I've been pondering the possibilities of taking one manufacturers' ECU, wiring harness, and maybe some sensors and adapting them to another engine. The reason for this is cheap available components and tuning. For example I can get a Saab wiring harness and ECU in the junkyard for $70. The tuning software is free. Say I want to put a turbo on a Miata Once you get the MS and do the mods you're several hundred dollars in. So am I crazy? Not in general just with this idea.
I think the most important thing to match up would be the crank (and cam) position sensing. Most other sensors are an easy retrofit, but if you can't get the proper tooth wheel that the ECU wants to fit the particular engine, it would be a struggle. Some engines use comparatively weird tooth patterns on the crank wheel.
You could try playing with Speeduino. The bare boards are super cheap, you have to source components yourself though. The trick is, electronic components are often cheaper for 10 or 100 than they are for qty 1. So you go to DigiKey or Mouser and order more components than you need to get the best price, but then for Challenge budget purposes you can prorate it back down to the quantity you actually used.
In reply to Stampie (FS) :
I think it could work. Some things off the top of my head that you'd need to determine & sort out in no particular order:
Also I presume the cylinder count would need to remain the same, but maybe there's a switch or settings in the Saab software to set that?
You can usually pick up a used MS1 v2.2 and a db37 connector for <200 sometimes cheaper if it's broken, and will work with hall senders (which there is a version of in the miata range, just don't remember the year). If you are shopping OEM type solutions something open source/easy to tune like from a 4g63, etc
I tend to help out challenge teams with cheap repairs and upgrades for MS FYI
newrider3 said:I think the most important thing to match up would be the crank (and cam) position sensing. Most other sensors are an easy retrofit, but if you can't get the proper tooth wheel that the ECU wants to fit the particular engine, it would be a struggle. Some engines use comparatively weird tooth patterns on the crank wheel.
Yup. I've seen people take the 3.8L systems and adapt them to the 250ci I6 and the reluctor wheel is the hardest part to figure out.
I think the crank wheel could be solved easy enough. I had a thought, are camshaft sensors always in the same location? For instance at 0 degrees? If one manufacturer had it at 15 degrees and another at 345 degrees that could be an issue.
Cam and crank sensors are not set consistently across many engine makes. Some variation will introduce some spectacular results. Megasquirt allows you to tune those events so you can get the ignition/injection timing happening correctly. If you are going to the effort of making an external crank sensor to retrofit, a cam signal wheel would not be too much more of a reach.
Even across the same engine family of 1UZ Lexus V8's the crank sensor wheel changed with the inclusion of variable valve timing (to keep better tabs on when to apply it). They changed from 12-tooth to 36-tooth wheels. It also follows that the electronic hardware was getting better, so the engineers increased complexity to make the engine run better.
The saab uses that crazy DIC and good luck getting that thing to work on a different motor! (did you know it does knock sensing - get this - through the spark plugs?) It's measuring resistance or something to understand cylinder pressure maybe? I forget exactly.
But you should just swap the whole saab motor into whatever you want. e85 and the biggest turbo you can find = winning.
Paul_VR6 (Forum Supporter) said:You can usually pick up a used MS1 v2.2 and a db37 connector for <200 sometimes cheaper if it's broken, and will work with hall senders (which there is a version of in the miata range, just don't remember the year). If you are shopping OEM type solutions something open source/easy to tune like from a 4g63, etc
I tend to help out challenge teams with cheap repairs and upgrades for MS FYI
I mean I picked up a Mini-MS (MegaSquirt clone that is actually quite similar to a MicroSquirt in a few ways) for $10 and put the rest of the components on the board/in a box and upgraded it to MS2 for about $150 (mostly the cost of the MS2 daughter board).
That said, some of the Porsche 924 folks figured out that putting the EFI from a later model VW SOHC of similar displacement worked quite well out of the box. Obviously sticking with similar engine configs goes a long way to being functional.
Robbie (Forum Supporter) said:The saab uses that crazy DIC and good luck getting that thing to work on a different motor! (did you know it does knock sensing - get this - through the spark plugs?) It's measuring resistance or something to understand cylinder pressure maybe? I forget exactly.
But you should just swap the whole saab motor into whatever you want. e85 and the biggest turbo you can find = winning.
ION Sensing:
https://www.pistonheads.com/regulars/ph-explains/what-is-ion-sensing-knock-detection-ph-explains/38892
https://www.eeuroparts.com/blog/tech-corner-saab-trionic-and-ionization-sensing/
My cousin is a huge SAAB head. He rents a shop near Silicon Valley to work on his cars/LeMons racers. The guy in the shop nextdoor has a Lotus Esprit running a modified SAAB Trionic solution. It all supposedly works quite well, but required a lot of work to adapt properly.
About the time the original Megasquirt started to get popular I remember a lot of people poopooing it because someone had cracked Fords EEC-IV and made software so you could set it up on many engines.
No one I know did this. They all opted to go megasquirt. I just remember a lot of excitement about it. Anyone remember this? Was it Tweecer?
That’s interesting about the DIC knock sensing.
I remember reading about some people having success adapting DSM engine management to the Miata's 1.6. Not sure if that would be any better than a used gen 1 megasquirt.
Using DSM ECU's is a thing for Miatas. Then you have DSMLink for tuning.
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