Lasted 2 Weeks

[marrat]

Even a Prius going at high speed doesn't take a huge hit on MPG, that's a myth. Read some reviews and such. Start-stop is the strength of the hybrid system. What do you think the electric engine does?

[Linas.P]

No, I have not owned Lexus hybrid, though it doesn't mean I don't know what I am talking about. Take for example the journey I often do in my IS250. Gatwick to Romford, mostly M25 and M23. when I set 90MPH on autopilot (~84MPH GPS) I get 37MPG, average diesel would do ~50MPG, I did same journey in IS/RC300h and MPG was 34 and 32 respectively. If I would drive like 65MPH, I could get like 50MPG from IS250 and up to 60MPG from hybrids (because of more efficient petrol engine)... but I never drive at such speed.

I don't like diesels and I mostly do city driving where hybrids would be the best choice, but the diesel is still king of motorways when it comes to fuel economy.

And yes...sorry I might been not very clear... What I have in mind by "start stop".. is not city like start stop, but rather when you doing 90MPH in outside lane and, you have to slow down and then accelerate again, so say 90-65-90... on neither of those speeds electric motors or Battery helps.. they are just ballast. And it is completely true, in start stop city traffic the hybrid is the best option, but you still need to drive like a granny... the reason - trying to do as much as possible EV and as little as possible engine starts. That is why many people who first acquires hybrid don't feel that huge MPG improvement, after some time they start driving hybrids in careful fashion avoiding using engine much and then get good results. To paraphrase, hybrid drive is there to help you save fuel if you want, but if you going to continue driving it like petrol/diesel car, in most part it going to be just heavy petrol car.

[Shahpor]

Don't worry chaps, he grows on you.

And Linas,  stop telling people you are breaking the law on the motorway.   You are going to get police camped out on the M25 looking for speeding Lexus IS's if you are not careful

 

Sorry.  You can now continue your serious discussion.

[ganzoom]

5 hours ago, Linas.P said:

  To paraphrase, hybrid drive is there to help you save fuel if you want, but if you going to continue driving it like petrol/diesel car, in most part it going to be just heavy petrol car.

This is just not correct, the Toyota hybrid setup achieves better efficiency through a very efficient combustion cycle using the electric motor to compensate for the lack of torque in the atkinson combustion cycle. 

Our IS300H gets better mpg than our diesel Civic in all conditions regardless of the manner driven despite the Civic been roughly 300kg lighter. 

Weight also little impact at M-way speeds, not when your looking at 300kg of difference. Its the aerodynamic efficiency that makes the difference.

This aero test by Car and Driver shows the importance of aero, despite weighing a massive 680kg more and been a much bigger/faster car, a Tesla Model S uses exactly the same amount of power to sustain 70/100mph as a Toyota Prius. 

http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test-drag-queens-performance-data-and-complete-specs-page-7

Ofcourse that doesn't take into account rolling resistance and engine thermal efficiency.  But as you can see form the graph below aerodynamics is by far the biggest contributor to energy consumption at M-way speeds. 

If your really obsessed by M-way economy than a pure EV should be your dream car. The thermal efficiency of the electric motor is about 90% at any speed compared to less than 50% for even the best combustion engine at optimum revs. Add in better aero thanks lack of air intakes/exhaust system this is the reason all EVs score >90mpg in EPA tests (the latest Hyundai EV is over 120mpg) but even the best combustion cars (like the Prius) struggle to hit over 50mpg.

The current IS250 is rated at 24mpg by the EPA so over 100mpg less than the best EV and half the efficiency of car like the Prius, and even the 4WD NX300H is better at 30mpg. And don't compare the EPA mpg tests with the joke European tests we have, it was the EPA that first picked up the dieselgate saga, and their mpg rating are very close to real life mpg. 

[marrat]

@Linas.P: you seem to think the Toyota/Lexus  hybrids use a conventional petrol engine with some electric power usage at low speeds. You are incorrect on both parts. I suggest you read up on the underlying hybrid tech, it's very interesting really and it'll give you a better view on how it exactly works.

