Low Budget DIY Throttle Body EFI with Speeduino

[19-VW-74]

Over the past year, I've been designing and building a "homemade" EFI system for my mechanically stock 1974 Beetle. I started putting it together back in February and have been driving on it since the Summer, and troubleshooting and tuning the quirks that it has with the goals of reaching the reliability of a OEM style EFI system that a more modern car would have - say a late 80's or early 90's EFI system.

It has been a super fun project, and I've been taking lots of pictures and learning a ton, but the weather is starting to turn and the days have gotten shorter, so I think it's a good time start cataloging the progress for posterity.

So last winter, I set out with the idea that I wanted to build my own EFI system for my Beetle, including designing hard parts, wiring it all in, and tuning it from scratch.

The goals were pretty simple:

- Low cost (<$1000 or as close as I could get)
- Programmable fuel and ignition
- Reliable cold starts without pumping the pedal
- Reliable hot starts without holding the pedal down or hard starting like the stock carb
- Closed loop idle control
- Increased power and economy
- The durability of an OEM EFI system (or as close as I could get)


There are a few VW vendors out there that sell very high quality EFI kits, like CB and The Dub Shop. These are excellent kits, and I would love to own one, but I don't want to pay the price, and I want the satisfaction of building my own. The goal of this project is to have fun, not to spend money to have the best of the best. And this isn't the best of the best - I make no claims that it is, or that I am some expert on the subject of EFI.

Anyways, in the early stages of the project, I put together 5 parts list to accomplish EFI in several different ways.

1. Dual throttle bodies (IDF style) with port on port and 4 injectors
2. A single throttle body (IDF style) with port on port and 4 injectors
3. A single throttle body (Jenvey style) with port on port and 4 injectors
4. A single throttle body (IDF style) with two injectors (TBI)
5. A single throttle body (Jenvey style) with single point (TBI) injection

The first option came out to be the most expensive, as it would require:
1. A pair IDF manifolds ($110 - 150)
2. Two IDF throttle bodies ($400 - $2k)
3. A decent quality IDF linkage, like CSP or CB's ($140 - 180)
4. A pair of decent quality IDF air cleaners ($120+ if you don't want the flimsy stamped ones)
5. 4 Injectors (~$200 for OE quality set)|
6. Two fuel rails (if going with CB or Jenvey Manifolds - $70)

These parts alone go for $970 on the low end to nearly $3k if you buy top end throttle bodies. Realistically I would be closer to $400 on throttle bodies.

Couple this with the fact that it's going to go on a stock 1600, and the dual throttle bodies are overkill. And it will require removing the throttle bodies whenever the engine comes out, which requires adjusting the linkage when reassembling, unhooking several fuel lines, etc. Doesn't sound too appealing.

On the plus side, it would be great for future proofing when more power comes later, and it wouldn't require manifold heat like TBI would in cold weather. Also, port on port injection is overall better for power, emissions, idle stability, tuning, etc. But it comes at high cost.


The second option is less expensive, but not by a long shot. To build a decent EFI system with a single IDF throttle body and port on port injection, you will need:

1. A decent quality single IDF manifold ($150 - $200)
2. A single IDF throttle body ($200 - $1k)
3. A single IDF air cleaner ($60+, $100 if bought with CB's throttle linkage)
4. A single IDF throttle linkage (most of these are not great - I hear CB's is good)
5. CB's EFI end castings ($300)
6. 4 injectors ($200)
7. Fuel rails ($70 if buying CB or Jenvey - sold as pair)

This comes out to around $950 on the low end to $1900 on the high end.
You don't really save anything over dual throttle bodies here in the grand scheme. And you are still horsepower limited by the end castings. It's nearly the cost of dual throttle bodies, but without the potential for power.

On the plus side, it doesn't require synchronizing ITBs and disassembling everything to remove the engine. And port on port injection shouldn't require manifold heat or stovepipe preheat like TBI.


