then it will be on to the fuel/regulator/pump stuff and installing a return line through the car.

Stay tuned(LOL!)


2016 Vintage Spyder 2165 type1 EFI/Dry Sumped

Last edited by DannyP
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Ha ha ha. 

I already have two CB Performance 48mm ITB(Individual Throttle Body), fuel rails and a TPS(throttle position sensor). I also have an MSD 2225 EFI pump and a Mallory 4305m adjustable regulator. I also have injectors, but they are the old low impedance peak&hold style. I'll buy new high-impedance injectors for this project, they'll actually bolt-on and are compatible with the Speeduino directly.

The throttle bodies are bolt-on, and I can re-use my linkage, air cleaners, air cleaner bases and intake manifolds with zero modification, so that's a big win for easy right there. 

I'll be taking them apart and cleaning the throttle-bodies. I got them from LennyC in a trade a few years ago when he went to Dell carbs and a distributor.

Last edited by DannyP

The ECU and VR connector will both be here on Monday.

I did some calculations, and my engine requires 28 lb./hr. injectors, or 295.31 cc/minute. The fuel pump I have, MSD 2225, flows 43 gallons per hour at 40 psi, and 39 gph at 80 psi. That translates to about 8 or 9 times the required flow, so I'll have way more than enough flow. The specs say 500 hp, but I think more like 300-350hp for that pump, which is still overkill for 170 plus hp.

This is an easy to use calculator for fuel rates and injector sizing:

I'll be using the Mallory 4305m fuel pressure regulator that I also already have(thanks Lenny!). The fuel pump will be under the tank, and the regulator will be in the engine compartment just after the fuel rail. I'm currently working out connections, returns, and possible surge tank. AN6 fittings will be used at either end. Hard line through the chassis for feed and return to tank.

I found 25 feet each of 11 different-colored automotive wire for a really good price. Chrysler and Ford certified harness wire, in 20 gauge, with insulation that isn't too thick to fit the Speeduino harness connectors:

I've decided to keep a running tally each time I spend more on this. And I'm sure to spend more than initially figured. Of course!

Right now I'm at exactly $200.

Last edited by DannyP

Phil, I know you are kidding here.

No, I haven't looked at Jake's stuff, Phil.

The whole point of this for me is to DIY, and to do it with the least expenditure possible. Plus, use components I already have(pump, regulator, throttle bodies, fuel rails). I really enjoy the process of researching, buying, and building it all up. And then running the crap out of it when it's done.

The ECU will be here tomorrow.

@550 Phil check your PMs.

Last edited by DannyP

This is going to be great, Danny.

The sheer betterness of modern EFI and crankfire spark should improve these engines by an order of magnitude compared to an 009 and typical enthusiast-tuned Webers. 

But that's for normal duffers.

Given how close to perfect your particular Webers are maintained, I'll be very interested to hear how much better EFI makes the engine, and how (if at all) you change your spark table to take advantage. 

I received all the electronic stuff last night. It's very nicely made. I'll post pictures tomorrow.

The Spyder needed some attention, which it got this morning. The steering was a bit loose around center the last time I drove it. First thing, found the RF wheel bearing a little loose. Front suspension needed grease also. Then I adjusted the steering box. Ahhhh perfection, as much slop as possible is now gone. What a fun-to-drive car!

Today was 78-80 with a light breeze and sun. My wife and I went for a good old Spyder ride this afternoon, and it was good. Real good.

When I left the house for a ride this morning (about 9am) it was just hitting 67F.

Got back home at around 11am and it was just hitting 77F.  Relatively dry, too.

Gotta love it.

Except for the Ragweed pollen, which makes me sound like Kermit the Frog, as Merklin found out when he called the other day.   My family and neighbors are used to Kermit always being around, but you guys sure aren't.   It's getting so bad I've re-started my allergy shots in a Covid world.  Scary for my age group, but I don't seem to have much choice.  Never had these allergies when I was a kid, but your body chemistry changes over time and I guess mine is getting lazy (like the rest of me).

Last edited by Gordon Nichols

Sorry about your allergies, Gordon, and the heat, Lane.

Pictures as promised. First the ECU case, slightly thicker than one pack and longer than two packs of cigarettes. But still, very small as far as an ECU is concerned.20200819_10423420200819_104312

No, I don't smoke people! Here are all the components that came in the box:


Clockwise from top left: Arduino Mega board, the "brain", the Speeduino UA4C, ECU board that interfaces the car to the brain, a USB cord and the case, connectors, the case endplates(beautiful and copper-clad for interference-blocking), the idle stepper driver, VR conditioner, and finally the bluetooth module.

