Home › Forums › Bike Forum › Fuel economy on motorways.
- This topic has 29 replies, 20 voices, and was last updated 14 years ago by cr500dom.
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Fuel economy on motorways.
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joolsburgerFree MemberPosted 14 years agoJust a general rule of thumb question.
I do around 60 mostly motoway miles a day and will be looking to get another car in the new year specifically for the task. I’m not spending much as I’ve had enough of wasting money on cars.
As a rule will a larger engined car ticking along at low revs on the motorway be more or less fuel efficient than a little engine getting ragged?
My Volvo used to do 70 in 6th at about 1800 rpm. Today I’m in a loaner micra that does 4500 rpm to do 70 and it got me thinking. Is there a little engined car that has a high 5th gear for cruising that is cheap to buy and run? Brands and performance are irrelevant it’s just cheap transport I’m after.
stumpy01Full MemberPosted 14 years agoI had a 1.1 micra as a loan car while mine was in for bodywork repairs & it did 54mpg I think on my 60 mile each way commute.
Wasn’t terribly pleasant, but couldn’t grumble with the mpg.My current Ibiza – 1.9TDi averages about 55mpg on my commute and that includes a few guaranteed hold-ups.
On a traffic free run it will nudge 60mpg. 70mph in 6th comes up at about 1800rpm.My first car – a ’94 Fiesta 1.4 would struggle to get more than 38mpg on a motorway run.
How much is not spending much? £3k should get you a decent Ibiza 1.9TDi – probably the lower powered 100bhp version, which to be honest is still plenty quick enough and will get you a few more mpg.
ken_shieldsFree MemberPosted 14 years agoMy 320d 3 series (according to the wee fuel economy meter) is doing about 60/70mpg at a constant 80mph
Had a loaner Mini Clubman when mine was in for a service and it was a lot less economical coz I had to cane it to keep going at the same pace as I would in my Beemer
PeterPoddyFree MemberPosted 14 years agoMy 320d 3 series (according to the wee fuel economy meter) is doing about 60/70mpg at a constant 80mph
It might well SAY that, but do the sums properly and it won’t even be close to it.
cynic-alFree MemberPosted 14 years ago4500 rpm to do 70
Really? That’s a lower than 4th in my 60s Volvo!
lungeFull MemberPosted 14 years agoI would suggest a small to mid size diesel. My 1.5 diesel Megane does around 70mpg on the motorway at a steady 70mph, I get around 60mpg combined (edit, I have pics to prove the latter figure on my speedo thing for the nonbelievers should anyone want tehm). It is not quick but the engine is very efficient at cruising speed.
However, whatever you do, don’t buy a Megane, the engine might be good but the electrics are astonishingly bad, really poor and not even slightly reliable.
PeterPoddyFree MemberPosted 14 years ago4500 rpm to do 70
Really? That’s a lower than 4th in my 60s Volvo!
Sounds about right for a small engine & car.
4500rmp @ 70mph, guess red line is 6500rpm gives a theoretical top speed of 101mph. Knock off a bit for the overdrive 5th gear = 95mph which is reasonable for the top speed on a samll car 🙂
cr500domFree MemberPosted 14 years agoPeak torque is where the engine is at its most efficient….
So find a nice small, light TDi where peak torque in Top gear equates to the desired cruising speed 😉
Most small petrol stuff is pretty inefficient at Motorway speed due to the Cat placement, good for CAT warm up but hopeless over 1/2 throttle as they are hosing fuel in to keep the cat temps down and stop it melting 👿
Thank the people who make up the emmissions regs for that one 🙄
Real world driving conditions , latest cars are less fuel efficient than those of a few years ago.
Their cold start emmissions are better (But never checked post Homologation) but real world driving conditions they are worse
joolsburgerFree MemberPosted 14 years agoYup definately 4500 to do 70.
Thinking of spending a couple of thousand can’t see the point in spending more for what I’m going to use it for. I figured a small deisel would be the thing, looking on autotrder the premiums for these are quite high though. You can get a lot of big car for 2k so I wondered if something like a high geared 2 litre saloon would do better than a little hatchback for the motorways.
cr500domFree MemberPosted 14 years agoI bought a 54plate Megane 1.5dci estate for £2.5k
£80/year for tax
and even with my “Digital” driving style I get 60mpg on the M-way
A few problems with it, but still cheap to run
_tom_Free MemberPosted 14 years agoMy Fiesta Zetec S is awful for efficiency. Just about reaches 40mpg on motorways, for regular driving it’s about 38. It could do with a 6th gear really, the rpms are quite high at motorway speed in 5th.
brFree MemberPosted 14 years agoMy car has seriously better fuel consumption when ‘ticking’ over on the motorway – I can get over 25mpg this way!
