Fuel consumption concerns

[royoftherovers]

1 hour ago, Zotto said:

It sounds strange to me that nobody has considered in answers the great difference in air resistance from driving a large front area SUV compared to a minor and more aerodynamic shape of a saloon or a coupe, this is the main reason because at high speed fuel consumption rise so much  in SUVs of all kinds and not specifically hybrid ones. The solution? Do not exceed 70-75 mph or don't care about sparing fuel. Besides, I noticed that NX300h compared to RX450h at speed over 80 mph has a worse fuel consumption, probably because higher rpm; same reason because usually diesel cars have a good consumption in high speed cruising, provided that they have a advantage more, the specific energy in diesel fuel is higher than in gasoline. The big advantage for hybrids, energy recovery during braking is quite noticeable in city driving and wherever there are many variations in speed, and of course is less noticeable in motorways.

I have often said that an SUV has the aerodynamics of a brick Zotto.

[Linas.P]

1 hour ago, royoftherovers said:

I have often said that an SUV has the aerodynamics of a brick Zotto.

Sorry did someone mentioned Brick-Wagen somewhere? 

[oraman]

On 11/16/2020 at 3:30 PM, Linas.P said:

Sorry did someone mentioned Brick-Wagen somewhere? 

I must admit I love the look of those "Brick-Wagons"

[royoftherovers]

1 minute ago, oraman said:

I must admit I love the look of those "Brick-Wagons"

Some of them are the price equivalent of a house !

[oraman]

Just now, royoftherovers said:

Some of them are the price equivalent of a house !

Yup - stupid price for people with a ridiculous amount of money where reliability isn't an issue. Lexus is a good option for the down-to-earth sensible consumer. 

[paulrnx]

The original post was a wind up surely?

[royoftherovers]

4 minutes ago, paulrnx said:

The original post was a wind up surely?

Not been present since Nov 10 Paul, so who cares? And possibly posted from Merkleland ?

We can all continue to enjoy what may or may not be somewhat academic.

Have as pleasant an evening as you can make it and a very Happy 2021.

[Linas.P]

On 12/31/2020 at 5:39 PM, oraman said:

I must admit I love the look of those "Brick-Wagons"

I don't mind it either as proper "utilitarian" vehicle, in theory that is what U stands for in SUV. G-Wagen has good off-road capabilities, especially combined with good all-terrain tires, low range diff and large low-revving diesel engine. If I would have escape estate somewhere in woodlands and marshes that would be my to go vehicle for trip there.

But what I find hilarious, if not a little bit stupids is "guchyied-out" G-Wagen, with track tyres and high revving petrol engines driving around towns or on motorways - the thing handles like a literal brick on it's ladder chassis, the wobble in the corners can make anyone sick, the fuel consumption is horrendous and the wind noise is hard to live with at any speed over 30 MPH.

G-Wagen is basically a fashion accessory and very stupid one at that. Maybe one day we will have fashion to wear these to "black-tie dinner":

....and they will be exactly as fitting for purpose and as silly as G-Wagen G63 AMG as family vehicle to go around the town.

[dutchie01]

Just found this thread and still a little puzzled about the first post. Doing 200kmh and beeing surprised about fuel consumption?

A bit like... I was doing 200kmh on the autobahn with my Merc G-Wagen G63 AMG with 100 bottles of Malbec in the booth ( in case i need it) and 8 wintertyres and wheels and the car was doing 6 mpg. Can this be correc

 

[royoftherovers]

19 minutes ago, dutchie01 said:

Just found this thread and still a little puzzled about the first post. Doing 200kmh and beeing surprised about fuel consumption?

A bit like... I was doing 200kmh on the autobahn with my Merc G-Wagen G63 AMG with 100 bottles of Malbec in the booth ( in case i need it) and 8 wintertyres and wheels and the car was doing 6 mpg. Can this be correc

 

Read  the peni peni ultimate post Bernard. Have a great New Year, if at all possible. Regards.

[Linas.P]

19 hours ago, dutchie01 said:

Just found this thread and still a little puzzled about the first post. Doing 200kmh and beeing surprised about fuel consumption?

A bit like... I was doing 200kmh on the autobahn with my Merc G-Wagen G63 AMG with 100 bottles of Malbec in the booth ( in case i need it) and 8 wintertyres and wheels and the car was doing 6 mpg. Can this be correc

Actually, I think the post is pretty reasonable if one assumes "not to know how hybrid system works".

