Fuel consumption concerns

[Zotto]

27 minutes ago, Linas.P said:

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?

Partially No 🙂 You justify this because there is a extra weight to move, but, at constant speed, it does NOT affects fuel consumption.

Of course to reach and maintain that speed a lighter and more aerodynamic car uses less energy (lighter to reach a aerodynamic to maintain).

The right comparison should be between a 2.5L TD and a 3.5 L aspirated Atkinson 

[Linas.P]

1 minute ago, Zotto said:

Partially No 🙂 You justify this because there is a extra weight to move, but, at constant speed, it does NOT affects fuel consumption.

Of course to reach and maintain that speed a lighter and more aerodynamic car uses less energy (lighter to reach a aerodynamic to maintain).

The right comparison should be between a 2.5L TD and a 3.5 L aspirated Atkinson 

Not sure what makes comparison wrong or right?

The comparison I suggested was between 3 real life cars all of which I have driven at 200KPH (or been "driven in", in case of Q5), so I know what is the fuel consumption without any theories involved and I am not trying to justify it by anything. I don't remember exact MPGs, but starting from most fuel efficient to least would be Q5 3.0TDI, Lexus IS250 and Lexus IS300h. Obviously, IS300h will be more fuel efficient than NX300h, so I just assume NX will have even worse MPG.

The best two cars for fuel consumption at 200KPH, were BMW 530d and new MB E300, to be honest I was closer to 250KPH in E-Class and it was still about the same as 530d, but that is apples to oranges as 530d was 2007 and E300 was 2019, so I assume new BMW 5-series would be like for like comparable with MB E-Class as well.

Regarding the weight at constant speed - partially true, partially false. Yes weight of the car will impact fuel consumption more when accelerating than when cruising at constant speed, but even when cruising more weight = high consumption. So additional weight from batteries is not completely irrelevant.

[Al D-Much]

1 hour ago, Linas.P said:

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.

Er it is possible.

It does state in all the literature that the NX is limited to 112mph, and it sort of is, tried mine in Eco and Normal modes, it hits the speed limiter and does not go any faster

However, in sport mode I’ve pushed mine to an indicated 125mph, and using WAZE gps the actual speed was 121mph (WAZE calibrated accurate) with a little room to go faster, but I ran out of clear ‘test track’ 

In fact I’ve tried my NX at various speedo indicated speeds against WAZE, and the speedo always exactly 4mph ‘optimistic’, which is surprisingly accurate for a car speedo.

 

[Linas.P]

Quite interesting... although in my old IS250 Waze has failed me - as it would not show more than 120MPH in one occasion. I could clearly feel car is still accelerating, but waze won't move any further. So I would be careful with "WAZE calibrated accurate" speed, but at the same time at least from my experience it could show less, but perhaps not more.

[Al D-Much]

34 minutes ago, Linas.P said:

Quite interesting... although in my old IS250 Waze has failed me - as it would not show more than 120MPH in one occasion. I could clearly feel car is still accelerating, but waze won't move any further. So I would be careful with "WAZE calibrated accurate" speed, but at the same time at least from my experience it could show less, but perhaps not more.

Even if the latest version of WAZE was ‘stuck’ at 120 it’s still higher than the “limited” 112.

[Linas.P]

I guess that is besides the point, I am just saying waze is not some professional speed measuring tool, but I do agree that at very least up-to ~90MPH is is far more accurate that car speedometer itself.

At higher speeds I found any mobile phone GPS app accuracy hit and miss... and if you go like 200MPH+ (not KPH) it refuses to work at all. I tend to believe this is linked to mobile data or tower triangulation being used for more accurate results - at high speed phone cannot keep-up the connection meaning that GPS data becomes incorrect.

Obviously, we going into proper off-topic now, but I take your point - it may have been actual 200KPH, it may have been just indicated. I guess we never know unless OP confirms this.

[Las Palmas]

Hi all and hope we soon can get vaccinated so we can live more freely use our nice cars more.

Gallons are impossible to understand. For me.

From Wikipedia, the free encyclopedia:

The gallon is a unit of measurement for volume and fluid capacity in both the US customary units and the British imperial systems of measurement. Three significantly different sizes are in current use:

the imperial gallon (imp gal), defined as 4.54609 litres, which is used in the United Kingdom, Canada, and some Caribbean nations;

the US gallon (US gal) defined as 231 cubic inches (exactly 3.785411784 litres), which is used in the US and some Latin American and Caribbean countries; and

the US dry gallon ("usdrygal"), defined as ¹⁄₈ US bushel (exactly 4.40488377086 litres).

There are four quarts in a gallon and eight pints in a gallon, and they have different sizes in different systems.

When it comes to miles it is just as confusing.

1                    Scandinavian mile (Finland, Norway & Sweden) is more or less 10km

Spanish mile a bit more than 5km

Nautical mile 1.8km

Great Britain mile 1.609.3426km

London mile 1.524km

 

I believe that if growing up with miles, gallons, pints (that all can come in different sizes) it is easy to understand gallons per mile. I also do not fully understand the AM/PM but OK.

Must be me that is a slow learner as I find km/l a lot easier and as far as I know it could be a more precise way of figuring out how much it cost in fuel to drive from A to B. I grew up learning that.

Lexus Spain tell us that the CT200H Luxury/Premium will use 3.8 litre pre 100 kilometres which is 26km/l.

I think without having calculated yet when filling up and driving that I get about 20km/l but the island here is not flat at all. When going uphill gasoline engine is running constant and going down again, I get full hybrid Battery rather fast so on flat roads I believe the 26km/l are possible.

Anyway, we are happy with our CT and if it run 20 or 25km on one litre is all good. Tax is cheaper and insurance also than our previous cars.

The pics are found searching with Google