john hennessy wrote:
a question, as if it's not all questions
what happens if the map sensor never saw boost but only vacuum?
my concern is that the maf will handle the total amount of air ingested at 6000 rpm or will it run out of volts (0 volts to 5 volts) when the supercharger demand out strips the original engine demand, should i replace the maf with one from a bigger engine, (at 7 lbs of boost i would need a maf from an engine of 3.54 liters) or alternatively adjust the quantity of fuel in the fuel map to be richer per volt.
Megasquirt can use a MAF-only setup and use the MAP sensor for barometric adjustment at startup only. With a supercharger, your boost is pretty directly locked to your RPM. The stock MAF may cover 250hp, it's hard to say without knowing the calibration. You can pull any MAF out of the junkyard that has a known calibration, use
this page for MAF curves. The 5.0 Explorer is a good source - the junkyard is littered with them and they're the correct voltage-signal 4-wire type.
But you need to know how much boost you're running, and having the MAP sensor on the boost side is definitely best practice. The 2012-up Focus ST with a factory turbo actually has no MAF at all and runs MAP only. With the MAP on the boost side.
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perhaps i could find a similar EEC-V pcm from a bigger engine, say a 3.8 of the same year that had 4 cylinders?
Ford's biggest four cylinder engine is a 2.5L.
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i do think this is a valid discussion point as i have never been one to just throw money at a problem and always looked for a cheap and simple solution that may just be hiding around the corner, after all, i could just throw $3000 + at the problem and get a kit with a tune, right now i have $133.00 invested in this project.
The Megasquirt
is the cheap and simple solution. You could go with a Haltech or other name-brand ECU for $2000+, the MS is a steal at <$500. If you really want to get dirty with bad solutions that are cheap but won't work well, there are modifications you can do to the stock MAF like shoving a paperclip somewhere or putting a resistor inline to mess with the reading and make the ECU think that more air is passing through so it will enrich the mixture. But I've never ever ever seen someone do that and end up happy with it.
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i am looking for something that once set can be ignored from then on
I built my Megasquirt two years ago and haven't had to touch it since. I gave it a minor retune when I changed the intake tubing, but that's it. Once it's dialed in, it's done.
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no, as with excessive consumption of bath tub gin, (mothers ruin) E85 is the road to ruin for my little engine
E85 content varies, you'll need a flex fuel sensor to feed the ECU data on how much ethanol is in the fuel. E85 is a proven winner with boosted engines as long as they're set up properly with components that are resistant to the ethanol. Everything has to be sized a little bigger, but the high octane is a major help when it comes to preventing knock, especially when boosting engines that didn't originally come with forced induction. Obviously it's no fun and no use if you can't find it nearby.