I guess the surprise from the owner is that 2.5l hybrid claims higher MPG, but in actuality consumes more than 1.8l turbo petrol. Yes there is sprinkle of ignorance -but it is not unreasonable, because on pure petrol the consumption scales e.g. if you have 2 petrol cars and one does 50MPG extra-urban, whilst other does 32MPG - then even at 120MPH this ratio going to be more or less true (obviously I am oversimplifying and there are more variables), but say maybe 24MPG vs. 18MPG.

What I am trying to say - if one ignores difference between hybrid and petrol and assumes that consumption scales like on petrol. Then it is possible to assume "if 38MPG translates into 26MPG, then 50MPG should translate into ~34MPG". What owner is asking - why it is not 34MPG and not even close? And the answer - because it is hybrid and hybrids doesn't scale like petrol and overall hybrids are not-beneficial on motorway, especially when we talking high speed (like 90MPH+). Oh... and as well it is SUV, not a car, and probably has larger, wider wheels... and few other things which makes it terrible choice for autobahn, at least where fuel consumption is concerned. 

All in all, if you doing long journeys and especially on autobahn where 180kmh (112MPH) is about base speed for cars, then hybrid is terrible solution for you. This is really the place where you actually want to own like 3L diesel. I am quite certain that Audi Q5 3.0TDi would still do solid 30MPG+ despite being SUV as well.

[Zotto]

1 hour ago, Linas.P said:

I am quite certain that Audi Q5 3.0TDi would still do solid 30MPG+ despite being SUV as well.

You are quite optimistic. The story that hybrids are a wrong choice for motorways is true only for speeds suitable to be arrested.

In my last motorway trip respecting speed limits (+10 km/h), AC on, and moderate traffic , with RX I made about 37 mpg.

But giving a look to Q5 vs NX300h :

Diesel consumption: Audi - Q5 - Spritmonitor.de

Consumption: Lexus - NX300h - Spritmonitor.de

The average is 7.53 vs 7.63 l/100 km , almost the same, but if you give a look to extreme averages  between users, you will notice that in Q5 they vary from 4.13 to 10.25, while NX  are from 6.48 to 8.65. What does this mean? If you pay attention to your driving style you can achieve better mpg with Audi, but if you drive without attention ( with strong speed changes and braking) you become a friend of your gas station guy much more than with a Hybrid.

 

[Linas.P]

Luigi - you just proving my point further.

What is "the speed suitable for being arrested" on unlimited autobahn? - quick answer, there is no such speed.

Just my observation - people on autobahn are travelling at approximately 180-200KPH (112-120MPH). This is "the middle lane speed", obviously there are slow traffic in the first lane, but even then everyone doing at least 130KPH (90MPH) with exception of trucks. Outside lane speed is anything above 200KPH (120MPH) and if you pulling into outside lane at 200KPH you need to check your mirrors well - it is not unusual (maybe every 3rd car) to do 260KPH (160MPH) and often more.

So when you saying "that hybrids are NOT a wrong choice for motorway", you simply ignore the environment we talking about. If somebody says they are living in Germany and do long-ish journeys, it is safe to assume they mean they will be travelling at 200KPH for extended period of time. 

Yes hybrids are "ok" on UK motorways, they perhaps are "ok" on Italian motorways... maybe... but they are "not ok" for German motorways. Although, I would argue that even on European motorways they are not great - I consider hybrid to be beneficial up to 60MPH, 60-80MPH they are still viable. Most European countries have 130KPH limit (90MPH) meaning that if you driving on mostly on motorway simple petrol is better choice. Ideally diesel. 

[dutchie01]

That is not my observation of Autobahn use Linas.  More and more areas are beeing restricted in speed mainly caused by ever increasing number of cars on the road. This also causes traffic jams mainly in the Ruhr area and around big cities. On top of that roadworks are a big nuisance. Not effective and it is quite common to have 1 lane blocked for miles without works going on at all. Also restrictrions caused by noise are common as well. If you want to have a top speed run you will have to look for a free stretch, Sunday morning or late at night will do best. I see an average speed of 120/150kmh with some 150/180 in quieter areas. The occasional jet fighter will fly past but i sincerely think this is getting less and less. Years of neglect have made the autobahn a shadow of the past 

[Linas.P]

Let's say your example is worst case scenario (and yes I agree driving past major cities during peak time will be like you described), my example is best case scenario - reality is somewhere in between. What I meant was "drivers behaviour" in free flowing traffic conditions, but you right - more and more unrestricted areas are being restricted, roadworks are common and obviously limited to 80KPH and so on. So true unrestricted autobahn moments are getting less and less common. 

