Just wondering what people have found to be the best cruising speed on motorways and A roads to get the best economy out of a 2005 Fabia vRS?

Also does anyone have any other economy tips, I've been doing quite alot of mountain and moorland roads recently and its made a bit of a dent in my wallet fuel wise

Edited 5 November, 201015 yr by TomStarkey

motorways 70mph 6th

a roads a combination of 5th and 6th....

don't let the engine struggle as this will sap fuel

Just wondering what people have found to be the best cruising speed on motorways and A roads to get the best economy out of a 2005 Fabia vRS?

Also does anyone have any other economy tips, I've been doing quite alot of mountain and moorland roads recently and its made a bit of a dent in my wallet fuel wise

As to speed on the motorway, the faster you go, the more fuel you'll use, so 70mph in 6th if you want to make progress. Fuel economy-wise, you'd be better off sitting in with the trucks at 55mph, but then you'd probably want to crash just to relieve the boredom.

On A roads, again, it's about economy versus actually getting where you want to in good time, and the road conditions. Somewhere around the 1900/2k revs mark will give the welly you need for hills etc, without wasting too much fuel, and not putting too much strain on the engine. If this means using 5th instead of 6th, so be it. If it's very flat, and you therefore only need light throttle, you might get away with 6th @ say 50mph, but in my (not very scientific) testing, there doesn't seem to be much economy difference between 50mph in 5th or 6th, so why not have the extra oomph of 5th in case you need it, and be a little kinder to the engine/clutch/dmf etc?

As to speed on the motorway, the faster you go, the more fuel you'll use, so 70mph in 6th if you want to make progress. Fuel economy-wise, you'd be better off sitting in with the trucks at 55mph, but then you'd probably want to crash just to relieve the boredom.

I'm not sure that's true in a vrs. You need to be doing at least 60 to get into 6th or it'll struggle, thus wasting fuel

Matt

63 (2000rpm in 6th) seems best for me - I can easily see 80mpg on the computer if the road's flat. High enough revs that the turbo's ticking over and the engine's not labouring, but no faster than necessary to conserve fuel.

The slower the better - I don't hold with this "struggle" faction.

On a trip from Gloucester to Birmingham Airport on 9 August 2007 I achieved a reading of 78.5mpg on my reasonably accurate 2004vRS's computer leaving the motorway at the other end. That was with cruise control set at about 55mph.

On a trip from Gloucester to Birmingham Airport on 9 August 2007 I achieved a reading of 78.5mpg on my reasonably accurate 2004vRS's computer leaving the motorway at the other end. That was with cruise control set at about 55mph.

If it weren't for the fact you have an Ariel Atom, that statement might nominate you as the most boring-sounding person in the world

Only joking. My non-vRS PD100 5-speed seems to be very economical around the 50mph mark in 5th, 30-35mph in 4th, and so on, if you're driving smoothly. Be interesting to see how that compares to the vRS.

Edited 5 November, 201015 yr by Leodhasach

I'm not sure that's true in a vrs. You need to be doing at least 60 to get into 6th or it'll struggle, thus wasting fuel

Matt

Specific gears aren't really relevant to fuel consumption, other then their effect on revs. You'll get extremely good fuel consumption @ 40mph in 4th. Getting to 6th gear doesn't really matter; getting the right gear for the speed & revs is the important bit.

I agree with your second sentence, and can't see where I've said otherwise. I didn't say 55 in 6th, but then again, I didn't say 5th either! My 55mph comment is more to do with wind and other resistances, rather than gearing. At 55mph, I'd be in 5th.

I'm sure someone much better at physics will be able to explain the whole thing better than I've attempted to.

Edit: From a fuel economy point of view, you'd probably best doing the whole trip at 40mph (or maybe even less: I don't know the specifics for the vRS). My 55mph figure is based on what I consider a minimum speed for a motorway. You don't want wagons overtaking you with all the havoc that causes!

Edited 5 November, 201015 yr by Slamby

Wind resistance increases proportionately by the square of the speed - hence economy is always better at slower speeds.

0 mph is a good cruising speed, doesn't use any fuel at all!

Wind resistance increases proportionately by the square of the speed - hence economy is always better at slower speeds.

