I port/polish heads for high perfor

[racear]

I port/polish heads for high performance engines. At present I use a pitot tube to map a port in the head. Sometimes the tube causes problem in checkin. Im wondering if there is a way of using a bare resistance wire and induce voltage and measure how quickly the wire cools or something similar. Any thoughts please.
reed

 

[gruntguru]

You mean like a hot-wire anemometer? Link

je suis charlie

 

[VEBill]

Even if you did want to use a Hot Wire mass airflow sensor, you could just get a used one from a junkyard. It's not something where you'd need to develop your own design. You could even reuse the interface circuitry in the ECM.

Almost every car has some sort of mass air flow sensor. Several different technologies.

But a better approach might be to find an old flow bench. I've not check prices, but I have seen them thrown out for scrap metal value. They seem to something that should be affordable.

 

[gruntguru]

racear.
When you say "map a port" are you talking about a flow vs lift chart (as assumed by VE1BLL) or do you check velocity at multiple points inside the port (my original assumption)?

je suis charlie

 

[140Airpower]

racer, when you say the pitot tube causes problems, do you mean from disturbing the airflow? If so and it's due to size, a hot wire probe could be much smaller.

 

[TrackRat]

IME a hot wire mass flow sensor as used in a production vehicle would drastically impact air flow in a typical port. A very small hot wire would be required and even that might still cause air flow disturbances that would negate it's use. It's amazing how minute changes impact air flow in a port or manifold.

As a reference point I was tasked with resolving a 50% spread in air flow between two runners of an intake manifold on an I-4 engine ready to go into production. After cutting the manifold in half horizontally and studying the casting I made a very minor change that most people would not even notice and was able to balance all runners within 5% flow. The change I made to the manifold casting was about the size of the end of a typical pitot tube.