# boosting only under load?



## The Ben (Jun 14, 2005)

I know this is a newbieisk question. I have a very good understanding of turbocharging (at least I think I do) but can someone explain to me why you don't boost under load? I am sure it is a very easy answer once you know what the answer is. Thanks.


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## NotAnotherHonda (Aug 7, 2003)

please explain what you mean


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## wes (Apr 30, 2002)

The Ben said:


> I know this is a newbieisk question. I have a very good understanding of turbocharging (at least I think I do) but can someone explain to me why you don't boost under load? I am sure it is a very easy answer once you know what the answer is. Thanks.


It is not load it is throttle position and the amount of pressure needed to overcome atmospheric pressure. So until a certain throttle position and RPM you will not overcome atmospheric pressure to create boost.


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## chimmike (Oct 17, 2002)

wes said:


> It is not load it is throttle position and the amount of pressure needed to overcome atmospheric pressure. So until a certain throttle position and RPM you will not overcome atmospheric pressure to create boost.


which is basically load though. obviously not totally load, but you know.....at 3/4 or full throttle, the engine is under higher load....so I guess we could say the engine will boost under high load based on rpm, while the high load would denote a higher throttle position.


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## The Ben (Jun 14, 2005)

So if you were to put the car on jackstands and run the car you would still see boost if you put it to full throttle?


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## chimmike (Oct 17, 2002)

no because there's no load to the wheels. When you free rev the tires in the air, there's no force applying against them to make the engine work harder..........you know how this all works?

I'm not quite sure you understand this stuff.


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## The Ben (Jun 14, 2005)

Ok i think i get it. There needs to be a big enough load to create pressure to overtake the atmospheric pressure. That makes sense.


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