To be fair I always used to time my driving through the Germany to be at night/early morning so that I pretty much cross it at full speed, with only ever slowing down for refuel and I often average ~120MPH across entire Germany East to West. Not top speed, but average including fuel stops. As such my experience probably isn't "normal conditions".

However, OP clearly stated he is driving it in Germany and his speed supposedly was 200KPH, I assume he found place and time to do it - so why not, see nothing wrong with this. He was disappointed with fuel consumption in comparison to previous Audi A4 and I see how one could have expected better MPG considering claimed figures.

It seems many people are arguing how one suppose or not suppose to use the car based on their subjective needs, beliefs, laws in their country etc. Like "you should not be driving SUV at 200KPH, because in my country that is criminal offence". Well yes, but in Germany it is allowed so why exactly one should not be doing it. If road conditions allows for it and you want, then you could drive it like that.

Finally, I am not hating on NX300h - it is fine car to drive around the city, practical... shop runs, school runs, family needs, dogs, occasional motorway trip... all that is good. But if you commuting 100 miles a day on motorway, especially in Germany and especially if you planing to take advantages of unrestricted zones and do like 200KPH... then no it is quite terrible car for that. At very least you can expect fuel consumption to be bad.

 

[Zotto]

19 hours ago, Linas.P said:

What is "the speed suitable for being arrested" on unlimited autobahn? - quick answer, there is no such speed.

I do not live in Germany, here the speed limit is 130 kph. Besides, even on autobahn in Germany limits exist for many traits, and being worried of mpg driving at 200 kph is a nonsense.

If  I'd need 250 kph I would again drive an hybrid, like my previous GS450h, but even now, with RX that can reach 200 kph I just teste that speed one time in Germany for few kms.

[Al D-Much]

200kph, approx 125mph, so near to flat out for an NX. Therefore no surprise whatsoever that the mpg is worse than stated.

And, a 4x4 at almost 2 metric tonnes is worse than a lighter A4

Jeez some people!

 

[Linas.P]

2 minutes ago, Zotto said:

I do not live in Germany

Exactly my point... this is not about you Luigi. Generally when responding to the question one should consider the circumstances of the person asking and not about his own.

I am not even sure what is your argument anymore. Are you not just basically saying "this is fine, because it is fine for me". The question was not what is speed limit in Italy and not whenever GS/RX450h can reach 200kph... the question was - is the fuel consumption right for given situation? NX300h @200kph.

The answer is - yes it is correct, and fuel consumption is so bad because it is hybrid and it is not good for 200kph autobahn. Would the car be diesel and even non-hybrid petrol it would not be as bad, the fuel consumption would be less.

Again going back to your previous statement about Q5 3.0 TDi and NX 300h, your statement that fuel consumption depends on how you driving is not wrong. However, we don't need to guess the conditions - conditions are provided in the questions and that is 200kph driving. Are you saying just cruising at 200kph diesel would not be more efficient? 

Likewise at 200kph RX350 and GS350, sharing fundamentally the same engine with RX450h or GS450h, will be more fuel efficient then hybrid counterparts. Why? Because hybrid system is just additional weight past ~60-70MPH.

It just seems you trying to blindly defend the hybrid technology without considering the actual question. Hybrid systems are very good in many ways, but high-speed motorway driving just isn't one.

[Malc]

19 hours ago, Linas.P said:

are "ok" on Italian motorways... maybe

last time I was on Italian motorways, a few years ago tho mind you, they were either jam packed solid ( like Milan ) or just petered out into a mud bath of impending roadworks ( mainly going south maybe ! ) .......  the opportunities to do any sort of speed was amazingly limited

Has the Italian Govt suddenly found a raft of dosh to get the roadworks going again I wonder

Malc

[Linas.P]

6 minutes ago, Al D-Much said:

 near to flat out for an NX.

It is not near flat out, it is outright impossible. Max speed for the car is 112MPH/180KPH... 200KPH is simply indicated speed on the speedometer which we all know is about 8-10% more than real speed.

Like the other you again ignore the premise of the question. On paper NX300h is more fuel efficient for extra-urban driving than A4 1.8T, so I guess the owner is surprised why this does not translate into real life fuel consumption figures. And the answer is partially because it is hybrids and partially because it is SUV. Where better fuel consumption my still be true at 60MPH, it is no longer true at 112MPH.

