Engines really have gotten better in recent years

Dear Car Talk:

I was reading a review of the Kia Optima (next to your esteemed column here in the paper). It mentioned that the base 2.4-liter engine produces 192 horsepower. That works out to 80 hp per liter. I started thinking about the car I learned to drive in – a 1956 Chevy with the Power Pack option: 4-barrel Rochester carburetor and dual exhaust. That 265-cubic-inch (4.3-liter) engine was rated at 205 hp, which is 47 hp per liter. It's a bit hard to believe that the "performance" version of a big mid-20th-century V-8 engine would have over 40 percent less output per liter than today's run-of-the-mill sedan. Are engines really that much better, or has horsepower been redefined – maybe based on today's slimmed-down horses? – Gary

Ray: Believe it, Gary. There are a number of engines that produce well over 100 hp per liter now. And in general, engines today produce far more power, use far less fuel and create a fraction of the pollution.

Why is that? There have been a ton of incremental improvements in technology since 1956. First of all, tolerances are much tighter, so a cylinder no longer loses half of its compression through gaps around the rings (OK, “half” may be an exaggeration). Fuels and lubrication are far better. There’s been a huge reduction in friction.

Fuel injection and computerized engine management allow us to precisely meter how much fuel goes into the cylinders. In your old ’56 Chevy, it was like they poured gasoline into the engine from a boot.

And instead of two valves per cylinder, most cars now have four or even five valves per cylinder. That allows the engine to breathe better, taking in air and sending out exhaust much more quickly and efficiently.

We even have variable valve timing, which adjusts the opening and closing of the valves for maximum power and efficiency at different engine speeds.

There’s coil-on-plug technology, which sends a much higher voltage spark to each cylinder, with almost no power leakage, since each cylinder gets its own, dedicated coil.

And in the past few years, cars have adopted gasoline direct injection, sending the fuel-air charge into the cylinder at very high pressure, at just the right millisecond.

Then there are turbos, twin-turbos, tri-turbos, quad-turbos, superchargers and turbo-supercharger combinations. Electric turbos and electric superchargers are coming, too.

All of this is why you now see full-size sedans getting plenty of power from four-cylinder engines, when they used to need six- or eight-cylinder engines.

And soon we’ll be seeing more three-cylinder engines. When you can easily get enough horsepower out of three cylinders, why not save the weight and add to your gas mileage?

In fact, you already can get a three-cylinder engine in a subcompact Ford Fiesta that produces a very respectable 123 hp. It’s a one-liter engine, Gary.

Can power steering fix itself?

Dear Car Talk:

I have a 2003 Toyota 4Runner with about 150,000 miles on it. I bought this vehicle used about a year ago. It looks great, and has been a great, dependable vehicle so far. Toward the end of the winter, however, I started having issues with the power steering. Then it completely failed. My mechanic told me that I'd need to replace the rack and pinion. So I started saving up for the repair, and lo and behold, the power steering went back to normal, even after driving for extended periods of time. Needless to say, I would like to save the cash for other things. Did it fix itself? What could explain why it failed and now seems fine again? – Luis

Ray: The weather. Failing steering racks are famous for misbehaving just like this in colder weather.

Perhaps you’re too young to remember the great Rack-and-Pinion Epidemic of the 1980s. It hit GM cars particularly hard, so we know the symptoms well.

In cold weather, things shrink. See the Seinfeld “shrinkage” episode if you need any further elucidation on that.

Back in the ’80s, GM’s problem was that certain seals inside the rack would shrink in colder weather. And when they shrank, they’d allow power-steering fluid to sneak by them, causing a loss of pressure. That caused the power steering to fail, sometimes only in one direction. The only solution was a new rack.

The symptoms were always worse when the weather was cold. And they tended to go away after the car was driven for a while, because everything heated up under the hood.

I don’t know if those same seals are causing your problem, Luis. It could be one of the valves, too. Or something else. But if your mechanic investigated and says you need a new rack, he’s probably right.

And based on historic temperature ranges, I’d say you have until around Columbus Day to save up a thousand bucks or so. Good luck.

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