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In the latest BBC TopGear (S24 E07) Chris Harris reviews the new Porsche Cayman 718.
BBC Two - Top Gear, Series 24, Episode 7

He has quite a lot to say about the bad change from a 6 cylinder to a 4 cylinder turbo engine because it "no longer sounds right".
In his expert opinion, he says the change is because Porsche wanted to get the co2 emissions down to make it Euro 6 compliant.

As part of his review, he does a demonstration of how silly the test is, by strapping some official dieselgate looking test equipment on the car and doing a lap of the top gear track at an unrealistic slow speed to see what he actually gets. Even at his slow speed, he is still higher than the official figures.

Historically we know that TopGear used to be a "factual" program, but around the time of the Tesla court case, or the actors on the Transit Hovercraft item, the BBC redefined the description to be "fact based entertainment", but it got me thinking....

How much time/effort/money did it take for Porsche to redesign the car so that they got better performance, handling and economy over the previous model and still manged to get it through an obviously flawed test system so that it is under a magic threshold so they can actually sell it.

I read somewhere that the MPG and/or co2 measurements on PHEVs are based on doing one test with a full battery and another test with a flat battery and taking an average of the two?
If they can do the test twice for a PHEV, why not do multiple tests to work out more "real world" figures for "typical usage" scenarios for vehicles, and then use that more realistic figure to work out incentives, VED and BIK rates?

So a Porsche driven slow using the standard test, and also being driven quickly away from the lights and at high speed on the motorway, or on the topgear track, and take the average? perhaps the new co2 figure might be 500g co2/km?

Range Rover Vogue, driven slow on the test, and then a 2nd test with a yummy mummy with a couple of toddlers doing a hard acceleration away from her parking spot on the zigzags outside the school, brake hard at the end of the road, then sharp turn when turning on to the high street and hard acceleration down the wrong side of the road to get around the bus that is trying to pull out. (that is where I see them most)

As demonstrated by Porsche, if you give the makers targets to aim for, perhaps those revised figures might give car makers more of an incentive to produce cars that are not taxed so much, which might happen to be cleaner cars?
Or perhaps it would be the final straw that would get the world to change? or at least stop those who are preventing change?
 

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The test really is to blame here, and I think that is changing soon - as far as I'm aware a more realistic test is commencing within the next year? Although there is obvious resistance from the motor industry.

Below I include a screenshot of the EPA fuel economy ratings for 2016/17 Boxster and Boxster S. As we know the EPA fuel economy ratings are generally speaking reliable.



The new 4 cyclinder cars return the same MPG as the 6 cylinder cars - combined - however are marginally worse on the motorway. Great!

I don't have the time at the moment to extract the NEDC figures deep from the internet on old Porsche brochures etc (EPA website is great for looking up figures!) but presumably the new 4-cyl cars have considerably better ratings... sigh!
 

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I think the government is over-complicating things - making fuel punitively expensive would be far more effective, trouble is you lose votes.

If people want to own a V8 but only do 1000 miles a year in it then, so what? Presumably its the people doing 80,000 miles a year in their company cars / 4x4's and driving diesels who are really pumping up the CO2 numbers and ruining our air?

Increase the tax on fuel by 10% every year for the next 15 years and see what happens .... lol

J (never afraid to oversimplify a complex problem, lol)
 

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Below I include a screenshot of the EPA fuel economy ratings for 2016/17 Boxster and Boxster S. As we know the EPA fuel economy ratings are generally speaking reliable.

[...]

The new 4 cyclinder cars return the same MPG as the 6 cylinder cars - combined - however are marginally worse on the motorway. Great!

I don't have the time at the moment to extract the NEDC figures deep from the internet on old Porsche brochures etc (EPA website is great for looking up figures!) but presumably the new 4-cyl cars have considerably better ratings... sigh!
EPA figures seem pretty reliable (for EV's too) but those reading just keep in mind all EPA MPG figures are US miles/gallon not UK.

So that 25MPG figure doesn't look that great at first glance but its actually 30 miles per UK Gallon.
 

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I think the government is over-complicating things - making fuel punitively expensive would be far more effective,
Umm, hasn't that already happened, with or without action from the government ?

Anyone doing a reasonably long commute these days (my commute just went up from 16 miles a day to 38 miles a day) is already paying through the nose for Petrol/Diesel.

In fact the cost of petrol being so high per mile is what pushed me over the edge into buying an EV in the first place. Sure, I was interested in EV's already, wanted one already, but couldn't justify buying another car until I realised that the petrol savings alone would pay for a cheap EV like my Ion and then some, so I'm basically getting the car for "free".

