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LONG WAIT

Scania has put its EDC-equipped R143-470 through strenuous operational trials. Rather than waiting for a UK model to test, we put a left-hooker through its paces.

• "You want me to wait how long?" . . picture the scene: a local Scania dealer "somewhere in England" (or Scotland, or Wales or Ireland). 'The time: December 1987, just after the Scania's 3 Series tractive units had broken cover in Commercial Motor. The conversation goes something like this. Owner-driver: "Hello, I'm thinking of replacing my old tractor and I want the new Scania R143-470 — you know, the one with EDC." Salesman: "Ah yes, the R143-470 with Electronic Diesel Control — delivery in 1990 suit you?" Owner driver: Thanks, I'll get an F16."

We can only guess how many fans of high-powered Scanias actually gave up waiting for their 470s and switched to a rival marque. But what's clear is that despite the undoubted pressure to launch it, Scania was certainly not going to launch the R143-470 onto the market until it was absolutely ready.

That meant running extensive operator trials on the EDC system in Scandinavia before finally releasing it to the rest of the Continent last August. Inevitably, the right-hand-drive British market was at the end of the production queue, so it wasn't until the start of this year that righthooker R143-470s started to appear over here in any numbers.

Despite the odd scare story of "technical problems" with the early Scandinavian 470s, the long wait for the EDC-equipped R143 appears to have been worth it. It's interesting to note that Volvo, which is also carrying out EDC trials in Scandinavia with its F12, has experienced similar (and only to be expected) teething troubles with the Bosch electronic fuelmanagement system. But it says that these have now been overcome and that the first series-production EDC F12s should be around by the start of 1991.

So why all the ballyhoo over EDC? And why are the two Swedish giants so keen to fit it?

Scania (Great Britain) is currently preparing its road test programme for 1990 and normally we would have to wait for a

UK-spec R143-470 to find out. Instead we've gone ahead and tested a left-hooker as part of our Continental road test programme, helped by our colleagues on the Belgian truck magazine Transporama.

Until recently the most powerful R143 tractor available in the UK was the 320kW (435hp) R143-450, which has the same mighty 14.2-litre DSC 14 charge-cooled, vee-eight as the R143-470, but without the EDC package.

The newcomer has inevitably put the R143-450 in the shade, and while Scania (Great Britain) will continue to offer it "until its current Type Approval Certificate runs out", it is likely that operators who want big power will go for the R143470. For those who don't, there is always the R143-400 or the R113-360 with the smaller 11-litre straight-six.

• DRIVELINE

Outwardly there's little to distinguish the 470 from the 450, apart from a small grille badge. They have pretty much the same basic cab and power unit, as well as the GR880 10-speed range-change box and Scania R770 hypoid back axle. What separates the R143-470 from the rest is EDC which begs the question, what is EDC anyway?

In simple terms, EDC is a 'drive-bywire' electronic fuel management system interposed between the throttle pedal and the fuel injection pump control rod. Using data supplied by sensors on the rate of acceleration, charge pressure, charge-air temperature, engine speed and road speed, the 'black box' microprocessor sends a signal to the fuel pump to release exactly the right amount of fuel to the engine for the operating conditions.

But controlling fuel injection is just one string to EDC's bow. It can also act as a cruise control unit which is pre-progranunable by the driver, and will improve cold starting. A sensor analyses the coolant temperature, and the microprocessor ensures that the right amount of fuel is used to suit that temperature. If the coolant temperature is below 20°C the idling speed is raised by 600rpm. This continues until the coolant temperature exceeds 10°C, or for a maximum of five minutes.

To prevent damage to the engine and turbine from excessive speeds when starting from cold, EDC also acts as an automatic engine speed limiter. If the coolant temperature is 0°C the engine revs are prevented from exceeding 1,000rpm for the first 30 seconds.

Finally, as EDC replaces a mechanical centrifugal governor, it also allows the normal maximum engine speeds to be raised from 1,900rpm to 2,100rpm in the first seven gears. The logic is that when operating over tough terrain in low gears the extra revs will help overall drivability, and when in eight, nine and 10 at higher cruising speeds, they are unlikely to be needed. A sensor in the gear lever advises the EDC microprocessor which ratio is selected so the revs can be adjusted accordingly.

