Author Topic: MPG - How accurate is computer??  (Read 7393 times)

Offline Teutonic_Tamer

  • Forum addict
  • *
  • Posts: 4,562
  • GreasedMonkey - HoofHearted - GTI now mod'ed, ASK!
Re: MPG - How accurate is computer??
« Reply #30 on: 08 April 2009, 18:53 »
Trip 2 never clears, UNLESS you either clear it manually, or disconect the battery.

does your Trip 2 computer not reset it self after 99 hours and 59 minutes of driving then like in the MKIV?

Yes it does

so Mr T_T is WRONG!!!  :shocked: :shocked: :tongue: :grin: :grin:

<cough, cough>

Meeeeeee . . . . wrong, never!  :shocked:  :grin:  :grin:

Erm, just because Trip 2 runs out of fingers and toes at 99 hours and 59 minutes - that doesn't mean it resets.  The time just cycles round to zero again.  And the miles are the same - at 9999 miles, one more and it goes back to zero.

H O W E V E R
.
.
.
.
.
.
.
Just because the the elapsed time and total distance cycle back to zero, it still don't mean the Trip 2 has "reset".  Because the average speed and average fuel consumption will still be active!  :tongue:

<sticks out tongue, puts thumbs in ears, waves hands, and makes silly school-boy noises>
Sean - Independent Automotive Engineering Technician (ret'd)
-----
'06/7 Golf Mk5 GTI 5dr (BWA) DSG, colour coded,

I feel like a homo


Offline stealthwolf

  • I live here
  • *****
  • Posts: 1,056
Re: MPG - How accurate is computer??
« Reply #31 on: 08 April 2009, 20:16 »
I've found 'miles remaining' or 'range' to be dependent on your last average mpg reading, so if your average mpg was 20, your 'range' on a full tank will be lower than if your mpg was 40.

Not quite correct.  The 'miles remaining' constantly recalculates, but displays (in multiples of 5 miles) based ONLY on your last driving habits.  So if you cane the car, the miles remaining will drop considerably - but then if you start to drive it really carefully, you can actually see the miles remaining increase, even without adding any fuel to the tank.
That's what I was trying to get at - your average mpg would have been an indicator of your driving style, which would affect the range displayed.
BTW, Stealth, did you manage to get a Haynes manual?
Went down to halfords the weekend after your PM and couldn't spot it there. Will have another look tomorrow. Thanks for reminding me!

I had the one that reads while you drive show 99mpg  :laugh:

Yup, and some makes of car can read 999 mpg.
The highest I've made mine read was 234mpg.
The average is accurate,
I personally havn't checked mine, but they are supposed to be within 10% accurate.  However, if anyone does want it to be more accurate, then there is a setting the stealer (or vag-com) can tweak to adjust the accuracy of the MFD mpg readout.
So why isn't it already set to the tightest accuracy?

Sorry, but disagree.  The 'while you drive' reading is an instantaneous readout, rather than an average.  And it is very good in helping to drive in an economical manner, just like the old-skool vaccum gauges.
As T_T has stated, the current mpg reading (as opposed to the average mpg) is great for trying to drive economically. Quite amusing to see the effects of road gradient on mpg when you stick it 6th gear and leave it on cruise control at 60mph. I knew it had an effect but didn't know how the extent until I did this.

Offline ub7rm

  • I live here
  • *****
  • Posts: 1,476
Re: MPG - How accurate is computer??
« Reply #32 on: 08 April 2009, 20:20 »

 Quite amusing to see the effects of road gradient on mpg when you stick it 6th gear and leave it on cruise control at 60mph. I knew it had an effect but didn't know how the extent until I did this.

Indeed, my journey to work is on average an incline and there is about a 3mpg difference between going to work and coming home (downhill).
2020 BMW 128ti
2017 Golf GTD Estate

Offline Rhyso

  • Global Moderator
  • Sir Postalot
  • *****
  • Posts: 26,720
Re: MPG - How accurate is computer??
« Reply #33 on: 08 April 2009, 21:19 »
Trip 2 never clears, UNLESS you either clear it manually, or disconect the battery.

does your Trip 2 computer not reset it self after 99 hours and 59 minutes of driving then like in the MKIV?

Yes it does

so Mr T_T is WRONG!!!  :shocked: :shocked: :tongue: :grin: :grin:

<cough, cough>

Meeeeeee . . . . wrong, never!  :shocked:  :grin:  :grin:

Erm, just because Trip 2 runs out of fingers and toes at 99 hours and 59 minutes - that doesn't mean it resets.  The time just cycles round to zero again.  And the miles are the same - at 9999 miles, one more and it goes back to zero.

H O W E V E R
.
.
.
.
.
.
.
Just because the the elapsed time and total distance cycle back to zero, it still don't mean the Trip 2 has "reset".  Because the average speed and average fuel consumption will still be active!  :tongue:

<sticks out tongue, puts thumbs in ears, waves hands, and makes silly school-boy noises>

well it must be different from the MKIV then as the average fuel consumption and average speed also resets along with the time driven and miles covered  :tongue:

Offline ifti

  • I live here
  • *****
  • Posts: 1,117
Re: MPG - How accurate is computer??
« Reply #34 on: 08 April 2009, 22:02 »

 Quite amusing to see the effects of road gradient on mpg when you stick it 6th gear and leave it on cruise control at 60mph. I knew it had an effect but didn't know how the extent until I did this.

Indeed, my journey to work is on average an incline and there is about a 3mpg difference between going to work and coming home (downhill).

I have exactly the same scenario myself! lol

Offline smartypants

  • Here all the time
  • ****
  • Posts: 461
Re: MPG - How accurate is computer??
« Reply #35 on: 08 April 2009, 22:05 »
Trip 2 never clears, UNLESS you either clear it manually, or disconect the battery.

does your Trip 2 computer not reset it self after 99 hours and 59 minutes of driving then like in the MKIV?

