Comment by vctrnk | Hacker News Reader

Comment by vctrnk | Hacker News Reader

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I'm still looking for an open ECU focused only on old, carbureted cars. Projects like Speeduino, rusEFI, MegaSquirt, etc. are wonderful, but I have no use for them because they're more geared towards fuel-injected engines (though some do have ways to run injector-less).

Case in point: I have a Renault R5 GTL with a Renix pseudo-ECU module [1] taken from a Renault R11 TX, along with its camshaft, head, double barrel carb and other bits. It has inputs only for manifold vacuum & crankshaft sensor (some support a knock sensor, mine does not). A crude ROM map is applied to the advance curve from just those two parameters. It works really well, but that's it, no way to change or fine-tune anything.

> while testing showed it produced more power and better emissions

A customizable "ECU" similar to the Renix approach that does EXACTLY this, would be a godsend to me (and also my local old Fiat/Lada/you-name-it heads). At these small displacements, we just don't care how the engine sounds: every HP gained is a win.

[1] http://boursinp.free.fr/pdgdiag2.htm

PS. Yes, I know an 123ignition dizzy is what I need, but they're way too expensive - and proprietary. Where's the fun in that?

Electromotive sells a waste spark system they call "XDi" that seems to be the go to replacement ignition system for the earlier carborated Ferrari folks. Perhaps something to look at if you haven't already?

> and also my local old Fiat/Lada/you-name-it heads

If you've got any Fiat friends who have a car with a Digiplex ignition system that needs a replacement, my ignition units will work with many of them as well, as the Fiat units are basically identical to the Ferrari units but with different curves in them. I've never actually sold a unit to a Fiat customer, but I do have curve information on several Fiat and Lancia cars. The exterior boxes are 100% identical, and I've used some of the Fiat boxes as cores before (I use the old boxes to make the new units, as sandcasting new replacement aluminum boxes would be way too cost prohibitive)

> 123ignition dizzy

I've heard good things about those distributors, but I've never played with one myself. I've used the Petronix solid-state triggers to replace points in a distributor plenty, but several of my mechanic friends now use the 123 ignitions instead.

Don't even need Pertronix. You can use a TFI module from 1990's Ford vehicles and trigger it directly from the points distributor, or build a simple circuit with 1 transistor to invert the signal and trigger an HEI ignition module.

This is true, but the Pertronix units are cheap, easy to install, easy to remove and put points back in, and readily available. The downside I've found from them is that their reliability isn't perfect, but they're definitely better than points!

An OEM TFI or HEI is even cheaper and more reliable. If you splice everything with bullet connectors and keep the points coil with you, it's the same thing to go back to points, with no tools.

There's at least one Speeduino based model aimed at carbureted cars:

https://wtmtronics.com/product/carbumate/

Check out this guy. He built what calls a "carb cheater". It's a Chevy Idle Air Controller (IAC) from a TBI setup, and is essentially a very controlled vacuum leak. Using it, he's been able to get some pretty impressive feats done. Might be the level of hackery you're looking for. It doesn't do timing, but this is the right kind of tinkering you're looking for, I think.

https://www.youtube.com/watch?v=FwhMz2kR4pw

You can use a single injector at the intake—Throttle Body Injection (TBI)—to replace the carburation metering with a fuel injector. A lot of domestic manufacturers did this for a time when they were struggling to convert to EFI.

For the MegaSquirt (at least) the default metering is speed-density which sounds like what your Renix is, and this is the minimum needed to run the MS, unless alternatively you go for Alpha-N fuel mapping.

https://www.holley.com/blog/post/fuel_injection_fundamentals...

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