In the US petrol is so incredibly cheap compared to the UK that there isn't a strong incentive to go EV purely on fuel costs, but here in the UK the difference is eye watering.

I worked out that commuting in my Petrol V6 was costing me 28p/mile, a typical 40MPG Diesel would cost me 14p/mile and my Ion costs me just under 3p/mile without using the heater... Even the most efficient little 1 litre petrol econobox can't beat an EV or even come close.

The general population are being stung by punitive fuel bills for their vehicles already but have not yet woken up to or been made aware of just how low the per mile running costs of an EV can be, whether old or new. Although old EV's have a short range they are pretty much just as efficient as a modern EV (apart from the heater, if the new one has a heat pump) and still perfectly good for a fixed distance commute, at an affordable price.

Range at an affordable purchase price isn't quite there yet with EV's but as soon as the prices come down a bit more, range goes up a bit more and the general population has that epiphany moment when they realise there is an alternative to paying through the nose for petrol and diesel, ICE for general purpose passenger commuting will be dead in the water.
 

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The general population are being stung by punitive fuel bills for their vehicles already but have not yet woken up to or been made aware of just how low the per mile running costs of an EV can be, whether old or new. Although old EV's have a short range they are pretty much just as efficient as a modern EV (apart from the heater, if the new one has a heat pump) and still perfectly good for a fixed distance commute, at an affordable price.

Range at an affordable purchase price isn't quite there yet with EV's but as soon as the prices come down a bit more, range goes up a bit more and the general population has that epiphany moment when they realise there is an alternative to paying through the nose for petrol and diesel, ICE for general purpose passenger commuting will be dead in the water.
For most people buying their own car, a 2nd hand ex company lease car is so much cheaper then a EV that the savings on fuel bills is not enough to make it worth while having a EV. Few people drive enough mile every day to make best use of current EVs while not wanting to travel long distances often. The drivers we need most to get into EVs are the people that spend their time driving round cities, these are also the people that make the least savings as they drive so few miles.....

(EVs are also hard to buy, I can get a good 2nd hand "normal" car just by looking on AutoTrader and seeing what is for sale within 20 miles of my home, and drive it home the same day.)

So I think we need company car drivers to have the "epiphany moment" 3 years before most other drivers will get the option as about 60% of new cars in the UK are company cars.

There are some people with the correct length commute so the fuel savings covers the full costs of a "commuting ev" letting them get the best of both worlds by owning two car. Work place charging would greatly increase the number of such people........
 

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If people want to own a V8 but only do 1000 miles a year in it then, so what? Presumably its the people doing 80,000 miles a year in their company cars / 4x4's and driving diesels who are really pumping up the CO2 numbers and ruining our air?
If only it was that simple, CO2 is not what is making lots of people in the UK sick, it is the other pollution from car mostly in cites. Therefore a car driven for 5000 miles a year in a city making lots of short trips on a cold engine can be much worse then the same car doing 80,000 miles a year on the motorway. Hence taxes on fuel don't hit the correct people. (Fuel taxes even tend to get more people buying diesel cars.)

Also by reducing CO2 a car often has high levels of the other pollution, after all if we did not care about CO2 and MPG we would not have so many diesel cars in use..... Most cars get used as "city cars" in their old age even if they were used as "motorway cars" in the first few years of their life.
 

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For most people buying their own car, a 2nd hand ex company lease car is so much cheaper then a EV that the savings on fuel bills is not enough to make it worth while having a EV. Few people drive enough mile every day to make best use of current EVs while not wanting to travel long distances often. The drivers we need most to get into EVs are the people that spend their time driving round cities, these are also the people that make the least savings as they drive so few miles.....

(EVs are also hard to buy, I can get a good 2nd hand "normal" car just by looking on AutoTrader and seeing what is for sale within 20 miles of my home, and drive it home the same day.)
What you're saying is only the case today for two reasons:

1) There aren't enough EV's in circulation yet to easily find one on the second hand market. Obviously there are 100x more ICE cars of every shape and size on the second hand market, but that will change as the number of EV's in circulation goes up.

2) EV's aren't old enough yet to fill out the second hand market, with most EV's only being one or two owner cars so far. Realistically the EV market didn't really start until about 2011 with the introduction of the Leaf, (yes I know the i-Miev came 2 years earlier, but it never sold in large numbers) so the oldest "modern" EV's are still only about 6 years old, so are still relatively expensive, just like a 6 year old ICE.

Give it another 5 years and we will have both more EV's to choose from in the 2nd hand market and many of them will be further down the trade in chain on their 3rd or 4th owner where people on smaller budgets can afford them.

I think you're a bit pessimistic about people not doing enough mileage to afford a 2nd hand EV.

