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• The gestation of the Eagle Tx400powered ERF was a

2nd April 1992, Page 34
2nd April 1992
Page 34
Page 36
Page 37
Page 34, 2nd April 1992 — • The gestation of the Eagle Tx400powered ERF was a
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bit like an elephant's. As far back as July 1990 the Sandbach team issued a spec sheet for the E12 range which included a model designated El 2.40.

That must have caused some raised eyebrows at Perkins because the Tx400 hadn't actually been launched at the time. Inevitably industry pundits began to ask how long we'd have to wait for the most powerful version of the 12-litre Tx Eagle family.

Amid rumours of backstage work on reducing noise levels, its debut was anticipated after the Motor Show. The launch date drifted into 1991 and finally, almost exactly a year ago, ERF formally announced that it would be the first manufacturer to fit the new engine.

Since then Seddon Atkinson has specified the Tx400 for the Strato; Foden is waiting for a Euro-1 version.

With hindsight ERF didn't lose anything from the delay: the advent of speed limiter legislation has increased demand for engines like the Tx400 which can supply the sort of power and torque needed to maintain high average speeds.

When Perkins boosted the power of the charge-cooled Tx Eagle range to 298kW (400hp) — it was previously available in 18kW (25hp) steps from 224kW (300hp) to 280kW (375hp) — it could hardly have known how changes in legislation would work in its favour.

The move to 298kW (282kW installed) entailed a new piston and ring pack with a rematched turbocharger and changes to the fuel pump setting and injectors. Gallery oil cooling was modified to extend service life of piston and liner.

An all speed mechanical governor manages the engine when driving a PTO for blowing or tipping. The air to air chargecooled Tx400 has a high level of parts corn

patibility with other versions of the Eagle TX engine.

At 1,784Nm (1,216Ibft) net torque is up by some 2% over the E12.375, albeit at a slightly higher 1,250rpm. Like all Eagle units with Perkins' fast burn combustion system, the Tx400 meets current exhaust emission requirements without resorting to electronic control.

Behind it sits the familiar 12-speed Eaton Twin Splitter constant-mesh box and S180 Rockwell single-reduction axle. In this case it is running with a 3.73:1 ratio and is slightly faster than the axle used in the E12.32/37 tractors.

Taper leaf springs are standard on El 2 drive axles, but our test vehicle was fitted with the alternative four-bag air suspension which is becoming popular for all types of operation.

The E12.40ST can be bought as a 4x2, 6x2 twin-steer (with or without electronically controlled air suspension) or, most recently, as a 6x2 with mid-lifting pusher axle (CM Vehicle News 26 Mar-2 Apr).

Most manufacturers rely on plastic panels to protect vulnerable areas from the ravages of the UK environment, but ERF remains one of only two British-based truck builders to offer composite cab construction. A single bunk comes as standard. have had worse weather, but not much worse: very strong headwinds on the third day put paid to any chance of even average fuel returns.

However, the consumption figures for the first two days — 33.791it/100km (8.36mpg) and 39.51it/100km (7.14mpg) respectively — do give some idea of the fuel consumption we could have expected under more reasonable weather conditions. The key to this level of economy is the Tx400's torque output, which is higher than most other European trucks in the 400hp (298kW) class and in particular it offers a torque output comparable to the larger capacity and more powerful Cummins NTAA465 specified in E14 tractive units. Its specific fuel consumption of 190g/kWh is also a match for many engines which are significantly less powerful.

Accelerating up to 80km/h from rest the E12.40 showed a clean set of wheels to the Foden 4450 and Leyland Daf 95.400, although surprisingly it was slower than the less torquey Volvo F12.400.

In any case, the E12.40ST's overall performance is better reflected in its journey times. Over our three-day route its average speed of 73.8km/h (45.9mph) was well up with the other tractors in its class, and as it was fitted with a speed limiter there was no risk of over speeding on the motorway, except on downhill sections.

On motorway gradients the Tx400 pulls very strongly in top gear, with no downshift needed unless the road speed drops away to below 80Iun/h. It was noticeable that while unrestricted vehicles crept by on the flat we could overtake them again on the hills. At a governed 96km/h (60mph) in top gear the Perkins Tx400 turned over at a sedate 1,580rprn.

Few operators will sniff at the chances of hauling over 24 tonnes of freight, and that's exactly what the 4x2 E12.40ST can handle running with an alloy-wheeled tri axle curtainside, Its 24.12-tonne payload is only a whisker behind the Cummins-powered Foden 4450, and beats the 95.400 and Volvo F12.

