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R34 Airflow Meter

mad34

By mad34,
in Engines & Forced Induction

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mad34 Experienced

mad34

Posted
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Posted

hmmm.

well i just had my emanage fitted. and the tuner said that the airflow meter is maxed out at 180rwkw at 12psi??

i know my brother using the exactly the same afm on his r33 was pulling around that 200-220rwkw mark with pfc.

the tuner said that i will need z32 afm as mine is maxing out at the moment at 5volts?? he is saying that the ecu is not liking any more than that?

its got me F**ked i wonder why. I need some expert answers ;P??????????????????????????????????

could the greddy emanage be running a different current to the afm than the pfc?

mad34 Experienced

mad34

Posted
  • Author
Posted
Why not consider the extra map sensor plugin harness for the emanage.

It will read boost pressure off the map sensor once the afm maxes out.

Just a thought.

yeah i was looking at that on mohd parts. thankyou most helpful. i wasnt 100% sure what it did.

Sydneykid Grand Master

Sydneykid

Posted
Posted
Why not consider the extra map sensor plugin harness for the emanage.

It will read boost pressure off the map sensor once the afm maxes out.

Just a thought.

How does that help?

The boost controller should be ensuring that the boost stays constant, especially at the sort of rpm the AFM is going to be maxing out at. So the MAP sensor shouldn't see any differences in the pressure. That means there is no variation in the load signal to cause the load mapping reference to move. So all you get is RPM mapping reference changes, which is what you would get with a maxed out AFM anyway.

The only time you really need an AFM upgrade is when unanticipateable changes in airflow occur, ie; not linear with rpm changes. At high rpm (ie; past boost build and camshaft timing effects) this shouldn't be an issue. The fuel and ignition requirements are satisfactorily driven off the rpm change.

That's why I don't change the AFM's until it is necessary because of tuning requirements, and reaching 5.1 volts at 6,000 rpm in an RB25DET is not one of those. It would seem that RacePace have a similar philosophy.

:D cheers :(

RB30-POWER Mentor

RB30-POWER

Posted
Posted
How does that help?

The boost controller should be ensuring that the boost stays constant, especially at the sort of rpm the AFM is going to be maxing out at.  So the MAP sensor shouldn't see any differences in the pressure.  That means there is no variation in the load signal to cause the load mapping reference to move.  So all you get is RPM mapping reference changes, which is what you would get with a maxed out AFM anyway.

:huh: cheers :)

Yeah your right.

But with regards to the original question, i was under the impression he wanted to run more boost then what he had, which would require someway of the ecu knowing that the extra boost is being run.

Sydneykid Grand Master

Sydneykid

Posted
Posted
Yeah your right.

But with regards to the original question, i was under the impression he wanted to run more boost then what he had, which would require someway of the ecu knowing that the extra boost is being run.

It's not the amount of boost, but the change in boost that the ECU would need to make use of for mapping purposes. MAP sensors are usefull when boost is building or decaying. But when the pressure stays the same for periods of RPM change they are not much use at all. You still have to use the RPM axis to determin the fuel mapping.

:huh: cheers :)

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