Megasquirt Advice and discussion.

[85rx-7gsl-se]

Its all formalities I think. Almost all cars either use a MAP or a MAF system exclusively. 2nd gens use a MAF system. 3rd Gens use a MAP system.

[RETed]

Originally Posted by 85rx-7gsl-se

Its all formalities I think. Almost all cars either use a MAP or a MAF system exclusively. 2nd gens use a MAF system. 3rd Gens use a MAP system.

Not true...

Although the FC uses the air flow meter as it's primary load sensor, the pressure / boost sensor also affects both fuel and ignition timing.
More specifically, we have confirmed that for a turbo FC, changes in vacuum will change fuel delivery.
Once in positive boost, the boost sensor will primarily affect ignition timing.
The RTEK guys (Henrik) will also tell you this.
So to use the word "exclusively" is not correct in this case.

The FD does use a MAP sensor based load system.
The FD MAP sensor is some funky version that goes up to like 17psi, I think.
(Most MAP sensors are in 15psi increments.)
The FD has no idea what the actual amount / mass of air going into the engine, but it does calculate that figure by looking at the engine RPM's and MAP sensor readings (primarily).
This is why it cannot tell differences in engine VE when you start modding your engine, i.e. change intake, exhaust, engine porting, bigger turbo, etc.
To the FD stock ECU, 15psi is 15psi.


-Ted