New project - your opinion - "Old MAP sensor to be used to measure wind pressure on front of car"


Joined Sep 30, 2009
but they are a direct indicator of Engine-Load, by definition.
That deserves an explanation. Having been around and working on old cars my whole life, I've never heard anyone say that about a vacuum gauge, or seen such a thing printed on the face of one.

Thread Starter


Joined Sep 24, 2015
kudos lowqcab and a few others for your attempts at clarity, it seems to fall on deaf ears.
First - this isn't falling on deaf ears. Rather, those who offer advice - as is what I've asked for - aren't listening to what I want to achieve.
Puncturing the rear of the map sensor effectively kills any accuracy it ever had. map sensor response time is slow which is why most efi systems went with maf. NAPA is wrong, a map sensor does NOT measure the airflow into an engine, it measures pressure on the absolute scale and does so slowly.
Again, for those who refuse to listen to what I'm asking for - "Accuracy doesn't matter". As for the "Slow" response time - didn't look that way on the scope. When I puffed into the pierced hole, the gauge responded nearly instantaneously. And yes, I know it kills the accuracy of the sensor, but - and yes, I'm going to say it again, ACCURACY DOESN'T MATTER TO THIS PROJECT.
the best option for reliable data is a scan tool that can display instantaneous fuel consumption.
Perhaps so, but it also requires one to look away from the roadway, which is - to quote your final word - "Stupid".
the entire experiment is flawed, however, since the required distance to the vehicle in front necessitates tailgating which is dangerous, illegal and stupid.
Awe geez! I'm not looking to build the "Perfect" experiment. You called it a toy. OK, perhaps so. But children play with toys all the time and sometimes they learn something in the process. For a middle school science project my son wanted to show how you could measure differing variations in light intensity and material reflectivity. It was his idea. I helped him with an oscillator that responded to the amount of light the sensor took in. Was it accurate? Nope. But the entire class didn't need to get out of their chairs and come to see a small meter (d'arsenal movement). The whole class could HEAR the change in light level as he pointed it at different materials to see how they reflected light. Did it tell them How Much light was reflected? No. It DID, however, give an audible change in tone when something by comparison to something else affected the tone. Toy? Yes. And no. He learned something, and so did the whole class. He got an award for his project. When asked, he admitted that I designed and built the circuit; which was beyond his young ability, but the project was HIS sole idea. I only recommended that instead of using a light meter, which he could have bought - but then what would he have learned - I recommended an audio tone so that everyone could hear the reaction.

I've tested small batteries using a motor and a soda cap glued to the shaft. How? By hooking the motor to a battery holder. When I put one battery in - the motor would spin at some RPM. Using a plastic strip against the ribbed side of the soda cap I heard a tone relative to the spinning cap. When I placed the next battery in the holder the motor spun at a different speed. The lower tone told me the second battery had less energy than the first. A meter will tell you the voltage, but the motor/cap system told me which had more charge. I've had 12 volt car batteries that couldn't light a headlight but still had 12 volts. Reading its voltage told me nothing of serious concern. But under the load of a motor the battery would respond differently.

Some people think outside the box. Others may think that's "stupid", but sometimes discoveries come of it. I don't expect to change the world with my stupid, dangerous and illegal project, but I also don't expect to stuff the nose of my truck under the bumper of a tractor trailer at 80 MPH. While I can clearly see this project yielding something of some value, others can't. They just point their finger and criticize. If that's all you have to say - I respect your opinion. But please tone down the derogatory tone. It's unbecoming of an AAC member.