Author Topic: 46 MPG.  (Read 19453 times)

Offline monkeyhanger

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Re: 46 MPG.
« Reply #40 on: 05 July 2019, 10:52 »
52.3 MPG. 

160 miles on M6/42/40/25/4. 

Average speed 56mph due to roadworks / traffic. 

3 month old GTI.

MPG is getting better as the engine has run in, currently 3k.

Some that "getting better" is down to the weather getting better - it will drop off again in Autumn /Wnter.
Whey ya bugger! It's finally arrived after an 8 month wait....
MK7 R 5 door, manual, Lapiz Blue, Prets.

Offline kmpowell

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Re: 46 MPG.
« Reply #41 on: 05 July 2019, 11:05 »
52.3 MPG. 

160 miles on M6/42/40/25/4. 

Average speed 56mph due to roadworks / traffic. 

3 month old GTI.

MPG is getting better as the engine has run in, currently 3k.

Some that "getting better" is down to the weather getting better - it will drop off again in Autumn /Wnter.
Forced induction petrol cars perform more efficiently in colder weather. Warm air/temps are a hindrance.

It's the complete opposite to diesel which performs more efficiently in the summer months and struggle in winter.
SOLD March 2021
2019 GTI Performance, 5DR, DSG - Isaac Blue, Leather, Pan Roof, 19" Brescias, DCC, Dynaudio, Rear Camera, Keyless, Electric Memory Driver Seat.

Offline monkeyhanger

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Re: 46 MPG.
« Reply #42 on: 05 July 2019, 14:09 »
52.3 MPG. 

160 miles on M6/42/40/25/4. 

Average speed 56mph due to roadworks / traffic. 

3 month old GTI.

MPG is getting better as the engine has run in, currently 3k.

Some that "getting better" is down to the weather getting better - it will drop off again in Autumn /Wnter.
Forced induction petrol cars perform more efficiently in colder weather. Warm air/temps are a hindrance.

It's the complete opposite to diesel which performs more efficiently in the summer months and struggle in winter.

So you get better mpg in your petrol car in the winter? Seriously doubt that.

I'm assuming you're talking about heat soak and all that. Hotter temps have a progressively detrimental effect on power, but also a positive effect on mpg. The fuel is denser in the winter, the air has a higher oxygen content (and lower moisture content) per given volume, and so your car will be a bit more powerful in winter, and be using more fuel if you take advantage of it.

Fuel economy is all about maximum gaseous expansion for minimum fuel input.

Don't forget that a modern DI turboed petrol car is a lot more like a diesel than they used to be, with higher compression ratios taking a petrol engine to the verge of auto ignition (pinking) and then igniting it under spark.

Fuel (whether it be petrol or diesel is denser in cold temps. The air carries less moisture due to lower humidity levels in winter, so you get less expansion of the air/fuel mix under ignition (or auto ignition, in the case of diesel), relative to the fuel put in.

All that without even thinking about the negative effects of using your lights and heating more.

I rarely heat my car in the Winter and my petrol mpg dips about 5% on my Polo GTI and my previous Golf R. It is a lot more pronounced on the diesels (10%)
« Last Edit: 05 July 2019, 14:33 by monkeyhanger »
Whey ya bugger! It's finally arrived after an 8 month wait....
MK7 R 5 door, manual, Lapiz Blue, Prets.

Offline Mutley75

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Re: 46 MPG.
« Reply #43 on: 05 July 2019, 14:14 »
I bought mine in March and I’m getting better mpg since it has been warmer. I leave the aircon on all year round too.
Golf GTi Performance Edition (2019), 5dr, DSG in Isaac Blue, Dynaudio & Brescia alloys.


Offline kmpowell

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Re: 46 MPG.
« Reply #44 on: 05 July 2019, 14:59 »
52.3 MPG. 

160 miles on M6/42/40/25/4. 

Average speed 56mph due to roadworks / traffic. 

3 month old GTI.

MPG is getting better as the engine has run in, currently 3k.