The third option is nearly the same as the 2nd, but using a single 40mm Jenvey SF style throttle body. This is not a dual throat throttle body like an IDF, just a single universal throttle body. This option requires:

1. A stock 34 PICT manifold (free - I already have it)
2. A single Jenvey SF style 40mm throttle body ($115 - $240)
3. A custom adapter to attach throttle body to manifold ($40)
4. A stock air cleaner (free - I already have it)
5. A custom throttle arm (Free - homemade from whatever)
6. CB's EFI end castings ($300)
7. 4 injectors ($200)
8. Fuel rails ($0 - $50)

This comes out to around $655 to $830 for these parts.

This is a significant savings over the 2nd option, and would likely produce the same power on a stock 1600. Looking through some of Paul H's posts, I've seen that a single 36mm throttle body can support the same power as a 40mm IDF throttle body if both are limited by the stock end castings.


The fourth option is our first TBI option, where we abandon port on port in the interest of cost. Remember, this is supposed to be cheap, reliable fun on a stock 1600, not the best of the best. Building this option will require the following parts:

1. A decent quality single IDF manifold ($150 - $200)
2. A single IDF throttle body ($200 - $1k)
3. A single IDF air cleaner ($100 for CB version)
4. A single IDF throttle linkage (included with CBs air cleaner)
5. Stock end castings (free - I already have them)
6. 2 injectors ($100)
7. Fuel rails ($70 if buying CB or Jenvey IDF - sold as pair)

This set of parts runs from $550 to $1470, if you buy a name brand IDF throttle body. So, on the low end, slightly cheaper than option 3. The money is mainly saved in the end castings and running two fewer injectors. There are significant drawbacks to this option though.

The main issue is the very long distance between the injectors and the port on this configuration. Single IDF manifolds are very tall and require a lot of manifold heat in cooler weather. Since this is TBI, we will still experience the wall wetting and evaporative cooling that comes from a center mount carburetor. Since it is an IDF style throttle body, it will require a lot of customization if we want to collect preheated stovepipe air in cool weather.

This could be a fun project to do, just cause it's different, but there are other issues. Since the firing order is 1-4-3-2, the cylinders fire RIGHT - LEFT - LEFT - RIGHT - RIGHT - LEFT - and on and on. Unless a cam sync is used, which is another $60 minimum, we will not be able to able to alternate the firing of the injectors. They will have to be fired in parallel (batch) every 180 degrees of crankshaft rotation. This will require two medium sized injectors, as they are shared, and very small injector pulse widths to avoid running rich at idle. With a cam sync, it would be possible to alternate the injectors to match the firing order, but that would require wiring each of the two injectors to two of the four injector channels at the ECU because the ECU can not fire injector two injector channels in that manner (like 1 - 2 - 2 - 1 - 1 - 2 and on and on). I haven't even talked about the ECU yet, I know.

And, as mentioned in option two, the single IDF is limited by the end castings, just the same as the small 40mm Jenvey single throttle body. Additionally, the single IDF will effectively have double the throat area of the 40mm single throttle body. This will make the engine act as if it is experiencing full throttle, when the throttle isn't open yet. So part throttle resolution will suffer, just by the nature of it's size. I recognize this is not a huge deal on a single IDF carburetor, but the carburetor has ~30mm venturis which reduce this effect somewhat. The throttle bodies are wide open 40mm.


Finally we come to option 5. This option is the final option to reduce cost and complexity for this project. This option is a TBI setup that uses the 40mm single Jenvey throttle body on the stock intake manifold. This setup requires the following:

1. A stock 34 PICT manifold (free - I already have it)
2. A single Jenvey SF style 40mm throttle body ($115 - $240)
3. A custom adapter to attach throttle body to manifold ($40)
4. A stock air cleaner (free - I already have it)
5. A custom throttle arm (free - homemade from whatever)
6. Stock end castings (free - I already have them)
7. 1 injectors ($50)
8. Fuel rails ($0 - $50)

This brings the cost down to $205 - $380 for the main components. Of course, none of these cost breakdowns include the other underpinnings of EFI, like the fuel lines, pump, IACV, ECU, crank trigger, wideband, wiring harness, etc. But those costs are pretty constant and would be obligatory for each of the options detailed so far.


