Where does the Cobb accessport read boost?

[Indyteecee]

Kind of a noob question but I’m curious where the Cobb accessport gets its boost reading from. If I had a boost leak somewhere, would the gauge show low boost pressure?

 

[letitreign]

The accessport doesn't have it's own boost line, just references the boost from the ECU. I believe the ECU boost reading is right off the compressor housing. If you had a leak somewhere you should see a drop on your accessport even if the leak is downstream of the compressor housing. The compressor would have trouble pressurizing the volume as the air would escape as quickly as it was being compressed, showing a lower reading on your port. Somebody please correct me if that's wrong.

 

[JDG]

The accessport doesn't have it's own boost line, just references the boost from the ECU. I believe the ECU boost reading is right off the compressor housing. If you had a leak somewhere you should see a drop on your accessport even if the leak is downstream of the compressor housing. The compressor would have trouble pressurizing the volume as the air would escape as quickly as it was being compressed, showing a lower reading on your port. Somebody please correct me if that's wrong.

The accessport doesn't have it's own boost line, just references the boost from the ECU. I believe the ECU boost reading is right off the compressor housing. If you had a leak somewhere you should see a drop on your accessport even if the leak is downstream of the compressor housing. The compressor would have trouble pressurizing the volume as the air would escape as quickly as it was being compressed, showing a lower reading on your port. Somebody please correct me if that's wrong.

This is not correct. Pressure is read from the TIP sensor in the cold side charge pipe. The OEM unit can read up to 3 BAR (atmospheric) or 44.1 PSIA (Or 29.4 PSIG at STP which is how it would read on your accessport).

https://stratifiedauto.com/blog/how-to-run-over-29-psi-on-the-ecoboost-focus-st/

If you had a large boost leak, you would likely notice a change on your accessport in boost pressure. If it was a small leak, you would see an increase in WGDC which is interpreted as the turbo spooling more to make up the difference in boost pressure.

 

[letitreign]

Appreciate the clarification

 

[Alkoran]

I always thought the sensor reading on the Cobb came from the MAP sensor on the intake manifold since it shows Boost and vacuum reading. Correct me if I'm wrong but the sensor on the intercooler can't show the vacuum pulled at idle since it's located before the TB.

 

[Indyteecee]

I always thought the sensor reading on the Cobb came from the MAP sensor on the intake manifold since it shows Boost and vacuum reading. Correct me if I'm wrong but the sensor on the intercooler can't show the vacuum pulled at idle since it's located before the TB.

I thought it was the MAP sensor as well. Just wanted someone to clarify, but now with the replies on this thread idk.

 

[MagnetiseST]

Focus strategy may be slightly different. The readings come from information compiled by both sensors.