Yes it does

so Mr T_T is WRONG!!!  :shocked: :shocked: :tongue: :grin: :grin:

<cough, cough>

Meeeeeee . . . . wrong, never!  :shocked:  :grin:  :grin:

Erm, just because Trip 2 runs out of fingers and toes at 99 hours and 59 minutes - that doesn't mean it resets.  The time just cycles round to zero again.  And the miles are the same - at 9999 miles, one more and it goes back to zero.

H O W E V E R
.
.
.
.
.
.
.
Just because the the elapsed time and total distance cycle back to zero, it still don't mean the Trip 2 has "reset".  Because the average speed and average fuel consumption will still be active!  :tongue:

<sticks out tongue, puts thumbs in ears, waves hands, and makes silly school-boy noises>

I'm sorry to say, that as I said earlier my trip 2 was at 99hr 51min - I watched it tick over and the whole memory reset - everything went to Zero... Mpg, mileage, time etc.

Just as the manual said :)

Offline smartypants

  • Here all the time
  • ****
  • Posts: 461
Re: MPG - How accurate is computer??
« Reply #36 on: 08 April 2009, 22:06 »
well it must be different from the MKIV then as the average fuel consumption and average speed also resets along with the time driven and miles covered  :tongue:

Nope, to hammer the point home - you are right... I watched it with my very eyes :D

Offline Rhyso

  • Global Moderator
  • Sir Postalot
  • *****
  • Posts: 26,720
Re: MPG - How accurate is computer??
« Reply #37 on: 09 April 2009, 07:54 »
well it must be different from the MKIV then as the average fuel consumption and average speed also resets along with the time driven and miles covered  :tongue:

Nope, to hammer the point home - you are right... I watched it with my very eyes :D

 :smug: :smug: :smug: :laugh: :laugh: :laugh:

Offline Teutonic_Tamer

  • Forum addict
  • *
  • Posts: 4,562
  • GreasedMonkey - HoofHearted - GTI now mod'ed, ASK!
Re: MPG - How accurate is computer??
« Reply #38 on: 10 April 2009, 11:40 »
BTW, Stealth, did you manage to get a Haynes manual?
Went down to halfords the weekend after your PM and couldn't spot it there. Will have another look tomorrow. Thanks for reminding me!

Have a look on Amazon - prolly much cheaper than Halfrauds too.  Or try one of the A1 motor accessories shops, they are always cheaper than Halfrauds - might not have it in stock, but could order it in for you.

I had the one that reads while you drive show 99mpg  :laugh:

Yup, and some makes of car can read 999 mpg.
The highest I've made mine read was 234mpg.

Not trying hard enough then!  :lipsrsealed:  :grin:

The average is accurate,
I personally havn't checked mine, but they are supposed to be within 10% accurate.  However, if anyone does want it to be more accurate, then there is a setting the stealer (or vag-com) can tweak to adjust the accuracy of the MFD mpg readout.
So why isn't it already set to the tightest accuracy?

Manufacturer tollerances and mass-production.  Just like a speedometer is not 100% accurate.  A GPS speedo is much better than the standard one - and if you have the factory fit sat nav, you can get it to display the GPS mph.

Sorry, but disagree.  The 'while you drive' reading is an instantaneous readout, rather than an average.  And it is very good in helping to drive in an economical manner, just like the old-skool vaccum gauges.
As T_T has stated, the current mpg reading (as opposed to the average mpg) is great for trying to drive economically. Quite amusing to see the effects of road gradient on mpg when you stick it 6th gear and leave it on cruise control at 60mph. I knew it had an effect but didn't know how the extent until I did this.

Don't do it for too long, as it turns you into an obsessive nerd though!  :embarassed:
Sean - Independent Automotive Engineering Technician (ret'd)
-----
'06/7 Golf Mk5 GTI 5dr (BWA) DSG, colour coded,

I feel like a homo


Offline Teutonic_Tamer

  • Forum addict
  • *
  • Posts: 4,562
  • GreasedMonkey - HoofHearted - GTI now mod'ed, ASK!
Re: MPG - How accurate is computer??
« Reply #39 on: 10 April 2009, 11:42 »
Trip 2 never clears, UNLESS you either clear it manually, or disconect the battery.

does your Trip 2 computer not reset it self after 99 hours and 59 minutes of driving then like in the MKIV?

Yes it does

so Mr T_T is WRONG!!!  :shocked: :shocked: :tongue: :grin: :grin:

<cough, cough>

Meeeeeee . . . . wrong, never!  :shocked:  :grin:  :grin:

Erm, just because Trip 2 runs out of fingers and toes at 99 hours and 59 minutes - that doesn't mean it resets.  The time just cycles round to zero again.  And the miles are the same - at 9999 miles, one more and it goes back to zero.

H O W E V E R
.
.
.
.
.
.
.
Just because the the elapsed time and total distance cycle back to zero, it still don't mean the Trip 2 has "reset".  Because the average speed and average fuel consumption will still be active!  :tongue:

<sticks out tongue, puts thumbs in ears, waves hands, and makes silly school-boy noises>

well it must be different from the MKIV then as the average fuel consumption and average speed also resets along with the time driven and miles covered  :tongue:

Well maybe I AM wrong then - just don't get too carried away though - I won't let it happen often!  :evil:  :evil:  :evil:  :evil:  Anyhow, the book doesn't specifically state that the averages also reset too, which is why I interpreted it like I did!  :tongue:
Sean - Independent Automotive Engineering Technician (ret'd)
-----
'06/7 Golf Mk5 GTI 5dr (BWA) DSG, colour coded,

I feel like a homo