Gas Hogs?

It’s taken as gospel that pre-modern cars, especially those made in America, and particularly those with big V8s, were “gas hogs.”

But were they, really?

And are new cars as fuel-efficient as advertised?

The answer may surprise you.

Modern cars have, in general, smaller engines. These are tasked with moving cars that are, in general, heavier than the cars of the past. So they often have to work harder — especially if they’re tasked with moving the car quickly.

This has consequences.

I’ll give you a study in Now vs. Then and you draw your own conclusions.

First, the Now — a modern sporty car with a very small (1.6 liter) engine: The 2016 Hyundai Veloster R-Spec.

I picked this car because it’s almost a direct comparison in two critical ways — the power it makes and the performance it delivers — vs. the car I will use to represent Then.

The great pumpkin, my 1976 Pontiac Trans-Am.

You may think it’s an odd juxtaposition. A rear-drive muscle car with a V8 vs. a front-wheel-drive sporty car with a very small four. But, despite the huge difference in the size of their engines — 1.6 liters as opposed to 7.4 liters — both engines produce nearly the same horsepower (201 and 200, respectively) and both cars do the 0-60 run in about the same seven seconds.

So, they’re different in layout — but similar in terms of what you get.

And the same goes for gas mileage.

According to the government, the Hyundai is capable of 25 MPG in city driving and 33 MPG on the highway, or 29 MPG on average. It may well be capable of that. But it actually delivered 20.7 MPG during my week-long test drive.

Which is still good for a sporty car.

But it’s not all that much better than what my 40-year-old old muscle car can manage. Especially when you take into account that the Trans-Am’s engine is literally five times the size and doesn’t have the electro-tech advantages of such things as direct injection and variable valve timing — both of which the Hyundai (like most modern cars) does have.

And the Pontiac — when new — did not have an overdrive top gear to cut engine RPMs at cruising speed. It came with a four-speed. The Hyundai has a six speed.

Yet the ancient Indian still averages about 16 MPG (the same-year Firebird Formula with the smaller 350 cubic inch V8 and a two-barrel carburetor and a three-speed automatic averaged 21).

So, about 5 MPG’s difference in real-world driving after 40 years of technological “improvements.”

Color me not impressed.

Especially because my particular Trans-Am gets the same — or better MPGs — as the brand-new Hyundai. Because it has the one modification that’s worth real gains, MPG-wise: an overdrive transmission. I replaced the stock box with a modern one and without doing anything else to the car, it is capable of going about as far on a gallon of gas as a brand-new sporty car with a tiny four cylinder engine.

Many years have passed, but not as much has changed as you might think.

It’s true something new like the Hyundai is capable of giving better mileage — but not when driven as you probably would drive such a car.

Or at least, not as I would drive it.

To get the sporty acceleration of which it’s capable, it’s necessary to really wring that little engine out. Work it. If not, not much happens. The big V8, in contrast, is like a really big dude down at the gym. He has power to spare. Doesn’t need to work as hard to push the same weight as the smaller dude on the next bench.

But wait, you say. The 1.6 liter four and the 7.4 liter V8 both make about the same power — and they do. But the big V8 also makes tremendous torque: 330 ft.-lbs. at just 2,000 RPM vs. 195 ft.-lbs. at about the same RPM (1,750) for the Hyundai. It’s torque that gets a car moving; the more available, the better the leverage — the easier (more efficient) it is to get it moving. The Pontiac has to use less of its available motive force to get moving. And to stay moving. With the overdrive box, the TA lopes along at about 2,000 RPM at 75 MPH; the Hyundai’s engine is working harder (spinning faster) at the same road speed.

Anyone lucky enough to have driven a V8 muscle car knows all about it — about how effortlessly the big V8 propels all that steel and glass. You hardly have to touch the gas pedal. Which is why they use less gas than you might imagine — and have been told. At least, relative to the Now.

The car companies have added turbochargers (as here) to get more torque (and sooner torque) out of their smaller engines, but this adds complexity and cost and — all else being equal — the bigger engine still makes more torque. And — potentially, at least — can be surprisingly easy on gas.

Doubt it?

The new (2016) Camaro SS — packing a 6.2 liter V8 that makes 455 horsepower (and 455 ft.-lbs. of torque) carries an EPA rating of 17 city, 28 highway. That’s (once again) only about 5 MPG off the pace of the four-cylinder Veloster.

But here’s where it gets interesting — sad, actually.

If the Camaro weren’t such a bloated hog — it weighs 3,685 pounds, despite all the advances in metallurgy, despite the use of aluminum for the engine rather than cast iron — it would get better mileage than the Hyundai does. The new SS weighs about the same as my ’76 Trans-Am. And the Pontiac has a cast-iron engine that weighs hundreds of pounds more than the Camaro’s aluminum V8. It also has a cast iron rear axle and a heavy steel (and bolt-on) front subframe. Steel wheels. Stamped steel control arms. Etc.

That’s the bedrock problem — weight.

It’s the reason why, despite all the technology, the cars of Now aren’t all that economical vs. the cars of Then. They’re too damned heavy. Because they need to meet ever-escalating “safety” standards that can only be met (economically met) by adding structure, which adds weight.

The tragedy is a car like the Veloster could — and should — be averaging 40 MPG and modern muscle cars like the Camaro averaging about 30. We (cue the Six Million Dollar Man) have the technology.

But we also have too much government.

Comments?

www.ericpetersautos.com

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2 Responses to “Gas Hogs?”

  1. David says:

    The article makes a good point; one that is counter-intuitive and may surprise some people. Despite vast improvements in technology, the overall MPG of today’s small-engined cars is sometimes not much different from that of yesterday’s large-engined cars. One reason for this, as the author says, is the added weight of today’s safety equipment. I would add:

    1) The added weight of today’s creature comforts. There’s Air-Con; 10-speaker sound-systems; power locks & windows; 8-way motorized seats; motorized sliding doors and tailgates; built-in vacuum cleaners etc. Consider the difference in weight between a simple steel-and-glass door mirror from 1975 and today’s door mirror with an aerodynamic cowl, two-axis motorization, de-fogging heater, wide-angle insert and integral turn-signal repeater. Now scale that up over the whole car.

    2) Simple physics tells us that the work that must be done to accelerate one-pound of material from 0MPH to 30MPH has not changed (and never will). This does not represent a failure of small displacement engines to deliver on their promise.

    3) Two engines running at a stop light have the same fuel economy regardless of displacement: Zero MPG. Smaller engines don’t circumvent this (though Stop-Start technology does).

    4) Even if today’s cars and yesterday’s cars return the same MPG, there’s still a huge difference between the two in terms of the toxicity of their emissions. Yesterday’s cars expelled far more unburned hydrocarbons, Carbon Monoxide, soot, dangerous nitrous emissions etc…

    Good article.

  2. Corey says:

    Ah yes, another muscle-cars-are-better-because-they-don’t-rev-as-high argument. There are so many different ways to design an engine, and whether an engine is being stressed beyond its design capacity depends on many things only one of which is its engine speed.

    This article seems more at home in a comments section of a YouTube video, though, as it seems more likely to induce a flame/troll war over which engine design paradigms are better (a subject I’d prefer to leave to the respective manufacturer’s engineers) than a rational discussion on traffic law and an over-bearing EPA.