ArcaMax

In theory, choice is good. In practice, too many choices can be overwhelming - especially when the choices between X and Y come down to little things (and the price is little different).

VW's just-updated Golf is by no means the only choice among compact economy cars. There are lots of them. But it is the only compact economy sedan/hatch on the market that you can order with a high-efficiency (and long-legged) diesel engine. It's two other big things, too.

German - and inexpensive. Just $21,995. Making it - by far - the lowest cost diesel-powered passenger car you can buy at the moment. One more thing, too. The diesel engine is available with a manual transmission. That's rare. Unique, actually. So, what's the catch?

Well, they won't sell you the diesel engine in the two-door Golf. It's a four-door deal only. And VW has finally had to knuckle under to Uncle and add urea injection to make the tailpipe emissions cut. That means you'll need to add diesel exhaust fluid (DEF) every once in awhile.

There's one other thing, too: Several gas-engined cars approach the TDI's mileage numbers. Not quite - but getting there. And their price tags are lower. As is the cost of their fuel.

WHAT IT IS

The Golf is VW's entry-level compact, available in two-door hatchback and four-door hatchback bodystyles.

It comes standard with a turbocharged gas engine, but a more fuel-efficient turbo-diesel (TDI) engine is available and will be the focus of this review.

The base price for a Golf two-door with the 1.8 liter gas engine and manual transmission is $17,995. The TDI-powered Golf S starts at $21,995.

The gas-engined Golf has many competitors, but the Golf's optionally available TDI engine is unique in this segment. Chevy offers a diesel engine in the Cruze - but it's a larger car that competes more directly with the Jetta TDI. The Chevy's base price - $28,355 - is also much higher than the TDI Golf's price.

Mazda had planned to have a "SkyD" diesel version of its 3 sedan - a direct Golf competitor - available by now (Fall 2014) but so far, it's a no show. Which leaves the field pretty much to the Golf TDI.

WHAT'S NEW

The '15 Golf is all-new, with a revised chassis and suspension and updated exterior and interior.

The standard Golf engine is now a turbo four (gas) that delivers much better performance - and economy- than the previous Golf's standard-issue five-cylinder engine. The optional TDI diesel engine has also been tweaked a little to deliver slightly better mileage than before and so equipped, the Golf continues to be the most fuel-efficient compact sedan you can buy that's not a hybrid.

WHAT'S GOOD

Economical to operate - and to buy. Fun to operate (standard six-speed stickshift). Long legs (close to 600 miles on a tankful). Roomy hatchback layout.

WHAT'S NOT SO GOOD

Diesel engine isn't available in the two-door Golf. VW has had to join the DEF (Diesel Exhaust Fluid) club. TDI's mileage advantage isn't as compelling as it used to be - and diesel fuel's not as cheap as it used to be.

UNDER THE HOOD

The Golf's optional TDI engine is a 2.0 liter four that makes 150 hp - 20 fewer hp than the new 1.8 liter gas four (170 hp) but a lot more torque - 236 ft.-lbs. A six-speed manual with a very deep overdrive sixth gear is available, too. The gas engine's manual transmission has only five speeds.

You can also select a six-speed automatic - VW's "direct shift" (DSG) gearbox. It is a very efficient (and responsive) automatic.

Still, the manual TDI Golf does the best at the pump - carrying an EPA rating of 31 MPG in city driving and 45 MPG on the highway. But it's only better by a hair. The DSG-equipped TDI Golf earns the same 31 MPG in the city rating - and 43 on the highway.

I suspect the highway advantage of the manual is the deep overdrive gearing of sixth gear, as mentioned earlier above. At road speeds under 45 MPH, the engine will sometimes lug if you go from fifth to sixth. That sixth gear is meant to keep the revs low even when the Golf's road speed is high. At 85 MPH, the engine is turning just over 2,500 RPM. And that's why it's capable of 45 MPG. More than 45 MPG, actually.

Ask anyone who owns a VW diesel and they'll "amen" this statement. I've managed close to 50 myself (by keeping it under 80). It is definitely doable. And - to put a finer point on it - it's more doable to keep it in the mid-high 40s on the highway at 70-or-so-MPH in a diesel-powered car such as the Golf than it is to pull off that same trick in a hybrid car like the Prius (which also costs thousands more, by the way). Hybrids are extremely fuel-efficient ... when driven slowly. Especially when not driven at all - as when sitting idle in traffic - because during those moments of idleness, the onboard gas engine will usually not be running (and burning gas) at all.

But when driven fast, continuously - sustained highway speeds around 70 or so - hybrids are at a disadvantage. The electric battery depletes quickly, forcing the gas-engine side of the powertrain to kick in (and stay on). Since it's a gas engine, it's inherently less efficient than a diesel - and because most hybrids have smaller-than-usual gas engines - it's also working really hard to maintain the vehicle's speed. Which typically means it's using more gas than you'd expect.

The current Prius C, for instance, only rates 46 MPG on the highway. This is much less than its city rating of 53 MPG - and in real-world highway driving a speeds in the 70-75 MPH range, my experience has been that hybrids like the Prius typically average mid-high 30s. A TDI Golf, meanwhile, will still give you mid-high 40s, even when driven at today's highway speeds.

The one fly in the soup is that VW has had to add urea-injection to all its 2015 diesel-powered cars, including the new Golf, in order to continue to be able to sell diesel-powered cars at all.

VW used to be the only car company whose diesel-powered cars did not need urea injection - and DEF - diesel exhaust fluid - to comply with the government's ever-stricter emissions requirements. They're now so strict that DEF is necessary. Which means you'll need to periodically top off the DEF tank, which has a fill nozzle adjacent to the normal diesel fuel fill nozzle. It's a hassle - and an additional expense. Neither are huge, but they are part of the equation now. And they do detract somewhat from the appeal a diesel-powered car would otherwise have.