Of course, the main benefit to this option is cost. But there are other positives to consider. The single 40mm throttle body will allow me to maintain the stock 1974 air cleaner with it's stovepipe intake for better cold weather operation. It will also allow me to use the high quality stock 34 PICT manifold that does a great job of transferring heat to the intake air. It will also only require a single injector, without any funky wiring of one injector to multiple channels on the ECU. Also, being a single 40mm throttle body, it is close enough to stock size to maintain good resolution in transient throttle operation, but will support more horsepower at higher RPMs (within reason). And finally, it is as simple as EFI can get, with very little to go wrong - and you can drop the engine without removing everything!

If it isn't clear already from the title of this thread - I moved forward with the 40mm single Jenvey throttle body in a TBI configuration. I know this forum doesn't take kindly to TBI - I've read all of the threads bashing on the Holley sniper - but I've got my fire suit on.

At this point, I've already built it and my setup works. I'm just documenting history - so bring on the hate!

I've got loads of pictures incoming, so stay tuned.
_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[ArnoudH]

Hi!

I got my 40mm IDF-Jenvey clone-throttlebodies off of Aliexpress including two intake manifolds delivered for 270Eur incl.shipping to my door in the Netherlands.That would be 300Dollars-maybe?
Good luck with your project!

Cheers,Arnoud

[oprn]

Carry on, you have my interest!
_________________
Our cars get old, we get old but driving an old VW never gets old!

[clonebug]

I built my original FI system in 2013 for about $1300 total…
Used MS-1 ECU
Used crank trigger wheel
Home built trigger sensor mount
Used Ford escort crank sensor
Used EDIS module
Used EDIS coil
CB injection endpieces
Stock German beetle TB
Stock German fuel regulator
Used Volvo fuel pump
Used 32# Volvo 740 turbo injectors
Golf fuel filler
Dubshop wiring harness
Dubshop sensors

It all worked great…

Keep up the good work……you learn a lot when you build your own system.

Quality wiring system and well thought out design will give you years of trouble free driving….:
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[19-VW-74]

[19-VW-74]

The throttle body I went with came from "SherryBerg" and it's a copy of the Jenvey SF universal throttle body, but in a 40mm version. Looking at Jenvey's site, they don't sell a 40mm version - the smallest appears to 45mm, which isn't useful to me. I could probably get away with a 36mm throttle body like VW Speed Shop sells, but 40mm works great - plenty of part throttle resolution.

Here's what it looks like:

One thing you'll notice, is that these throttle bodies are not reversible. Unlike the universal throttle bodies that VW Speed Shop and The Dub Shop sell, these can't be flipped 180 out and their guts can't be flipped 180 out to change mounting position or the rotation direction of the throttle blade.

As you can see below, these throttles are more flexible that way:

You might think - well why didn't you buy one of these?

I almost did, but I had a few hesitations -

1. The throttle arm looks a little longer than the 34 PICT-3 throttle arm, where the cable barrel attaches. I was concerned I wouldn't get full throttle travel.

2. Because the throttle rotation is like the stock carb, the throttle blade tips downwards away from the intake manifold at part throttle, which could cause intake air to push the injector spray against the manifold wall. I wanted to avoid that, especially during cold starts (I live in Utah, so it gets cold).

3. Also, even with the stock 34 PICT carb, there is a limit on the throttle travel that is around 75 degrees sweep. So if the throttle arm is as long or longer than stock, then the throttle blade will be pointed away from the manifold at full throttle, which could present a restriction (however small).

4. Overall this throttle body is a bit taller than the Jenvey SF style. Since I want to use the stock air cleaner, this presents a packaging issue. You can only lift the stock air cleaner ~1/2" before it rubs on the decklid.

5. The throttle shaft is mounted much higher on this throttle body than on a stock carb, so it could cause the throttle cable to rub excessively on the cable tube in the shroud.

_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[EVfun]

[19-VW-74]

So, I decided on the 40mm Jenvey SF style throttle body. I paid around $115 for it shipped from China and it showed up in <2 weeks.

While it was being shipped, I worked on designing a linkage for it. Since this throttle is not reversible, I needed to find a simple way to rotate the throttle blade backwards compared to a stock carb.

