The FH 16-750 lined up behind FH16-700 for the test. It was launched in 2012 using the design of the Volvo F16, which had been introduced 25 years ago. Under the hood, there were new engines, showing the engine development at Volvo during the last 25 years.
Let’s look back: the cast-iron TD162 in the Volvo F16 debuted in 1987. It provided 456 HP and 1510 lb-ft (2050 Nm) from a displacement of 16.12 liters distributed over six big cylinders. During acceleration on the in-house track of lastauto omnibus magazine, it left all well-known competitors in the dust: Scania R143-450, MAN 19.462, and the strongest Mercedes at the time, SK 1844.
From 450 to 750 HP
Engines with 450 hp have long been the standard in heavy trucks. The current D16G is not even available with “so little power.” 540 HP (397 kW) is the minimum, and 750 HP (551 kW) the current maximum. The path from the old TD162 to the current D16G also describes 25 years of engine development. The large six-cylinder began with a mechanically controlled fuel injection pump (injection pressure 260 bar ) and a lateral cam shaft, but it had already four valves per cylinder. In 1993, this was changed to EDC (Electronic Diesel Control), and the TD162 became the D16A in the new FH16. A good ten years later, the single cylinder heads and fuel injection pump were replaced by a one-part cylinder head, an overhead camshaft and unit-injector elements. Performance now increased in big steps: 610 HP in 2004, 660 in 2006, and 700 in 2009. And now, in the anniversary year, it has reached 750 HP (551 kW) and a maximum torque of 2620 lb-ft (3550 Nm).
The FH16 Manages 54.4 mph (87.6 km/h)
This FH16 managed 54.4 mph (87.6 km/h) on a test track packed with inclines. However, the difficult topography is only perceived by the driver. The inclines are visible, but they have no noticeable effect on the speed. The motion is very steady and independent of the topography: 52.8 mph (85 km/h) on a flat surface, 52.8 mph (85 km/h) uphill , and 56 mph (90 km/h), all of which results in an average of approx. 54 mph (87.6 km/h), which was calculated from the driving time and the route length.
The driving dynamics are just as impressive as the steadiness. Wit a gentle growl from below, the FH16 builds up speed extremely fast at low rpm. The brisk acceleration is almost unbelievable for a fully loaded truck. All this happens very quietly and comfortably. I-Shift, the automatic transmission from Volvo (standard in the FH16-750), selects the gears sensibly, almost unnoticeably, and extremely fast. It usually keeps the big, strong engine at low rotation speed so that hardly any noise can penetrate the cab, while consumption stays low.
Air Resistance Pushes up Fuel Consumption
Keeping this Volvo rolling briskly has obvious consequences for fuel consumption. There are two reasons why the fuel consumption is higher than for conventional trucks. First, the constantly high speed causes increased air resistance. Where a conventional truck with 450 HP would drop to 31 mph (50 km/h), the FH16 keeps zooming ahead at 53 mph (85 km/h). The second reason is the higher friction loss in the large engine. Compared to the standard performance class, the overall consumption is therefore more than five percent higher, both on flat terrain and on hills. In other word, when you work faster by five percent , you can also demand or use five percent more. This is like a piecework bonus, and, what’s more, the law of physics, which cannot be avoided. The only remaining question is, if and how saving time is economical in day-to-day use.
6 mpg (39 liters/100 km)
Exactly 39.0 liters/100 km (6 mpg) passed through the injection nozzles of the Volvo FH16. This is on the level of the Scania R730 that was tested on the same track two years ago. The Volvo required two incline-related gear shifts, just like the Scania, and the uphill speed, too, only dropped twice below the specified cruising speed of 85 km/h. At this speed in the highest gear, the engine worked at slightly more than 1200 rpm, which would deliver almost 620 HP at full acceleration. Approx. 100 HP are required for rolling on a flat surface, and the other 500 are a continuous performance “insurance.” The I-Shift automatic only shifts down when the incline increases to more than 5%. This means that in this situation, at 1400 rpm, almost all 750 horses get ready to take care of noticeable acceleration uphill, up to the preset cruising speed, on inclines of over five percent.
The increased power of the D16 six-cylinder engine required two things: First, a new RSS 1360 hypoid axle, which stands for a single axle, single ratio, 13 tons of load capacity, and 60 tons of towing capacity (Sweden says hello…). Second, a new automatic ATO3512 I-Shift transmission with overdrive for approx. 2580 lb-ft (3500 Nm). The overdrive is a concession to the enormous power. It works with a factor of 0.78 and, with an axle drive ratio of 3.40, results in a ratio of 2.652 : 1 for the largest gear.
Retarder Costs 220 lbs. (100 kg) in Payload
For 25 years, the engine brake of the six-cylinder engine has been as striking as the six big cylinders with a displacement of 165 cubic inches (2.7 liters) each. Even the old TD162 delivered 275 kW of braking power. This was followed by the Volvo Engine Brake (VEB) with 380 kW and, finally, the VEB+ with 425 kW of braking power at 2200 rpm. This is more than enough for most circumstances and a good enough reason for many customers not to buy a retarder. Not only does the retarder cost a lot of money—and a payload of 220 lbs. (100 kg)—but also, as confirmed by many drivers, tire profile at the drive axle. The brake horsepower of the boost retarder and the VEB+ add up to a respectable 865 kW for the FH16 .
Retarder: Better Interaction of Cruise Control and Coasting Before Climb
The interaction between cruise control and coasting before a hill climb (5 km/h, 3 mph) works with the VEB+, but not nearly as well as with a retarder. The engine brake works on three levels: at 30, 60 and 100 percent of brake horse power. But the continuously variable retarder can do it more sensitively and smoothly. The Volvo always sticks closely to the driver presets, but during fast downhill drives, a noticeable jerking from below the driver’s cab reduces the comfort. In general, the operation and interaction of all the assists, such as cruise control, ACC, eco-roll function or multi-level engine brake do not work as smoothly as they do on the Scania R730.
Front Axle under Criticism
Although the power train technology makes a very good impression, these details betray the age of the FH. The performance of the front axle is no longer up to date, either. It steers more accurately than when FH debuted, but it is too hard and rough on uneven surfaces.
The Swedish trucks have made the best of the tight driver’s cab, which lacks more than 35 cubic feet (1 m3) compared to the best competitors. A swivel passenger seat turns the cab into a slightly tight but comfortable living room, and the lower bunk bed is 700 millimeters wide at its narrowest point. Once the rear console with a volume of 9 cubic feet (260 liters) has been mounted, the FH has ample stow room, but must then do without a second bed. However, large trays are in short supply in the FH, even in the largest driver’s cab, the Globetrotter XL. Small trays are plentiful and so are bottle and cup holders. Two large, outside stowing compartments, which are open on top, are standard in the FH.