OBD Torque Phone App

[Seany Orrsum]

With the new car, I am using my OBD2 BT adapter to connect to my phone/tablet for the real time diagnostics.

Mainly to monitor the boost/airflow and a few other key things without installing gauges.

Currently my boost gauge is a circular dial with 0 at the bottom and the top is 20/-20.
The left side of the gauge is positive values and the right is negative.

At idle, it sits at approx -17.4, under full acceleration it goes to 0, and under downhill coasting is hits up to -20-22.

Is anyone else familiar with that app able to help me configure my profile so that it correctly displays my boost (if the above is not accurate).
There is a adjustment to account for atmospheric pressure, currently is set to 0.

New to turbo engines, so I am still learning how things work.

[kiwigene]

The negative numbers sound normal (usually a vacuum measured in inches of mercury - google is your friend if you want to know more about historical measurements of pressure).
On idle and cruising you will always be pulling a vacuum. The positive numbers are usually in Bar or psi (pounds per square inch) (1 Bar - 14.7 psi). The Torque app is probably in psi.
Turbo cars can create positive "boost" pressure. A stock GT will see anywhere from ~8 psi to ~14 psi on "full acceleration" (depending if you have SI-drive and which mode you're in).
The fact you see only "0" on full acceleration seems a little strange. Perhaps you have a boost leak?

[Seany Orrsum]

My units are in Psi.

So with my idle of -17.4, hitting 0 Psi under hard acceleration is, mathematically, generating approx 17psi of boost.

Based on that, I should change my offset/adjustment in the car profile page so that my idle boost is at 0, so when I accelerate it shows positive numbers from a base of 0, to indicate the boost pressure?

Edit: I do have the SI-Drive and generally use the S-Sharp when the turbo is at temperature.

Double Edit: Some exploring the app and found a setting to change how the 'boost calculation method'. Default is the MAP sensor, after a google, others have said that using the MAF is better. There is also a 3rd option to use the ALT.

[Seany Orrsum]

Separate post, because I think I have this sorted.

I ended up changing the boost calculation setting from MAP to MAF.

Now on idle it sits at -10. Under normal acceleration it ranged from 1 to -3.

Under foot to the floor I get losts of positive boost pressure, usually from 5-10psi.

[kiwigene]

My units are in Psi.

So with my idle of -17.4, hitting 0 Psi under hard acceleration is, mathematically, generating approx 17psi of boost.

Based on that, I should change my offset/adjustment in the car profile page so that my idle boost is at 0, so when I accelerate it shows positive numbers from a base of 0, to indicate the boost pressure?

Edit: I do have the SI-Drive and generally use the S-Sharp when the turbo is at temperature.

Double Edit: Some exploring the app and found a setting to change how the 'boost calculation method'. Default is the MAP sensor, after a google, others have said that using the MAF is better. There is also a 3rd option to use the ALT.

Idle will not be "zero". You don't want it to read zero on idle. The engine is running and sucking air, so there is a vacuum. Should be about -20 in/Hg on warm idle (~-10psi).

A "normal" boost gauge has the vacuum measured in in/Hg (inches of mercury). The Torque app allows you the "uncheck" the box to make sure the -psi readings are in in/Hg.

My boost adjustment is 0.0 - so there should be no need to have any offset. I am using the default MAP sensor. Positive boost is still measured in psi (or bar).
So even if your whole gauge is in psi you should see ~-10psi on warm idle and a positive boost of ~14psi on WOT in S#.

Edit: wrote this before your post above...

[Seany Orrsum]

Thanks for the reply anyway.

So when is boost, too much boost?

In just a small test, the gauge peaked at ~21psi after flooring it from an on ramp.

Edit: As for Psi, I guess I use it because I am familiar with the measurement, I've never used in/Hg before.

[kiwigene]

Thanks for the reply anyway.

So when is boost, too much boost?

In just a small test, the gauge peaked at ~21psi after flooring it from an on ramp.

Edit: As for Psi, I guess I use it because I am familiar with the measurement, I've never used in/Hg before.

No worries. You should use whatever units you prefer.

Stock car? 21psi should not be possible... either a dodgy reading or you are about to lift your heads and will need to rebuild the engine

In all seriousness, boost spikes are not what you want to see. If your car is not tuned I recommend you get a tune ASAP.
The stock tune is not very good. I've used Matt McLeod to tune my car (KiDo_Tuning on this forum).

[Seany Orrsum]

Ok, cheers for the heads up.

For now I'm going to use the logging function and see if spikes occur often, or if it was just a once off spike.

Another forum member (ferret89) recommended a local place, Coyote Tuning, which is very close to me, so I'm going to contact them first and see what they offer.