[Fuel Consumption] Lower engine vs Higher engine for motorway.

[Blayzee]

So, i started a new job last week and using my car alot to and from work (25 miles there and back a day) Atleast 15 miles is on the motorway.

My question would be this:
Would having a higher engine car able to drive and steady rev's at 70-80mph but better on fuel consumption & costs than a lower engine car driving at higher revs at the same speeds?

Example:
My car right now is a petrol 1.4 MG ZR 105+ driving to work at steady 70mph i'm at around 3.5-4.5k RPM and obviously it'll consume more fuel than driving steady at 2-2.5k RPM.

Would having a higher engine car ideally 1.8 or something that can drive at around 2.5k RPM at 70-80mph consume less fuel evening though higher engine and obviously more £££ to fill up the tank?

Probably missing something here or it's kinda self explanatory but yeah. just wondering.

[stabetha]

engine rpm is far down the list of things that dictate MPG, design of the car/engine, weight, how you drive (i.e. hard acceleration drastically lowers MPG), even the tire design/size all have a much greater affect on MPG.

[Pitkanen]

In the past, cars with greater power also tended to have more optimal gearing at higher speeds. AKA a 90's metro automatic which shifts into it's 3rd and final gear at about 35 mpg is WAY out of it's prime at 60-80 mph. So it may not be an engine size issue but rather a gearing issue.

[Archaeon]

They did this on top gear comparing a prius to a bmw m3, where they made the prius go around the track at full speed and the bmw just had to keep up. The bmw was more efficient because it didn't need as much juice to keep the same speed. It makes sense, I mean, if you have to drive at high rpms constantly you're going to go through more gas. I'd say it depends on if you think you spend more time in heavy traffic or not. Obviously it's not worth trading up if you're spending most of the time at traffic lights and stop signs.

[Spikeydeath]

I have to drive 30 miles for work so i got a cng engine dunno if you guys have cng across the pond

[Blayzee]

I have to drive 30 miles for work so i got a cng engine dunno if you guys have cng across the pond

Im not aware of it. The only things i tend to see at petrol stations is unleaded petrol, diesel and LPG.

They did this on top gear comparing a prius to a bmw m3, where they made the prius go around the track at full speed and the bmw just had to keep up. The bmw was more efficient because it didn't need as much juice to keep the same speed. It makes sense, I mean, if you have to drive at high rpms constantly you're going to go through more gas. I'd say it depends on if you think you spend more time in heavy traffic or not. Obviously it's not worth trading up if you're spending most of the time at traffic lights and stop signs.

Humm, well it's 50/50 really. The journey to work its fast as its early so i'd be steady 70-80 down the motorway and 50-60 across the national speed limit roads which i mainly use to access the motorway. However the journey home usually is the same but if i'm later out i.e. after 4.30pm the traffic starts and can take upto an extra hour to get home rather than 30-35mins due to traffic.

[Tradewind]

If your car sounds like a lawnmower whenever you hit highway speeds, chances are it's going to be using much more fuel and much more inefficiently than something with some chutzpah.