A few questions

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RobTurbo
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Joined: Sat Apr 19, 2014 10:23 am

A few questions

Post by RobTurbo »

Now that I've had my neglected mx5 running and checked everything over I've ordered a Frankenso kit. After spending the last few days (and then some) reading up on rusEFI, I have a few questions;

1. My mx5 is already running on megasquirt, the fuel map is fairly close, can I copy this straight into the rusEFI?

2. Knock sensor, I understand this is alpha version and I believe none of the components are included in the kit, but I would like to use it if at all possible. First off, I don't understand any of the settings for it in tuner studio, second, what sensors are compatible, and third, there's no spec for X161 on the hardware manual. Is there anywhere I can get more info on this or is it best left alone for now?

3. I plan on using a MPXH6300 or MPXH6400 MAP sensor, I saw there was a PCB being made for these sensors, is it available to order anywhere?

4. This may need it's own thread. I've seen that it's possible to read the MAF/RPM fuel map from a stock ECU, would it be possible/how hard would it be to use the rusEFI as a "piggy back" to the stock ECU to learn any map you needed? Sort of like how auto tune in tuner studio collects data to alter the current map, could you use the stock ECU with rusEFI collecting data while you drive around or rolling road if available, for however long it takes to gather sufficient data. It would likely require some specific driving styles to collect all relevant data and I imagine some things you will still have to figure out, but if you can read the timing and duration of ignition or injector pulse width and feed it into a MAP/RPM map, you could also figure out warmup enrichment etc. by capturing a cold start or two. One or two people per engine could possibly build a database of base maps, if you were going to be the first doing that engine anyway, it may even make your own job easier, would it be much extra work to make this possible, or is that a completely different project?

If you could get past the hurdle of getting an engine running by making it as "simple" as, for this engine use this firmware, with this map, and assemble your board like this, then you could get to tuning a lot faster, I'm not saying this would make rusEFI a plug 'n play replacement for your stock ECU, but it would be a lot closer, and the data collected in theory wouldn't need updating, maps from the stock ECU would always be a great starting point.
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AndreyB
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Re: A few questions

Post by AndreyB »

1. I do not know since I never tried megasquirt which I have.

2. Frankenso kit comes with all parts for knock input but noone was able to make a definitive validation of the hardware or software. Let's postpone this.

3. why not GM 3 bar or anything else automotive with a proper case? rusEfi approach is to use external MAP sensor, not on-board MAP sensor. I believe we have a board for on of them see https://github.com/rusefi/rusefi/tree/master/hardware/Map_MPX

4. this is a big question and I am now convinced not worth the effort - easier to just tune it from scratch. Strategies are too different, reverse-engineering too vague. I could be very wrong :) See also https://github.com/rusefi/rusefi/issues/538
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RobTurbo
Posts: 11
Joined: Sat Apr 19, 2014 10:23 am

Re: A few questions

Post by RobTurbo »

I'll (try) to start with the megasquirt map then, I think my wideband controller may have developed a fault, it appears works fine to start with but once the engine gets up to around 70-80 degrees C it reads 22 AFR no matter what, I need to test it with the Innovative software to double check it's not a megasquirt/tuner studio problem.

I'll solder all the knock sensor parts anyway, so if you need volunteers in the future I may be able to help.

The megasquirt has an internal MAP sensor (MPXH6300), the vac hose already runs inside the car to the ECU, so I figured I'd go internal with the rusEFI too.

Another question, I see most, if not all mx5s/miatas use the op-amp for hall sensor rather than the MAX9926, as mentioned in the hardware manual, is this solely because of difficulty soldering the MAX9926? Would there be any advantage to using one rather than the other, other than ease of assembly? I have no problem soldering the MAX9926.
puff
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Re: A few questions

Post by puff »

According to @Darxfame, transferring Tunerstudio maps from another ECU to rusefi doesn't work (at least as expected) ;-(
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