[capese21]

13 hours ago, Linas.P said:

No, I have not owned Lexus hybrid, though it doesn't mean I don't know what I am talking about

You clearly don't know much about how Lexus Hybrids work in real life though

[Linas.P]

3 hours ago, capese21 said:

You clearly don't know much about how Lexus Hybrids work in real life though

I believe is exactly opposite.. I don't pay much attention to all marketing blurb or much theoretical stuff, both available in internet or in the long (and probably correct) post above.

What I am saying is exactly the experience driving Lexus hybrid without theoretical non-sense, exactly how it is on the road. I am not going to pretend I have years of experience, but ~1000miles, that is one CT200h for ~200 miles, one IS300h for 300miles and one RC300h for ~540miles. So based on my experience, I had to drive hybrid Lexus more carefully than my petrol Lexus, to achieve meaningful increase in MPG. I did exactly that... and if I could adapt to new driving style in less than 24h, than anyone could. Lexus hybrids really encourages careful driving style and pulling-off in very relaxed fashion .. which I think is a good thing, but my point that you need to drive Lexus hybrid more carefully to achieve good MPG still stands.

@Shahpor - I agree with you that is not the best thing to do..... but I have said that to reflect realistic use of vehicles, furthermore I considering them merely advisory.. based on government own guidance. There is no reason why modern cars cannot go faster safely. 70MPH speed limits is based on real life test conducted in 1931 (based on the source presented to me in speed awareness course), general practice for setting speed limits is 80th percentile rule aka they should reflect 80% of drivers speed, otherwise it is said and I quote "speed limit is over restrictive and will decrease respect from the motorists and increase non-compliance" - Barbara Castle, 1965 (the minister responsible for introduction of speed limits). Back in 1965, 70MPH was aligned with 80th percentile rule - in fact average speed was ~55MPH. Based on statistics from 2014 49% of drivers were speeding on motorways (I guess that would be 100% if not the traffic jams) and average speed on all motorways (that is including stretches where 70MPH strongly enforced) was 82MPH... therefore goverment own 80th percentile rule is long broken.

Based on above I see no reason to respect 70MPH limit and finally I would point you to the government own guidance for setting speed limits, particularly below part:

26. Where there is poor compliance with an existing speed limit on a road or stretch of road the reasons for the non-compliance should be examined before a solution is sought. If the speed limit is set too low for no clear reason and the risk of collisions is low, then it may be appropriate to increase the limit. If the existing limit is in place for a good reason, solutions may include engineering measures or changes to the road environment to ensure it better matches the speed limit, or local education and publicity. Enforcement may also be appropriate, but should be considered only after the other measures and jointly with the police force. - https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/63975/circular-01-2013.pdf

So to brake it down, where compliance is poor e.g. all motorways (49% over the limit, average speed 82MPH). And the speed limits set low for no good reason (exactly that on motorways)... and risk of collision is low (the risk of collisions were at all time low on Motorways last years and still decreasing), the limit may be increased ... ohh indeed. Finally, it says enforcement may be considered only after engineering measures and other means to adapt the road to the "de-facto" speed at which motorists are driving - I guess that is why speed cameras are always off on M25 unless there is accident.

[Shahpor]

Perhaps you guys can just agree to disagree?

As for speed limits, don't get me wrong, I agree with you Linas that they are a bit archaic and should be modernised.  I also believe that bad driving habits, not speeding, is the major factor in accidents on the motorway.

Having said that, I do value having no points on my licence, so don't plan to challenge the current regulations.

Regardless of all the reasoning you have posted, you will still get points, and possible a summons, if you were caught doing 84MPH.

If that does happen, please let me know where and when your appearance in court would be;  I would love to see you against a Judge.

[ISJason]

I always see lots of undertaking on dual carriageways these days and to a lesser degree on motorways. Just an observation.