ON THE ROAD

One important thing to know about the Golf TDI relative to many of its gas-engined competitors is that it's equally peppy with with either transmission, because of the mighty torque output of the diesel engine.

Sometimes - oftentimes - a small car with a smallish gas engine will perform noticeably worse when paired with an automatic transmission - because smallish gas engines (especially if not turbocharged) tend to not make much torque and the torque they do make tends to be made fairly high up the rev range (around 4,000 RPM being typical). With a manual transmission, you can bring the revs up to get the car going expeditiously. But if you've got an automatic, it'll take a moment - or several - for the engine to work its way up to the RPM where it produces its decent power. Which is why smaller cars with small gas engines paired with automatics sometimes feel sluggish getting started.

The Golf's TDI engine, in contrast, will easily squeal the tires accelerating from a standstill - if you're not careful with the accelerator - because all that torque blooms full flower at just over 1,700 RPM. And it stays with you, as the revs climb. The TDI engine is especially punchy in the mid-rage, which is arguably the real-world-range most engines operate in. All that means is you don't have to spin the thing to redline to get a reaction. Half-pedal will get the job done almost every time.

It's like having all the power a gas engine produces immediately available - rather than having to wait a few for the engine to rev to produce it. And keep in mind that the TDI engine makes more total power (torque) than the gas engines in competitor cars. Torque - twisting force - is what gets a car moving and smart buyers will give more weight to that number than the other number (horsepower).

AT THE CURB

Though new, the '15 Golf is not obviously different - at first glance - from the old Golf. Exterior and interior styling changes are very conservative and minimalist - a good thing, I think. Why fix what's not broken?

So, the basic shape - and layout - remains familiar. And, sensible. The Golf has 22.8 cubic feet of cargo capacity with all seats in place. To get a sense of how much that is, the Chevy Cruze sedan - the only other car available with a diesel engine anywhere near the VW's price range - has only 13.3 cubic feet of cargo capacity. And the Cruze is - technically - a mid-sized car. The Golf is a compact. The Mazda3 hatchback wagon is a closer shave. But, alas, no diesel... for now.

The VW's cabin feels bigger, too - for people in the back seats, especially. Because the Golf's roofline doesn't slope rearward as sharply as in several competitor models. The result is second row headroom (38.1 inches) that's virtually the same as headroom up front (38.4 inches).

The rectangular shape of the Golf's doors is also smart policy, providing a larger opening to the interior. The sedan's rear glass is larger (wider) than the front door glass. It even has (fixed) rear quarter glass. It'd be extremely cool if VW - or any automaker - made these operable.

Though the TDI Golf is a step up in price from the base (gas-engined) Golf S ($20,695 for the four-door) VW does not charge an arm and a leg to step up to the TDI. The price difference is $1,300 - and to VW's credit, you get more than just the TDI engine.

Most of the amenities that are included in the gas-engined SE Golf - including a sunroof, power seats and the otherwise-optional Fender premium audio system - are included in the base TDI Golf S (yes, it's a little confusing). The relevant take-home point here is that the buy-in cost of the TDI is pretty low, which is pretty unusual for diesel-powered cars in the United States.

Chevrolet, for instance, charges $9,255 to step up from the base/gas-enginedversion of the Cruze sedan ($19,100) to the Cruze diesel ($28,355). It's true the diesel-powered Cruze is also laden with luxury and convenience features. But the Golf TDI's not a stripper, either.

It's much harder to make a case for the Cruze diesel than it is for the Golf TDI. Both are nice cars. But only one of them makes economic sense.

THE REST

The Germans are often odd about their diesels, parceling them out in this bodystyle but not that bodystyle. Mercedes-Benz and BMW, for instance, sometimes only let you buy a diesel in a wagon. And VW has decided to offer the TDI engine in the Golf sedan only. Well, for the moment. I hope.

On deck - slated to arrive at dealers a few months from now - is the Golf Sportwagen (German spelling), a wagon-ized version of the Golf. VW has not announced whether the TDI engine will be available in the Sportwagen. But it ought to be.

Probably the biggest sweat for VW is the narrowing gap between the fuel economy of the TDI - and the fuel economy offered by some of the gas-engined competition. The '15 Mazda3, for example. Its "SkyActive" gas engine rates 29 city and 41 on the highway - too close for comfort, especially given the Mazda's much lower buy-in price ($16,945 for the sedan). Three or four years ago, mileage in the 40s was exceptional - and exclusively the province of diesel and hybrid vehicles. Gas engines are catching up.

The problem - for diesels - is that circumstances increasingly favor gas engines. The fuel (ethanol-alcohol laden) allows for very high compression ratios, which makes gas engines much more fuel-efficient. Meanwhile, diesel fuel is now more expensive - courtesy of the government's "ultra low sulfur" requirements that have made refining it costlier. And modern diesel engines are rendered less efficient than they could be by emissions mandates which among other things have forced all manufacturers (including VW) to "DEF" their diesels. Owners must periodically top off the DEF tank, which fluid is then sprayed into the exhaust stream to chemically alter the composition of the exhaust to more government-agreeable compounds. Back in 1979, diesel-powered VW Rabbits (the Golf's predecessor) were knocking on 60 MPG.

That's what's needed today - to make diesel-powered cars like the Golf TDI really stand apart from the crowd.

THE BOTTOM LINE

Though it's a tighter race at the moment, the TDI Golf still makes a solid case for itself, if only because it hasn't really got any direct competition. If you want a diesel - and a manual transmission - and the prospect of 45 on the highway - and you don't want to spend more than about $22k - this one's got your name on it.

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www.ericpetersautos.com or EPeters952@aol.com for comments.