Just a quick one - I know the accuracy of the Fabia trip computer has been discussed quite a lot ... but is it just me that has found it to be quite accurate if you only tend to make long distance trips?

 

I've worked out my MPG a few times now and it's been accurate to within about +/- 1 mpg, however when I first go the car I was doing a mix of town and long distance driving and the trip computer was overreading by around 5mpg!

 

Just curious really

Mine seems to vary slightly depending on the type of driving. Typically it under reads by 6.5%, but on longer constant speed trips it becomes slightly more accurate.....but still under reads by 5% or so.   

Under reading -

Does this mean it underestimates by x%

Or it overestimates by x% ?

I.e : actual mpg - 50 // trip reading 60mpg

Or : actual mpg - 50 // trip reading 40 mpg ??

JRJG

Mines about 10% over reading.

 

I.e : actual mpg - 50 // trip reading 55mpg

 

It's the same with the Speedometer also. Actual 50 MPH - Speedo reading 55 MPH

 

It's a good advertising ploy too.

 

I use a MicroFusion gadget, it gives you accurate Speeds and Speed Camera warnings etc, and is legal because it works on the GPS system.

 

DB

Mine over reads by A LOT. Drove to Kent and trip indicated 76mpg which is never going to happen. Got home and refilled and calculated the mpg and it was about 55mpg.

Under reading -

Does this mean it underestimates by x%

Or it overestimates by x% ?

I.e : actual mpg - 50 // trip reading 60mpg

Or : actual mpg - 50 // trip reading 40 mpg ??

JRJG

 

 

By under read, I mean the trip computer says 58 mpg but when I calculate it manually the car has actually done 61.7 mpg.  

Mine is bang on perfect. I've checked numerous times to see how accurate it is and every time it has been within less than 1mpg of my calculations. 

I see

Thank you everyone for the informative replies - as usual

I knew about the over reading of the speedo, it has caused many a sudden "IT'S A 40 !!" by mates/parents/girlfriend when travelling through speed cameras at just over the 40 mark!

I am having a service on Saturday. Then I'll top up with some v power and see what I can get economy wise.

JRJG

Mine is bang on perfect. I've checked numerous times to see how accurate it is and every time it has been within less than 1mpg of my calculations. 

what do you get Matt just out of interest? average around town and then motorway cruise?

Then I'll top up with some v power and see what I can get economy wise.

 

It'll be interesting to see how your economy goes with V-power. I've never used it in my Fabia, but as an experiment I ran my Octavia on V-power diesel for 2000 miles a while ago. 

 

I actually found average MPG was down slightly on V-power.......on researching this I found that this is actually to be expected as the Synthetic diesel ingredient in V-power has a lower calorific value than normal diesel. It did burn very cleanly though........I noticed the exhaust was much less smoky when the throttle was floored.

 

In the end I didn't think it was worth the extra cost so stopped using it.  

what do you get Matt just out of interest? average around town and then motorway cruise?

 

My short 15 min trip to work gets about 37ish and on a run maybe 50ish. If I drove like a tit knock ten off each, if I drove like a saint add ten on each. 

If I drove like a tit knock ten off each, if I drove like a saint add ten on each. 

 

That's a very good rule of thumb when it comes to Fabia economy!......I have found much the same on my non vRS Fabia 1.9 TDI 

Okay so I've just filled up today - computer was reading 60.4mpg but I worked it out to be 62.5mpg

As long as the average mpg is reading over 45mpg, i feel like i'm doing alright, and 50+ mpg on the motorway, not accurate but enough to know how you're driving.

Edited 2 May, 201412 yr by Harry1212

As long as the average mpg is reading over 45mpg, i feel like i'm doing alright, and 50+ mpg on the motorway, not accurate but enough to know how you're driving.

 

Yeah it does give you a good idea of how you're driving, I ocasionally feel the urge to thrash it and it does tend to drop a bit.

They really are cracking engines for economy aren't they! 

 

I managed 83mpg as my best average coming home from Uni which is a 28 mile commute. Makes me happy knowing the computer isn't way off from this thread. My speedo is absolutely bang on too with the GPS if that makes any difference to the reading.

They really are cracking engines for economy aren't they! 

 

I managed 83mpg as my best average coming home from Uni which is a 28 mile commute. Makes me happy knowing the computer isn't way off from this thread. My speedo is absolutely bang on too with the GPS if that makes any difference to the reading.

 

Yeah, I think the 1.9 is more relaxed at higher speeds than my 1.4 but it's still economical, just what I need for the kind of driving I do! 83mpg?! If that's your best, I guess you average around 60-70mpg? Really impressive

 

My speedo is around 3-4mph out according to my sat-nav

I managed 83mpg as my best average coming home from Uni which is a 28 mile commute. Makes me happy knowing the computer isn't way off from this thread. 

 

To be honest, I'd be very surprised if that 83 mpg is genuine. In reality the trip computers vary quite a lot and you'd need to do a few brim to brim calculations to verify your trip computers readings......I'd bet it's over reading. 

 

My record in my 1.9 TDI PD100 is 74 mpg (calculated) on a very early morning commute......but I really did have to drive like an undertaker to get that....including tailing a 50 mph limited truck on the motorway! 

My trip computer is within a1-2 MPG. Recently averaging 43-44MPG driving 20miles in morning rush hour.

 

On the same stretch of  motorway 59 MPG @ 60MPH

                                                       54 MPG @ 70MPH

                                                       57 MPG @ 80MPH

My trip computer is within a1-2 MPG. Recently averaging 43-44MPG driving 20miles in morning rush hour.

 

On the same stretch of  motorway 59 MPG @ 60MPH

                                                       54 MPG @ 70MPH

                                                       57 MPG @ 80MPH

 

 

So travelling at 80mph gives you better MPG than travelling at 70mph?!

Edited 3 May, 201412 yr by Midlands95

So travelling at 80mph gives you better MPG than travelling at 70mph?!

That's what I've found, but could depend on wind, following a car in front eyc. When I drove to the south of France I averaged mid 60's at 80mph on the way home at 70mph I was in the high 50's.

 

I've read that the best MPG is achieved where torque and power cross on the engine map, not 100% sure if that's true but if it is could explain the better MPG at 80mph.

 

 

Stephen

So travelling at 80mph gives you better MPG than travelling at 70mph?!

 

That's what I've found, but could depend on wind, following a car in front eyc. When I drove to the south of France I averaged mid 60's at 80mph on the way home at 70mph I was in the high 50's.

 

I've read that the best MPG is achieved where torque and power cross on the engine map, not 100% sure if that's true but if it is could explain the better MPG at 80mph.

 

 

Stephen

 

Remember the Fabia vRS has a 6 speed gearbox, and the early models had quite a high ratio in 6th gear. So it's not as weird as it sounds that MPG might be better at 80 mph.

 

We wouldn't experience this in our standard 1.4 TDI or 1.9 TDI models.

Ah yes that makes sense

Only had mine a few weeks so can't really comment on mpg figures, due to the fact that the torque novelty is still well and truly causing a big grin across my face, but I must say, sixth gear, cruise control on, watching the 'average mpg' trip slowly creeping up is very impressive.

JRJG