Qhat exactly is engine load, and how is it measured?
03-27-2007, 09:46 PM
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Staging Lane
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Qhat exactly is engine load, and how is it measured? I've been reading up on cars for a while now, and one concept I can't get my head around is engine load. Is engine load a resistance to the motor for it to make power? IF this is true, then why is it calculated using air metering devices, such as MAF and MAP sensors?
03-27-2007, 10:07 PM
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I have always wondered the exact same thing.
How does MAP have anything to do with how much load or resistance the motor has on it.
Like if you rev it in nutral you can see the MAP rise really fast then once you rev to a steady rpm it drops off. Or you can be in a low gear and give it some gas and the MAP rises to the 80skpa.
How does MAP have anything to do with how much load or resistance the motor has on it.
Like if you rev it in nutral you can see the MAP rise really fast then once you rev to a steady rpm it drops off. Or you can be in a low gear and give it some gas and the MAP rises to the 80skpa.
03-27-2007, 10:18 PM
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Yes load is resistance to the engine
Lets take a given RPM say 1600 RPM's. Lets put the car on a dyno with varying wheel loading abilities. Now put no load on the wheels and run the car to 1600 RPM's and hold it there, then put a bit of load to the wheel and the load will force the engine to drop RPM's unless the driver opens the throttle more to keep the RPM's at 1600. So at a certain RPM you can go through many different load values on the engine which is part of throttle position and pressure in the manifold. A lot of the MAP has to do with the throttle position which effects airflow majorly.
Lets take a given RPM say 1600 RPM's. Lets put the car on a dyno with varying wheel loading abilities. Now put no load on the wheels and run the car to 1600 RPM's and hold it there, then put a bit of load to the wheel and the load will force the engine to drop RPM's unless the driver opens the throttle more to keep the RPM's at 1600. So at a certain RPM you can go through many different load values on the engine which is part of throttle position and pressure in the manifold. A lot of the MAP has to do with the throttle position which effects airflow majorly.
03-28-2007, 07:07 AM
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But how is the map pressure almost equal to the bap pressure when say you are in a low gear and go to 30-40%throttle.
Is it becuase you are at a lower rpm so more air is allowed to get in the cylinder.
I just would think that tp would have more effect on map rather than how much of a load there is.
Is it becuase you are at a lower rpm so more air is allowed to get in the cylinder.
I just would think that tp would have more effect on map rather than how much of a load there is.
03-28-2007, 07:11 AM
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Originally Posted by cmitchell17
I just would think that tp would have more effect on map rather than how much of a load there is.
