Torque Pro vs OBC: Which is more accurate?
Discussion
Interested to hear from those that know which is more accurate?
I've had the torque pro app a couple of months and use it every now an again. I'm not expecting it to be perfectly accurate but results are rather interesting.
I drive a 2.0 diesel so nothing interesting but mpg at the time was important.
When the OBC instant mpg reads low - say 20-30mpg the app says about 75% of this.
When instant mpg says around 50mpg the app reads around 60-70% of this.
When instant mpg says 80+mpg the app says roughly 50% of this.
So which is the more accurate figure?
Any suggestions for the big difference?
This is monitoring over a few hundred yards+ as opposed to the figures going up and down all the time from stop start etc.
I've had the torque pro app a couple of months and use it every now an again. I'm not expecting it to be perfectly accurate but results are rather interesting.
I drive a 2.0 diesel so nothing interesting but mpg at the time was important.
When the OBC instant mpg reads low - say 20-30mpg the app says about 75% of this.
When instant mpg says around 50mpg the app reads around 60-70% of this.
When instant mpg says 80+mpg the app says roughly 50% of this.
So which is the more accurate figure?
Any suggestions for the big difference?
This is monitoring over a few hundred yards+ as opposed to the figures going up and down all the time from stop start etc.
HustleRussell said:
The only accurate method is calculating volume of fuel used vs. distance. Instant read outs are indicative at best.
Well yes this is true, I'm not too bothered about long term, it'd take me 3 weeks atleast to use a full tank and with varied driving all the time it would change.TheEnd said:
For most OBD bits and bobs, they'll all be the same as they all read the same data.
What you MPG differences will amount to is differing way they average out the instantaneous mpg readings.
Ill try resetting my OBC average and use the app over a journey see how far out it is then. What you MPG differences will amount to is differing way they average out the instantaneous mpg readings.
It may be that the OBD port which Torque pro gets the data from won't report data which gives an indication of fuel use directly, so Torque use other data to estimate it (TPS, MAF, rev readings, along with the vehicle speed), Diesel injectors also leak back some fuel into the tank so it might not be easy to measure actual fuel being injected easily for any computer to report (OBC or an aftermarket one such as Torque). I imagine the manufacturer knows how the engine and specific fuel pump setup work, and how much actual fuel will be used on that engine, reasonably accurately, whereas the Torque will be using a generic set of assumptions. Also the onboard computer might interrogate the fuel pump directly, and the data Torque use might not be such a direct measurement of fuel use, for example it might use the TPS, MAF and rev settings to estimate fuel use, i.e. a catch all set of data it reads that allows it to work on most cars, whereas the fuel pump ECU might have data on requested fuel quantity (still an estimate though as each fuel system will behave slightly differently).
I have a Scangauge on mine, and I believe the only data it can access to work out the mpg over the OBD port is throttle position, revs, and MAF value, with some type of load data too from the ECU (old Bosch VP30 pump, pre-OBDII). At default settings, for a 2 litre engine size, and no +/- fudge factor (there is a fudge factor section to allow fine tuning), the Scangauge shows that my car gives 20mpg over a tank, about half what it actually delivers. Through many hours of playing around, I found that setting the engine size in the Scangauge to 0.4 litres instead of 2 litres, but increasing the fudge factor figure massively (+150%), gives a very accurate mpg report over a tank, often within 1mpg of the actual mpg.
If there is a way of fine tuning the Torque calibration like there is on the Scangauge, it might be possible to get that very accurate.
The OBC might also be inaccurate (possibly on purpose so that manufacturers can make the car appear slightly more economical). The only way to know for sure how accurate the OBC is would be to do a brim to brim calculation, I suspect the OBC will be 5-10% optimistic, and the Torque app. even more inaccurate from what you described.
It's too easy to get hung up on these computers, I know, I've got the habit too!
I have a Scangauge on mine, and I believe the only data it can access to work out the mpg over the OBD port is throttle position, revs, and MAF value, with some type of load data too from the ECU (old Bosch VP30 pump, pre-OBDII). At default settings, for a 2 litre engine size, and no +/- fudge factor (there is a fudge factor section to allow fine tuning), the Scangauge shows that my car gives 20mpg over a tank, about half what it actually delivers. Through many hours of playing around, I found that setting the engine size in the Scangauge to 0.4 litres instead of 2 litres, but increasing the fudge factor figure massively (+150%), gives a very accurate mpg report over a tank, often within 1mpg of the actual mpg.
If there is a way of fine tuning the Torque calibration like there is on the Scangauge, it might be possible to get that very accurate.
The OBC might also be inaccurate (possibly on purpose so that manufacturers can make the car appear slightly more economical). The only way to know for sure how accurate the OBC is would be to do a brim to brim calculation, I suspect the OBC will be 5-10% optimistic, and the Torque app. even more inaccurate from what you described.
It's too easy to get hung up on these computers, I know, I've got the habit too!
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