[Zotto]

3 minutes ago, Linas.P said:

Are you saying just cruising at 200kph diesel would not be more efficient? 

They have almost the same efficiency. The difference is mostly because specific energy in gasoline is LESS than in diesel fuel, so the main factor is about cost of different fuels , not about efficiency itself. That's the reason because in Europe there are so many diesel cars.  Usually the point not considered is that, even when electric is not used, the Atkinson cycle of Toyota/Lexus hybrids are efficient like diesel engines and with less complications. Of course there are also disadvantages, but electric traction compensates the scarce low rpm power of Atkinson's engine.

[Linas.P]

11 minutes ago, Malc said:

last time I was on Italian motorways, a few years ago tho mind you, they were either jam packed solid ( like Milan ) or just petered out into a mud bath of impending roadworks ( mainly going south maybe ! ) .......  the opportunities to do any sort of speed was amazingly limited

Has the Italian Govt suddenly found a raft of dosh to get the roadworks going again I wonder

Malc

Well, I only had posted speed limit in mind, not necessary the actual road conditions. But that said last time I was in Italy like 5 years ago I had a blast between Rome and Naples on E45. If anything at least the stretch I was driving on was as good if not better than autobahn and average speed of cars passing by was comparable to that of Germany. + police didn't pay attention into Lamborghinis and Ferraris just flaying past.

Autobahn nowadays is really rough, it only has iconic status because of those unlimited speed zones, but as the motorway itself it is quite unimpressive to be honest.  

2 minutes ago, Zotto said:

They have almost the same efficiency. The difference is mostly because specific energy in gasoline is LESS than in diesel fuel, so the main factor is about cost of different fuels , not about efficiency itself. That's the reason because in Europe there are so many diesel cars.  Usually the point not considered is that, even when electric is not used, the Atkinson cycle of Toyota/Lexus hybrids are efficient like diesel engines and with less complications. Of course there are also disadvantages, but electric traction compensates the scarce low rpm power of Atkinson's engine.

I think we just going deeper into the woods with this... specific energy and Atkinson-cycle has nothing to do with the question. I just know from practice that as soon as you cruising at constant speed hybrid ~= simple petrol, the real advantage of hybrid system is start-stop traffic. Hybrids can recover otherwise wasted energy when braking or simply slowing down and reuse it when accelerating. If you just driving for long period of time at constant speed there isn't much benefit + you carry extra weight.

When you cruising at specifically high-speed, then hybrid becomes really detrimental. Where at normal motorway speed they can still be used to modulate inclines and declines at constant high-speed, they literally becomes just a ballast. I am not saying they completely useless - they will help you to get to that top speed quicker, but once there they will do nothing and they certainly won't help you save any fuel.

Do you agree that that in practice at constant 200kph 3L TD will be more efficient than 2.5L Hybrid? Or for that matter even 2.5L v6 petrol will be more efficient than 2.5L hybrid?

[dutchie01]

One thing that has always worried me is that non Germans ( including many Dutch) think they HAVE to drive 200kmh on the Autobahn...

Besides some parts of the Autobahn if traffic and weatherconditions permit it is pretty complicated nowadays to go 200 or more. Heavy policing, radarzones, and even in France private companies that are allowed to catch speeders make it almost impossible or very expensive. In France you have to pay NOW or the car will be confiscated until you arrive with the money.

Anyway, coming back to the first post, maybe once i would try topspeed with an NX but its not the right car for that, you bring it outside of its comfort zone. Like Linas says a German with a big diesel  ( or petrol) would be more suited to cruise at 200 for hours on end. Not an NX.

[Linas.P]

Not much more to add, I noticed myself that German own cars seems to be better adapted for exactly that. Especially, more exec cars like A6 or BMW5 - seems to be able to cruise at 200kph all day everyday and still return very reasonable MPG. Probably Germans specifically tune them for that sort of driving.

That is not to say NX300h is bad car, just not for top-speed runs...  Again seems to be specifically tuned for city driving, where it is actually great car all around.

[Zotto]

May be the topic has slighltly changed during debate, from "has a NX a good mpg performance in motorways" to "is a hybrid SUV a right choice to drive at 200 kph compared to a diesel?". Coming back to original question, and considering "normal" motorway use, a Hybrid SUV is quite comparable for fuel consumption to a diesel. And this is valid for cars too. Besides, when traffic increases, mpg gets better because of energy recovering during  braking hybrids do it and diesels not (excepts and only partially in mild hybrids diesels); that 's the reason where best mpg are achieved in city driving.