[sc2dave]

i am thinking of building a homemade flowbench. all i want is something that will give me an indication if improvements were made or lost. no cfm's,no inches of mercury. just a basic,no frills setup. can a mass airflow meter be hooked up to a digital display to display numbers? any suggestions?

[2-manytoyzs]

Ford MAF systems monitor the voltage of the resistance wire in the MAF unit to calculate the air moving thru it. The wire is designed to maintain a specified temperature. When more air moves across it the wire cools and the computer sees that and ups the voltage to keep it at that specified temp. The computer then monitors the voltage used to maintain the temp in the wire to get its reading and calculates the air flow. I dont know how the other systems monitor their air flow.

[2-manytoyzs]

I dont recall the specifics of the VAF used in earlier fuel injection systems but the ones I've taken apart in the past use a variable resistor the sweeps with the movement of the vane.

[sc2dave]

so has anyone made one without any electrical parts? just using a manometer?

[Beenaway2long]

Hmmm, (Adjusting thinking cap to the right),,

If you were to take a small 12v electric fan, and seal it within a chamber, which could be sealed to the head, then use a vacuum cleaner to provide suction,,hook 12v fan to a voltmeter and check the voltage? The more it flows, the higher the rpm on the 12v fan. The higher the rpm, the higher the voltage.. Ya think so?

[johnsongrass1]

I copied David Vizards idea in his book about small chevy heads. I've used it with good results for a few years. The shop vaccum I use can't pull enough air to read on stuff with bigger than 240 cc ports though. I could use a bigger vacuum anyway.

[sc2dave]

what's the title of that book?

[johnsongrass1]

How to modify small chevy heads.

[fiscus]

I've been thinking of using a MAP sensor to make a flowbench, can anyone think up a logical way to employ it to measure flow? I have a spare one sitting here so it would be nice to put it to use. If I can't use it then I will try the 12v fan method.

[unstable]

Originally posted by huge rod
Or you can use twin screww roots type blowers hooked up to 150 hp electric dc motors and really get near to simulating a operating condiditon somewhat.

This is precisely what my machinist (and old shop teacher) is doing. I bought an old 8v71 off ebay awhile back, with plans of running it on my motor. Stupid me, the V models mount stupid. Instead of bolting straight down into the manifold they have an angled bolt. I'm sure you could fabricate something to make it work...but it's probably not worth the trouble.

Anyhow, I gave him the blower years ago...figured he could use it to show kids in class how a blower works. Talked to him the other day and he's going to turn it into a flow bench. Pretty cool stuff.

I'd just be interested to know how he's going to detect the air flow.