I've got a bit of soldering to do, and firmware/software downloading. Then some testing and harness-building. This is going to be done over the winter off-season. 


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Last edited by DannyP

With an aftermarket ECU, you need a wide-band O2 sensor. In order for a wide-band O2 sensor to work, it needs a controller board. Without getting into all the details why, just know that you need to output a signal that varies from 0-5 volts(A narrow-band O2 sensor outputs between 0 and 1 volts and does this without a controller board). The Speeduino can read this voltage and know the A/F ratio and adjust it, this is what's known as "closed loop" A/F control.

A narrow-band can control the idle mixture and cruise mixture, but defaults to open loop when not idling or cruising. That's why it's called narrow-band. Conversely, the wide-band reads all the time and can help with tuning in all modes: warmup, cruise, WOT, decel, etc.

I got the wideband controller, wiring, and a little 3-digit LED display. I may not use the display, I can read the AFR through the app, but for $7.50 why not?

Once I solder it up and verify function, I'll pot it in epoxy in the little black case that it came with.

$47.50 for that, without Bosch O2 sensor, which I already have from my AEM POS that died. I got this a week ago, but forgot about it. 20200819_103234

@Carlos G : this is wired exactly like yours, diode on the red(+12v) lead, and fuse on the black(ground) side.

Total expenditure to date: $247.50


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Last edited by DannyP

Today I spent a couple hours on ECU assembly. I did quite a bit of soldering, thankfully I bought myself a nice temperature-controlled soldering station some years ago.

Those who don't want to read, skip to the pictures at the end. Summation: I did a LOT of soldering today.

I started out with the stepper driver for future idle valve control. It's all surface mount components on a board with 8 pins down each side, so soldering that in is like soldering an old 16 pin integrated circuit.

Then I soldered the connectors for the wiring harness, a 22 pin and a 24 pin. They were easy, the plastic connector snaps right to the board.

Then the rest is all header pins, but a LOT of them. The Arduino Mega has about 80 female contacts.

Then there were a few more for jumpers to select different options, and a 4 pin header for Bluetooth. 20200820_12093820200820_12252720200820_12274620200820_19051920200820_19070120200820_19080420200820_190825

The Bluetooth board will get a heat-shrink on it and probably a dot of hot glue.

It's pretty cool that the board/case came with the vacuum bulkhead fitting and hose for the MAP sensor. It even comes with a 3D-printed plastic piece that keeps the board pushed toward the connector end of the case.

Tomorrow, firmware/software download and testing.


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I caught the serial number on your Speeduino board of 488 and remembered the number of our (still dead) Bosch dishwasher when I called in for a service visit:  00042

I wonder if they got stronger after 400 or so?  (The dishwasher, not the Speeduino)

Also, it's good to see someone actually soldering stuff to a circuit board again.  Last time I messed with a PCB was when the SMD power switch detached from my Tom Tom GPS board.  I, too, bought a professional level soldering station (you can find anything on Amazon) with a micro tip and itsy-bitsy solder to get those tiny SMD legs soldered back onto the board, then fab'd a micro bracket to prevent over-pressuring the switch to keep from tearing it off the board again.  

Maybe next you can be on the lookout for a depreciated wave-solder machine or a "Happybuy" reflow oven for SMD stuff - Everyone needs one of those in their shop, ya know?  It would be a lot better than my GE counter-top "Easy-Bake" oven.

But then, making the fixtures to hold the PCBs and components in place as they get machine-soldered might take longer than the rest of the project!   


Yeah, I've got no need for a reflow oven...........

Today I got a couple things done that were important. First, I downloaded and installed the Speeduino on the Arduino Mega board. Then I tested connectivity with Tunerstudio, check. Next, I downloaded the Speeduino base tune.

No pictures, they wouldn't be showing much anyway.

Tomorrow, I'll attach the Mega to the Speeduino board and test the TPS, O2 sensor, coolant and intake air sensors. I need to download a VR signal simulator, load that into a spare Arduino and test the VR input. 

Once testing is complete, I'll be waiting a while to build the harness and install all this stuff.

Thanks guys. In my post above, I should have said "download and install the Speeduino FIRMWARE on the Arduino Mega". Oops.....