With a £4200 Ion I was able to break even buying it over 4 years and doing a total of about 500 miles a month, 320 of that daily commuting 16 miles a day. Recently my daily commute has gone up to 760 miles a month (38 a day) and total mileage around 1000 a month. With those figures I'm actually saving about £100 a month compared to the petrol car while I'm still paying the Ion off....

Now if you're talking about a £7000 battery inclusive Leaf, yeah you'd have to do quite a lot of miles to make it pay for itself, but those £7000 Leaf's will be £4000 in just a few more years...

And if you're needing to replace an existing car anyway for other reasons, that is a good time to consider an EV, because whether you buy an EV or an ICE, either way it is going to cost you money...
 

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What you're saying is only the case today for two reasons:

1) There aren't enough EV's in circulation yet to easily find one on the second hand market. Obviously there are 100x more ICE cars of every shape and size on the second hand market, but that will change as the number of EV's in circulation goes up.

2) EV's aren't old enough yet to fill out the second hand market, with most EV's only being one or two owner cars so far. Realistically the EV market didn't really start until about 2011 with the introduction of the Leaf, (yes I know the i-Miev came 2 years earlier, but it never sold in large numbers) so the oldest "modern" EV's are still only about 6 years old, so are still relatively expensive, just like a 6 year old ICE.

Give it another 5 years and we will have both more EV's to choose from in the 2nd hand market and many of them will be further down the trade in chain on their 3rd or 4th owner where people on smaller budgets can afford them.
Only if EVs start to become common as company cars as there are not enough "normal car drivers" buying new cars to fulfill the needs of all 2nd hand car drivers. Small automatics have the same issue hence my wife was forced to buy a new car as her first car as she could not find any 2nd had small automatics.

I think you're a bit pessimistic about people not doing enough mileage to afford a 2nd hand EV.

With a £4200 Ion I was able to break even buying it over 4 years and doing a total of about 500 miles a month, 320 of that daily commuting 16 miles a day. Recently my daily commute has gone up to 760 miles a month (38 a day) and total mileage around 1000 a month. With those figures I'm actually saving about £100 a month compared to the petrol car while I'm still paying the Ion off....

Now if you're talking about a £7000 battery inclusive Leaf, yeah you'd have to do quite a lot of miles to make it pay for itself, but those £7000 Leaf's will be £4000 in just a few more years...

And if you're needing to replace an existing car anyway for other reasons, that is a good time to consider an EV, because whether you buy an EV or an ICE, either way it is going to cost you money...
Most people would expect to have a EV in addition to their current car, the savings also have to be a lot better then "break even" for most people to take the risk.

Fuel savings will not on their own be enough to get most city car drivers to convert to EVs.
 

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Marginally off topic but I saw some car adverts on YouTube from the 90s and the mpg figures they showed were at constant speeds, for example a 1litre car showed 44mpg at a constant 75mph which I think is a more accurate measurement of mpg rather than these 'realistic' EU tests.
 

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I read somewhere that the MPG and/or co2 measurements on PHEVs are based on doing one test with a full battery and another test with a flat battery and taking an average of the two?
I don't think what you read could have been accurate. I doubt my car could do better than 45mpg over the NEDC starting with minimum battery, but it would need to achieve at least 67mpg to get an average over two runs of 135mpg. I think it's tested once and the ICE kicks in for the tiny spike of accelerating to 120kph at the end of the test. Let's hope the WLTP is better than the NEDC. And arrives sooner rather than later...
 

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It is not possible with PHEVs to have a meaningful way of testing MPG if any electrical power is allowed to be used, as it is so dependent on how each person drives and how far they drive.
 

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IMO the best way to do it is with a pollution profile. An agreed formula for simply describing the makeup of the crap that comes out of the back of an ICE.

Each pollutant would have a weighting based on public health and environmental damage. So a low CO2/high NOX car might get a higher pollutant rating than a high CO2/low NOX car.

The car would need to be measured every year, from new, and the rating would set the level of tax for the next year.

Set the levels right and natural selection will see the worse offenders off to the scrapyard.
 

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The problem is that for type approval you do need a consistent test, so one performed in a lab environment on a dynamometer makes a lot of sense. The issue is firstly that people do not drive the same way every time and secondly the test currently being used has an awful lot of loopholes both in the test itself and in the conditions under which the emissions control system has to be working. There's a lot of good articles in the ICCT and the Transport & Environment websites if you need an insomnia cure.

