Ford-owned Volvo has added a new V8 engine featuring a six-speed automatic transmission and latest-generation AWD system to its range-topping XC90 SUV line.

The new V8 is the company's first since it was founded in 1927.

 "An SUV in the premium segment needs a V8, especially on the North American market where we sell about 60% of all the XC90s we make," said Vic Doolan, president & CEO of Volvo Cars of North America.

The new V8 is installed transversely, like all other Volvo engines.

 "A transverse engine is helpful in maintaining the frontal crumple zones in the XC90 and thus does not compromise on protective safety," said Hans Wikman, Volvo's head of large cars.

For this reason, extremely compact external dimensions were essential for the new engine. This explains the choice of 60 degrees between the two banks of cylinders instead of the more conventional 90 degrees.

In order to maintain overall compactness, all the ancillary units such as the alternator are fitted directly onto the engine itself without any space-stealing brackets. The starter motor is fitted above the transmission for the same reason.

The exhaust camshafts are driven by secondary chains running off the inlet camshafts, saving additional space. The use of cam timing chains instead of belts means less maintenance and better long term durability.

The left-hand cylinder bank is offset half a cylinder ahead of the right bank, contradicting standard practice, so the engine can slot neatly into the structural beam network of the XC90 and thus enhance collision safety.

 "We've tailored this V8 specifically for the XC90," said Wikman. The result is a V8 that is just 29.7 inches long and 25 inches wide - claimed to be the most compact on the market compared to engines of equivalent volume.

As a result of these compact dimensions and its cast aluminium block and cylinder head, Volvo's new V8 weighs just 419 pounds.

The new engine from Volvo is claimed to be the cleanest petrol V8 on sale today. It meets the American ULEV II (Ultra Low Emission Vehicle, stage II) requirements and the forthcoming Euro 5 requirements for Europe - which no other petrol V8 has yet managed.

 "This is an achievement we're really proud of," said Volvo's chief programme engineer Jörgen Svensson, "and a good day for the environment. With the proliferation of SUVs, we want to prove that meeting ULEV II with a gasoline V8 could be achieved".

Meeting ULEV II/Euro 5 has been achieved with four catalytic converters, two of which are the close coupled type and fitted to one exhaust manifold each. The other two are installed under the floor.

The higher idling speed, about 1250rpm, and optimised ignition allow faster warming of the engine from a cold start and thus faster heating of the catalytic converters. Lean air/fuel mixture lowers cold start emissions.

The result is extremely low emissions before the catalytic converters are activated - which takes place just 15 to 20 seconds after the engine starts up.

 "It is during these 15-20 seconds that the majority of the emissions of environmentally harmful substances take place," said Svensson.
The four-valve-per-cylinder engine also features continuous variable inlet and exhaust valve timing (CVVT). This system adjusts the valve opening times so they suit the engine's current revs and load conditions.

The new Volvo V8 develops 315 horsepower while torque is 325 lb/ft at a rather high 3,900 rpm. But Volvo claims at least 273 lb/ft is available at the sort of revs at which most driving takes place, around 2000 rpm.

To increase the low end torque, the engine has a two-length inlet manifold. Below 3200 rpm the air flow between the two cylinder banks is cut off, which creates a broader and more even torque curve.

Acceleration from 0 to 60 mph (96km/h) takes a claimed 7.0 seconds and fuel consumption is 18 mpg (preliminary figures for US gallons; say 15mph imperial).

Like BMW a decade ago, Volvo, when launching its V8, said the engine note is an important detail for buyers of a car with bent-eight power, and in the hunt for that characteristic V8 rumble, engineers found that the position of the inlet manifolds is the main deciding factor.

"Our new V8 has just the right sort of charismatic off-beat V8 burble, but it is somewhat more sophisticated than the more traditional meaty American throb" said Svensson.

The V8 is combined with a new six-speed automatic transmission dimensioned to handle high torque. This unit is also of particularly compact dimensions so as not to interfere with the car's overall structure. Sixth gear is a pure overdrive ratio to ensure quiet cruising and low fuel consumption.

 "We get simply massive 'take-off' force with this new auto transmission," said Svensson. "At the same time, it has a very sporty nature and does not change up in the middle of a curve, for instance, but instead stays in the same gear until the bend straightens out."

The new transmission is a so-called 'Geartronic' unit, which means that it can also be shifted manually.

To ensure the optimum balance between driving properties, performance and fuel consumption the engine and transmission are treated as one unit. This is achieved with new software developed by Volvo, called CVC (Complete Vehicle Control). CVC is part of the integrated software package used both in the engine control module and the transmission control module.

Among the many benefits of this approach was the possibility of integrating an overdrive 6th gear while still maintaining good driving performance by adjusting gear and torque to suit current conditions.

The new electronic AWD drive system features 'Instant Traction' - a claimed industry first - which considerably improves scope for quick getaways and provides enhanced traction on slippery surfaces. It has been developed by the Swedish company Haldex.

 "A non-return valve allows us to use software to control the base torque that is programmed into the AWD system. When starting off from standstill, 59 lb/ft of torque is pre-charged in the system since the non-return valve prevents the unit from becoming totally drained of hydraulic fluid" said Svensson.

 "This reduces the usual wheelspin of about one-seventh of a turn that the current system permits before the power is delivered to the rear wheels."

The AWD system has also been upgraded to handle the power of the V8 engine. Maximum short-term torque at the rear wheels has been increased by 50% compared to other XC90 models.

XC90s with the new engine have V8 badges on the grille and tailgate, new 18" wheels, body colour side mouldings and door handles, graphite-grey grille, chrome trim around the bumper air intake and new twin exhaust pipes.

Volvo said the V8 XC90 is the first example of a new design for the engine compartment in its upcoming models.

 "We want there to be no doubt that this is a V8, and a modern and technically advanced V8 at that. We therefore chose not to hide the engine beneath large covers but instead to enhance the V-configuration and the eight inlet pipes," said engine bay design head Anders Myrberg.

On the inlet manifold, the US-Swedish car maker's classic 'iron' symbol is used in relief against a background of brushed aluminium and complemented with a V8 emblem.