The 3.8m-wheelbase tractive unit is designed to run with a maximum length 13.6m semitrailer. On this occasion we borrowed a BoaEby Cabriolet curtainsider built on a Crane Freuhauf air suspended chassis with wide-single tyres, but for comparison with other tests we have quoted the weight of CM's standard tri-axle trailer.

Air suspension on the drive axle — at an extra £1,400 on the base £53,800 list price — and on the trailer adds to comfort of the driver and the protection of the load: we were impressed by the way the whole outfit rode over uneven road surfaces through the several roadworks encountered enroute. The tractive unit's long wheelbase and the position of the fifth wheel removes any suggestion of cab pitching while the air suspension adds nothing to roll angles. An air dump facility removes the hard work of coupling and uncoupling the semi-trailer. Air tanks supplying both suspension and the braking system are housed out of harm's way within the confines of the chassis rails.

The extra overall length caused no problem, either in the congested traffic conditions of Edinburgh city centre or through the tight hairpin manoeuvre at Shottley Bridge.

Steering is effortless, but not so light as to lose that essential quality of positive feedback from the road wheels. The brakes also had a positive feel and although we never had cause to bring the anti-lock into play on the road, during maximum braking track tests it worked very smoothly, No wheels locked and we recorded a high overall response. Worthwhile retardation from the exhaust brake was easily built on to check speed during long descents by taking an early down-split or two. This is quick and easy with a flick of a switch on the Twin Splitter box — and ERF's installation is as good as any we have tested.

The four-position gate, each with two additional split ratios, minimises full gear lever movements, and most gearchanges can be made without using the clutch. On the flat the vehicle pulls away easily in fourth and once up to speed most conditions can be handled with only the top three gears. Even on the toughest climbs we never needed to drop lower than fifth and were able to recover using the clutch brake, at the bottom of pedal travel, to assist fast positive upchanges.

The cab's composite construction is not only a good heat insulator; the rear window is double-glazed and between them they keep out noise effectively, helping make this one of the quietest cabs in its class.

An eight-year warranty against corrosion is a good indication of its durability. Inside it has an air of roominess but mounted high on the chassis it needs the well-placed steps in front of the wheel to make easy work of the climb to the driver's high-backed suspension seat, Universal adjustment allows settings to suit most driver shapes and sizes and the steering wheel arrangement adds a further degree of individuality.

The dog-leg fascia displays the instruments clearly and brings switches, heater controls and park brake lever within easy reach. Instruments are electrically driven and nearly all electrical functions are protected by mini circuit breakers located behind a panel at the front of the passenger foot well. Stowage for smaller items and paperwork is accommodated by a central oddment tray and overhead ledges.

Rear-view mirrors are electrically heated and electronic control allows the passenger widow to be operated from the driving seat.

Unfortunately dark brown trim, while eminently practical, is made to look even more dowdy by the dark interior. Larger windows would go a long way to cure this and it is an area that ERF will want tc change on the replacement cab which is now under development.

Standard equipment includes a night heater, radio-cassette, driver's air suspension and, for once, a pillow for the bunk. A good size locker at each end of the single, highmounted bunk provides ample stowage space for regular overnight use. In our cabtest (CM 12-18 March) we found the bunk comfortable, but because of the high engine hump it is easier to get to from the passenger side than from the driver's seat. But fortunately once the driver is in his bunk the heater control can be reset without having to get out again.

A manual pump tilts the cab through 60' to give good access to the engine, but daily check items such as clutch fluid, windscreen wash, engine coolant and engine oil can be completed more easily via the front grille.

From our list of comparisions we note that the ERF E12.40ST is only beaten on price by the 14-litre Cummins-powered Foden S104. At £53,800 it costs substantially less than either the Leyland Daf 95-400 or the Volvo F12-400, and while the cost of a basket of parts follows a similar pattern the ERF has the lowest contract maintenance costs.

Overall consumption figures were not as good as we had expected but the best results are only achieved in ideal weather conditions.

The high torque of the Perkins Tx 400, matched to a well set up transmission, makes the ERF E12 very easy to drive and contributed to average journey times for a vehicle of this power.

From a driver's point of view the cab is roomy and relatively quiet, if a bit dated, and even with its long wheelbase and driveaxle air suspension it can command a payload in excess of 24 tonnes. Pricewise it betters its major competitor, even if it does not do quite so well in its own backyard, and whole life costs look even better.

With the advent of the speed limiter this level of power will be more in demand and, given a slight improvement on the fuel figures we achieved, ERF is well placed to win its share of the business.

Eby Bill Brock

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