awilson40

Hi Guys,
At what RPM will the stock VAF max out at 4.5 v ?
Would someone be interested in looking t a Zeitronix file where I'm
logging the VAF as the user 1 input?
I'm wanting some feed back to see if the unit is maxing too soon.
Thanks

hosrom_951

Stock would max out at 4.6v IIRC

hally

From my tech edge logging, mine flat lines at 4.2 volts

awilson40

at what RPM does it hit that voltage ??
Mine is at 4.5 v by 4800 - 5000 rpm.

hally

i'm logging mine as a % of 5V. I'm at 82% at 4500rpm and 84% at 5200. its hard going to extract that last 2% so i think the AFM is effectly maxed out (tuning wise) for me around 4500.

Tomas L

The boost level will effect the airflow through the AFM and therefore the rpm it will max out at.

hally

good point Tomas, my results above were for 15psi

Danno

"at what RPM does it hit that voltage ??
Mine is at 4.5 v by 4800 - 5000 rpm."

It depends upon the throttle-position and max-boost level. I'm assuming you're talking about under WOT? I've measured the max of 4.6v on my car at stock boost around 6000rpm. Increasing boost to 18psi has it hitting the fully-open max-voltage at about 4000rpm.

awilson40

thanks guys, it looks like mine is OK then.

badass951

Awesome! I think you are the first user I have ever seen use the term VAF. We have such outdated air-flow metering devices!

awilson40

TT set me straight as to the correct nomencature

One thing I did notice in the datalogging is that I get a bit of overswing when I floor in resulting in a momentary lean spike.
Thats another thing that makes me think I should tighten the spring a couple of clicks.

See...

Travis - sflraver

I was under the impression that the DME did not take into account the AFM signal when it was under WOT or at idle. The load signal was only put to use in part throttle situations. Is that just on the NA cars or the Turbo as well?

Tomas L

I can only speak of the turbo, but I'd be surprised if the BA was different, and I'm quite sure it uses the AFM signal for all maps, idle, PT and WOT.

One thing to note about bottoming the VAF. The engines max airflow will occur at, or near, the rpm where you have max power. After that the airflow will start to decline. This can be misstaken for bottoming the VAF.

Tomas

hally

You can't tune against load on the full throttle map (only RPM), but that does not mean that the load signal isn't utilized in calculating the duty cycle.
hth