Peugeot Forums banner

1 - 14 of 14 Posts

·
Registered
Joined
·
1,616 Posts
Discussion Starter · #1 ·
I’ve been following the 1.2 thread with interest and thought it would be a good idea to start a new thread for the diesel versions.

The last full tank to full tank result for my 2.0 litre 180 hp diesel auto is 45 mpg. A mixture of short (8 mile) return trips and a few slightly longer (35 mile) return trips. 'My app' is registering 47.5 mpg for this month and 49.5 mpg for today. This is better than my previous 2.0 litre Focus on the same roads so I’m fairly pleased, but I’ve yet to compare on a much longer journey.
 

·
Registered
Joined
·
20 Posts
I do a mixture of driving, mostly on "A" roads. Average journey around 10-15 miles but have done about 5 long drives along motorway. 1.6 Blue Hdi GTLine Line Pearl White


Sent from my SM-G935F using Tapatalk
 

·
Registered
Joined
·
1,274 Posts
In my experience these on board computers and apps don't actually give you true readings of MPG. The only true way is to rim the tank, drive it then rim it again and do the calculation. I haven't had a car yet that told the truth. My current GT says I'm getting 41.2 MPG but in actual fact I'm getting 44.1
One of my other 2.0l says 52 MPG but is actually doing 48MPG. I do a MPG exercise on all my vehicles every 3 months as a matter of course.

Grumpy.
 

·
Registered
Joined
·
1,616 Posts
Discussion Starter · #4 ·
In my experience these on board computers and apps don't actually give you true readings of MPG. The only true way is to rim the tank, drive it then rim it again and do the calculation. I haven't had a car yet that told the truth. My current GT says I'm getting 41.2 MPG but in actual fact I'm getting 44.1
One of my other 2.0l says 52 MPG but is actually doing 48MPG. I do a MPG exercise on all my vehicles every 3 months as a matter of course.

Grumpy.
I agree Grumpy, I have an iPhone app that calculates my real mpg every time I fill up and enter the necessary details, the values never agree with the on-board computer.
 

·
Registered
Joined
·
1,274 Posts
Hi Dautres,

do you see much of a discrepancy like I do? Just wondering how curate your App is?

Grumpy
 

·
Registered
Joined
·
5,928 Posts
Fuelly is the best app for REAL mpg ^^:)
I agree that fuelly is very good but then I would as I use it myself as my signature shows but the best - hard to say. There are many programs, apps and web applications that can keep fuel records and some do so much more. They will all use the same kind of routines for the immediate and long term calculations so be pretty much the same fugures plus or minus a couple of tenths / hundredths depending on the rounding used.

While filling the tank at each visit isn't required, what is required to get accurate long term figures is calculations done between a starting full tank to the next full tank.This is the only way to 'accurately' calculate the fuel used against the miles driven according to the odometer (which itself could be slightly inaccurate).

I've read posts where some people state they get xx miles for £20. That is really a nonsense figure as the amount of fuel you get today for £20 could be quite different from the amount you get tomorrow for the same money.
 

·
Registered
Joined
·
111 Posts
I don't know how you're using fuelly, but I have just made it 'my duty' to put in the mileage, liters and price on each fill-up, that makes it 100% accurate for the average mpg :)


I agree that fuelly is very good but then I would as I use it myself as my signature shows but the best - hard to say. There are many programs, apps and web applications that can keep fuel records and some do so much more. They will all use the same kind of routines for the immediate and long term calculations so be pretty much the same fugures plus or minus a couple of tenths / hundredths depending on the rounding used.

While filling the tank at each visit isn't required, what is required to get accurate long term figures is calculations done between a starting full tank to the next full tank.This is the only way to 'accurately' calculate the fuel used against the miles driven according to the odometer (which itself could be slightly inaccurate).

I've read posts where some people state they get xx miles for £20. That is really a nonsense figure as the amount of fuel you get today for £20 could be quite different from the amount you get tomorrow for the same money.
 

·
Registered
Joined
·
5,928 Posts
I don't know how you're using fuelly, but I have just made it 'my duty' to put in the mileage, liters and price on each fill-up, that makes it 100% accurate for the average mpg :)
I fill my tank virtually every time I add fuel and enter the information into fuelly, a fleet management software and excel for each fuelup but how I use fuelly is irrelevant. If you read my previous post properly then you will see that I already stated that full tank to full tank is the only way to be accurate.