Sent from my iPad using Tapatalk

[ISJason]

Just wondered if anyone can recommend a good independent Toyota or Lexus for service/ cam belt in the Birmingham area? I know there used to be Cutlers in Aldridge but they went bust I think.

Sent from my iPad using Tapatalk

[rayaans]

1 hour ago, ISJason said:

 

I always see lots of undertaking on dual carriageways these days and to a lesser degree on motorways. Just an observation.

 

Sent from my iPad using Tapatalk

I would have to be honest and say I am a culprit of this behaviour.

Its not something I seek to do actively but there are certain situations in which it occurs. For example. cruise control on the motorway at set speed in first lane. Middle lane hogger driving along under my cruise control set speed. The options I have are to either undertake and prove a point or go all the way around. I prefer to choose the first option as hopefully itll knock some sense into the plonker and get him to move over (does actually work most of the time).

Another scenario would have to be on a dual carriageway or a motorway where a car zooms past you, then realises they are going significantly over the speed limit and slow down to slower than cruise control speed. but won't actually move into the left hand lane

[C Mclean]

4 minutes ago, rayaans said:

I would have to be honest and say I am a culprit of this behaviour.

Its not something I seek to do actively but there are certain situations in which it occurs. For example. cruise control on the motorway at set speed in first lane. Middle lane hogger driving along under my cruise control set speed. The options I have are to either undertake and prove a point or go all the way around. I prefer to choose the first option as hopefully itll knock some sense into the plonker and get him to move over (does actually work most of the time).

Another scenario would have to be on a dual carriageway or a motorway where a car zooms past you, then realises they are going significantly over the speed limit and slow down to slower than cruise control speed. but won't actually move into the left hand lane

Totally agree with you...

[ISJason]

I understand completely what you say, but in the case of motorway driving you have to be very careful as a car undertaking you can take you out completely. My dad was almost smashed by an idiot undertaking .. as the fool was in his blind spot, but fortunately he swerved in time. Also undertaking is completely illegal and you would be done for it if caught.. always best to overtake as normal.

Sent from my iPad using Tapatalk

[doog442]

3 minutes ago, ISJason said:

 Also undertaking is completely illegal and you would be done for it if caught.. always best to overtake as normal.

 

Its not illegal I'm afraid. Anyone changing lane really should pay full attention to both offside and nearside. Often on motorways you can be advised to stay in your lane, so undertaking is inevitable. 

 

[Spacewagon52]

You are correct, it is not illegal but if your action causes an accident you have the possibility of being prosecuted.

[doog442]

11 minutes ago, Spacewagon52 said:

You are correct, it is not illegal but if your action causes an accident you have the possibility of being prosecuted.

Anyone has the possibility of being prosecuted if their action causes an accident whatever the circumstances. 

 

However I would agree its not good practice :-)

[ISJason]

Hi.. I just saw this on the BT website: "What you must not do while driving in lane one or two is overtake traffic to your right. Known as undertaking, it’s illegal in the UK and dangerous, and could result in a conviction for driving without due care or even careless driving."

http://home.bt.com/lifestyle/motoring/motoring-features/motorway-middle-lane-hoggers-beware-youre-breaking-the-law-11363989000725

So I don't know who is correct.

Sent from my iPad using Tapatalk

[ColinBarber]

The highway code should be your guide - undertaking isn't illegal (no MUST/MUST NOT in the rule) but it is against the code, therefore in an accident you would be at fault.

Many of the rules in the Code are legal requirements, and if you disobey these rules you are committing a criminal offence. You may be fined, given penalty points on your licence or be disqualified from driving. In the most serious cases you may be sent to prison. Such rules are identified by the use of the words ‘MUST/MUST NOT’.

https://www.gov.uk/guidance/the-highway-code/motorways-253-to-273

Rule 268

Do not overtake on the left or move to a lane on your left to overtake. In congested conditions, where adjacent lanes of traffic are moving at similar speeds, traffic in left-hand lanes may sometimes be moving faster than traffic to the right. In these conditions you may keep up with the traffic in your lane even if this means passing traffic in the lane to your right. Do not weave in and out of lanes to overtake.

