Best MPG for cruising @ around 100-120mph

[12gauge]

anonymous said:

[redacted]

Ever heard the saying assume every other driver is a complete idiot and you wont go far wrong?

If it is this country, driving at 120mph is idiotic, all it takes is granny and gramps, or whoever in their micra to pull out and overtake a truck expecting that BMW in the distance behind is doing 70-80mph, not nearly double that.

[torres del paine]

anonymous said:

[redacted]

Give over.

120 is perfectly doable on certain stretches of the motorway network during off peak hours. Come to think of it, I'm pretty sure the unofficial NSL on the M40 after about 10pm is 120mph.

[Steameh]

Ry_B said:

Hello all.

Quick question. What car will give the best (or good) MPG for cruising at around 120mph?

My friend does a lot of late night shift driving and she was wondering what would be best suited as her 330i currently is drinking like a fish. I've suggested something with a big diesel engine should hopefully get high 20's, but have no experience in economical cars.

Thanks

If it's the UK, she is braver than I that is for sure at those speeds.

[utgjon]

i do enjoy these threads...

i would urge those admitting to breaking the law on a public forum frequented by officers of the law to perhaps refrain in future.

bear in mind that should you be pulled over by plod/be in an accident etc...your PH posting history may be called as a witness to your character and attitude towards speed/driving.

i refer, if i may, to 10 Pence Short's synopsis of events.


it's really not too clever to brag about law-breaking to anyone, ever...let alone giving a written statement in the public domain. i do have my concerns regarding the foresight and the judgment of those doing 120mph+ on our motorways if this has been something they people have overlooked.

perhaps you shouldn't be doing those speeds at all?

[Tunku]

An awful lot of Mumsnet type replies here. Please give yourselves a bloody good slap. You know who you are, and now, so do we.

[Trommel]

Observing that there are situations where it would be possible to travel at 100+ mph is quite different from incriminating yourself by claiming to have done it.

[busta]

120mph is safe a perfectly legal in many situations. The question here is what car is most economical at that speed. It is not 'should my friend be doing 120mph?' or 'Is there a situation when doing 120mph on a british highway is safe?'.

As far as I can remember nobody has admitted to breaking UK speed limits so far in this thread anyway so we're all ok.

Edit: Ok, someone has but I think if they where bothered they might just edit their post anyway.

Edited by busta on Tuesday 14th September 01:21

[TheEnd]

Hmm, for 120mph..

best economy..

at night....





steal a car!

[RWD cossie wil]

To be honest, 80% of drivers on the motorway network do 90Mph+ in the daytime.


100Mph+ on an empty day motorway at night is perfectly safe, if not legal.
Is 30Mph outside a school in a 30Mph zone at kicking out time, in the rain & dark REALLY safe? one is legal, one isn't.......

Back to the topic in hand, I would be interested to hear some suggestions for this, what would best suit the bill for comfortable 100Mph cruise {with cruise control on}(Germany of course!) with a decent return? I am thinking a 330d, 530d or Mondeo ST TDCI?

[fluffnik]

anonymous said:

[redacted]

Why?

The problem is our stupid limits, not people breaking them.

[CraigyMc]

Condi said:

dcb said:

balls-out said:

At that speed I think she'll struggle to get anything that doesn't use a lot of fuel. The law of physics dictate that it'll need a lot of power to maintain.

Some nonsense where dcb both questions someone elses' intelligence and also points out their own lack of it.

I doubt that for a 50% increase in speed your car uses a 5% increase in energy. If you can do this, bottle it and make a fortune.

Doubling the speed of a car requires approximately a squaring of the force involved, and since engines don't get more efficient as they run faster, it requires the amount of fuel going in to increase by a similar amount.

C

[BlueEyedBoy]

CraigyMc said:

Condi said:

dcb said:

balls-out said:

At that speed I think she'll struggle to get anything that doesn't use a lot of fuel. The law of physics dictate that it'll need a lot of power to maintain.

Some nonsense where dcb both questions someone elses' intelligence and also points out their own lack of it.

