Mercedes-Benz S 300 BlueTEC Hybrid 2014 Review

With a fuel economy figure closer to a Prius than a prestige limousine, the new Mercedes-Benz S 300 BlueTEC Hybrid is one impressive bit of kit. Priced at $195,000 plus on-road costs, it competes toe-to-toe with diesel-only entry-grade class rivals, yet still manages to match or even exceed the level of comfort and equipment offered as standard. One of four new S-Class variants due in Australia over the next 12 months, the S 300 BTH will do its bit to ensure Mercedes’ maintains its sales dominance of the upper-large prestige segment.

Mercedes-Benz has launched its most efficient – and most affordable – S-Class model in Australia, the diesel-electric S 300 BlueTEC Hybrid.

It’s the first four-cylinder S-Class to ever be offered in Oz, and is also the first hybrid S-Class, which also means it’s the most fuel-efficient S-Class we’ve ever seen.

Capable of achieving a figure as low as 4.5L/100km on the combined cycle – while emitting just 118g/km of CO2 – the S 300 BTH challenges many cars half its size on the economy front; a remarkable effort considering its two-tonne kerb weight.

Powered by the combination of a 150kW/500Nm 2.1-litre turbo-diesel four-cylinder and 20kW/250Nm synchronous electric motor – which is set in the bell housing between the engine and seven-speed automatic transmission – the S 300 BTH gains further fuel savings from an ultra-low drag coefficient (0.23Cd), idle stop-start technology, brake-energy recuperation, increased under-bonnet thermal management and low rolling resistance tyres.

The high-tech and super-efficient price leader of the S-Class portfolio, the S 300 BTH (from $195,000 plus on-road costs) is set to extend Mercedes’ sales dominance of the VFACTS category in which it competes (Upper Large >$100k), appealing to both private and fleet buyers. Currently just 10 per cent of S-Class sales go to non-private buyers.

As it stands, the Mercedes-Benz S-Class (with sales of 126 units to May this year) exactly doubles the sales numbers of its nearest competitor, the Maserati Quattroporte (63 sales), is streets ahead of its closest German rivals in the BMW 7 Series (45) and Audi A8 (35), and miles past its English counterpart, the Jaguar XJ (25).

At base level, all of those models rely on 3.0-litre turbo-diesel motive power and an eight-speed automatic transmission, and all are rear-wheel drive. All are priced within $20,000 of the entry-level S-Class on price, though none can match the Merc’s staggering fuel economy and CO2 emissions.

For reference, the Quattroporte ($198,800 plus ORCs) makes 202kW/600Nm, consumes 6.2L/100km and emits 163g/km of CO2; the Audi A8 (from $195,000) 190kW/580Nm, 5.9L/100km and 155g/km; the BMW 7 Series (from $205,100) 190kW/560Nm, 5.6L/100km and 148g/km and the Jaguar XJ (from $198,800) 202kW/600Nm, 6.3L/100km and 167g/km.

Even the nearest hybrid competitor to the S 300 BTH, the Lexus LS 600h (from $217,700) can’t near the Merc’s figures – its 290kW/520Nm petrol/electric 5.0-litre V8 using 8.6L/100km on the combined cycle while emitting 199g/km of CO2.

OK, that’s a lot of facts and figures. But they do point to just how impressive an achievement the S 300 BTH really is, and are numbers that will likely appeal to a growing cast of chauffer businesses faced with the very real challenge of finding a replacement for their now-defunct locally-sourced long-wheelbase fleets.

But perhaps just as notable as the S 300 BTH’s efficiency is its high level of standard equipment. The full bounty of S-Class inclusions are available and with Mercedes’ Driving Assistance Package Plus, PRE-SAFE, Parking Package, panoramic sliding sunroof, COMAND on-line infotainment system (with 31.2cm screen!), KEYLESS-GO entry and start and 18-inch alloy wheels among the long list of standard equipment items, the package elevates the S 300 BTH well ahead of its nearest competitor.

Optionally, the S 300 BTH is available with a LED Intelligent Light System for $3500 and a Vision and Sound package for $6500. The model now also includes rear seatbelt airbags with illumination and extension functionality, thanks to an active buckle (outboard positions only), adding to the S-Class’ highly evolved safety package.

Out back, there’s enough room for a weekend’s luggage, though the boot is 20 litres smaller then conventionally-powered S-Class variants (510 v 530 litres) owing to the position of the lithium-ion battery pack.

On the road the S 300 BTH is a smooth operator and, despite the complexity of the workings beneath, feels as fluid to drive as the regular S 500 L sampled previously.

Mercedes’ has taken impressive steps to ensure the S 300 BTH’s brake pedal response is as natural as that of a conventionally-powered vehicle, which anyone having sampled other hybrid vehicles is bound to appreciate.

The linearity of acceleration from standstill (0-100km/h in 7.6 seconds) is equally welcomed, the electric motor covering the void often experienced from turbocharged diesel engines. As the internal combustion engine takes over there’s barely a flinch felt through the driveline, and the automatic, which is decoupled from the engine via a wet clutch and not a torque converter, shifts imperceptibly through its seven forward ratios. There’s also a Gliding mode available at speeds under 160km/h, which allows the S 300 BTH to coast to save fuel.

From outside of the vehicle the S 300 BTH is obviously diesel in its voice, though inside you wouldn’t know it. The cabin is expectedly quiet, even when the engine is required to operate at idle, though it’s here that a constant, albeit mild, vibration is felt from within.

In this respect the S 300 BTH isn’t as refined as the petrol-powered model we’ve sampled previously. Though, the intrusion is rarely felt thanks to the idle-stop system, and will only really be noticed when the HVAC system, or myriad of other electronics, ask the engine to supply supplementary power.

From the driver’s standpoint, the S 300 BTH is just the ticket for relaxed and efficient motoring, though we did find a slight visibility issue from the vehicle’s thicker A-pillar.

On test, we returned 6.4L/100km according to the trip computer, which is a fair effort considering the city-oriented driving mix. It also proves Mercedes’ most efficient S-Class yet is indeed just that.