Volvo’s range for Euro 6 is more standardised than at Euro 5, with the number of engine variants halved to just three. The 7.7-litre D8K replaces both the previous D7E and D9B, being a six-cylinder variant of the bus range’s four-pot D5K. .
Its D8K-powered B8R chassis is very similar to the outgoing B9R, explains Volvo Bus UK’s Product Engineering Manager Norman Thomas. The revised power and cooling pack is its only alteration of note, although it has gained I-Start, the manufacturer’s solution to flat batteries and standard on coaches at Euro 6.
Plaxton’s Leopard body remains the same, and contrary to original expectations it has proved possible to fit 59 seats at Euro 6. The vehicle tested, shown at Coach & Bus Live 2013, was kindly made available by Ian Downie, Volvo Bus UK’s Coach Sales and Product Director.
The Leopard is unashamedly marketed as a basic coach, and the test vehicle is not as well-specified as a previously encountered B9R-based Leopard. It lacks gullwing mirrors, for example, and its I-Shift gearbox is a simplified, ‘fleet spec’ model.
What it does retain is the same degree of practical functionality. The in-swinging door works quickly and access to mechanical components is good. Besides its two-piece engine door (the lower of which is removable in seconds), the radiator unit pivots outwards from the rear to give excellent access for cleaning purposes â€“ important at Euro 6, where more heat is generated.
Reaching mechanical units from inside the coach is also easy, with several gangway trapdoors present. These allow engineering staff to reach the fuel tank sender, rear axle, gearbox and engine rocker cover, and another hatch on the platform â€“ beneath the carpet â€“ enables the standard-fit spare wheel to be lowered.
The B8R’s two sets of batteries â€“ one solely for the starter motor, the other for everything else â€“ are also easily accessed, while a useful touch on Plaxton’s part sees the fuse box sited in a lockable compartment at the front of the nearside luggage rack. Complete with a diagram and spares, it means fuses can be changed in seconds.
It would be wrong to say that the engine bay is airy, but compared with some coaches on the market there is a reasonable amount of space to work in. The offside-mounted exhaust unit is not huge, and easily reached.
[tab title=”Passenger Access”]
Access is good, although the in-swinging door limits usable width compared with a plug type. The courier seat doesn’t obstruct entry and exit as much as in some other coaches thanks to the wide steps, and the underside of its tip-up section is usefully equipped with a sturdy handrail.
Five steps lead to the flat gangway, with the steepest being the initial climb from the road, at 380mm. That is mitigated by the B8R’s kneeling facility, which reduces step height by 100mm. Internal steps are all 230mm.
An additional step is required to reach the rear bench seat, where headroom is restricted owing to the Leopard’s low height. Gangway width is 390mm, slightly wider than the Prentice Coaches example previously tested, thanks to more basic seats.
The rear emergency exit is sited in front of the penultimate row of seats on the offside. It includes a well-designed set of slide-out steps, which secure themselves once the door has been fully opened.
[tab title=”Passenger Comfort”]
The Leopard as tested is a basic coach and its internal fittings reflect this.
The seats are covered in hard-wearing fabric. They recline, but lack drop-down tables and footrests. Naturally for a coach whose remit will undoubtedly include school movements, they have three-point belts.
Lighting is provided by LEDs above each pair of seats and two ceiling-mounted strips the length of the saloon. Luggage racks are reasonably-sized and have large lips to prevent items falling out when cornering.
Air conditioning and heating comes from a roof-mounted Thermo King unit at the front. No perimeter convection heaters are fitted; temperature is controlled by a simple panel in the cab, adjacent to the driver’s own heating dials.
Any worries about the roof-mounted unit’s ability to heat the coach are misguided, says Plaxton Marketing Manager Andy Warrender. He explains that it has been evaluated at Thermo King’s test chamber in the Czech Republic, and no issues were encountered.
A Blaupunkt CD player is present, with individual speakers above each pair of seats. A microphone is provided at the courier position, with volume controlled by the driver via a rotary switch. Hard-wearing carpet lines the gangway, while below the seats is a similarly durable grey plastic covering.
One significant area of improvement for passengers is a reduction in engine noise intrusion. Volvo accepts that the previous D9B unit had a slightly unpleasant tone under certain circumstances, and the replacement D8K â€“ derived from a Nissan unit â€“ has comprehensively addressed that.
When the coach is cruising, passengers sitting at the rear will find little engine noise. Those at the front will hear almost none.
Under full throttle the D8K is also more restrained; on the coach tested, the dominant source of noise was from the emergency door.
Norman Thomas says that Plaxton is aware of this and is looking at a revised seal arrangement.
[tab title=”Driver Comfort”]
The Leopard is a workaday coach, reflected in its cab. A fabric-covered Grammer seat is provided, which retains the same level of adjustment and support as a higher-specification example, and the I-Shift’s lever is attached to the left. This can fold down to enhance access.
