Speed effect on MPG

[bearded bloke]

Just to bung in another variable here,where do buy your fuel supermarket or branded forecourt ?

Quite a few of us on 4x4 forums have been recording fuel economy figure for both sources in our vehicles & without exception branded forecourt give better economy & performance figures,if it works well enough for us to notice just think of the gains for lighter & more aerodynamic cars

[Kristen]

Thanks for that. I resent the lengths of the queues for Supermarket fuel (and at BP now that they have M&S shops and the queues inside are lengthy) ... now I can feel good about driving straight past them and buying at a brand with no queue

I keep meaning to brim-fill at the same station and pump and record mileage ... never actually remember when I fill up though

[chris]

I might be playing devil's advocate here a bit, but...

I think a lot of it is to do with small underpowered engines just aren;t designed for m-way cruising. They're fine for pootling about town but when you have to get up to 60+ they have to rev so high that they're drinking fuel.

I agree.. this mini doesn't like long motorway driving, it's starting to get rattles - and it's quite a nice car really. My old car mine, just ate up the m'way miles - though had the fuel bills to match it!

The car I'd really like next is definitely a cruiser, though I'll be looking for one without the 'coq' badge on it

[bearded bloke]

Ere yer go Kristen (& all) ............

Been doing some testing with fuel recently. With Tesco fuel the lc seemed a bit flat at times and averaged about 14 mpg!! Been using bp and average is about 19mpg and performance feel better.

That was posted this weekend by a mate with a 4.5litre petrol Toyota Land Cruiser,that was BP but my diesel Frontera always seems happiest using Shell,keep notes on brand & mileage to see if a pattern appears for your car

[chris]

Just to bung in another variable here,where do buy your fuel supermarket or branded forecourt ?

Quite a few of us on 4x4 forums have been recording fuel economy figure for both sources in our vehicles & without exception branded forecourt give better economy & performance figures,if it works well enough for us to notice just think of the gains for lighter & more aerodynamic cars

I used to better economy out of ron97 (branded), than 95 - though when I knew I was going to sell, I went back to 95 to see me through the final weeks! It also gave much better performance too, especially if you used the "launch control" mode (I didn't race, but on empty, private roads it was fun whilst it lasted). Much more punchier.

[Kristen]

Ere yer go Kristen (& all)

Thanks BB

keep notes on brand & mileage to see if a pattern appears for your car

I need to do that, but now that I you have alerted me that other people have found a measurable difference I'll make the effort.

[WendyC]

Our car computer shows on the dashboard the current MPG. When we went to Norwich get our son from uni there were 2 adults and a roof rack on the car. Think we did something like 46mpg. On the way home a bike was on the roof, a term's washing and a student. It dropped about 2mpg, same route and same driver.

[bearded bloke]

If we "take it as read" that fuel is fuel is fuel,then the differences are the additives that are specified by each retailer,these are generally added by the tanker driver at each drop point & are the reason that shell (for example) have two types of diesel (I use the standard type) the more expensive of which guarantees better performance & economy (it has more/different additives) & it does work,my mate that runs the same car as me can easily "out drag" me from either a rolling or standing start.So it may well be that spending the extra few pence a litre will result in better mpg for him as well.

[bearded bloke]

Our car computer shows on the dashboard the current MPG. When we went to Norwich get our son from uni there were 2 adults and a roof rack on the car. Think we did something like 46mpg. On the way home a bike was on the roof, a term's washing and a student. It dropped about 2mpg, same route and same driver.

Not surprising there Wendy,pretty much all of that will be in the extra drag caused by the irregular shape of the bicycle on the roof

[bearded bloke]

At the risk of boring you I can remember reading this form 2006 talking about the little flag that clipped onto side windows..............

He said: "The extra drag generated by these flags can reduce a car's fuel economy by up to 3% during a one-hour journey.

"This may not seem significant to the individual, but if half a million cars are flying these flags we could see up to 1.22 million litres of extra fuel burned during the World Cup."