Not quite - wind resistance at 60 may be twice what it is at 40, but using a higher gear means you cover more ground for each revolution of the engine - for legal speeds, the lowest 'comfortable' speed in top gear is usually the most economical compromise

Just to add to that, wind resistance is (I think) the only parameter that increases with speed - drivetrain resistance, tyre rolling resistance and WHY are all constant, and it's only at high speeds where wind resistance becomes such an overwhelming factor. This is why virtually any car (even with a pretty feeble engine) can do over 90, whereas very few are capable of more than 200..

I'm not sure that's true in a vrs. You need to be doing at least 60 to get into 6th or it'll struggle, thus wasting fuel

Matt

dont agree with this at all. How would the engine struggle if your not doing 60? id happily put mine in 6th doing around 45mph + the engine is never really going to struggle, and as long as you dont boot it, and just steedily increase your speed then your fine.

Specific gears aren't really relevant to fuel consumption, other then their effect on revs. You'll get extremely good fuel consumption @ 40mph in 4th. Getting to 6th gear doesn't really matter; getting the right gear for the speed & revs is the important bit.

I agree with your second sentence, and can't see where I've said otherwise. I didn't say 55 in 6th, but then again, I didn't say 5th either! My 55mph comment is more to do with wind and other resistances, rather than gearing. At 55mph, I'd be in 5th.

I'm sure someone much better at physics will be able to explain the whole thing better than I've attempted to.

Edit: From a fuel economy point of view, you'd probably best doing the whole trip at 40mph (or maybe even less: I don't know the specifics for the vRS). My 55mph figure is based on what I consider a minimum speed for a motorway. You don't want wagons overtaking you with all the havoc that causes!

Why would you do 55 in 5th not 6th? the engine would be doing less revs in 6th than 5th and if your just cruising along then your going to get better economy, surely that is the reason for the 6 speed?

the slowest speed 6th will pull - ie tickover in 6th gives the best mpg in pretty much all cars i have driven...

If you want economy, you're going about it all wrong Sure, you can get the best speed/gear combination to suit your engine to get its best MPG but that counts entirely on traffic-less, hill-less roads. It has everything to do with how much effort the engine is making. For example you guys with cruise control can see for yourself, set the car for 60mph and sit on a motorway, does your MPG go up as you are going up hill? You're still doing the same speed, in the same gear - its all about engine labor, accelerating maintaining speeds.

The best way to get good MPG is to have good road sense, and good perception. You are in the middle lane and you see a truck in the lefthand lane approaching another truck infront of it. Its 10-20 car lengths infront of you. Good economy means you realise that truck is going to want to pull out (and will pull out) and you change lanes before it does with you having plenty of time to accelerate gently up to the traffic speed in the other lane. This is important for a few reasons. You don't change lanes and the truck pulls out just in front of you, this either means you have to brake (which means accelerating again afterwards = bad economy), or you have to change lanes at that moment meaning you will probably have to accelerate hard if there is someone else in the right hand lane which you should try and match (sure you can ignore the guy in the fast lane if there is one and make him brake, but well i shouldn't really have to go into the reasons why you don't wanna pull out infront of people going faster than you ). Preparing for situations like this, keeps slowing down and accelerating to a minimum - that will save you MUCH more fuel than sticking religiously to one specific speed, purely just because you can't stick to one speed religously without being a danger to other road users. Hills are the same deal, slowly get up enough speed before a hill so you have momentum on your side going up it.

Basically, good road sense will save you much much more fuel than finding that sweet spot speed and gear where your MPG meter is reading its highest.

Fair point.

Why would you do 55 in 5th not 6th? the engine would be doing less revs in 6th than 5th and if your just cruising along then your going to get better economy, surely that is the reason for the 6 speed?

This is the old "too low revs make the engine labour, using more fuel" argument. I'm not clever enough and don't have enough info to say one way or the other. Can't remember what the revs in 6th are at 55, but is it around the 1600 mark? Some on here would argue it's too low, and you'd be better off dropping to 5th, as there's maybe not that much difference in fuel economy, and you're in a more responsive gear in case you want to nip around something/otherwise get out of trouble. For cruising on a flat road at light throttle, you may well have a point. I don't know for sure, and there doesn't seem to be a definitive answer with data to back it up. I've no idea what effect boost has on this, and at what (lower) revs economy starts to suffer.