But there is no way I’d want to go back into a small car and have to cover ‘miles’, especially commuting drags.
A Mondeo/Vectra sized car would be my choice, my last company Vectra 2.2i auto averaged 33mpg, and was thrashed (fuel card) – get a manual and probably 40mpg is easily achievable.
SkillWillFree MemberPosted 14 years agoMy 1.6TDCi Ford Focus has averaged 53.1mpg across all driving types in the 3000 miles I’ve had it since new. Hardly ever fill it up! Mixture of motorway driving and Surrey back roads.
The really nice thing about it is that the vehicle excise duty is £0.00.
cr500domFree MemberPosted 14 years ago_tom_ – My Fiesta Zetec S is awful for efficiency. Just about reaches 40mpg on motorways, for regular driving it’s about 38. It could do with a 6th gear really, the rpms are quite high at motorway speed in 5th.
See what I said above^
Its because to keep the Catalytic converter cool at higher load (as its close coupled to the exhaust manifold for fast warm up from cold) there is a lot of fuel added to stop the Cat melting !! 😆
Stoiciometric Air/Fuel Ratio is 14.7:1 for best economy
somewhere about 12:1 for best power
somewhere about 9:1 on a Modern Ford Petrol 4 cylinder above 1/2 – 2/3 throttle 😯
Adding fuel is a cheap way (For the manufacturers not the end users) to meet the emissions targets, which bear no real resemblance to real world driving cycles
stumpy01Full MemberPosted 14 years agoMy Fiesta Zetec S is awful for efficiency. Just about reaches 40mpg on motorways, for regular driving it’s about 38
Fords never seem to be that good on economy – as I mentioned above, my 1.4 Fiesta struggled to get above 38mpg and that was a tin box that weighed <900kg, as opposed to well over a ton for a more modern supermini.
My mate has a Corolla T-Sport with the 1.8 VVTi engine in it (something like 190bhp) and he can get 40mpg out of that if driving it ‘normally’.
joolsburger, do you know what you are actually getting out of the Micra in terms of economy? As I said above, the 1.1 (I think it was a 1.1, perhaps a 1.2) I had as a loan car did 54mpg.
Admittedly, they gave me one a few days later that was lower spec and I think was only 1 litre. That poor thing really struggled and gave rubbish fuel economy.
neil853Free MemberPosted 14 years agoMy Octavia 1.9 TDI easily hits 50mpg on the motorway, take it easy and keep it to 70 and you hit 55mpg without much of a problem. Practicle mtb car too.
HolmwoodDaveFree MemberPosted 14 years agoI would agree with Lunge about the Megane, great engine but rubbish electrics. My wife gets 45ish on short journeys out of our 1.5 TDi and about 60 on a m/way journey. Tax is only £30 😀
I have a 1.9TDi SEAT Altea and I get 50mpg on a 50 mile journey (with not a lot of traffic), to get anymore than that is a struggle…
thisisnotaspoonFree MemberPosted 14 years agoSmall engine + turbo will be the most efficient as it gives the highest compression ratio. If anyone got arround to building an engine designed arround LPG you’d see some pretty phenomenal efficiencies as you can run really high compression ratios, but still have the performance of a petrol engine.
epicsteveFree MemberPosted 14 years agoMy daughter’s 1.2l Jazz can easily exceed 50mpg on the motorway if sticking to 70mph however if cruising at 90mph it’s no more fuel efficient than my 2.5l petrol Merc.
A couple of colleagues have diesel Accords and they seem to get impressive fuel consumption at realistic motorway speeds.
missingfrontallobeFree MemberPosted 14 years agoI had a C3 for a couple of years, the 1.4 HDi engine. Was the top end model with cruise control, trip computer would show approx 60mpg in 5th at 60mph on longer runs, and a proper calculation of fuel consumption would back those figures up. The most economical car I’ve ever driven.
