Fuel Economy: Here’s What We’re Missing

By Eric Peters, Automotive Columnist

Best-case mileage you can get in a new car is 48 MPG – the advertised highway mileage of a 2012 Toyota Prius hybrid.

It sucks.

If, that is, you can remember… .

Back in 1981, the Dodge Omni (and several other small cars) was delivering 50 MPG. And 40-something was common. That’s gas-powered cars, too. Diesels – like the ’80 VW Rabbit – posted highway mileage pushing 60 MPG.

See here for an interesting little graph.

Mind, these cars were returning mileage better than – or at least as good as – “state-of-the-art” 2012 model hybrids, even though they were primitive in terms of their technology. Most had carburetors; none had overdrive transmissions.

But they lacked the one thing that a new hybrid – a new car, period – has too much of: curb weight.

These ’80s-era economy cars were flyweights. All weighed barely 2,000 lbs. – some, less. Since it takes less power to move less weight, they used less gas – even without modern technological advances.

And with those advances?

The results would be nothing less than spectacular.

Swap in a modern six-speed dual clutch automatic (or CVT) for the inefficient four-speed manual (or three-speed automatic) those early ’80s cars typically came with. This would drop engine RPM by 20-30 percent in top gear, during steady-state cruising. A dual-clutch (or just a modern automatic with lock-up converter) or a CVT would also dramatically reduce driveline efficiency losses. Probably good for another 5 percent improvement. Replace the original carburetors with a simple, but modern, Throttle Body (TBI) fuel injector and computer to maintain the ideal air-fuel ratio at all times. Probably another 10 percent efficiency improvement there (plus “modern car” driveability).

Finally, for the maximum effort, use modern low-friction manufacturing techniques to decrease rolling resistance. Maybe some aerodynamic tweaking of the exterior.

We’d have 55 MPG gas-burning cars. Probably 70 MPG diesels.

And it could all be done without having to resort to costly 21st century hybrid technology – which, remember, is only just barely matching the at-the-pump performance of early ’80s-era economy cars.

If, that is, the curb weight could be kept to 2,000 lbs. or so.

This is the key to efficiency.

Ever wonder why a motorcycle with a tiny 1,000 cc engine that only makes say 160 hp can out-accelerate the quickest supercars and still return 45 MPG? It’s because the bike is light.

Unfortunately, new cars are heavy.

A new Toyota Corolla sedan weighs almost 2,800 lbs. A new Honda Civic sedan weighs 2,608 lbs. A new Jetta TDI (diesel) weighs in at almost 3,200 lbs.

On average, current-year compact sedans weigh about 500 pounds more than an ’80s-era compact sedan.

If you put 500 pounds of bricks in the trunk of an ’80 Rabbit or Dodge Omni, you’d end up with circa 2012 fuel economy: low-mid 30s in city driving and maybe 40 MPG on the highway.

But if, on the other hand, you could remove 500 pounds of “bricks” from a new Corolla or Civic or TDI Jetta, the result would be fuel economy substantially better than Reagan Era economy cars.

And better than current-era hybrid cars, too.

They’d be more affordable than current-era hybrid cars too.

Adding an overdrive gear (or two) to a transmission involves orders of magnitude less expense in terms of R&D, the physical parts themselves and manufacturing/assembly than designing (and building) a car with two powertrains, (a standard gas engine/transmission, plus an electric motor/battery pack, as in a hybrid).

How much less expense?

Well, on the retail level, one can buy a ready-to-install TBI fuel injection system for about $1,500. Let’s say $2,000 for an overdrive transmission. Call it $4,000 to add the essential technological updates to an ’80s-era compact.

The brand-new MSRP of a 1980 VW Rabbit diesel was about $5,000. Adjusted for inflation, that’s about $13k today. So add $4,000 for the updates.

A 60 MPG car for less than $18,000.

That’s at least $6,000 less than the cost of a new Prius hybrid – and 10 MPG better at the pump.

And remember, the $4,000 for the updates assumes retail prices for the components – you or me buying the parts over the counter. The economies of scale a car manufacturer could exploit would likely cut the per-car cost for these improvements in half.

Imagine: a 60 MPG car you could buy for $15,000.

But, of course, you can’t. Because the car companies have been told they must build safe cars – which means, heavy cars.Those ’80s-era cars didn’t have to have four (or six or eight) air bags and didn’t have to meet the bumper impact crash standards that 2012 cars must. So, of course, they were less “safe” – if you got into a wreck – than a modern economy compact with all the Stuff that the government now requires.

Put another way, fuel economy (and low-cost) takes a back seat to “safety” – as defined by the government.