I openly hold up my hand and say I'm not a mechanic or physicist, and I'm quite happy to be corrected/educated, as it's an interesting subject . I'm only going on my own experience trying to get good economy out of the car. The last tank got me over 53mpg, so I must be doing something right. Sad ******* that I am! :S

If you want economy, you're going about it all wrong Sure, you can get the best speed/gear combination to suit your engine to get its best MPG but that counts entirely on traffic-less, hill-less roads. It has everything to do with how much effort the engine is making. For example you guys with cruise control can see for yourself, set the car for 60mph and sit on a motorway, does your MPG go up as you are going up hill? You're still doing the same speed, in the same gear - its all about engine labor, accelerating maintaining speeds.

The best way to get good MPG is to have good road sense, and good perception. You are in the middle lane and you see a truck in the lefthand lane approaching another truck infront of it. Its 10-20 car lengths infront of you. Good economy means you realise that truck is going to want to pull out (and will pull out) and you change lanes before it does with you having plenty of time to accelerate gently up to the traffic speed in the other lane. This is important for a few reasons. You don't change lanes and the truck pulls out just in front of you, this either means you have to brake (which means accelerating again afterwards = bad economy), or you have to change lanes at that moment meaning you will probably have to accelerate hard if there is someone else in the right hand lane which you should try and match (sure you can ignore the guy in the fast lane if there is one and make him brake, but well i shouldn't really have to go into the reasons why you don't wanna pull out infront of people going faster than you ). Preparing for situations like this, keeps slowing down and accelerating to a minimum - that will save you MUCH more fuel than sticking religiously to one specific speed, purely just because you can't stick to one speed religously without being a danger to other road users. Hills are the same deal, slowly get up enough speed before a hill so you have momentum on your side going up it.

Basically, good road sense will save you much much more fuel than finding that sweet spot speed and gear where your MPG meter is reading its highest.

Very good points. How you drive, and maintaining smoothness makes a big difference. I think advanced driving stuff goes into this kind of thing?

Just to add to that, wind resistance is (I think) the only parameter that increases with speed - drivetrain resistance, tyre rolling resistance and WHY are all constant, and it's only at high speeds where wind resistance becomes such an overwhelming factor. This is why virtually any car (even with a pretty feeble engine) can do over 90, whereas very few are capable of more than 200..

have you ever driven a 1.2 corsa b with 44bhp.....?

im telling you the only way that will do 90mph is if you drive it off a cliff

Just wondering what people have found to be the best cruising speed on motorways and A roads to get the best economy out of a 2005 Fabia vRS?

Also does anyone have any other economy tips, I've been doing quite alot of mountain and moorland roads recently and its made a bit of a dent in my wallet fuel wise

As fast as you can go without getting caught, as your in 6th gear, pity no 7th gear like the NEW Fabia VRS, (for best economy). LOL

Why would you do 55 in 5th not 6th? the engine would be doing less revs in 6th than 5th and if your just cruising along then your going to get better economy, surely that is the reason for the 6 speed?

The last chat I had with Ben I'm fairly sure he said that the car was most economical with a few revs on it. If I recall correctly the reason was that the engine had to burn extra fuel to generate torque at low revs to pull the car up hills etc. therefore it was better to have a few revs dialled in at all times.

have you ever driven a 1.2 corsa b with 44bhp.....?

im telling you the only way that will do 90mph is if you drive it off a cliff

I did say virtually any car, and I chose 90 instead of 100, as I'm not convince

SWMBO's MPi could muster three figures!

As fast as you can go without getting caught, as your in 6th gear, pity no 7th gear like the NEW Fabia VRS, (for best economy). LOL

7th gear in the new vRS is slightly shorter than the old box I believe. You just get 7 gears more closely spaced together to allow faster acceleration. The fact that the car doesn't need to change to 3rd gear for 62mph is a major reason why the new car has such a good 0-60 time.

And it's definitely not economical. Over 300 miles I managed only 32mpg, which is fairly horrific when my 170bhp diesel will do 45-55mpg.

I did say virtually any car, and I chose 90 instead of 100, as I'm not convince

SWMBO's MPi could muster three figures!

Official max speed figure is 101mph I think. Surprising given the weight of the Fabia. Here's one doing about 180 kph

180kph = 111mph. I hope they're on the Autobahn

Edited 6 November, 201015 yr by anewman