CAFE Standards

Published in the November 2012 issue of “Die Porsche Kassette”

Let’s talk about CAFE                   by Pedro P. Bonilla GCR PCA

CAFE Standards

To learn more about CAFE Standards and more, please visit my website at:

Happy Porscheing,

Ⓒ2012 Technolab /

This time let’s talk about CAFE.

I’m not referring to café, the dark liquid that wakes you up in the morning or the place where you pay an outrageous amount of money for a cup of it, but to the Corporate Average Fuel Economy (CAFE) regulations.

These regulations were enacted by Congress in 1975 and were intended to improve the average fuel economy of motor vehicles (cars, light trucks and SUVs) sold in the US, and came about in the wake of the 1973 Arab Oil Embargo.

The CAFE number for a particular manufacturer is the sales-weighted fuel economy of their fleet for a particular model year for sale in the US, expressed in miles per gallon (mpg) of the corresponding cars, light trucks and SUVs with a gross vehicle weight ratio (GVWR) of 8,500 pounds or less.

If the average mpg of their annual fleet falls below the CAFE standard for that year, the manufacturer must pay a penalty (tax), which is currently $5.50 per 0.1 mpg under the standard, multiplied by the manufacturer’s total production for the domestic US market.

In addition a gas-guzzler tax is levied on individual passenger cars (not trucks, minivans or SUVs) that get less than 22.5 mpg.

If for instance, a particular manufacturer is just 1.0 mpg below the standard for model year 2012 (2012 CAFE = 25.2 mpg) and they produce 350,000 cars, trucks and SUVs destined for the US market that year, they would have to pay: $19,250,000.

(1.0 mpg x $5.50/0.1 mpg x 350,000 =  $19,250,000)

The Obama administration just released the new CAFE standards for 2025.  It requires the manufacturer’s fleet average in the year 2025 to be at 54.5 mpg!

Wow. You may think, manufacturers are really going to have to develop new technologies and make cars that much more efficient to get to double the fuel economy in just 13 years.  But in a way it’s really a game the government plays with the car manufacturers in order to generate more tax revenue while also improving fuel economy (somewhat).

And the way the manufacturers answer is also mostly a game.

There’s no doubt that manufacturers have made great strides in making cars much more efficient and less-polluting in the last 30 years, since the standards were enacted, but they can’t keep repeating those results because there’s just no that much more to improve upon.

Fuel-efficient technology has computerized engine management systems to bring emissions to the minimum and maximize economy, so how will the manufacturers do it?

Well, to start, they will produce and include as part of their fleets one or two all-electric models which offer infinite mpg (they use no gas) as well as hybrid technology which combines gasoline and electric powerplants and produce very high mpg numbers.  This alone raises the average tremendously.

We will see transmissions with many more forward gears.  Already, seven gears is not uncommon.  Car makers will reduce the displacement size of their gasoline engines, swapping out six-cylinder engines with four-cylinder engines equipped with a turbo or a supercharger, which improves economy while maintaining power.  Such is the case of the announced and un-announced but still rumored 4 cylinder Porsche entry model which some believe will be a joint-venture with VW.  You can see two versions here, the 356 from VW and the Baby Porsche.

Manufacturers will also reduce the gross vehicle weights of vehicles by reducing their physical size (Fiat Cinquecento and SMART), by the use of lighter materials, such as exotic metal alloys and plastic composites.  They have also reduced the weight of motor oil from 50 weight to 40 to 30 to 20 to 10 weight.  Lighter weigh (less viscosity) reduces the engine’s internal friction, thereby using less fuel.

They will also streamline the aerodynamics for less drag and will do away with rear view mirrors which can rob 1.0 - 1.5 mpg.

You think I’m joking?

Take a look at the just-announced Panamera Sport Turismo Concept presented at the Paris Auto Show.  It is what Porsche calls an e-Hybrid 3.0 L V-6 / electric cell, with a fuel consumption of 3.5l/100 km or 62.21 mpg.

Notice the sides.  There are no external mirrors.  It uses cameras integrated into the side air outlets and two video monitors on either side of the center instrument cluster show the rearview images.

Car makers will also have to cooperate on technology development to keep rising costs to a minimum.  Porsche and Volkswagen have already been doing joint development projects for years with the Cayenne/Touareg SUVs and now with Porsche/VW manufacturing.

But all of these mandated changes come at a price.  The cost of a new car will go up.  The National Automobile Dealers Association complained that full implementation of the 2025 CAFE Standards will add at least $3,000 to the average price of a new car.

Right now, the only Porsche that would meet the 2025 standards is the upcoming 2014, 918 Spyder which is slated to sell at $845,000 but can produce 78 mpg.

Another way auto manufacturers are getting better mileage without touching the engine is by replacing some of the secondary systems such as the Power Steering Pump with electrical motors instead of by pumps run by the engine through a belt.  Point in case the new Boxster and Carrera platforms that now offer electrically assisted steering.    We are also seeing from Porsche and other auto makers: electrically operated oil pumps and electrically operated water pumps which both reduce drag on the engine, making them more efficient but also allowing the ECU to control flow by varying the speed of the pumps adjusting it to the engine’s needs.

press here to go back to the TECHNICAL ARTICLES PAGE