air flow meter

[terry allen]

Hi has anyone tryed useing a mass air flow meter from a car to get air flow readings i am no good at electronics but is it possible to some how do it as it is a cheap part from scrapyards Terry

[49-1183904562]

Terry;

From strictly a theoretical point of view yes it can be done as that is what the OEM do with it, the real issues that one will run into are 1.) need of advanced electronics knowledge (Analog and Digital), 2.) The ability to display your information (Analog to a electromechanical meter or digital to the computer) these again are advanced skills and 3.) The mass air sensors are designed to work within the given range of the application thus accuracy and repeatability may be an issue when you move out of the working range of the sensor. (this all assumes you know the calibration of the given unit)

In comparison to a metal plate with a hole bored in it (cheep from Bruce) or a piece of pvc with a APT (also Cheep from Bruce) inserted in it, a couple of yard/meter sticks, a few feet of vinyl tube and a cup of water. I am hard pressed to see where this would end up being cheaper or even close to as accurate.

That said with a working bench in hand as a test bed it might be a fun project to get a cheep Mass air sensor flow it on the bench and begin an advancement in education.

JMO

Rick

PS. I think if you search the board you may find a post or two where Tom Vought discusses building such a device in his years of experience.

[thomasvaught-1]

As was said by the other poster, I played around with the mass air meters in the past for a few flow benches.

We have a very high quality Hatachi mass air meter flow bench to check mass air meters for quality purposes. Think many zeros for the cost of the bench.

This flow bench will give you a "transfer function" which will be a series of points relating output voltage (0-5 volts) vs airflow in Kg/hr. You then can write a simple excel spreadsheet program to calculate cfm based on mass flow from the meter. Course the mass flow will change vs the ambient conditions. Different people in the Turbocharger game use different corrections but for air flow purposes you could go by Standard Temp and Pressure with corrections for where you are.

All that being said you then need a 12 volt power supply (think computer power supply) that will maintain 12 volts accurately to the meter even though the line voltage might change. Otherwise the meter will read incorrectly.

All that being said the orifice measurement system is a ratiometric deal when used in a flow bench and is not affected by typical weather conditions. A lot cheaper too.

TOM VAUGHT