cold air and maf voltages

[Dooie Pop Pop]

what with the lovely chilly weather we' re having :shock: :lol: will the increase in air density create a higher voltage at the maf and max it out sooner and other stuff i dont understand yet?

 

[Rishi]

what with the lovely chilly weather we' re having :shock: :lol: will the increase in air density create a higher voltage at the maf and max it out sooner and other stuff i dont understand yet?

No i don't think it will..

The volume of air going through will give the MAF the same voltage as always...

But because the air is denser you will have more oxygen particles per volume of air and so your oxygen/fuel mix may shift out... More oxygen for the same amount of fuel so you cars mixture may lean out slightly...

Not much though... Remember that the Volume of Air going through is the same ish... But because your oxygen content is higher you will get a better burn... i.e More Power...


In short... Your car will run slightly leaner but with more power...



Rishi

 

[AJ4]

Just to be awkward, I think the opposite of Rishi The MAF works by trying to keep a hot wire at the same temperature, therefore the colder air will cool it more, making the engine think there is more airflow and hence supply more fuel.

But then again, it references it to another hotwire that is hidden from the airflow at ambient temperature so it should compensate... :?:

I think its safe to say that you get better power though

 

[Dooie Pop Pop]

see how this has confused me :roll: :lol:

its a hot wire so cooler air will require more voltage to keep it at a stable temp or what ever it does. surely this idicates an increase in flow CONTENT therefore telling the ecu to supply more fuel giving more power?

the increase is why i mentioned maxing out the maf.

what other hotwire?

Stu

 

[AJ4]

There are two hotwires, one is used as a reference, the other is used to measure the airflow.

The weak point of the MAF system is that colder air or more flow both look the same to the ECU. It has a reference hotwire that is out of the airflow that basically just measures ambient air temperature, so it can tell whether the measuring hotwire is seeing more flow, or just colder air.

To answer your question, more flow or colder air will max your maf out quicker...

 

[Dooie Pop Pop]

iv got a z32 i take it that has 2 hotwires as well.

cheers, Stu

 

[Rishi]

Just to be awkward, I think the opposite of Rishi

You would... :lol:


But at least we agree on the more power part...




Rishi

 

[ram5ay]

I agree too, it's free power , but yeh it will max out sooner.
The hotwire measures air mass right! so this takes into account density as well as volume so your mixture should always stay right.
Colder air = more density, so more air molecules travelling over the hotwire. The colder the air, the higher the number of air molecules pulling heat away from the hotwire, so the more voltage is used to compensate and heat the wire.

 

[Dooie Pop Pop]

thought as much :roll: unfortunately im already a little high/over on my maf. it overfueled on the old high boost setting and made the car backfire :shock: :lol: :lol:

at least i hope thats what it is :lol: iv knocked it back .1 bar and it seems fine i think iv ruined Matties GTR for him a little anyway 8) go on, now deny it matty :lol: :lol: