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What are they like, these iew engine spec Volvos?

19th September 1981
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Page 58, 19th September 1981 — What are they like, these iew engine spec Volvos?
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Tim Blakemore found out, with hundreds of miles of open road before him in the sparsely populated Swedish outback

1TH-EASTERN SWEDEN is the most obvious place in ;h to gain driving impress of commercial vehicles :ined for the British market. when the manufacturer of ;s3 vehicles is Volvo, which a cab manufacturing plant at ea, on the Baltic Coast, then reason for the choice of locabecomes clearer, it why does Volvo have its manufacturing facility so far iy — over 1,000km (620 )s) from the company's head :e and main assembly plant iothenburg? The answer can 'ound in Volvo's history. Like ly British lorry makers, Volvo d timber cabs in the early s and the material came from heavily forested area around ea.

/hen steel replaced wood in 8, Volvo management deId that it was more cost ictive in the long term to ve material rather than 'We so the cab plant stayed 3 re it was. Today 1,040 of the versity town's population of )00 people are employed at ! plant. The large recent estments made there by vo show that it has no plans nove cab production closer to :henburg,

n many ways the roads und Umea are well suited to nparative road testing, at st during the six months of year when there is no snow, ffic density is lighter than you ild hope to find almost anyere in Britain, and once clear the town, even though there are no motorways, it is possible to drive for considerable distances without interruption from roundabouts or traffic lights.

The nearest towns of any size are Ornskoldsvik about 100km (62 miles) to the south and Skelleftea about 150km (93 miles) to the north, If you take the European Highway E79 (the socalled "blue road") that runs north-west from Umea, you can travel for 475km (295 miles) before reaching any town with a population of more than 10,000, and that would be after you had crossed the Norwegian border.

This was the road that the convoy of eight lorries from Volvo Trucks (Great Britain) used after leaving Vindeln, to the north-west of Umea; however, it was not the Norwegian border but the much closer Lapland border that was our destination.

It says something for the unflappable Swedish character, and perhaps indicates their respect for road transport, that our convoy attracted so little attention from the locals. It can hardly be an everyday occurrence in Vindeln for seven right-handdrive articulated combinations and a six-wheeler tipper to pass through the town in quick succession.

Even when one of the tractive units blocked a narrow road leading down to a local beautyspot after its wheels had spun and dug through the shallow road surface to soft sand beneath, there was no hostile reaction from the local residents. The tractor driver who cheerfully pulled the artic out of its predicament was typically stoical, shrugging his shoulders with a Swedish phrase that must roughly translate to "C'est la vie." Nevertheless, there was a general feeling of relief among the British party that the vehicle that was stuck was not the one bearing the legend "British Built by Volvo."

The selection of vehicles from Irvine was chosen to be representative of the Volvo range that will be available in the UK from the beginning of next year and to allow comparisons to be made between the performances of the new specification engines and the old.

There is to be no change in the specifications of the 6,7-litre engines used in the F7 range (except that, like its big brothers its oil change interval has been ex

tended). Two versions will con tinue to be available, the TD70C rated at 151kW (202hp) at 2,401 rpm and the inter-cooled variant the TD7OF rated at 224hp (217h, with the viscous fan fully en gaged).

The engine designation of thi TD70 engines gives a clue to thi thinking behind the new speci fication 10and 12-litre engines From January next year in thi UK the TD100A and TD100B en gines will be replaced by Oil TD100GA in the F10 range. (Thi horizontal TD100A will continui to be used in coaches). 8+ contrast, the one version of thi 12-litre engine that is currentl, available in F12s in Britain, th, TD120C, will be replaced by twi versions, the TD120FC an TD120GA.

On the gentle gradients of thl roads leading to the Laplanl border none of the engines wa stretched.

Once top gear was reached, change down was needed oil' very infrequently even with th

,ehicles having the lowest )ower to weight ratio — the F10 it 38,000kg and the F7 at 12,500kg.

We kept close to the legal naximum speed limit for heavy 'ehicles of 70km/h (44mph) even hough most of the fully-laden imber-carrying drawbar combiiations travelling in the opposite lirection seemed to be closer to speed of 70 miles per hour.

Some of the Volvo tractive inits were fitted with turboharger boost pressure gauges, n item that is to become an opional extra on British Volvos rom January next year. Over his kind of undemanding terrain t relatively low speed the intrument could really be used to load effect.

The pressure gauge indicates he pressure drop behind the urbo-charger, in other words, ,ow hard the turbo-charger is vorking in forcing air into the ngine's cylinders. Since the Dad on the engine and conseFuently the rate at which fuel is leing. consumed, is directly

proportional to this pressure, the gauge gives an indication of how fast fuel is being used.

A fuel-economy-conscious driver can save fuel by aiming to keep the boost pressure as low as possible.

It is surprising how even a slight variation in the throttle opening can affect the boost pressure quite dramatically. The air-operated accelelerators on the right-hand-drive FlOs and F12s are particularly sensitive and the gauge's needle could be made to swing over an alarming range simply by resting one's right foot on the pedal in what most drivers would regard as a normal manner.

While this boost pressure gauge can be a useful fuelsaving accessory then, especially on the TD120FC with so much power available, I think it should be emphasised that it should only really be used when the engine is running under light load conditions.

If a driver were to try to keep the boost pressure low when climbing even a slight gradient, its effect on fuel consumption would almost certainly be counter-productive, by not allowing the turbo-charger to work efficiently.

Another change on the 1982 spec Volvos aimed at making better fuel consumption easier to achieve is the new tachometer. The instrument's face had to be altered to suit the lower speeds of the latest engines. At the same time Volvo has taken the opportunity finally to remove the often criticised revs per second calibration, leaving only the more conventional rpm scale.

The colouring has been simplified too with a solid green sector to indicate the most fuel efficient engine speed range from 1,200 to 1,700rpm and a shaded green sector from 1,700rpm up to 1,900rpm to warn when the engine speed is too high for the best economy.

On all three of the new specification engines the governed

speed has been reduced fri 2,200rpm to 2,050rpm and thi: the reason for the lower rilEmum power outputs of • TD100GA compared with • 100B and the TD120GA cc pared with the 120C.

The question that will asked by many British operat of TD100B-engined F1Os (. TD100A version was hardly e' specified) is "Do I now nee( 304hp F12 to replace my 278hp F10 or will a 257hp F10 the same job?"

To find out how their perfor ances compared on Swed roads, I drove three F1Os ove hilly section of the E4 south Umea. As our results ta shows, the quoted maximt power outputs do not tell whole story by any means.

Maximum torque on the I jine is slightly higher than it s on the B engine and it is /.eloped lower in the rev ige.

he difference this makes to

climbing performance bene apparent on the first of our ee chosen hills. I would estite this hill's average gradient 3e similar to Carter Bar, about 1 13, but it is longer at 4.4km


he GA-engined F10 at a gcw 32 tons 3limbed the gradient a slightly faster time than the nilarly loaded Fl 0 with 100B engine. Sixth low was 3ded twice with the older Ivo, but only once on the new chine.

)r-i the next two shorter and eper hills, the old specificari F10 was faster because its ver gearing, 4.86:1 rear axle io compared with 4.63:1 beid the TD100GA, and the hills' -ticular gradients allowed the :ra power at the top of the ler engine's speed range to be ad.

'uel flow meters were not fitted to the vehicles so no fuel consumption results are available, but in theory at least over hills such as these, the new spec engine's fuel consumption should be the better because it is almost always working at a lower speed.

Both these FlOs were fitted with the 16-speed SR62 gearbox though the standard spec for the UK will be the eight-speed R62 coupled to a 4.25:1 single-reduction rear axle. This combination gives a maximum geared speed of 97km/h (60 mph).

Two options will be available to operators requiring a higher geared speed: they can choose the SR62 with the same rear axle giving a geared speed of 114km/h) (71mph) or the SR62 and a 4.63 differential for a geared speed of 105km/h (65mph).

Volvo GB's thinking is that on British roads at an operating weight of 32 tons or even at 38 tons the eight ratios of the R62 are adequate when coupled to the higher-torque GA engine.

On the way back to Umea from our hillclimb section, I tried driving the new F1Os using only the overdrive gears, le shifting from 2 high to 3 high to 4 high and so on, which are virtually the same ratios as in the eightspeed gearbox. At 32 tons gcw on Swedish roads the splitter is certainly redundant and indeed at 38 tons gcw for most of the time there was no need to use it.

Volvo has relocated the exhaust brake button to just behind the steering column. It is a lot easier to reach than in its old position in front of the seat, but I cannot report any improvement in its effectiveness. In fact, at the lower operating speeds of the new engines, it is even less effective than it used to be. The inter-cooled version of th TD120 engine will be official available in Britain from ear next year. When this 1,546N1 (1140 lbft) engine was de veloped, a decision had to made as to which gearbox to I behind it.

The SR62 could have bee beefed up to cope with the hic torque, but it would have bee unacceptably heavy with almo impossibly high-gear-shi loads. Volvo admits to havir considered a constant-mesh ar even a semi-automatic gearbo but finally the Swedish enc neers came down in favour of new 12-speed synchromeE gearbox — the SR70.

This was my second opport nity to become acquainted wi the unique gearshift pattern the SR70, having tried one la year with CM's LDoY Dixie Dea The second time around ti gearchange is very easy to ada to and there is no doubt that tl spread of the ratios and the spacing is extremely we matched to the powerful, hic torque TD120FC engine. TI SR70 will also be available as ; option with TD1200A-engint F12s.

The gear-lever-mounted spl ter switch which was introduo on this gearbox is to becon standard on all gearboxes wi overdrive.

Top gear, on the SR70 direct, 1:1 and coupled to tl new, standard 3.79:1 hub-redL tion rear axle ratio which give: maximum geared speed 111km/h (69mph) the potentia there for excellent fuel econor at high average speed.

Volvo Trucks (Great Brital Ltd has not yet announced t price of the FC-engined F12 indeed any of the 1982 specific tion vehicles.


Organisations: British party

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