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EMAP (Exhaust Back Pressure) Sensor

Grant Baker

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I know it's been asked before, but can't find it...

Has anybody tried using one of these sort of sensors in a petrol turbo car?



I assume the EGT is going to be too high, but is there a sensor that can screw directly (or nearly directly) into an exhaust manifold to measure EMAP?

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I have never seen one connected directly.  The sensor needs to be protected from the temperature and contamination/condensation.  Usually a length of stainless tube from manifold running "uphill" to a small canister - normally filled with steel wool, then the EMAP sensor is connected to that.




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Here is an example of mine. Source is EGR port, which may skew the number from actual, but I don't have a way to source off the manifold of turbine housing right now. The far side of the canister will go to a braided line. The braided line will go to a firewall mounted pressure transducer. I suppose the transducer could be screwed directly into the canister.


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  • 4 years later...


sorry to bring this old thread back to life, but i recently purchased the Race Spec EMAP Kit.



i am trying to figure out what sensor i need to get for it. they recommended i get the same as my MAP sensor, which i am using my built in 7 BAR MAP sensor on the 350z LinkECU.

my question is, do i need a MAP sensor or can i get a regular pressure sensor?

7 BAR MAP sensor: 




0-150 PSI sensor:




i would find it hard to believe that the exhaust would even be in vacuum, but im not sure.

ive seen some kits show them with regular PSI sensors and others with MAP sensors.


thanks for the help!!

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You typically want an absolute pressure sensor rather than gauge or sealed gauge, not so much because you expect a vacuum, but typically because you want to see pressure differential across the engine or across the turbine - so you need to factor in atmospheric pressure which is acting on both the intake and exhaust. 

It doesnt necessarily need to match the same range as the MAP sensor, just something with enough range to measure the anticipated max exhaust manifold pressure. Either of those 7bar MAP sensors would be fine.   

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