It’d be nice if the government allowed consumers to make the choice themselves.

Given the popularity of 48 MPG hybrids like the $23,520 to start Prius – which reportedly sells for full MSRP sticker and forget about haggling – it’d be interesting to see how well a 60 MPG $15,000 economy sedan would do in the marketplace.

Too bad the government has decided we’ll never get the opportunity to find out.


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5 Responses to “Fuel Economy: Here’s What We’re Missing”

  1. binderme says:

    The current epa rating when it comes to diesels like the VW, BMW, MB and Audi offerings is admitted to be low by a minimum of 25-30 % below real world. So this make the window sticker rating less than useless when it comes to diesel offerings. The Hybrid offerings rating are at least 25-30 % above real world. The automatic offerings of all type make the silly not backed up by reality claim that automatics can achieve close to or more mpgs than manual trans models. SUVs and Pickups are given ratings that are as much as 40 % above what will be ever seen real world.

  2. binderme says:

    >Today diesels are rated at what is actually the real world mixed consumption for a highway rating. The epa ratings also ridiculously claim automatic ratings to be the same or higher than manual equipped models which in no way matches real world.

    What the ratings should be on the current Passat TDI manual trans 35 city/ 45 mixed/ 52-54 highway. The Passat TDI DSG model should be 30 city/ 38 mixed/ 45-48 highway. The other diesel offerings from the other German auto makers are similarly under rated from real world. Having the window epa rating today be extremely low below what they actually should be is hurting sales to for people that would purchase a diesel if the epa rating actually gave a real picture of consumption.

  3. binderme says:

    The over rating well above reality today given to all hybrids gives them an unfair made up advantage over diesels and small displacement gasoline powered with manual trans models……..

    Today the epa is giving automatics of all sorts similar or higher ratings than manual trans versions of the same models, numbers that no one will ever see lowers real world CAFE by at least 30-40 % today.

    And lastly giving SUVs and Pickups ratings that no one will ever get within 40-50 % of real world is allowing these gasoline wasting models to continue to be sold.

    I wonder what the reaction of drivers will be this summer if we actually do hit the $5 or more mark for RUG this summer???????? I already drive a ~50 mpgUS diesel VW so the impact will not be that much to me. But the cost will be devistating to the idiots that still is under the illusion they can drive a 6-12 mpgUS real world SUV or Pickup as a passenger vehicle.

  4. binderme says:

    Our current light duty diesel emissions ( car specific emissions rules ) rules don't give any clean air but they do block the highest mpg vehicles ever built from the US market. It is completely stupid to have these strict emissions requirements on vehicles that make up less than 1 % of the on road today fleet……….These over stringent emissions rules on vehicles that no one but VW has sold in the US since 1986 model year. Pickups sold in the US over the last 26 years haven't, still don't have to pass these emissions rules…….

    Today in Europe you can buy a BlueMotion TDI Polo that has no trouble hitting close to 80 mpgUS in real world driving, A similar Golf BlueMotion that easily hits mid 70s mpgs US, A similar Passat BlueMotion that achieves high 60s to around 70 mpgUS. Every auto maker sells similar models to these everywhere else in the world. In countries where diesel offerings like described above are sold they can't give away hybrids of any type………..Why would anyone want an expensive hybrid of any sort when a diesel can easily beat their mpgs @ as little as 1/3rd the cost?????…….they don't……

  5. bryan says:

    as i understand it the epa changed the way mpg is computed. the car people advertised and stretched the truth a little . in response to the fuel crtunch.
    also newer cars are hevier for crash standards even in similar sized vehicles. so a car that get38 mpog lik my toyota echo would have had a sticker mpg of 43-45 back in the day an d no crash rating youd want to be in.
    one idea is to insulate the engine and use the steam produced from the cooling system to compress air. The motor could have jsut 2 cylinders this way. first the air tank would be filled at home. the vehicle takes off between the air and the cylinders it has normal performance. then as the engine heats the coolant water to steam it compresses more air. the compressed air runs all auxiliary systems located in the trunk of the car. ( eisier to work on too also cooler and cheaper to make) the heat made by the air comprssor is conserved with insulation and removed with coolant. the brakes heat is also conserved this way and air is also compressed when coasting . also more air is made while ideling so that fuel is not lost. the 2 cylinders can also run a t a constant ideal speed as well. no heavy batteries are needed. and the engine is so small now it can be put anywhere. jsut some ideas. of course the engine would be made to run hot. this would reduce the need for an elaborate steam generator i was thinking the radiator could be put under the vehicle so that where normally ithere is a lot of drag there it wouldnt matter as much.