New member looking for mpg advice

[Lloydy92]

Hi everyone, need some help/opinions on my Polos mpg figures.

TLDR would you expect a 95ps 5 speed and 110ps 6 speed to achieve similar mpg figures over the same trip with very similar driving styles? (More details below)

So I’ve just bought a 21 plate R-Line Polo, 110ps manual 6 speed box. A few months ago my wife got a 20 plate 95ps 5 speed. Was impressed with it so thought I’d go for something similar. Since I got it I’ve been a bit disappointed with the mpg figures when compared to her car. I’m a ‘smoother’ more economical driver than she is but I’m regularly getting noticeably lower figures than hers.

So I decided to run a little experiment. We drove exactly the same route, nose to tail pretty much the whole way. Told her to just drive as she normally would but stick to limits and keep in the gear the car suggested. I did the same.

Over a 10 mile drive we both averaged ~33mph. Her: 49mpg Me:42.1mpg.

On the return journey (same route in reverse) my average went up to ~49mpg (not quite as focused on economy) hers to 58mpg (still keeping to limits etc)

I’m going to do a brim to brim actual miles test on the next tank, but even going from the ranges on the last fill ups (me 385, her ~440) it looks like me is a fair bit thirstier)

This seems like a fairly large discrepancy, I would expect them to be much closer. The car drives fine otherwise, tyre pressures all fine, oil fine etc. No lights on dashboard indicating a problem. Any ideas if this is just a normal difference between models or could something be up? And if so any ideas what could cause this.

To be clear, if I didn’t have hers to compare to, I probably wouldn’t give it a thought. I get more miles from a tank than my old car, on a smaller fuel tank. I’m just bemused to be honest. I’m thinking of taking it to the local garage but wondered if anybody here had suggestions.

[Harrihealey02]

Make sure you both use the same fuel station so that the fuels in both cars are the same, and that rules out the possibility of a cheaper fuel used in yours and levels the playing field. I would also check the tyres and see if they are different. She may have more efficient tyres than what’s on your cars with less drag. The other thing is as your car is slightly newer, I believe it may come with a GPF which was mandatory around 2021 so it could be that her car does not have that and has less resistance in the exhaust so is more fuel efficient. The other thing is that the car learns over time how you drive, and if it’s a new car to you, the previous owner could have been heavy on the pedal and it may take time to gradually adapt to your more considerate driving habits. Make sure both cars have matching tire pressure too. If after a few weeks it is still considerably off I would recommend checking it out but what you are achieving is well within what’s usual for most 1.0 tsi engines, so the dealer may not do anything as there are no warning lights. Also engine oil may have a slight impact on efficiency, so if they are the same brand and spec but really shouldn’t make much difference as long as it’s meeting the spec.

[PoloGTInoob]

the car learns over time how you drive, and if it’s a new car to you, the previous owner could have been heavy on the pedal and it may take time to gradually adapt to your more considerate driving habits.

Is this actually a thing? I might possibly believe it in an automatic car, but in a manual?

[PoloGTInoob]

my average went up to ~49mpg (not quite as focused on economy) hers to 58mpg (still keeping to limits etc)

I agree, im surprised her car is ~20% more fuel efficient. Assume same engine size? you only mentioned the HP being 95 and 110 respectively. I would have expected the higher HP car to perhaps have up to 10% lower MPG, so yeah 20% is a surprise.

Have you checked the quoted MPG for both cars? Check parkers.co.uk

[Lloydy92]

my average went up to ~49mpg (not quite as focused on economy) hers to 58mpg (still keeping to limits etc)

I agree, im surprised her car is ~20% more fuel efficient. Assume same engine size? you only mentioned the HP being 95 and 110 respectively. I would have expected the higher HP car to perhaps have up to 10% lower MPG, so yeah 20% is a surprise.

