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Discussion Starter #1 (Edited)
Hey guys,
I recently purchased an Bluetooth ODB adaptor and Torque (android app) (Total for all of this was ~30USD)
I've managed to get some nice information out of it. Best part is it allows you to log the sensor information that you like.
I generated this plot :

It also logs the GPS coordinates, heading, gps speed, acceleration (phone accelerometer) and more at 2-3Hz (depends on how many sensors you query from the car)
Here's the kml data that can be imported into Google earth. Clicking on nodes shows you the sensor data I recorded:
 

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Hey guys,
I recently purchased an Bluetooth ODB adaptor and Torque (android app) (Total for all of this was ~30USD)
I've managed to get some nice information out of it. Best part is it allows you to log the sensor information that you like.
I generated this plot :

It also logs the GPS coordinates, heading, gps speed, acceleration (phone accelerometer) and more at 2-3Hz (depends on how many sensors you query from the car)
Here's the kml data that can be imported into Google earth. Clicking on nodes shows you the sensor data I recorded:
Looks great, and the price is even better!

The boost data on the Google image is wrong, according to the info presented you were operating at less than absolute vacuum :)
 

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>> The boost data on the Google image is wrong, according to the info presented you were operating at less than absolute vacuum

It's reading boost and vacuum. Negative number is vacuum.
 

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Discussion Starter #5
Which bluetooth adapter and are you using the Pro version of Torque?
I personally bought this adaptor, but there are several like this on ebay.
You could also check Torque's recommendation for adaptors (even though the others are more expensive).
As for the app, I use the Pro version (but then again it's only 4CHF...)

Anyway, I really like this thing. I haven't been able to test the 0-60, 1/4 mile,etc...but I really want to. They should be pretty accurate since it's getting the speed directly from the car @ several Hz (phone's GPS only updates at 1Hz) and times it when you actually start moving till you reach the speed.

I really really wished Sensus would have integrated this type of information into some "hidden" menu. It already has access to everything, so I don't really get why they don't just put this in there...
 

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>> The boost data on the Google image is wrong, according to the info presented you were operating at less than absolute vacuum

It's reading boost and vacuum. Negative number is vacuum.
On an absolute pressure gauge a perfect vacuum is 0 psia and atmospheric pressure is approximately 14.7 psia. There are never negative numbers.

On a gauge pressure gauge atmospheric pressure is 0 psig and a perfect vacuum is approximately -14.7 psig.

Since the numbers shown are negative, they are gauge readings, which is not unusual for a boost gauge.

However, the value shown is -16.7 which is less than a perfect vacuum, and clearly impossible.

I suspect that somewhere a conversion from absolute to gauge was attempted by subtracting 14.7 from a reading, however the reading was already in gauge resulting in the displayed value being 14.7 psi too low.

Assuming level ground and minimal acceleration while traveling at 30 mph a boost reading of -2.0 psig is reasonable. At idle the boost reading should be about -7 psig and under heavy load it will swing positive.
 

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Got it. Makes sense. Looking closer, I think the units should be in/Hg when negative and the error is in the label for the data.
 

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Discussion Starter #8
Honestly, I don't know what's wrong with that figure. I can provide additional plots if you guys want, if that helps you figuring it out.
 

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Got it. Makes sense. Looking closer, I think the units should be in/Hg when negative and the error is in the label for the data.
That would certainly be the units a traditional mechanical boost gauge uses - in/hg for vacuum and psi for boost. And if so, -16.7 in/hg would be approximately -8 psig which is about the lowest I would ever expect to see, i.e. at idle or when coasting.

stormlv: despite the google earth image showing units of psi, does the documentation for your ODB device indicate what units it uses?
 

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Honestly, I don't know what's wrong with that figure. I can provide additional plots if you guys want, if that helps you figuring it out.
I checked the Torque FAQ and vacuum is recorded in in/Hg. So the number is correct but the way it
is presented is not (which is misleading). It should be something like this:

Vacuum(in/Hg) & Turbo Boost (PSI) Gauge: -16.7

It's a pretty slick app and the total cost is very low considering what you get. I'll have to
go check when I'm due for a new phone :)

The Faq : http://torque-bhp.com/forums/?wpforumaction=viewtopic&t=1272.0
Search for: And when negative, Torque provides the boost readings as in/Hg
 

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I checked the Torque FAQ and vacuum is recorded in in/Hg. So the number is correct but the way it
is presented is not (which is misleading). It should be something like this:

Vacuum(in/Hg) & Turbo Boost (PSI) Gauge: -16.7

It's a pretty slick app and the total cost is very low considering what you get. I'll have to
go check when I'm due for a new phone :)

The Faq : http://torque-bhp.com/forums/?wpforumaction=viewtopic&t=1272.0
Search for: And when negative, Torque provides the boost readings as in/Hg
Interesting that they went to the extra effort to change units between vacuum and boost to emulate a traditional gauge. Too bad their software guys didn't keep up :)
Should be an easy fix for the next software update they do.
 

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Discussion Starter #12
Cool that you guys solved the riddle of that reading.
Anyway, I've used it to get more data yesterday (like logging instantaneous fuel consumption, MAF sensor data, etc). It is a really nice app indeed (I think there's just one guy behind that!)
What I find most incredible is how cheap a system like this has become.
 

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Stormlv, you have a T5 or T6? I didn't think turbo pressure was an available parameter for these bluetooth OBD interfaces?
 

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Thanks! Does anyone know if turbo pressure(“intake manifold absolute pressure) is available on the T5?
 
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