Lucky for me, Jenvey publishes the dimensions of the SF throttle body online, so I could model it up in Fusion 360 and work on a mounting solution. This is what I came up with:

This is designed to use a longer than stock cable, but keep it at close to the stock angle, and pull the cable around a 65mm pulley to change the direction of the throttle blade opening. The pulley is to be mounted on a sealed ball bearing, for smooth operation.

I worked on designing several different 4-bar linkages to actuate the throttle similar to the mexican EFI throttle, but I settled on this. It's a simple solution, with virtually nothing to wear out. I made the pulley as large as I could to increase the radius that the throttle cable would be wrapped around.

Also pictured in this CAD model is the adapter plate, which supports the pulley and fuel pressure regulator. Above the throttle body is a first draft of the adapter for the air cleaner. It's a rough model to show where the IAT sensor will be mounted.

Space here is at a premium. I needed to keep this assembly as short as possible, but a compromise of several needs must be met.

1. Air cleaner adapter needs to be as short as possible to keep the air cleaner away from the decklid but still able to mount an IAT sensor. It also needs to keep the air cleaner in the correct position to attach to the breather port on the oil filler neck.

2. The intake manifold to throttle body adapter needs to be thick to maintain rigidity for the pulley and FPR mounting. It will also have tapped threads, so it needs to be thick to get good engagement. But it also needs to be as thin as possible to keep the air cleaner from hitting the decklid.

3. The intake manifold to throttle body adapter needs to be long enough to provide space for a large pulley (65mm), but not so long that the pulley touches the decklid. This is also a give and take with the pulley size.

Luckily, this pulley design removes the issue of the height of the throttle shaft causing rubbing on the throttle tube in the fan shroud. I have complete control of cable positioning now, so raising up the throttle shaft above the stock position is not an issue.
_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[19-VW-74]

For the fuel pressure regulator, I went with an older L-Jetronic regulator off an Isuzu I-Mark Turbo.

I didn't want an adjustable regulator, and most adjustable regulators are either cheap junk or very expensive showpieces. There doesn't seem to be a middle ground there. I wanted to go with a basic 3-bar fuel pressure regulator that came stock on some 80s or 90s vehicle.

Of course, there are packaging constraints here too. Since I'll be using 5/16" or 8mm fuel lines and hoses, I need a regulator that has the right size inlet and outlet. A handy threaded portion to mount it to something would also be a nice feature.

I found a few modern Subaru FPRs that fit the bill, but I would have to either buy used or pay $70+ for a dealer item.

Then I stumbled upon this NOS regulator on ebay for under $8:

It interchanges with the Standard Motor Products PR62 regulator, which fits the 1987-89 Isuzu I-Mark turbo.

After some googling on some very old Australian Isuzu forums (they call it the Gemini there), I was able to find some documentation indicating that this regulator operates at 3 bar (45 psi).

So, for $8 bucks, I took the plunge and ordered it. When it arrived, I modelled it up in Fusion 360 and added it to the assembly.
_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[19-VW-74]

Once the regulator and throttle arrived in the mail, I could 3D print some prototypes of the manifold and air cleaner adapters.

The adapter looks like this at this point - it is 3/8" thick:

It has mounting on the left for the FPR and a an eyelet that the throttle return spring will attach to. It uses the stock 34 PICT spring for a stock feel. I also laid the spring flat in this position to remove most of the pressure on the throttle shaft by the spring. It's not a huge deal, because the throttle shaft is supported by ball bearings, but it will prolong their life.

Here is a top view of the CAD assembly:

You can see that the throttle body is actually offset towards the rear of the car. This is so the injector will spray straight down towards the "T" portion of the intake manifold. When the throttle body is centered, the injector port is aimed at the inner bend at the top of the intake manifold. Looking at the curve of the stock manifold, you can see that the intake port is vertical for the first inch or so. Once the adapter is ready, I'll use a burr to blend the 40mm opening down to the 35mm opening in the intake manifold.

_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[19-VW-74]

After 3D printing the first draft, I assembled the parts:

The quality of the SherryBerg throttle is excellent. I have no complaints about fit or finish.