Storage is reasonable but not on a par with a higher-level coach. A large bin is provided for atlases, work tickets and the like, and a small cup-holder is present. No secure storage is available.
Apart from that, the cab is almost as described in the previous Leopard test. A slightly revised steering wheel is fitted, and the dashboard is a little different. The on-board computer is less advanced than the B9R’s, lacking a reading for fuel economy for example, but other than that the workstation is well laid out and functional.
Three stalks are present, with the one on the left governing the variable cruise control, which is easy to use and a boon for the driver. On the right another stalk controls headlight flash and wash/wipe, with a smaller one for the Intarder.
As with all Volvo coaches, this is very strong. A road traffic collision (RTC) meant the usual Midlands route was followed in reverse, allowing a descent of Rockingham’s famous hill on the A6003.
Even without resorting to the Intarder’s strongest setting, it easily brought the coach’s speed down to below 30mph without needing to use the footbrake.
A skilled individual could potentially drive the B8R with little to no use of the brake pedal under normal circumstances, but when it is required the bottom-hinged fitting has a very reassuring feel.
Mirrors are basic. The internal mirror would benefit from being mounted on the windscreen rather than above it, and those externally are one-piece units on simple arms. No convex wide-angle mirrors are fitted.
Visibility is OK, but a close watch needs to be kept on the offside blindspot.
Heating and ventilation for the driver is controlled by three dash-mounted dials, and sufficient vents are present. The demister is powerful.
The untried part of this coach is its driveline, so it is appropriate to devote a larger portion of the test to that aspect.
Contrary to expectations before Euro 6 vehicles began to appear, the Leopard-bodied B8R as driven is actually lighter than Prentice Coaches’ Euro 5 B9R example by 75kg. Over a largely comparable route, the B8R also proved to be nearly 0.5mpg more efficient.
The 7.7-litre D8K loses 1.6 litres on its D9B predecessor, which translates to a reduction of 30bhp and 340Nm of torque. This is not noticeable in normal conditions, but when full power is demanded, as it was during a climb while overtaking two lorries, the difference is definitely detectable.
This coach’s engine is not its original, with Norman Thomas explaining that a pre-production unit has been replaced by a standard model, allowing an accurate verdict to be delivered.
When started from cold, the B8R automatically engages its exhaust brake, putting a load on the engine and speeding the warm-up process.
The D8K is keen and Volvo’s I-Shift gearbox can be counted on to do the right thing every time. Normally, even under full throttle, it will shift up at or around 1,500rpm, but on three occasions instead took the engine speed up to 2,000rpm on detecting a steep uphill section and a demand for full power.
This proved to be the right thing to do, rather than labouring in the torque band, and the coach quickly picked up speed. The new engine is flexible, however, and when accelerating normally delivers a good amount of torque from 1,100rpm onward.
I-Shift is reluctant to let engine speed drop below that speed, but clever gearing means that it will cruise at both 40 and 50mph at 1,100rpm, in 11th and 12th gear respectively. In the latter case, that contrasts with the Euro 6 9700, which required 12th to be selected manually at 50mph.
Reflecting its status as an entry-level coach, the B8R is equipped with Volvo’s most basic application of I-Shift. Dubbed the Commuter, it lacks the functionality of the two other versions, which may be specified optionally.
This means the driver is unable to control shifting entirely, as would otherwise be possible. The Commuter does retain a manual mode, although this is limited in capability to holding the current gear. The driver cannot up- or down-shift manually, and no kickdown switch is fitted to the accelerator.
The bold truth with gearboxes such as I-Shift is that they have made manuals on new coaches as good as extinct. And for good reason.
It is difficult to imagine any reason why a driver would want to return to stirring the cogs themselves, demonstrated when passing through the congested and narrow streets of Market Harborough and Stamford.
They can forget about gears and concentrate fully on the road, which in places like Stamford in particular is no bad thing.
The B8R’s long wheelbase (6,850mm) is very noticeable and calls for a significant degree of forward planning, although in its favour, the steering lock is excellent.
[tab title=”Verdict & Specs”]
Plaxton’s Leopard is well on its way to becoming a known commodity, and many have already rolled out of Scarborough.
It’s a simple product designed for a simple job: to move as many people as possible as efficiently as possible, and it’s equipped to do that with no fuss. It seems well put together and the interior trim is tough, useful in a coach which will find children among its regular passengers.
What is new is Volvo’s driveline contribution to the package. Prophets of doom who vocally derided Euro 6 before its introduction have long since been silenced, and the B8R demonstrates why.
In the D8K engine Volvo has a winner. Despite a modest size it will lug from 1,100rpm onwards, and is equally keen to rev freely when the terrain dictates. A modest output means it may struggle slightly if used on luggage-heavy extended touring work, but that’s a sector neither it nor the Leopard are aimed at.
High-specification touring coaches may hog the industry’s limelight, but its bread and butter work remains what the Leopard-bodied B8R is designed for. It’s capacious, fuel-efficient and reasonably priced. And those arguably count for more than anything at this end of the market.