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TAKE TH TIMES DAILY

22nd June 1989, Page 151
22nd June 1989
Page 151
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Page 151, 22nd June 1989 — TAKE TH TIMES DAILY
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Which of the following most accurately describes the problem?

• "I would buy a diesel van — if only they went faster." Despite what some manufacturers might tell you, this criticism of diesel-engjned light commercials has not been answered to the satisfaction of many operators.

Certainly, many old and often justified criticisms levelled at small diesel engines such as noise, vibration, poor cold starting, and poor fuel availability have been generally overcome, as witnessed by the ever-growing number of diesel models sold.

Compression-ignition engines clearly have the edge over petrol engines on fuel economy, but on performance they are less attractive. On a like-for-like basis they simply cannot compete against petrol engines in the power stakes.

Light vehicle operators, particularly those running with high-profile box bodies, have the dubious choice of either accepting the plodding performance of a diesel engine or sticking with a more powerful but less economic petrol unit.

This performance deficit was clearly in the minds of Iveco's engineers when they started planning the little 2.5-litre 68kW (92hp) turbocharged, direct-injection 8140.21 diesel engine — first glimpsed at the Geneva Motor Show in January 1984.

At the time it looked as if Iveco would become the world's first manufacturer to offer a small, high-speed DI diesel. However, development problems prevented its arrival in Daily vans and chassis cabs between 3.5 and five tonnes gross vehicle weight until April last year.

As a result of the delay Ford beat lveco to the "world's-first small direct-injection diesel" title when it launched its own naturally aspirated 2.5DI Transit engine three months earlier.

lveco's Turbo range went an sale in the UK only last November, but it already accounts for almost a third of all Daily models sold in Britain.

The Turbo engine option doesn't come cheap — on average it costs E950 more to buy a Turbo Daily than a non-turbocharged model with the 53kW (72hp) 25litre indirect-injection Sofun diesel. For your extra money, though, you get 28 per cent more power (68kW compared with 53kW delivered at a lower 3,800mm) as well as a massive 47 per cent increase in torque — 215Nm (159 lbft) on the Turbo Daily compared with 147tim (108 Ibft) on the naturally-aspirated model.

By going to direct-injection Iveco has also increased engine efficiency by 15 per cent and improved cold starting performance.

While some cynics might suggest that the only reason Iveco decided to turbocharge the direct-injection engine was to bring down its inherently higher noise levels, there can be no doubt that it has also boosted fuel economy and power, as well as providing a more flexible torque curve.

When Iveco offered CM the chance to test the 3.5-tonne 35.10 Turbo Daily chassis cab there was a choice of either F

a dropside or boxvan. ''Why not test both?" was our answer, and for good measure Iveco threw in another 35.10 boxvan fitted with its own aerodynamic Drag Foiler system — available to boxvan operators for an extra 229 — to see if it really can save fuel.

Although we normally test vehicles up to 3.5 tonnes GVW around our 137km (85 mile) light van route, Neal is pushing the Turbo Daily as a machine for high mileage operators. We therefore decided to give it a real workout around our 338krn (210-mile) Welsh truck route which includes over 113km (70 miles) of top-speed motorway running.

With its low-height body, the 35.10 dropside — not surprisingly — turned in the best fuel consumption with a good overall average of 11.88 lit/100km (23.73mpg). The results for the two boxvans were even more impressive, however, considering their higher drag. The standard version returned a creditable 15.01 lit/100km (18.82mpg), but its twin with the Drag Foiler pack gave an excellent 13.3 lit/100km (21.23mpg) overall figure.

Just in case these figures need any further underlining, it is worth remembering that the average petrol-engined 1 5tonne boxvan does well to return 17.65 lit/100Jan (16mpg), while on the motorway its consumption can be as high as 23.5 IitilOOkm (12mpg).

As the 35.10 is the only 3.5-tonne turbocharged diesel chassis cab currently in the UK, direct comparisons are not easy. However, it certainly measures up well against the more aerodynamic 4.6-tonne GVW Volkswagen LT45D panel van with the 76kW(102hp) six-cylinder turbo diesel engine. This returned 1186 lit/100km (2(.37mph) over the same route in September 1984.

Closer analysis of the fuel figures for the two boxvans reveals more interesting facts. On urban running, at speeds of up to 801cm/h (50mph), the Drag Foiler provided a fuel saving of over 15%. On the motorway, however, it dropped to just over 4%.

This difference is not as paradoxical as it may seem. At 113kra/h (70mph) the deflector kit, rather than save fuel, allows the Daily boxvan to maintain a higher speed niore easily, which naturally uses up more derv. Cut down the speeds, and the wind resistance, and the deflector kit starts to save money again.

On our Welsh route the total fuel saving produced by the Drag Foiler package worked out to around 13%. This means that running on a similar mix of A-road and motorways an operator will need to cover between 51-63,000km (32-39,000 miles) before the cost of the package (029) is recovered in fuel savings. For the highmileage operator, however, this should not prove a problem.

So much for the pounds and pence; what is the Turbo Daily like to drive? One word sums it up nicely: 'lazy'. With 68kW to play with, and 215Nm of torque, the Turbo Daily is just about the easiest light commerical to drive on the market. In third, fourth and even fifth gear on the level, the DI engine will lug down to 1,500rpm (peak torque is delivered at 2,200rpm), at 24kinth (15mph) yet still have enough power to pick up out of slow bends and roundabouts. Once in top gear you seldom need to change down unless on a steep gradient.

Hills are no problem though. The 35.10 flies up them and restarts on 33% (1 in 3) slopes without fuss.

