November 2, 2004 - In the early 1990’s I had an hour-long-with-good-traffic daily commute into downtown Ottawa. The decision to buy my first diesel car, a Volkswagen Golf, seemed wise at the time.

With the Golf generating about 50 horsepower, the only drivers I threatened at stoplights were the one’s with two wheels and pedaling. To say my car was slow would only distract you from the fact it was also noisy due to the clattering diesel engine.

The best way to describe my relationship with the only diesel car I have ever owned would be "bittersweet".

It consistently delivered less than 7L/100 km in fuel consumption. With diesel at the time amounting to around 47 cents a litre, my costs per kilometre were pretty "sweet".

The "bitter" part? Ah, let me count the ways…

First, like most diesels of the time, I had to wait for the glow plugs to warm up before ignition. Second, explaining to my girlfriend about my smelly hands from pumping diesel fuel at hard-to-find stations that were mostly dedicated to professional truckers was always tenuous.

Did I mention the car was slow and noisy?

Needless to say, I had sworn off diesels—period—never to be known again as The Man with the Smelly Hands Who Drives a Slow and Noisy Car.



When I picked up the new-for-2005 Mercedes-Benz E320 CDI test car, all I could do was wistfully gaze at the horny-looking E55 AMG supersedan parked next to it in the press fleet lot. I had to suppress my diesel flashbacks, and ask myself: Just who did I piss off in the Mercedes-Benz Canada press office to get stuck with this? … this? … diesel?

It’s not like the E320 CDI (Common rail Direct Injection, by the way, which I’ll get to in a moment) had vertical exhaust stacks, airhorns, or a How do you like my driving? sticker to confess its diesel identity. Except for the CDI badge on the trunk lid, the diesel’s external appearance is the same as its gas-sipping E Class sibling.

Apart from a wiggly-worm shaped glow plug status indicator, and a tachometer with a markedly lower redline, the interior fitments were also identical to the high level of luxury found in any current E Class. That meant power everything, soft leather fittings, and polished wood and chrome pieces all meticulously assembled.

Trying to pacify my initial reactions to the E320 CDI, the Mercedes press folks were encouraging about the E320 CDI’s new turbo-charged 6-cylinder engine’s surprising performance. Try it Mikey, you’ll like it!, was their mantra. So I tried it.

I came to a stop at my first traffic light and the usual diesel engine clatter was not aurally apparent. Mercedes claims the extra sound deadening materials that went into the E320 CDI are to be credited for that.

I nailed the throttle, then whoosh; there was a momentary lag until the turbo started coming on. Then chirp, as the rear tires and traction control system reigned in all that low-end torque. Then I hung on, as the car really started to freight train. Whoosh again, chirp again, another velvety upshift from the five-speed automatic transmission, and finally my rearview mirror was filled with the grille of the shocked Z28 driver that was (was!) beside me.

This? … This? … This was a diesel?



Coming to a stop at the next light, both the Z28 driver and myself were left with little doubt of Mercedes’s claim that the E320 CDI could reach 0-100 km/h in 7.0 seconds, one third of a second faster than the current E320 gasoline engine model.

Highway driving was effortless, with the low-revving engine just ambling along and with a squeeze of my right foot the wealth of torque had the car at illicit speeds post haste. Not very "diesel-like", I might add.

What’s Mercedes’s secret? Well, the turbo-charger helps, but the real answer to the demystification of this particularly powerful diesel is in that unpretentious CDI badge.

CDI stands for Common-rail Diesel Injection, the state-of-the-art fuel delivery system that promotes smoother, cleaner and quieter diesel operation that’s popping up in all kinds of European-only cars.

CDI is partly responsible for the minimal glow plug warm-up time. It accomplishes this by injecting a small amount of diesel into each cylinder before the main charge is sent through a high-pressure delivery system. This initiates the fuel burn cycle so that when the main charge is ignited, the action inside the combustion chamber is more progressive, making for a more thorough burning of the diesel fuel, less noise and vibration, and ultimately, shocked muscle-car owners at stoplights.

Technical details aside, what matters most is that this gee-whiz fuel delivery system aligned with the variable-rate turbo-charger allows the 3.2-litre DOHC 24-valve inline-6 diesel engine to produce a whopping 369 pound-feet of torque. That’s more torque than such sporty cars as a Ferrari 360 Modena, or a Mustang Mach 1.

With a relatively low horsepower rating of only 201, the E320 CDI is a reminder that the tug of torque is as important to acceleration times as out-and-out horsepower.



Nice (very nice!) numbers for a performance car, but you’re probably been patiently reading this article to hear about the fuel efficiency and cruising range. Compared to the E320’s gasoline engine fuel economy, Transport Canada’s test numbers claim the E320 CDI’s city mileage improves by 40 per cent (8.7/100kms) and highway mileage by 27 per cent improvement (6.4 l/100kms).

At optimum conditions, Mercedes claims a 1,129 km range per fill up, which means you’ll have to stop before the E320 CDI does.

Mercedes is asking for a $2,350 premium over its gas model with the E320 CDI’s $74,400 base price. Depending on the amount of kilometres you drive, and the cost of diesel in your area, you’ll have to figure out how long it takes for you get your initial investment back. As far as diesel sedan alternatives go, Volkswagen has just launched it’s Passat 2.0 TDI, but its performance, features and price ($31,450), aren’t really in the Benz’s league.

Of course, your mileage may differ, blah-de-blah, however, I recorded 10.6/100kms during the week I had the car, which is almost a 40 per cent improvement over an E500 V-8 wagon I recently drove that had 60 less pound-feet of torque.

Mercedes is hinting that this is only the start of more diesels in their lineup. Imagine this engine in the new ML Class SUV, or an E Class wagon?

In the past, if you owned a diesel car, you had to make sacrifices (and run the risk of being called funny names). But with the introduction of the E320 CDI, Mercedes-Benz has drastically lessened the pain of derv drinking car ownership.

- John LeBlanc, Publisher, straight-six.com

2005 Mercedes-Benz E320 CDI