Since I'm premixing, the oil injector holes are plugged in the rotor housings. Could I use those spots to measure the manifold pressure for each rotor face? Kind of like a compression test? Would be just for information, not for running the ECU's MAP, that is taken from the intake manifold.. I would assume you'd see 3 spikes per revolution?

 

I don't see why not. The only downside is they aren't located near the spark plugs to where you could get CYLINDER Pressure and really hone in on tuning the engine. As such, you'll be getting them during the Intake Phase.

Plenty of cool stuff you could do with this, but I'd suggest keeping the OMP and Running 2-Stroke reservoir so that when you decelerate and fuel cut, the motor stays oiled.

 

No, I remember someone tried this and they got too much pulsation in the MAP signal.

I personally have experience with this from when I put my MAP signal on my ported polished intake manifolds at the furthest most ports on the FD UIM (right on the UIM to LIM flange.

Pulsation from the dynamic effect intake was 2psi positive pressure when running NA (no turbo). It made it so I couldnt transition my 2ndary injectors in using MAP as load when running NA.

I moved the MAP line to stock location and all was fine.

 

Oh, whoops- for data. No issues.

 

Kind of that's what I'm wondering. Would it give me any useful data? Getting a hole next to the sparkplug would be ideal with a transducer, but not practical.

I have a second map2 on my megasquirt and could put each rotor in a toggle pressure switch, and check between the two of them.

Could the intake phase give me any indication of how the apex and side seals are doing?

 

if you started with known good, and looked at it over time, probably

 

I keep wanting to do this to an engine/car that's a known quantity and isn't a development platform - read: NA grocery getter - mainly so was not to muddy the waters when I'm playing with other parts of a build so if you've got the inputs and a couple sensors lying around, go for it. At best you have some sort of indicative measurement of engine health and at worst you wasted some time and a few bucks.

On a side note, I'm still dreaming of a day when there is some real aftermarket support of using the actual spark plug as a transducer be it from measuring ionization or arc current. One day.

 

The aftermarket does have pressure tranducers thar fit undee the sparkplug. You could machine the sparkplug well a little more generous, torque the plugs with the sensor hooked up to the ecu to equalize them, then zero them out and see what the pressures are.

 

But that's not what I'm speaking of. I'm specifically talking about implementing non-invasive measurement capabilities such as ion sensing (that a few OEs are actually leveraging) or arc measurement (not certain if anyone has made this work in the real world, only read one paper on the subject) then on top of THAT a fleshed out control/feedback strategy to apply that data properly. These are the types of things that make me want to shell out for an M1 dev license.

 

Measuring the pressure during the intake phase would be interesting for sure. Useful? Maybe for the development of intake manifold designs...

I'm thinking it would have to be referenced against eccentric shaft degrees