By limiting the higher revs to the times when they are really needed EDC can in theory reduce fuel consumption.

• FUEL CONSUMPTION

When CM tested the R143-450 in October 1988 we were impressed by its power and productivity, which did not seem to incur an excessive fuel penalty. For the left-hooker R143-470 read ditto, only more so. Compared with our last Continental Test tractor — the 353kW (480hp) Mercedes-Benz 1748 — (CM 1824 January) the Scania is less thirsty and, in certain circumstances, it's quicker too.

During the Continental test route's 432km fuel-gulping slog through the Ardennes the R143-470 returned an overall 40.61lit/100km (6.96mpg) at an average 73.1km/h, against the 1748's 42.091it/ 100km (6.71mpg) at 72.1km/h. On the 2,200km run from Antwerp to Marseille and back the R143-470, operating at 40 tonnes, managed 28.631it/100km (9.87mpg) compared with the 1748's 29.23fit/100km (9.66mpg).

While these figures are impressive, they are obviously based on lower Continental motorway speed limits. Nevertheless, it's worth noting that when we tested the R143-450, albeit at 38 tonnes, its average motorway consumption up the M6 was 34.41it/100km (8.2mpg) at the higher UK limit.

So flexible is the power and the torque of the R143-470, that on normal roads you seldom need to resort to low range except when starting off. Not surpisingly, with a maximum torque rating of 1,940Nm (1,431lbft) at 1,250rpm, most gradients are tackled with ease.

But a word of caution. All that power requires a responsible attitude; slam your right foot down when pulling away and wheelspin is a likely result.

Bosch's ASR (anti-skid acceleration) package is about to be offered on lefthand-drive R143-470s, and Scania (Great Britain) is believed to be examining it as an option on RHD tractors.

• CRUISE CONTROL

On the dash of an R143-470 EDC you will find two extra rocker switches for the cruise controL This is engaged as soon as the driver releases the throttle pedal and presses the 'ACC' button until the desired speed is attained. Once actuated the microprocessor uses information supplied by the sensor on the injection pump and the electronic tachograph to maintain the preset speed until the driver either applies the brakes, declutches, accelerates past the set value or disengages the cruise control with the 'OFF' button.

If the driver wants to cruise at a higher speed he simply presses the `ACC' button until that speed is reached. Similarly, if he wants to reduce speed he presses the `RET' (for retardation) part of the rocker switch. If the cruise control is disengaged, for example by the driver braking, it can be reactivated simply by pressing 'RES' (for resume). The vehicle will then run at the most recently set speed.

To test the effect of running with cruise control we did the 168km motorway run from Kruibeke to Menen, and back, at a steady 90km/h, once with cruise control and once without. We couldn't help notic

ing that in practice the 'constant' speed fluctuates slightly.

With the cruise control engaged, the R143-470 completed the run slightly faster but with a higher fuel consumption of 29.41it/100km (9.6mpg) compared with 27.8lit/100km (10.2mpg). The problem with cruise control is that, unlike a driver, it can't anticipate a gradient and take a run at it. Instead it piles on the throttle as and when necessary when the speed falls below the set limit.

The good news, however, is that with cruise control higher average speeds are possible, irrespective of the driver's attention: you don't have to spend hours watching the tacho like a hawk and constantly feathering the throttle pedal of keep the needle steady. For the longdistance driver that's got to be a bonus.

• CAB COMFORT

Entry into the latest 3 Series cab is simple enough thanks to the well-placed steps and grab handles, and the interior is everything that owner-drivers have come to expect from the Swedish truck maker. The sweeping dash puts everything within easy reach of the drier and all the dials and instruments are well laid out and clearly marked, with the tacho and colour-coded rev counter holding centre stage.

The air-suspended drivers seat and fully adjustable steering column ensure that even the oddest-shaped driver can be accommodated.

Visibility from the driver's seat is excellent, thanks partly to the electrically heated mirrors: electrical adjustment would make them even better.

