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The Porsche 718 Cayman S may deliver 345 bhp but its new turbocharged four-cylinder engine is by no means economical with its real-world fuel economy rating.

Having worse fuel economy than the V6-powered Jaguar F-Type, the 718 Cayman S had a combined real world figure of 28.39mpg which is 18.7% less than the 34.9mpg Porsche has on paper. You’d think the change from a six-cylinder engine to a four cylinder would improve fuel economy but it still saw worse numbers than the F-Type. Jaguar’s F-Type had a real world fuel economy figure of 28.79mpg which is 14.3% less than the claimed 33.6mpg.

While this is not as bad as the 718 Cayman S, all that extra fuel used will add up for both vehicles. Both cars were tested along with 20 other models by What Car’s new True MPG process. The tests took place at a NEDC approved testing center and they made sure the Millbrook Proving Ground’s driving conditions were the same for every car tested.

But, we must remember that a car’s fuel economy can change depending on the driver, traffic and road conditions. This point was brought up by a Porsche spokesman; “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.”

At least the 718 Cayman S didn’t perform as bad as the Audi A4 3.0 TDI 218 which saw a shortfall of 36.2% when they compared its real world fuel economy rating (42.0mpg ) to Audi’s official fuel economy of 65.9mpg.
 

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I feel the same way. Besides, this is just going to be for occasional driving for me, so I could really care less about the fuel economy.
 

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My new 718 Cayman S first tank was 28.96 mpg driving varied terrain in Central Washington state. 293.3 on the trip odo, 10.127gal. I was pretty pleased, as an added attraction, to the basic sporty nature of the car. Good as this is, it's bettered by my smart car which has a cumulative average of 35.1 mpg over 5 years, but certainly not bettered in most other respects! I have a hard time expecting a reasonable gasoline-powered car to manage over 50 or 60mpg. Years ago I had a Yamaha XS1100 motorcycle that typically got about 48mpg, and a Honda SL350 that could manage an honest 65mpg. Impressive that a diesel auto gets into the same range...
 

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This is irrelevant, if you're going to get a car like the Porsche 718 Cayman S then fuel economy doesn't really matter all that much unless you plan to go on a long trip with very few gas stations along the way. 28.39mpg is good enough for me.
Exactly right, I can pretty much guarantee that no owner posting on here specifically bought their cars based on its economy figures. It's possible to achieve mid 30's mpg on a long run providing you leave the car in normal, use a light touch on the throttle & brakes & also keep a watchful eye on the speedometer. However in normal usage I still see somewhere around the 24-25 mpg, but that's partly due to the fact that by choice the car predominately lives in sport & our local roads are pretty twisty. Even with the hideous price of fuel in the U.K, that's more than acceptable. It wasn't really a consideration but I'm still actually quite pleased with that.
 

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Just in case someone does care about fuel economy, one of the best ways to improve it, if you have SC, is to not use Sport mode. All those farts and gurgles are wasted fuel.

But, I love my farts and gurgles so never mind :)
 

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While fuel economy is important it is not the most important aspect in my opinion. How much you drive is far more important that the actual fuel mileage of your car. If you have a Ferrari than gets 10 MPG and drive it maybe 1,000 miles a year you are using less fuel than someone who owns a Prius and drives it 15,000 miles a year. So the Prius owner pollutes more than the Ferrari driver.

In the US there is a gas-guzzler tax which I think is wrong. This is a tax on potential and not actual fuel usage. If they really want to tax people based on how much fuel their cars use it should be done at the pump. This way you actually tax them based on their usage and not their potential usage. This would be much fairer in my opinion.
 

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I just finished a round trip From Lodi,Ca. to Reno,NV and back. I experienced just over 29mpg. I am not going to publish my speeds, but I wasn't driving like I was trying to win some mpg contest. I drove I-80 to Reno and returned via HWY 88. Similar driving on the same route in my old '15 MINIS , I would probably experienced 34ish mpg.I have no complaint about my Cayman S PDK's potential mpg.
Also, I have noticed that staying out of sport mode does indeed improve my fuel economy. On trips I like to drive in normal mode and in manuel. I am not comfortable with the transmission's short shifting in non sport auto. The car feels like it's lugging.
Seriously, its amazing to me that a car like this ( awesome acceleration ) can achieve the mpg that I have seen.
Don
 

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If it's an issue for anyone then you clearly bought the wrong vehicle & don't forget fuel is relatively cheap in the U.S. Certainly by comparison to the U.K. & the rest of Europe it is in any case. Where I am Super Unleaded (Premium) is the equivalent of roughly U.S $7.10 a gallon.
 

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... reason #356 on the list ...
Freudian! >:D

But yeah: The number of cylinders is not directly correlated to fuel efficiency, particularly for those who drive it in any way other than an 80-year-old. My current car is a BMW 228i M Sport: 4-cylinder dual-stage turbo engine. It's a relatively quick car. I drive it with "passive aggressiveness", which is my term for my style. I average about 18.5 MPG. It's rated at 26 EPA combined.

In fact, the only car I've owned that I have averaged better than 20 MPG since my '06 MINI Cooper (I averaged 22 in it) was a hybrid: a Lexus CT 200h F Sport. Even in it, I typically averaged about 26 MPG.
 

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They obviously don't know how those numbers are reached for the EPA fuel mileage.
It's done on a engine test stand in a controlled environment so they can control all the variables and make sure all power trains are tested under the
same conditions.
It dosen't take much to fudge a driving test by altering tire pressures or even leaving or installing something in the air stream.
The funny thing is in 15 years I have NEVER had a customer complain about fuel mileage on their Porsche.
It's just not a factor for Porsche owners, Heck they probably use less fuel than an average commuter due to the amount they drive their cars.
 