I spent some quality but frustrating time today on the ECU. Got it connected to Tunerstudio ok, but could only test a little. I couldn't get the crank output simulator configured. I also couldn't get the Bluetooth board to pair with either my phone or laptop. I'm sure I will eventually get there, but this stuff is not easy, simple, or foolproof. There is a STEEP learning curve going on, even for me, who understands most of this stuff.

The learning curve leveled out a LOT today.20200824_16172120200824_16172620200824_16173420200824_16171520200824_161709

Tunerstudio GUI on top. After I did some initial selecting, all gauges are in range, no more red. Tested MAP sensor with a vacuum pump, and TPS, IAT and CHT with a potentiometer.

Second is Arduino UNO($7) and free software for VR crank signal generator. Download some code and attach a signal and ground wire. Easier now that I know how......

Third is the whole mess with a 12v battery.

Fourth is a little battery-powered oscilloscope. That was a gift from a real tech-geek customer when I installed his FiOS. The guy had a super-fast liquid-cooled computer. You can see the trigger pattern on the scope.

Lastly, the ECU. You can't see the ignition and injection LEDs flashing, but they do. 12v and 5v LED are on, plus tach output and fuel pump output. It's a really nice unit for the money. 

I'm so thankful that I have the option of Autotune. It's well-worth the price. It'll definitely flatten THIS (learning) curve! As in, I won't really have to learn all that much......


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Nothing much to report today. Bluetooth board looks OK, and lights up, but will not pair. I ordered a new Bluetooth board($9 Amazon) plus a usb-serial programmer($11 Amazon) and I'll do it myself! They MIGHT be here tomorrow depending on USPS.

I don't count on anything destined for Friday to actually get delivered anymore.

I soldered up, heat-shrunk and tested the wideband O2 controller and calibrated it.

Total= $298.50

$247.50 + $20 bluetooth stuff and extra Arduino $7(which I had already but will count anyway) + $23.99(Dupont pin crimper for ECU harness)


Bluetooth module was delivered today along with USB-UART serial board to program. Took about ten minutes. The module is now programmed to 115200 baud rate, that is the speed that Tunerstudio and MSDroid use. Even changed the PIN, so it isn't 1234 or 0000 any more.

The first pic is all gauges "clean and green" as we used to say at work.

In the second pic the bluetooth module is ty-wrapped on the upper right edge of the ECU in a clear plastic case.

Both my phone and laptop paired up with the ECU quickly, so this project is ready to be installed. The laptop stayed connected 20 feet away, even though the bluetooth antenna is inside the metal ECU case. I'm pretty sure the cover is permanently installed now.

I calibrated Tunerstudio for the wideband controller, and tested the analog O2 input the same way you check the TPS, with 5 volts and ground to the outside pins, and center potentiometer pin to the ECU input. All good.

I also paid for the full version of Tunerstudio at $60.

So we're a bit under $360. Yeah, I could have bought a different ECU, but what would I have learned?

Building an ECU harness and fuel plumbing(fittings and hoses and lines, oh my!) is up next, but it will be a couple months before I start.



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Last edited by DannyP

And on top of that, you're having a heckuva lot of fun getting it built and running!

Nice clean installation, too.

And what does "Gamma Enrichment" mean for us carburetor users?

Never mind - Just found it:

It's a term that includes warmup, closed loop O2, air density, and baro correction:

Last edited by Gordon Nichols

Thank you all, gentleman.

I'm going to steal a page from Mike Pickett's book next:

I'm going to install the spark portion first and get that perfect. Then add fuel to the mix. It makes sense to do it that way, especially since I'm already running crankfire/trigger wheel/coilpack.

What's the old adage? One change at a time.

Spark first, fuel later.

I ordered some more stuff:


Bosch coil: $50

Coil connector: $10

Resistor plugs NGK DPR8-EA9 : $11

18 gauge wire(6 colors, 10 ft. each): $12


20 gauge wire(11 colors, 25 ft. each): $34

CB Performance:

28 lb. high impedance injectors: $180

IAT sensor: $40

CHT sensor: $40 (these two sensors are more expensive than most, but they're 1/8" pipe thread and smaller)

Fuel injector, sensor, and TPS connectors and injector clips: $55

$450 including taxes and shipping

+$360 already spent

$810 total. All that's left is hose, fittings, lines, and adapters. I'm sure I'll be under $1000.

I'm ahead of the game here, as I don't have to buy a pump, regulator, throttle bodies, injector rails, and crank pulley/trigger wheel/crank sensor. That's gotta be another $800-1000. But still would only be about 2/3rds of CB's complete setup.

Last edited by DannyP
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