Can someone please explain the MAF Smoothing table and the MAF Sensor Filtering table.

What are they for? How do they affect MAF operation.

I am trying to solve random Hz spikes at idle. Will tuning these tables help? If so, how?

Thanks.

Paul

 

Smoothing is a multiplier that is used for the fuel calculation. It will not help random idle spikes.

MAF smoothing might help and will affect all load and fuelling calcs. There are two values shown, and IIRC a third value that isn't shown. The value in the filter divided by 256 can be thought of as the proportion that the old rolling average will contribute to the new rolling average. Don't think anyone has documented playing with them, but I know if you change the values to get rid of spikes then you'll also reduce response.

I would look for mechanical causes of MAF spikes, try another MAF, or you know my other solution.

 

Mechanical causes that might be a potential cause for the spikes....

1) No heat shield around the cone filter
2) Too small, or wrong type of filter
3) Filter adaptor is causeing flow issues
4) Cooling fan is disrupting airflow (see #1)

I am currently using a K&N small 4" cone. From what I read, I don't believe this to be the best filter for our application. Perrin, old style Buschur, or AmsOil seem to be the hot tickets.

The MAF adaptor, well I am stuck with it.

As for a heat shield.....guess it is time to do some fab work.

 

Have you tried the stock airbox with a lid cut on the coolest side? Very close to open cone for pressure drops in my testing, but this is only on the stock turbo.

 

No I havn't tried that.