Agree with comment about Fords, wife recently had a Fiesta 1.4TDCI for a while, for such a small car with an “efficient” engine it struggled to achieve 40mpg. When I drove it I found it needed a lot of right foot to make progress and on motorways felt sluggish.
I’m not sure that the OP’s original query of a large capacity engine running at low revs/high gear hold much water though, if it did we’d all be driving V8/V12 motors – brother had a Range Rover 3.9 V8 for a while, and shifted it on purely for fuel costs. Lovely car to drive, but not sustainable.
nickfFree MemberPosted 14 years ago60 motorway miles per day means 300/week, 1200/month, and that’s before you use it at weekends. You therefore want something that’s comfortable.
As for fuel economy, that’s just one factor. Cost of insurance, servicing, reliability…all factors to consider.
A quick look on AutoTrader shows a Saab 9- 2.2 TiD, a Volvo S60 2.4D, any number of Passat 1.9 TDIs …all with 100k+ miles, but all at £2k or less. Cheap to service at specialists (obviously avoid main dealers) and they’ll all do c.50mpg on a motorway. A hideous little 1.1 box might do a bit better, but the trade-off is frankly unacceptable.
cookeaaFull MemberPosted 14 years agoFrom my own recent experiences, having had a variety of Rental cars to do the same round trip on the same roads in recent months, I would definitely be looking for a mid-large sized saloon or estate car with a 2.0 TDi lump and a 6 speed gearbox if fuel mileage is on your mind…
Don’t be swayed too much by a lower CC engine or vehicle mass, I do think a good gear box and a bit of inertia can at moderate motorway speeds can be quite effective at keeping fuel use sensible…
I’ve had mid sized 5 Speed 1.8TDi cars (Leon) that cost a good £10-15 more to refill following a ~400 mile mixed (mostly Motorway) round trip than a decent 2.0TDI with a 6 speed gearbox (Passat, Mondeo, etc), Mid sized Petrol hatches (I get a lot of 1.6 & 1.8 Astras) are bloody awful on fuel, all of my fuel is claimed back for these trips, so the only moderating influences on my right foot are a desire to keep my licence and the 2 weeks that the company take to process claims and pay them back, hence most of my motorway mileage is done in the 70-80 mph range…
Cruise control doesn’t always mean steady or indeed sensible fuel consumption…
DO NOT BUY A VAUXHALL!!!
End of my “Advice”…
joolsburgerFree MemberPosted 14 years agoAt the mo I drive a 1.6 vtec Honda HRV this costs around 60 quid a week in fuel and I drive normally, the M3 only allows for around 70 at best and I sit in local traffic for at least 20 minutes of the 50 minutes I’m in the car.
I’m 100% not bothered by age, looks, performance, comfort or handling. It has to be reliable have a good heater that’s it for requirments.
I just want the cheapest possible way of getting from my house to the office for a max initial budget of 2k or less. I’m on a mission now!
nuttysquirrelFree MemberPosted 14 years agoI’ve had tons of cars and the best by far is my Honda Accord P reg 2.2 VTEC. When it’s not in the VTEC (under 4000 rpm) then I get 40 mpg out of it. Plus it’s rapid and I’ve changed the oil, filters and brake discs and pads since I got it at 157000 miles. It’s now at 229000. The older Hondas are amazing.
joolsburgerFree MemberPosted 14 years agoYeah that’s why I’m keeping mine!
Kia Picanto could be the ticket or possibly a Dihatsu Charade both can take a couple of bikes too apparently. Properly ugly which I quite like!
stumpy01Full MemberPosted 14 years agoHere’s some to get started….
Seat version of the Lupo
or an older Ibiza
mountaincarrotFree MemberPosted 14 years agoIf I eek it out, I can do a regular trip Surrey to Suffolk (300miles round), nearly 100% dual carriegeway, and average 68MPG in TDCI 1.9 Focus. I have once managed 76MPG for the 300mile round trip, but that required some lorry-tailing. I also run fuel-saving Michelin which I’m sure do help.
richmtbFull MemberPosted 14 years agoPeak torque is where the engine is at its most efficient….
Very true, however peak effiency doesn’t always equate to peak ecomony. A petrol engine is most efficient at full throttle not most economical though.
cr500domFree MemberPosted 14 years agoRead that statement again….and see if you still agree with it 🙂
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