Could someone please give me a break down on the function and location (I beleive its above the TB) of this sensor and what 2.0 or 3 bar map means?

 

Yes typically it is located above the throttle body or is conected by a hose to the top front of the throttle body.

Function: Reads manifold pressure by reading how far the diaphram moves caused by changes in pressure in the intake maniifold.

Bar is unit of pressure measurement. a stock map sensor is about a .7 bar which means it can read up to .7 bar of positive pressure = ~10psi. A 3 bar means it can read up to 3 bar of positive pressure = ~44psi

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Qveon &raquo;</TD></TR><TR><TD CLASS="quote">Yes typically it is located above the throttle body or is conected by a hose to the top front of the throttle body.

Function: Reads manifold pressure by reading how far the diaphram moves caused by changes in pressure in the intake maniifold.

Bar is unit of pressure measurement. a stock map sensor is about a .7 bar which means it can read up to .7 bar of positive pressure = ~10psi. A 3 bar means it can read up to 3 bar of positive pressure = ~44psi</TD></TR></TABLE>

Part of that bar is vacuum dont forget.. It will read from 0 to 3 bar absolute.. A 3bar map sensor will read vacuum and up to 28psi of positive (gauge) pressure

 

So its a must when boosting at higher psi, to upgrade to a higher map such as the 2 or 3 bar..?

 

Now that BAR has been explained, let's move on to function. Back in the old days, not too long ago, they used to have vaccuum chambers mounted on the distributor that advanced ignition timing at different engine speeds, the MAP sensor replaces the need for the vaccuum advance and does it electronically.

 

opps. thxs i forgot to deduct for the vacuum side. silly me.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slomofo &raquo;</TD></TR><TR><TD CLASS="quote">Now that BAR has been explained, let's move on to function. Back in the old days, not too long ago, they used to have vaccuum chambers mounted on the distributor that advanced ignition timing at different engine speeds, the MAP sensor replaces the need for the vaccuum advance and does it electronically.</TD></TR></TABLE>

Well it doesnt just use the map sensor for that.. When the ecu sees map value(load), tps valve, and a few other sensor inside the dizzy it can run the engine with the ignition timing and fueling that you need.. Basically the ecu uses all the sensors to figure out the timing advance except its not really timing advance..

Timing advance just advances timing from idle as rpms/load increase.. Modern fuel injection with ecu's uses a table to say at x rpms and x load the ignition timing is x..