The only issue is that the throttle shaft is not fixed laterally. It can float from side to side when the throttle is partially opened. When the throttle is closed, it self centers and seals well.

The throttle blade itself is chamfered all around so that it will fit precisely against the bore. It really is great quality all around.

To address the throttle shaft floating, I removed the throttle blade and pulled out the shaft to inspect it. It appears to be black oxide plated, and the finish is nice.

I replaced the shaft, re-inserted the throttle blade and closed it tight, then applied thread locker to the screws and tightened them down. The screws and threads were strong enough that I had no worries about stripping them out.

To lock in the shafts, you have to remove the seals over the bearings. These have sealed bearings, and then these green seals over the top of each bearing as well, probably to keep engine vacuum from sucking grease out of the bearings.

Once the bearings were exposed, I used some Permatex retaining compound to lock the shaft to the bearings. You have to work quickly here, because both bearings will need to be wet with compound at the same time. As soon as one starts to harden, you will not be able to move the shaft in and out to work in the compound.

I actually had to do this twice and replace the bearings because I overdid it on compound. The compound worked past the bearing on the shaft and began to fuse the throttle shaft to the housing. I had to work quickly to get it all out, and one of the bearings had already hardened to the shaft. So I had to press out the shaft and bearing, ruining one of the bearings.

So, I ordered a few more bearings on Amazon for $7 or so and did it over. So be careful if you attempt this. A little compound goes a long way.

_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[NJ John]

Early 2.8 V6 chevy’s had one injector and did 2.5 4 cylinder S10 pickups. You could use a open plenum progressive manifold.
Should be cool. Can’t wait to see the results.
_________________
1973 standard, yellow, lowered, 3” narrowed front, 1600 blo-thru turbo w/single dell 15.4@86, so far
11.41 et buggy. Long gone
Let’s go O’s! Let’s go O’s!
https://www.youtube.com/@AirSpooledGarage

[19-VW-74]

With the throttle shaft locked down, I went to mount the whole assembly on the car to mock it up and check dimensions. I extended the stock throttle cable with some wire I had laying around and tested the travel of the throttle arm that came with the throttle body.


Link

_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[19-VW-74]

I could see pretty quickly that the throttle arm would need to be modified a bit to get full rotation of the throttle shaft.

In my CAD model you can see the final prototype of the throttle arm I build.

This gives the same throttle arm length as the stock carb, between the throttle shaft and cable barrel (center to center). Its about 26mm, IIRC. This allows me to get full throttle motion with the stock gas pedal.

The eyelet at the bottom is for the spring mount. This also has the same radius as the stock arm for the spring eyelet, but allows the spring to be mounted vertically to take load off the shaft bearings. The goal here is to maintain stock pedal effort and feel.
_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[19-VW-74]

The SherryBerg throttle came with two different arms - one for mounting to a cable linkage when used to replace sidedraft DCOE carburetors, and another for linking the throttle arms together for an inline engine.

I decided to cut up this one and make my custom throttle arm.

I ended up using a torch to burn off the zinc plating (outdoors with a fan and a respirator - I'm not gonna be breathing this and you shouldn't either).

Then I got it hot enough to bend the tabs around (the arms are not ambidextrous). Finally I cut off pad and leaf spring.

I took some scrap flat bar and bent it into a U shape, then drilled a 6 or 7mm hole through it for the cable barrel. After a few trial fits, I welded it to the original throttle arm.

Finally I made the spring eyelet and welded that to it as well.

_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[19-VW-74]

Next on the list is getting a throttle position sensor and making sure it fits properly.

All of these Jenvey style throttle bodies seem to use the same TPS, but nowhere is it indicate what kind of vehicle they came from. SherryBerg sells their version for ~$40 unless you get it with a kit, and Jenvey is closer to $100.

As it turns out, the TPS for all of these kits is made by Wabash (part number 971-0001) for some Rover vehicles in the UK.

And you can get this TPS for under $20 on ebay or Aliexpress.

I ordered one for $16 shipped and got it in two weeks.

There are some threads out there about using an E36 BMW TPS with these Jenvey style throttles. While they look similar, the "D" profile of the shaft is clocked differently, so the have to be angled which requires extra fabrication and reduces clearance next to the alternator.