As for fuelly being 100% accurate - there is always some miniscule inaccuracy due to the rounding and /or significant decimal places (aka truncating error) used in calculations. With every computer and calculator when doing floating point calculations if you divide number (A) by number (B) you will get a result (C). Now if you multiply (C) by (B) you should get the result (A) but with the aforementioned errors you can get a slightly different result. Anyone who has experience programming where floating point calculations are used will no doubt have experienced this at some point in time. That being said, Fuelly is very accurate but so is the fleet management software I use and so is excel but there have been occasions when the same information entered into all three return different results because I choose to only display 2 decimal places and each one uses slightly different rounding or truncating algorithms.

As such I stand by my statement that fuelly is very good but the best.... Hard to say.
 

·
Registered
Joined
·
111 Posts
I don't get what you mean, maybe it's because English is not my main language, maybe it's because I don't get it all together but, why would it be more accurate to fill up from empty to full than from full to let's say half full and then back up again to full?'

If I have 40 liters in my tank, I then drive 200 km. and fill it back up to full and see how much I have used - (let's say I used 10 liters exactly) - then I know that my REAL WORLD fuel consumption is 20 km/l ... why would this NOT BE 100% accurate?

(The only reason I can see - and that would be the same no matter if it was empty or not, is to use the same petrol station and pump (there can be a little bit of difference between each pump)



I fill my tank virtually every time I add fuel and enter the information into fuelly, a fleet management software and excel for each fuelup but how I use fuelly is irrelevant. If you read my previous post properly then you will see that I already stated that full tank to full tank is the only way to be accurate.

As for fuelly being 100% accurate - there is always some miniscule inaccuracy due to the rounding and /or significant decimal places (aka truncating error) used in calculations. With every computer and calculator when doing floating point calculations if you divide number (A) by number (B) you will get a result (C). Now if you multiply (C) by (B) you should get the result (A) but with the aforementioned errors you can get a slightly different result. Anyone who has experience programming where floating point calculations are used will no doubt have experienced this at some point in time. That being said, Fuelly is very accurate but so is the fleet management software I use and so is excel but there have been occasions when the same information entered into all three return different results because I choose to only display 2 decimal places and each one uses slightly different rounding or truncating algorithms.

As such I stand by my statement that fuelly is very good but the best.... Hard to say.
 

·
Registered
Joined
·
1,243 Posts
I used to think the computed display was a bit of a gimmick.
Not now though.
The odometer is dead accurate.
Fill to fill 21km/L is now the norm @ 34,000kms
The distance covered + range tallies with the combined 1100kms average (taking into account end reading after longish drive v the combined figure early in a cold start period)
The 9999km figure is 'only' 5/100 BUT I average better than that -'4.9 fill to fill.
I see no reason to think it wouldn't be the same in the 3008 I'm lusting after.
 

·
Registered
Joined
·
64 Posts
Mpg

I’ve been following the 1.2 thread with interest and thought it would be a good idea to start a new thread for the diesel versions.

The last full tank to full tank result for my 2.0 litre 180 hp diesel auto is 45 mpg. A mixture of short (8 mile) return trips and a few slightly longer (35 mile) return trips. 'My app' is registering 47.5 mpg for this month and 49.5 mpg for today. This is better than my previous 2.0 litre Focus on the same roads so I’m fairly pleased, but I’ve yet to compare on a much longer journey.
I have just completed a 500 mile short holiday break trip to Devon(UK) and back, the average for my 2.0 litre manual was 47 MPG now this could have been bettered but I have a heavy right foot on motorways so never drove with economy in mind. Average MPG around town is 44 MPG both figures I am very happy with as these are better than the 2008 1.6 petrol this car replaced.
 

·
Registered
Joined
·
620 Posts
One thing to note, just by listening to the engine on the 1.6, is that the car takes a good 10-12 miles for the engine and gearbox to warm up. Before then the engine sounds "aaa" then after it sounds "errr".

If you're driving lots under that then it's highly likely the figures are going vary a lot.
 

·
Registered
Joined
·
1,302 Posts
One thing to note, just by listening to the engine on the 1.6, is that the car takes a good 10-12 miles for the engine and gearbox to warm up. Before then the engine sounds "aaa" then after it sounds "errr".

If you're driving lots under that then it's highly likely the figures are going vary a lot.
That would make a good entry for the topic 'Nobody buy a new 3008....because...because' the diesel version produces too many "aaa's" when what we need is "errr's". :D
 
1 - 14 of 14 Posts
Top