The wide power spread across the rev range, coupled with the excellent fivespeed gearbox, also means that there are none of the dead spots normally associated with laden diesel light commercials, particularly at mid-range speeds. First gear is really only needed for restarting on a hill or for a quick getaway at lights or a roundabout.

The most impressive thing about the Turbo Daily has to be its acceleration, however. It goes from 0 to 80km/h (050rriph) in 25 seconds fully laden — remarkable for a boxvan! In fact it was so rapid we began to wonder if it was fully laden. The only other 3.5-tonners tested by CM that came anywhere near it are petrol-enRifled models such as the Mercedes 310 and Renault Master P35.

When changing up through the gears it is easy to over-rev the engine, so it is just as well that Weal fits a rev counter as standard on all Turbo models.

Once up to cruising speed along the motorway, the 35.10 — dropside or box body — holds 112Icrn/h (70mph) easily at a comfortable 3,50Orpm. This is well within the broken green (economy) sector on the rev counter which ends at 3,800rpm.

That a fully laden 3.5-tonne diesel boxvan performs so well on the motorway is impressive enough, but when it then starts accelerating up gradients it moves into a class of its own. Indeed, on the motorway the 35.10 Turbo Daily driver needs to show not only a measure of restraint, but also a great deal of anticipation and move over for overtaking trucks just that little bit sooner.

Turbocharging the small DI unit also means that a driver will have to treat it with more respect than a naturally-aspirated engine, which can be fired up and shut down at will.

To make sure that the turbine bearings get a sufficient supply of oil there is a small sticker on the windscreen of all Turbo Dailys. It advises drivers not to rev the engine hard immediately after starting, and also to let it idle for 60 seconds before switching off.

If nothing else, the £245 replacement cost of a new turbocharger will be a strong incentive to treat the DI engine with care.

Around our test route, the 35.10 showed itself to have ride and handling equal to its performance. The front torsion-bar/rear leaf-spring suspension set-up provides a

fairly firm ride, although this is by no means uncomfortable. On undulating roads, however, the 3.6m wheelbase chassis has a tendency to wallow.

Regardless of its bodywork, the 35.10 chassis cab exhibits very little body roll, which is all the more impressive as antiroll bars are fitted only on high-roof panel van models.

On fast corners the Turbo Daily's otherwise precise steering has a marked tendency to self-centre which makes its rather heavy. The steering column and wheel also transmit a fair amount of roadshock from the front axle.

For all its excellent driveability, the Turbo Daily does have its weak spots. Most notable is noise. The switch to direction-injection may give better fuel economy, but at 1121cm/h (70mph) internal noise levels rise to a loud 85 dB(A), which is above the Ford DI Transit tested last year.

Our boxvan model with the Drag Foiler system also suffered with an irritating roaring noise created by wind passing through a small gap between the cab roof and the leading edge of the spoiler. The rear edge also banged against the roof, setting up a drumming effect. For £179 we expect a better fit.

The cab's interior is reasonably comfortable. The easily-adjustable 1sringhausen driver's seat, finished in smart orange and fawn stripes, gives plenty of support. The whole interior package is finished off with a practical rubber floor covering and a neat aircraft-style reading light mounted in the headlining.

One criticism of the driving compartment we have is that it has very little storage space. There is neither a locking box nor room for delivery notes. The twin bench seat could also be a bit of a squeeze for big passengers.

All controls and instruments are well laid out, although the handbrake is a bit of a stretch. The simple main instrument panel has an excellent colour-coded rev counter (standard on all Turbo Dailys) and useful, extra warning lights for the fuel sedimenter and, important for a turbocharged engine, for the air filter.

The top of the steering wheel, however, obscures the indicator repeater light on the far right of the panel, making it easy to leave it on inadvertently.

The long gear lever has a well defined pattern allowing for crisp changes. Throughout our test run the braking on all our vehicles was well above average.

Visibility from the driver seat is fairly good, although the nearside mirror arm needs to be further back as the mirror can be obscured by the A-post when the driver's seat is well forward.

Although the wipers give a fairly good spread, there is no intermittent wipe which would be useful in light drizzle.

Access into the driving compartment is simple enough, aided by the 35.10's deep step and wide door aperture, but it could be further improved with a grab handle on the door frame. Moving across the cab is more of a tight squeeze.

Most checks on the engine can be carried out without any problems, although getting to the distributor and injectors on the third and fourth cylinders will be a bit of a struggle. The standard sump guard also has to be taken off to get to the oil filter. All fuses, however, are well placed inside the cab.

Iveco quite rightly sees the 35.10 as the classic vehicle for express parcels/overnight delivery specialists, as well as operators running over tough terrain or with a box body.

Its 2.5-litre turbocharged engine packs the kind of performance punch that diesel operators have been waiting for, yet, as our fuel consumption figures show, it will not hit them hard at the fuel pumps.

For all its excellent driveability, the 35.10 does have a real drawback with its hefty kerbweight above 1.600kg without a body fitted. This will deter buyers looking for maximum payloads. It also places the 35.10 above the all-important 1,525 kg kerbweight breakpoint for annual Department of Transport testing, making it liable for a yearly inspection from new.

Moving up to the 4.5-tonne GVW 45.10 model would give a better payload, but it would mean 0-licences and tachographs.

The recent announcements of the merger between Ford and Iveco in the UK will not, according to Iveco, affect the 3.5tonne Daily range. However, if, as expected, Fiat brings a lighter 3.5-tonne Ducat() model into Britain, with the same 2.5 DI Turbo engine in 1987, Iveco may decide to drop the Turbo Daily below 4.5 tonnes.

This prospect, however, is very much in the future. For the present at least, the Iveco 35.10 is still a vehicle that will take a great deal of catching. 1]

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Organisations: Department of Transport

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