Have you checked the quoted MPG for both cars? Check parkers.co.uk

Yeah both the 1 lite engine. Parker’s does give a 46-49 range so maybe it’s actually about where it should be. I haven’t done a long run (say 1-200 miles) of very eco driving (55-60mph) constantly to really see what it’s capable of. Maybe hers is just a particularly good engine.

[PoloGTInoob]

FWIW On a good run i can manage 45MPG in my 2.0 GTI lol. WIth urban driving its closer to 30-35MPG.

[Lloydy92]

FWIW On a good run i can manage 45MPG in my 2.0 GTI lol. WIth urban driving its closer to 30-35MPG.

Yeah the figures I’m getting are from what I’d call urban driving mostly. Villages, towns, short journeys etc.

[SRGTD]

FWIW On a good run i can manage 45MPG in my 2.0 GTI lol. WIth urban driving its closer to 30-35MPG.

Yeah the figures I’m getting are from what I’d call urban driving mostly. Villages, towns, short journeys etc.

How does your normal mix of driving between short and longer journeys compare to your wife’s?

Maybe your car’s GPF has been going through an active / forced regeneration process? When this happens in my GTI+, the fuel consumption worsens significantly (by about 30%) until the regeneration has completed as the process uses extra fuel to aid burning off the accumulated particulate matter in the GPF.

If you’re driving mainly short journeys and the engine’s not getting up to normal optimum operating temperature, the frequency of active GPF regenerations is likely to be higher than someone who’s driving mainly longer journeys on a fully warmed up engine. Also, if you complete your journey and an active GPF regen is still in progress, it’ll recommence the regen on the next (and subsequent) journey(s) until the process has completed. If that’s what’s happening, then fuel consumption will be affected over a longer period - maybe that’s what’s happening with your car? When I’m aware an active regen is happening (I only get one every 9-12 months as my journey mix is heavily skewed towards longer journeys and it takes around 20-30 minutes with my car), I’ll extend my journey if possible to ensure it’s completed before I reach my destination.

[Lloydy92]

[quote=Lloydy92 post_id=602485 time=<a href="tel:1704145842">1704145842</a> user_id=35759]
[quote=PoloGTInoob post_id=602484 time=<a href="tel:1704145135">1704145135</a> user_id=35409]
FWIW On a good run i can manage 45MPG in my 2.0 GTI lol. WIth urban driving its closer to 30-35MPG.

Yeah the figures I’m getting are from what I’d call urban driving mostly. Villages, towns, short journeys etc.
[/quote]

How does your normal mix of driving between short and longer journeys compare to your wife’s?

Maybe your car’s GPF has been going through an active / forced regeneration process? When this happens in my GTI+, the fuel consumption worsens significantly (by about 30%) until the regeneration has completed as the process uses extra fuel to aid burning off the accumulated particulate matter in the GPF.

If you’re driving mainly short journeys and the engine’s not getting up to normal optimum operating temperature, the frequency of active GPF regenerations is likely to be higher than someone who’s driving mainly longer journeys on a fully warmed up engine. Also, if you complete your journey and an active GPF regen is still in progress, it’ll recommence the regen on the next (and subsequent) journey(s) until the process has completed. If that’s what’s happening, then fuel consumption will be affected over a longer period - maybe that’s what’s happening with your car? When I’m aware an active regen is happening (I only get one every 9-12 months as my journey mix is heavily skewed towards longer journeys and it takes around 20-30 minutes with my car), I’ll extend my journey if possible to ensure it’s completed before I reach my destination.
[/quote]

Broadly the same I’d say. Certainly not different enough to make a big difference to consumption. Took in to local VW garage and spoke to a mechanic there I know. He wasn’t concerned with the difference, certainly not enough to warrant a check over. He said they could do a diagnostic but they’d not find anything. He did I mention that the narrower tyres on my wife’s (185 vs 215 on mine) can make a reasonably difference due to extra drag etc. guess I’ll just live with it and maybe it’ll improve with time and a decent service mid-year.

[Maarten]

try switching drivers