Taken from : BBC NEWS | England | Manchester | Flag drag will boost fuel costs

[WendyC]

Not surprising there Wendy,pretty much all of that will be in the extra drag caused by the irregular shape of the bicycle on the roof

Actually I think it was the washing! No seriously . I'm sure you're right. Whilst I know top boxes are more aerodynamic than bikes we can never work out why some people drive round with roofbars and boxes on all year round.
And those flags, you can almost hear the petrol burning

[Kaiya]

I think a lot of it is to do with small underpowered engines just aren;t designed for m-way cruising. They're fine for pootling about town but when you have to get up to 60+ they have to rev so high that they're drinking fuel.

Agreed - and not even particularly underpowered engines per se. My 1.6l Honda can pull away easily, and is right nippy when I want it to be, but at 5th (top) gear at 70 it's doing 3-4000rpm. Quite effective at making me stick to the speed limit as travelling any faster just isn't pleasant! I just park myself behind a lorry, stick Radio 2 on and potter along at 60 in the slow lane quite happily. If I stick to 60 ish on the big roads and drive calmly on the little roads I get an average of 45mpg, not bad for a 10 year old petrol, and great considering that about 5 years ago in the same car driving the same roads I was getting 40mpg. The effect of me getting a little older and deciding that a) I don't like buying petrol and b) I rarely need to get someone 3 minutes earlier than I would do otherwise.

Drives me bonkers being behind people in perfectly good driving conditions who do not drive at the speed limits. It's dangerous as can make people too impatient to get past them.

Though seemingly contradictory, I agree also, for small roads! Nothing annoys me more than someone driving at 35 in a 50, especially when they then remain at 35 when they hit the 30 mph zone as well.

I tend to drive now like I view both the brake and accelerator as mostly optional. The accelerator is operated with a toe, and if I brake properly it usually means I wasn't paying attention or was surprised, as otherwise I would have slowed down using gravity/engine/air friction lol etc. The only excuse I have to use either heavily is to either accelerate up to road speed when pulling into traffic, or the obvious brake-or-you'll-stop-some-other-way issue.

I'm fascinated by the brand vs supermarket thing - I almost always buy from Tesco (or sometimes Sainsburys) as if I take clubcard (nectar) points into accounts it works out cheaper than most other places. However I've never appreciated that all fuel is not necessarily equal. Since I always fill a tank, I start a log...

[Two_Sheds]

I get 30% better MPG compared to how I used to drive.

Mr TS is the type of (Audi) driver who races to junctions then SLAMS the brakes on. He went on a drive aware course and learned to drive "smoother" and saved quite a few MPG.

He's back to racing-and-braking again now though (it's the Audi in him)

In essence try to never use the brakes

Me too, though of course I show them if someone is coming up quick behind me (usually an Audi, or a Bimmer)

Drives me bonkers being behind people in perfectly good driving conditions who do not drive at the speed limits. It's dangerous as can make people too impatient to get past them

I agree, but doing 55 in a 60 isn't a bad thing.

forums have been recording fuel economy ...without exception branded forecourt give better economy

Can you explain why (in blonde, please). I've had a look round some forums, and the majority seem to conclude that supermarket fuel is just as good (perhaps even the same as) branded fuel.
http://forums.moneysavingexpert.com/....php?t=3613927
for one

I might do me a little non-scientific experiment though, for a month. My supermarket fuel costs me 12p a mile. I'll get back to you with the BP result ...

extra drag caused by the ... bicycle on the roof

Yeah daft. The bike would give better fuel economy if it was on the road

I rarely need to get someone 3 minutes earlier

When Mr TS is in my (little) car observing *just over* the speed limit (its very very nippy round town, but top speed is 75 with the wind behind it), he gets really cross with the tailgaters and speeders, and cutting-inners.

When he's in his Audi he's tailgating everyone else *rolls eyes*



I should say, I don't use the car at all if the journey is cyclable (up to 9 miles most weathers, or up to 30 on a lovely sunny weekend)
I can carry 4 carrier bags of shopping AND the dog

[bearded bloke]

I almost always buy from Tesco (or sometimes Sainsburys) as if I take clubcard (nectar) points into accounts it works out cheaper than most other places

BP also give nectar points,leastways my local one does

[beefy]

As some of you will know I drive trucks - the big 44 ton ones . I am over the moon if I can average 10 miles per gallon in one of those . They mostly average around 8- 9 mpg .