[DanD]

On ‎17‎/‎12‎/‎2016 at 4:41 PM, C Mclean said:

Totally agree with you...

Ditto

[rayaans]

On 19/12/2016 at 4:19 PM, ColinBarber said:

The highway code should be your guide - undertaking isn't illegal (no MUST/MUST NOT in the rule) but it is against the code, therefore in an accident you would be at fault.

Many of the rules in the Code are legal requirements, and if you disobey these rules you are committing a criminal offence. You may be fined, given penalty points on your licence or be disqualified from driving. In the most serious cases you may be sent to prison. Such rules are identified by the use of the words ‘MUST/MUST NOT’.

https://www.gov.uk/guidance/the-highway-code/motorways-253-to-273

Rule 268

Do not overtake on the left or move to a lane on your left to overtake. In congested conditions, where adjacent lanes of traffic are moving at similar speeds, traffic in left-hand lanes may sometimes be moving faster than traffic to the right. In these conditions you may keep up with the traffic in your lane even if this means passing traffic in the lane to your right. Do not weave in and out of lanes to overtake.

Although in an accident you could argue that the other driver was not driving with due care and attention as you MUST NOT come into the path of a moving vehicle

[Davrobin]

 

Just adding to the "real life" figures on the fuel consumption debate....

I've had 2 Prius for the past 8 years, driving around 80,000 miles in each, with a mix of motorway cruising and driving around town.  The first Prius logged 51.7 MPG over its life. My next Prius averaged 53.8 MPG over 83000 miles.  I've had an IS300h (year old) since September, in which time I've covered 5300 miles and averaged 44.8 mpg.

Experience showed that the trip computer on the Prius was about 10% over-optimistic (it kept telling me I was achieving 55-60mpg).

I completely subscribe to the view that a diesel may be more economical for motorway cruising (my previous car was a Diesel Volvo V40). Also, with the Prius, I found that consumption started to get significantly worse at speeds over 65-70 mph (but, that said, a colleague tried driving the Prius one time and got it up to 105 on the M40 - not to be recommended! - & consumption was still in the low 50's).

Comparing the Prius with the Lexus - actual fuel running costs are not massively different - 10.1p/mile for the Prius, 11.2 for the Lexus.  As I do quite a lot of business miles, and the company mileage rate for the 2.5l Lexus is about 7p/mile more than for the 1.8 Prius, this is not a problem.  The Prius feels a lot lighter and flimisier to drive, BUT I'm finding it a bit irritating that the Lexus doesn't have much storage space for odds and ends (I miss the big centre console and 2 glove boxes in the Prius).  I'm also having to get used to not having a reversing camera - though the parking sensors seem to do a good job.

As far as braking is concerned, the real trick is not to brake at all but to decelerate in time to stop, or to brake very gently in order to use regenerative braking.

re brake noise - what I am finding a bit annoying is the whine from the compressor motor that seems to be charging up the brakes just after I've stopped, or am stuck in traffic!

[capese21]

3 hours ago, Davrobin said:

I completely subscribe to the view that a diesel may be more economical for motorway cruising

But not by much.  Take in the higher cost of diesel and the worse urban MPG and the Hybrid wins imho.  I was waiting outside a shop for the wife today and a guy came back to his quite new 320D.  As he fired it up the front bumper / grille literally shook.  I couldn't go back to a diesel even if it did  5 mpg more!!    I am not a Grandad & don't drive like one either!!  I do stay under 90 on the motorway though

[Slickk]

Computer showing an indicated 31.8 mpg, which was reset after a service roughly 1 month ago. Brimmed the tank with fuel and set about my usual driving, which really isn't much. I currently drive approximately 20 miles a day - mostly local city/town driving and a very short motorway stint to and from work.

Car is always in Sport mode but that doesn't mean that I 'floor' the throttle pedal or brake aggressively.

[ISJason]

The noise you were describing on braking is normal.

Sent from my iPad using Tapatalk