The twin-bunk R cab has always been a fairly comfortable place for a night out, but with the optional Topline roof extension (yours for an extra 23,100) it has an extra 220mm headroom to give a ceiling height of 1.7m.

This should be enough for most drivers, but it is still lower than the Volvo Globetrotter or Leyland Daf Space Cab/ Seddon Atkinson Stratocruiser. To help make the most of the available space the bottom bunk features a lift-up section, allowing the passenger seat to be pushed back up against the rear wall.

Add to that a standard night heater, central locking, air conditioning and seat belts (on Topline models) and the cab becomes an extremely attractive package for the person behind the wheel.

The right-hand-drive R143-470 EDC has parabolic springs all round as standard, but our left-hooker came with the optional air suspension on the drive axle. This combined with the Topline cab's four-point air suspension to give an aboveaverage ride. Our only complaint is that on some roads the damping could have been a bit firmer.

In the past we have criticised Scania tractors for their uneven braking performance, but the ABS-equipped R143-470 displayed no bad habits. Unfortunately the overall effect, was rather spoilt by an exhaust brake that squeaked and whistled but did little in terms of retardation.

Our fully-fuelled left-hand-drive 1(143470 tipped the scales at 7,115kg, which is fairly acceptable for a premium two-axle sleeper-cab tractor. At 40 tonnes GCW it gives a payload of 25,535kg after the kerbweight of the air-suspended tri-axle Van Hool tilt trailer is deducted.

For those of you who prefer that in 'real money', at 38 tonnes GCW you end up with a payload of over 24,000kg running with a fully-fuelled, 3.4m wheelbase right-hand-drive 4x2 Topline R143-470, coupled to a typical air-suspended triaxle curtainsider.

• MAINTENANCE

Electronics, being able to react faster, certainly offers superior control over mechanical systems in many cases — but the question hauliers are bound to ask is, "how reliable are they?" Judging by the fact that Scania has now made EDC available through Europe, the answer must be that they are capable of withstanding the harsh environment of road haulage. One area where EDC scores over traditional technology is in its ability to find faults in the system through self-diagnosis.

If a problem does occur, a warning light is automatically illuminated on the dash. If the driver then presses the EDC test button the warning light can indicate which component is defective by means of various flashing codes.

That aside, all daily checks are easy to accomplish, once you've lifted the large front panel. The vee-eight DSC14-04 engine is a snug fit inside the 11143 chassis, but it shouldn't be difficult to work on thanks to a cab tilt angle of 60°.

I SUMMARY

If the performance of the R143-470 during our Continental road test is anything to go by, it's not hard to see why Scania is such a popular tractor with long-distance TIR operators and owner-drivers alike. On the run from Antwerp to Marseille it turned in good fuel economy and trip times which were easily on a par with the recentlytested Mercedes-Benz 1748 (CM 18-24 January). The sophisticated electronic control of EDC is clearly a positive addition to the 14-litre Scania vee-eight.

The best analogy we can think of to describe the EDC system is that it is rather like a karate champion which only uses all his strength and power when absolutely necessary. Of course reliability and durability are the real hallmarks of a champion and plenty of UK hauliers remain sceptical of electronics. However, the fact that Swedish operators have tried and tested EDC and more importantly have stuck with it will help break down that prejudice.

A quick glance at our comparison charts shows the R143-470 EDC in a favourable light against the opposition, not least on price. But those figures only tell half the story. A standard sleeper-cab R143-470 might well look good at £59,060 but by the time you've added 23,100 for the Topline cab it starts to look less attractive against the F16 Globetrotter at £60,000 or the 1748 Mercedes with air suspension as standard on the drive axle at a highly competitive £58,685.

The biggest threat, however, is arguably from the likes of ERF, Foden and Seddon Atkinson which will shortly be offering the Cummins Super E465; then the feathers will really fly.

Still, high prices haven't put Scania buyers off in the past, and there is no denying the Swedish marques ability to command a good second-hand price.

For those long distance or heavy haulage operators who need the power and can justify the price, the R143-470 will deliver the goods and how,