The existing NEDC is highly stylised with relatively gentle required acceleration rates - as an example a CD class car (Ford Mondeo, VW Passat etc) will typically only need a peak power of less than 30kW to achieve them. Since even the lower powered variant pump out 100kW+ this means that only a small part of the engines power/torque profile is actually testing. This partly dates back to when the test was established coupled with the fact that getting agreement over a large number of different countries is very difficult. There are also lots of ways to game the system so if you took a production car and tested it straight out of the box you'd be lucky to get with 15% of the official figure. In addition there are a number of get-outs where the emission control system can be disabled eg: if there's a risk of engine damage which is all good meaning sensible stuff.

The problem is that some manufacturers use this as an excuse to shut the system down when the car is used outside of the NEDC profile either by time or demand - this has the added advantage for diesels that if selective catalyst reduction systems are used then the Ad-Blue consumption is dramatically reduced. Note that none of this is illegal under EU law - VW in the US employed something called a defeat device which actively worked out if the car was being driven on an official test and then modified the emission control system behaviour. It beggars belief that they did this because there have been several high profile cases in the US which have resulted in punative fines so how they thought they could get away with it escapes me. There is also defeat device legislation in the EU but it's far weaker and strictly it doesn't look like any manufacturer (including VW) has breached it. Not having to run the emission system or running it at a lower efficiency tends to give better economy, lower running costs, more power and better drivability so there is a big incentive for the manufacturers to exploit the system and in this respect Top Gear will be quite correct, the emissions control system and the need to meet CO2 targets is likely impairing the drivability etc. If that's your only concern and you don't care about the toxic emissions then that's an issue!

There are several things happening to improve the situation although they will only partially close the gap. Firstly a more dynamic test profile is being implemented from September this year for new vehicles and 12 months later for existing ones called the WLTP which also closes down some of the loopholes. This means that the same vehicle tested under the new WLTP will get worse results than under NEDC which is a challenge for taxation - the short term solution is to tax based on NEDC results. This profile still only covers a small portion of the engine power/torque profile but is an improvement.

A new road based test is also being introduced called RDE (Real Driving Emissions) where vehicles will be driven on public roads over a road circuit that has to include a number of defined elements (city, highway, altitude etc) while attached to portable emissions test kit. This is also being introduced this September for new vehicles and two years later for existing. Initially the results will only be for monitoring purposes and no enforcement will take place - that is probably going to be 2021 - and also conformity factors are applied to account for the test variability. The test itself, the introduction dates and conformity factors have been the subject of very heavy industry and government lobbying to delay and water down the proposals and only the production based elements have so far been agreed. There are proposals still under discussion for things like in-service conformity testing where showroom vehicles and cars a year or two old can be tested, plus having an EU wide independent body to perform the testing - at present the vehicle manufacturers perform their own tests overseen by the individual government authorities. Exactly what will be implemented is unclear at the moment - the UK and German governments in particular have been lobbying hard on behalf of their auto industries. Brexit is also unlikely to have much effect assuming the UK still wants to sell into the EU market.

It's worth noting that the US test is far more representative of real world usage and they rejected using the WLTP because it didn't cover enough (the W in WLTP is for World). The EPA figures for fuel consumption are much closer than the NEDC based ones.

Also for interest, commercial vehicles have to comply with a different test which is based on the engine power. The profile tests up to full power and included randomised elements to confuse cycle beating calibrations or devices. In addition commercial vehicles have in-service tests performed at the roadside on customer vehicles - by VOSA in the UK so there are far less loopholes. This leads to the rather perverse situation where trucks and buses in city centres where we have a serious pollution issue emit far less NOx and particulates than most cars, particularly diesels - up to 20x less!
 

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It is not possible with PHEVs to have a meaningful way of testing MPG if any electrical power is allowed to be used, as it is so dependent on how each person drives and how far they drive.
How people drive has a huge affect on ICE efficiency as well.

I agree that a range figure (66% of NEDC?) plus a post-plug-in economy makes more sense.

I have no idea how the range figure of a PHEV is decided over a 7 mile test program. Some (most/all?) PHEVs can complete it on battery only, which would allow a range to be extrapolated, but they are all assigned an economy figure. Maybe @Richard Butler was right and PHEVs are put through the NEDC more than once, but the first time it's with a full battery and the second time it's with whatever battery was left after the first cycle? I can just about imagine how that could result in a 150mpg figure, but it's not very helpful to anyone wanting to know whether the car will suit them.
 

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This leads to the rather perverse situation where trucks and buses in city centres where we have a serious pollution issue emit far less NOx and particulates than most cars, particularly diesels - up to 20x less!
Do you have any evidence for this? It doesn't sound credible.

When I researched it recently, it looked like a fleet of EU6 diesel cars would emit the same as a single EU6 bus, so you seem to be suggesting that real-world EU6 performance is twenty times worse than test performance.
 
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