sensor question.

[hugh]

hey guys, might be a bit of a stupid question...is map sensor and vacuum sensor same thing??

[Jason]

Well, yes. Vacuum - by the name will only be able to measure vacuum, not positive (boost) pressure.

[86xxx]

<div class='quotetop'>QUOTE (hugh @ Dec 5 2007, 04:33 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=447151)</div>
hey guys, might be a bit of a stupid question...is map sensor and vacuum sensor same thing??[/b]


<div class='quotetop'>QUOTE (jason @ Dec 5 2007, 04:38 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=447154)</div>
Well, yes. Vacuum - by the name will only be able to measure vacuum, not positive (boost) pressure.[/b]

Correct me if im wrong, but i think Jason is wrong....

A vacuum sensor will only measure vacuum, yes, but a map sensor will measure vacuum AND boost, yes?!

So, No. They arent the same thing.

[hugh]

hmm, I just talked to toyota who said they are basically the same thing...
I have a 16v Bigport 4age N/A which has been fckn up a bit lately and i was told it is probably my map sensor. It is an engine conversion and i was told the description of the sensor which i found but it says vacuum sensor. Would my car have a map sensor or just the vacuum sensor...Im fairly new to the sensor things, all my other cars have been AFM.

[Jason]

M.A.P = manifold air pressure

So it's open ended. And i also said vacuum will only measure vacuum, but it is impossible to tell without the specs of the sensor.

correct term is MAP sensor. Or even AP sensor. Vacuum is limiting it to only vacuum, most sensors will be able to ready slightly 'positive'. (Ie measuring absolute pressure)

But if its just NA dont even worry about it. Just map.

[Nikkojoe]

A map can be vacuum or +ve pressure sensor, each used for different situations (ie vacuum for na and +ve pressure for turbo/supercharged apps). It will say either Vacuum sensor or pressure sensor on the map sensor.

[RobertoX]

Actually, MAP = Manifold Absolute Pressure

The sensor is supposed to measure the pressure in the manifold relative to absolute zero pressure (ie a total vacuum).

A vacuum sensor measures the pressure of whatever you are measuring (eg your manifold) relative to some other pressure (usually ambient) and measures the relative pressure.

So really the MAP and Vacuum sensors are the same thing just measuring against a different reference pressure (0 bar and 1 bar respectively).

The thing you need to understand is that there is no such thing as negative pressure, (there can be a negative pressure differential though).

[hugh]

would a 4agze vacuum/map sensor go alright into an NA 4age??