Once installed, I have barely any clearance as it is, so a BMW TPS will probably be a no go here. I loosened up the mounting bolts on the the base of the throttle body and shifted it over a little, and the clearance is fine.

_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[19-VW-74]

Since I'll be laser-cutting these adapters through SendCutSend.com, it is much cheaper to cut all parts at once than cutting and shipping a few at a time.

So I went looking for other parts of this project that will require laser cut parts.

I'll need a solution for:

1. Coil mounting
2. IACV mounting
3. Air cleaner adapter
4. Throttle cable pulley and mounting

So first let's start with the coil.

Since this is TBI, and one injector will be firing every 180 degrees, a cam sync is not worth buying. This will leave me with wasted spark as my only option for ignition. This means cylinders 1 & 3 and 2 & 4 will each be fired as a pair, alternating every 180 degrees.


I could go coil-on-plug, but that means buying 4 coils that weren't designed to use with the fan shroud. So they stick out like a sore thumb, and don't seal against the cylinder tin. Also, they will run in wasted spark, so they don't offer performance benefit in terms of dwell.

So this leaves me searching for a 4 post coil pack that can operate in wasted spark. The coils must also have built-in drivers, as the Speeduino ECU board does not have drivers capable of sourcing the amperage needed to operate the coils directly. Additionally the coil must be compatible with 5V trigger signals, as that is what Speeduino provides.

There are two good, inexpensive options that I could find.

1. VW 2.0L 4 post coil - this is the one that all the EFI vendors sell. It came on early 2000s VW Beetles, Jettas, Golfs, etc.

2. Subaru 4 post coil - this comes on nearly all SOHC Subarus from ~2005 - 2010.

The VW coils are plentiful and cheap, but they require custom wires, which adds cost. They are also very tall, so mounting could be tricky - it will stick out a lot on the fan shroud in the stock location.

I decided to go with the Subaru coil, because I can use my stock wires, and mounting is reasonably easy in the stock location.

I ordered a used coil from this Subaru generation on ebay for $19.

Then I mocked up a bracket in Fusion to mount the coil in the stock location

Printed it out:

After a trial fit, I was satisfied and moved on to the next part to design.
_________________
-Austin
My 1974 Standard Beetle Build:
http://www.thesamba.com/vw/forum/viewtopic.php?t=492617

[panel]

Good work ! Love the documentation !!
_________________
My '65 Bus~Subaru EJ20 Megasquirted Turbo conversion

[mikedjames]

I am reading with interest.

I have all the parts of a K-jet/CIS system in a box I bought for £60 a few years back..

The throttle body has been hacked onto the plenum. It is off a Golf Mk2..

I propose to replace the CIS kit with a set of modern injectors and drive it off an STM32 based Speeduino.

I have started with a homebrew ignition ECU using the £8 STM32 "blue pill" module. That drives a £35 EDIS module.. Coil pack was £16 is off the UK Ford Fiesta (compact) . The £40 timing wheel was so far the most expensive part. The VR sensor was £15 second hand, vacuum sensor was a Bosch environmental sensor in a small chamber I made out of rubber sheet around a PCB module off eBay..

Coil and driver module are on a sheet of 2mm aluminium with fixing bolt holes matching the stock coil. Stuff is bolted down to the plate with countersunk head screws.


I fitted this so if something breaks , I can swap the coil and driver assembly for a stock coil, and drop in a distributor. This has happened when the crank timing wheel came off ( not using a longer crank pulley bolt, added more shims , replaced stock pulley with aluminium which have a thicker boss and ran out of thread..) . Ten minutes between rain showers and we were back underway..

Now I have a longer bolt and a few thousand miles of driving, I think its time to tidy it and make it more permanent..

I am going to switch to Speeduino firmware , mostly because I want to be able to use TunerStudio. and develop any further firmware on top of Speeduino, so I follow with interest.

I am going to make a custom ECU out of modules and discrete parts, because its cheaper to fit just the sensors and drivers I need for EDIS and four injectors.
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[Bad bug]