[Jeffman]

Can the Cobb AP read actual vacuum in the engine? Any sensor in the intake manifold, or do I need to hook up a vacuum gauge like how the P3 is connected?

[JStang]

Originally Posted by Jeffman

Can the Cobb AP read actual vacuum in the engine? Any sensor in the intake manifold, or do I need to hook up a vacuum gauge like how the P3 is connected?

It reads vacuum when you are monitoring boost. Mine reads about -8.0 psi's at idle so you know it is reading vacuum.

[RoyalFlush]

Originally Posted by JStang

It reads vacuum when you are monitoring boost. Mine reads about -8.0 psi's at idle so you know it is reading vacuum.

+1; you can monitor it in real-time with the Cobb v3.

[miringrains]

Just a side note, at what idle vacuum do you know theres a leak? Mines reading low

[RoyalFlush]

Originally Posted by miringrains

Just a side note, at what idle vacuum do you know theres a leak? Mines reading low

Are you throwing the 30FF code or SES light at WOT pulls? Are you hitting requested boost?

[Jeff@TopGearSolutions]

Originally Posted by miringrains

Just a side note, at what idle vacuum do you know theres a leak? Mines reading low

What is considered low?

30FF codes would appear if you underboost for 3-4 seconds.

Sometimes you are on the threshold of not throwing an underboost code in which the only solution would be to A) find the source of the leak and B) look at Wastegate duty cycles to see if they are elevated in logs.

[Jeffman]

Originally Posted by JStang

It reads vacuum when you are monitoring boost. Mine reads about -8.0 psi's at idle so you know it is reading vacuum.

That's odd. My boost values always starts at 0.0 or 0.1 psi. I don't ever recall seeing -8.0 psi, maybe -0.1 psi. I thought boost was measured before the throttle, not inside the manifold?

I took another look at the Cobb. There is a MAP output (manifold air pressure ?) which reads a low of about 400 (units? Maybe millibars? Maybe mm Hg ?) idling, to about 1000 (units?) with low revving at about 2000 rpm (easy driving), to more than about 2000 (units?) WOT. Sudden off accelerator I can hear the diverter valves open and the MAP value goes down to a low of about 220. If in fact the units here are millibars or mm Hg absolute pressure, (14.7 psi = 1013 millibars = 760 mm Hg) then it makes sense that MAP is in fact the absolute pressure in the air manifold.

[JStang]

Originally Posted by Jeffman

That's odd. My boost values always starts at 0.0 or 0.1 psi. I don't ever recall seeing -8.0 psi, maybe -0.1 psi. I thought boost was measured before the throttle, not inside the manifold?

I took another look at the Cobb. There is a MAP output (manifold air pressure ?) which reads a low of about 400 (units? Maybe millibars? Maybe mm Hg ?) idling, to about 1000 (units?) with low revving at about 2000 rpm (easy driving), to more than about 2000 (units?) WOT. Sudden off accelerator I can hear the diverter valves open and the MAP value goes down to a low of about 220. If in fact the units here are millibars or mm Hg absolute pressure, (14.7 psi = 1013 millibars = 760 mm Hg) then it makes sense that MAP is in fact the absolute pressure in the air manifold.

Interesting. Have you updated the firmware lately? Maybe it is something new that they recently added.

[Jeffman]

Originally Posted by JStang

Interesting. Have you updated the firmware lately? Maybe it is something new that they recently added.

I keep up to date on the AP firmware and AP manager. Last firmware update was about 6-8 weeks ago?