The four-cylinder Porsche Cayman S has fared worse than a V6-powered Jaguar F-Type in new real-world fuel economy testing by Autocar's sister brand What Car?

The Porsche 718 Cayman S has returned poorer real-world fuel economy than the V6-powered Jaguar F-Type in What Car? True MPG testing. 

The findings of the True MPG testing showed that despite Porsche opting to downsize the Cayman S from a six-cylinder to a turbocharged four-cylinder for better efficiency, the model still consumed more fuel than a Jaguar F-Type V6 auto.

See all of the latest What Car?'s True MPG results here

Under True MPG testing, the 718 Cayman S returned 28.39mpg, versus an official figure of 34.9mpg, equating to a shortfall of 18.7%.

The F-Type performed marginally better in the True MPG tests, delivering 28.79mpg, a 14.3% difference over its claimed figure of 33.6mpg.

The Cayman S was one of a batch of 20 models tested under What Car’s new True MPG process. A Porsche spokesman said “the basis of any official Europe-wide Government legislated testing is the NEDC - an agreed industry standard that provides a repeatable consistent platform for cars of all types to be assessed and which intends that data is easily and accurately compared with other cars. The car industry is currently working with legislators on revising the NEDC.

“Of course, the real world will present variations based on road conditions and driving styles. It can be higher than the official standard fuel consumption, but also lower if the driver adopts an appropriate driving style.”

The Porsche spokesman also highlighted the greater efficiency, power and torque in the new Cayman versus its six-cylinder-powered predecessor, as well as the model’s low real-world NOx emissions, under independent analysis.

The top performer in the first batch of True MPG testing was the six-cylinder BMW M2. The BMW strayed from a claimed 33.2mpg by just 5.3%, achieving 31.43mpg.

Meanwhile, other models that underperformed include the Volvo S90 D4. It has an official combined claimed figure of 64.2mpg, but under True MPG testing it achieved only 39.9mpg; this is the largest shortfall of all 20 cars tested, at 37.8%.

Volvo issued the following statement in response to the results: “Volvo cars meet all current emissions standards and figures quoted come from the current European testing procedure.

"There are well-known differences between results from the official laboratory tests and those performed on the roads with results varying due to a number of reasons including driving style, traffic levels and environmental conditions.”

Volvo also stated that the introduction of Real Driving Emissions (RDE) testing from next year will address the differences highlighted by the True MPG testing.

The Audi A4 3.0 TDI 218 was the next worst performing car, with a 36.2% shortfall on its official fuel economy of 65.9mpg; it returned 42.0mpg. Audi responded to the result, saying: "All new Audi models are tested independently in accordance with the current official Europe-wide government legislated NEDC regime to which every automotive manufacturer must adhere.

"These figures are intended by the NEDC as a guide only and the ‘real-world’ results will, of course, differ depending on a number of factors. This is made clear in all our public-facing communications."

True MPG tests are carried out at Millbrook Proving Ground, which is an approved NEDC testing centre. Conditions for testing are strictly monitored and are completely repeatable, meaning every car is tested under the same conditions. 

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Porsche 718 Cayman

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Comments
37

3 August 2016
Just goes on to prove that Volkswagen has perfected the rather scientific art of manipulating the official tests - with or without cheat devices or software on their vehicles. Also illustrates the archaic and redundant NEDC tests in collusion with the German car makers.

3 August 2016
fadyady wrote:

Just goes on to prove that Volkswagen has perfected the rather scientific art of manipulating the official tests - with or without cheat devices or software on their vehicles. Also illustrates the archaic and redundant NEDC tests in collusion with the German car makers.

S90 Diesel - " is the largest shortfall of all 20 cars tested,.."

 

Hydrogen cars just went POP

3 August 2016
fadyady wrote:

Just goes on to prove that Volkswagen has perfected the rather scientific art of manipulating the official tests - with or without cheat devices or software on their vehicles. Also illustrates the archaic and redundant NEDC tests in collusion with the German car makers.

Yes, mean old VW. All the other good car makers achieve their stated claims don't they...

To no-one's great surprise this is the theme of downsized engines. Designed and built to pass lab tests but not actually fit for purpose in the real world. Our own experience of a 1.6 VTi DS3 vs a 1.0 Ecoboost Focus shows this. The newer, award-winning engine has noticeably worse fuel consumption than the old 1600cc lump.


3 August 2016
fadyady wrote:

Just goes on to prove that Volkswagen has perfected the rather scientific art of manipulating the official tests - with or without cheat devices or software on their vehicles. Also illustrates the archaic and redundant NEDC tests in collusion with the German car makers.

I think it's diesel engines in general that come out of this looking not so good, rather than VW.

3 August 2016
Probably the only way a Jaguar will better a Porsche..

3 August 2016
Say £10 a year on a £2,000 fuel bill. I think I could live with that!

 

Hydrogen cars just went POP

3 August 2016
I paid no attention to the MPG figures when I ordered my wifes Polo GTI. I'd be even less likely to if I was ordering a true sports car like a Porsche (or F-Type, if you prefer).

3 August 2016
A V6 F-Type auto base price is £53,565, 0-60 in 5.1s and real world economy of 28.79 mpg. A PDK Cayman S starts at £50,756, 0-60 in 4.4s with real world economy of 28.39 mpg. Out of differences of £2,809, 0.7s and 0.4 mpg, is fuel economy really the biggest headline here?

3 August 2016
k12479 wrote:

A V6 F-Type auto base price is £53,565, 0-60 in 5.1s and real world economy of 28.79 mpg. A PDK Cayman S starts at £50,756, 0-60 in 4.4s with real world economy of 28.39 mpg. Out of differences of £2,809, 0.7s and 0.4 mpg, is fuel economy really the biggest headline here?

It can be as much as £10 a year you know.

 

Hydrogen cars just went POP

3 August 2016
xxxx wrote:

It can be as much as £10 a year you know.

£10/year?! Got to be the F-Type then, it'll only take 280 years to payback the difference in initial cost.

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