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They obviously don't know how those numbers are reached for the EPA fuel mileage.
It's done on a engine test stand in a controlled environment so they can control all the variables and make sure all power trains are tested under the
same conditions.
It dosen't take much to fudge a driving test by altering tire pressures or even leaving or installing something in the air stream.
The funny thing is in 15 years I have NEVER had a customer complain about fuel mileage on their Porsche.
It's just not a factor for Porsche owners, Heck they probably use less fuel than an average commuter due to the amount they drive their cars.
Exactly, just as with diesels that aint even close in polition irl.
A swedish magazine tested a couple of diesels an volvo was by far the worst and bmw was close to spec

And on topic, i have never ever tought about milage the 18 years i have ownend Porsche
 

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If it's an issue for anyone then you clearly bought the wrong vehicle & don't forget fuel is relatively cheap in the U.S. Certainly by comparison to the U.K. & the rest of Europe it is in any case. Where I am Super Unleaded (Premium) is the equivalent of roughly U.S $7.10 a gallon.
WOW! I know fuel prices in EU have historically been substantially more than in the US, but $7 a gallon puts performance cars only in the hands of the financially well off. Right now in the US, our prices for fuel are excellent at under $3 a gallon for Premium, but the "premium" fuel in Arizona (where I live) is terrible. 91 octane rating at best for Premium here in Arizona. There are a few gas stations here that offer racing fuel at a serious premium. I fill up my Golf (and switch to a higher octane tune on my ECU) on 95 octane race gas every month or so, for about $6 a gallon. 100 octane runs about $8 a gallon here, which is obviously very expensive, but seems more in line with what you pay for in the UK for your premium.
Question: what's the octane rating on your Premium there?
 

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Dont you use MON as we use RON in Europe?
We have 95 RON and 98 RON as standard all over Europe and some countrys have 91 and 99 as well.
The price is pretty even to over here.


Give or take a bit,
91 MON = 95RON
93MON = 98RON
 

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WOW! I know fuel prices in EU have historically been substantially more than in the US, but $7 a gallon puts performance cars only in the hands of the financially well off. Right now in the US, our prices for fuel are excellent at under $3 a gallon for Premium, but the "premium" fuel in Arizona (where I live) is terrible. 91 octane rating at best for Premium here in Arizona. There are a few gas stations here that offer racing fuel at a serious premium. I fill up my Golf (and switch to a higher octane tune on my ECU) on 95 octane race gas every month or so, for about $6 a gallon. 100 octane runs about $8 a gallon here, which is obviously very expensive, but seems more in line with what you pay for in the UK for your premium.
Question: what's the octane rating on your Premium there?
It's gone up considerably since my previous comment. The average U.K fuel price for super unleaded when converted is now US $8.11.
 

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Dont you use MON as we use RON in Europe?
We have 95 RON and 98 RON as standard all over Europe and some countrys have 91 and 99 as well.
The price is pretty even to over here.


Give or take a bit,
91 MON = 95RON
93MON = 98RON
91 octane (premium unleaded) is equivalent to 95 RON.
We don't use MON, or at least I've never heard of MON. It's most commonly referred to as octane or RON. We also use something called AKI (anti knock index), but that last one is really not commonly used here. In Arizona and a few other states we have weak gasoline for Premium. 91 octane (or 95 RON) is the minimum most performance engines can use effectively. In other states, we have 93 octane for Premium which I believe equates to 98 RON, but I'm not positive... 93 octane is really nice for performance engines!
 
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91 octane (premium unleaded) is equivalent to 95 RON.
We don't use MON, or at least I've never heard of MON. It's most commonly referred to as octane or RON. We also use something called AKI (anti knock index), but that last one is really not commonly used here. In Arizona and a few other states we have weak gasoline for Premium. 91 octane (or 95 RON) is the minimum most performance engines can use effectively. In other states, we have 93 octane for Premium which I believe equates to 98 RON, but I'm not positive... 93 octane is really nice for performance engines!
I just had to google it :)
Research Octane Number (RON)

The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane.
Motor Octane Number (MON)

Another type of octane rating, called Motor Octane Number (MON), is determined at 900 rpm engine speed instead of the 600 rpm for RON.[1] MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern pump gasoline will be about 8 to 12 octane lower than the RON, but there is no direct link between RON and MON. Pump gasoline specifications typically require both a minimum RON and a minimum MON.


Anti-Knock Index (AKI) or (R+M)/2

In most countries, including Australia, New Zealand and all of those in Europe,[citation needed] the "headline" octane rating shown on the pump is the RON, but in Canada, the United States, Brazil, and some other countries, the headline number is the average of the RON and the MON, called the Anti-Knock Index (AKI), and often written on pumps as (R+M)/2. It may also sometimes be called the Posted Octane Number (PON).




Difference between RON, MON, and AKI

Because of the 8 to 12 octane number difference between RON and MON noted above, the AKI shown in Canada and the United States is 4 to 6 octane numbers lower than elsewhere in the world for the same fuel. This difference between RON and MON is known as the fuel's Sensitivity,[5] and is not typically published for those countries that use the Anti-Knock Index labelling system.
See the table in the following section for a comparison.





 

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For the first time in years i checked my MPG on my Daily drive to work.
30 mpg and thats with a crusing speed at 78 mile per hour, pretty descent.
 
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