I doubt that for a 50% increase in speed your car uses a 5% increase in energy. If you can do this, bottle it and make a fortune.

Doubling the speed of a car requires approximately a squaring of the force involved, and since engines don't get more efficient as they run faster, it requires the amount of fuel going in to increase by a similar amount.

C

This is not entirely true. Gearing and aero play a large part. Most hybrids switch to leccy power when cruising at highish speeds.

I remember Clarkson in the veyron, I think be was cruising at well over 100 and only 10% of the engine power was being used.

[Guybrush]

anonymous said:

[redacted]

Why? That's a silly thing to say.

[CraigyMc]

BlueEyedBoy said:

This is not entirely true. Gearing and aero play a large part. Most hybrids switch to leccy power when cruising at highish speeds.

I remember Clarkson in the veyron, I think be was cruising at well over 100 and only 10% of the engine power was being used.

Sorry pal but it *is* entirely true. The assumption is that you're in top gear anyway (120mph) and as for your point about cruising and hybrids, and especially the veyron comment, can't you see why you're actually backing up what I'm saying?

[300bhp/ton]

bazking69 said:

I do hope she works in Germany not this country.

But if so, wouldn't it have been handy of the OP to say so....?

[300bhp/ton]

anonymous said:

[redacted]

For long enough periods of time too then worry about mpg??

[CypherP]

300bhp/ton said:

bazking69 said:

I do hope she works in Germany not this country.

But if so, wouldn't it have been handy of the OP to say so....?

Precisely. Far too many people just making the assumption that this relates to a friend in another country, when some of the comments are quite correct about openly discussing driving at that speeds on public roads.

The question I wanted to ask is why your 'friend' would even need to travel at that constant speed at night? Ok so the roads are quiet and they may want to get around quickly, but is NSL not quick enough at those times of night? It's a bloody lot quicker than you'll travel anywhere on motorways during the day. I'm aware that some people like to hoon it around on motorways, but to be honest, if your 'friend' is concerned about MPG at those kind of speeds, they shouldn't be going as fast as its pretty obvious they're not going to get anything like they would at a legal road speed.

[CraigyMc]

busta said:

Something slippery would be good. How about an Elise with longer gears?

I probably get around 25mpg* at 120 in my 106, but at 6,500rpm it's a bit noisy and you feel very vulnerable!

* never done a 120mph run and measured it but I get, at worst, 25mpg on a track day. That is full throttle, redline in each gear nearly all the time but with much lower average speed, so I don't imagine it'd be any less than that.

The elise isn't actually all that slippery shaped (it has a Cd of about .36, while good saloon cars get below .28). It does have a fairly small frontal area, which helps - but if you want a slippery shape, a saloon car isn't a bad shape to start with.

Elises tend to get decent mileage because they don't weigh very much by comparison to other cars (this is good for stop/start/racing and mixed driving - less mass to speed up). The "problem" with this is that unless we're driving up and down mountains, weight actually has very little to do with top speed or "cruising economy" since acceleration of mass isn't the defining factor anymore.
The only things that matter really are aero drag (probably about 85-90% of the drag side of the equation), tyre drag (maybe 10%?), transmission losses (not much), and on the "power side", the power from the engine and how efficient it is. Most roadcar IC engines these days fall into a fairly narrow band of efficiency. Aero is the defining factor.

C

[CraigyMc]

Matt UK said:

Why jump to conclusion - has the OP not stated that his friend lives in Germany?

Correct. OP has NOT stated that his "friend" is in Germany.

[redgriff500]

utgjon said:

i do enjoy these threads...

i would urge those admitting to breaking the law on a public forum frequented by officers of the law to perhaps refrain in future.

bear in mind that should you be pulled over by plod/be in an accident etc...your PH posting history may be called as a witness to your character and attitude towards speed/driving.

Yeah right.

The police spend hours on forums finding threads were speeding is admitted then trace IP addresses, then mount surveilance to prove who was at the computer at the time and prove it was an honest and accurate statement.

FFS !

IIRC 10p Short had a forum sticker on his car and was with several others who did too so even plod could figure out where to look.