Some that "getting better" is down to the weather getting better - it will drop off again in Autumn /Wnter.
Forced induction petrol cars perform more efficiently in colder weather. Warm air/temps are a hindrance.

It's the complete opposite to diesel which performs more efficiently in the summer months and struggle in winter.

So you get better mpg in your petrol car in the winter? Seriously doubt that.

I'm assuming you're talking about heat soak and all that. Hotter temps have a progressively detrimental effect on power, but also a positive effect on mpg. The fuel is denser in the winter, the air has a higher oxygen content (and lower moisture content) per given volume, and so your car will be a bit more powerful in winter, and be using more fuel if you take advantage of it.

Fuel economy is all about maximum gaseous expansion for minimum fuel input.

Don't forget that a modern DI turboed petrol car is a lot more like a diesel than they used to be, with higher compression ratios taking a petrol engine to the verge of auto ignition (pinking) and then igniting it under spark.

Fuel (whether it be petrol or diesel is denser in cold temps. The air carries less moisture due to lower humidity levels in winter, so you get less expansion of the air/fuel mix under ignition (or auto ignition, in the case of diesel), relative to the fuel put in.

All that without even thinking about the negative effects of using your lights and heating more.

I rarely heat my car in the Winter and my petrol mpg dips about 5% on my Polo GTI and my previous Golf R. It is a lot more pronounced on the diesels (10%)
As a standing item a petrol engine is more efficient in cold weather, yes, because the air is rich in oxygen and there's dramatically less heat soak/force through the induction. But the vehicle's aerodynamics are not more efficient because the air is thicker, so if the driver is doing consistent high motorway speeds that require the air to be moved by the car it'll be less efficient.
SOLD March 2021
2019 GTI Performance, 5DR, DSG - Isaac Blue, Leather, Pan Roof, 19" Brescias, DCC, Dynaudio, Rear Camera, Keyless, Electric Memory Driver Seat.

Offline Sootchucker

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Re: 46 MPG.
« Reply #45 on: 05 July 2019, 19:00 »
Got to be happy with this. Sure it’s only quite a small trip and a lot of it was spent in a 50mph average speed camera section of the motorway, but still - the best I’ve ever got from my GTI (not far off what my GTD would get), from my poor mans non PP 6 speed DSG.

« Last Edit: 05 July 2019, 19:02 by Sootchucker »
2022 Tiguan R-Line 2.0 TSI 4-Motion. Nightshade blue, pano roof, IQ lights, Nav Pro, Harmon Kardon, Heated Windscreen, Heated rear seats, Wireless charging, Heads up display, dual height boot floor, Keyless with electric tailgate, Electronic TPMS, underbody protection, Area View Cameras

Offline Guzzle

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Re: 46 MPG.
« Reply #46 on: 05 July 2019, 19:06 »
Those of you with dsg's, are you running them in auto or using the paddles?

7.5 GTD

Offline Sootchucker

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Re: 46 MPG.
« Reply #47 on: 05 July 2019, 19:13 »
 Normally auto for me (the above certainly was)
2022 Tiguan R-Line 2.0 TSI 4-Motion. Nightshade blue, pano roof, IQ lights, Nav Pro, Harmon Kardon, Heated Windscreen, Heated rear seats, Wireless charging, Heads up display, dual height boot floor, Keyless with electric tailgate, Electronic TPMS, underbody protection, Area View Cameras

Offline Guzzle

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Re: 46 MPG.
« Reply #48 on: 05 July 2019, 19:24 »
I see you have yours in Eco. I presume that's because you see a tangible benefit? How much so?
7.5 GTD

Offline Mutley75

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Re: 46 MPG.
« Reply #49 on: 05 July 2019, 19:27 »
I never use Eco on mine. It encourages harder throttle presses to get moving and just burns more juice. However if you drive like a 70 year old granny it can make a little bit of difference.  Although it mostly gains though cutting the fuel when going down hill etc. I achieve the same in normal or sport simply by lifting off when advantageous to do so.
Golf GTi Performance Edition (2019), 5dr, DSG in Isaac Blue, Dynaudio & Brescia alloys.