Trick Toyota Turbo
by
Australia's most highly respected 4WD magazine - Overlander
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APS makes a good thing better with its Safari Turbo Systems kit for the
turbo-diesel LandCruiser. Does 430 Nm OF TORQUE, kicking off at 1400 rpm and holding steady until 3200 rpm sound like a decent serve of grunt to you? To most people, it does – but to some 100 Series turbo-diesel Toyota LandCruiser owners, it’s been a case of the bare facts not telling the full story. Although the figures look impressive, it’s the way the engine delivers that puts the 1HD-FTE turbo-diesel – in certain applications – at something of a disadvantage. It’s not so much a matter of power-to-weight ratios as how quickly and how consistently the power is developed. The 4.2-litre engine might be endowed with good mid-range torque – handy for highway passing manoeuvres – but tends to lack the bottom-end ‘step off’ torque that gets the whole 2.6 or more tones of LandCruiser quickly under way. There is also a tendency for power to drop off under consistently heavy load situations, such as when towing a horse float, or a heavy trailer up a long hill. Enter the team at APS Engineering in Croydon, Melbourne. Specialists in the business of ‘enhancing’ factory engines forced into compromise so as to please a wide variety of world-wide markets, the people at APS turned their attention to the 1HD-FTE engine in the 100 Series Cruiser some time ago – even before its introduction to Australia towards the end of 2000. The decision to address the Toyota engine’s shortfalls centred on the particular requirements of the Australian market, and the manufacturer’s dilemma of needing to use a one-size-fits-all approach to developing engines for international application. Factors such as fuel quality, ambient operating conditions and consumer use vary quite widely from market to market, requiring the manufacturer to find an average level that works for everybody – which means that for some markets, a particular engine may not deliver anything like its true capabilities. Adding further to these complications is that car-makers also need to compensate for the cumulative variables in manufacturing that generally mean no two engines, even though they’ve come off the same production line, are exactly alike The APS mission is to extract the optimal performance from these compromised engines, without stretching normal factory levels of durability, economy or exhaust emissions. APS focuses its attention where it sees fit but has had experience at some level with practically every popular car-maker represented in Australia. The company’s research and development is basically carried out at the Bayswater headquarters, but its programs can go as far afield as the USA and the Middle East, where hot weather testing is carried out. Looking at the turbo-diesel Cruiser, APS engineers found the desired goals in achieving a more useable torque spread and improving throttle response could be addressed chiefly by attending to the engine’s breathing, while also optimizing control of the fuel delivery system. The system had potential to unleash more useable power without increasing boost pressure, but clearly something needed to be done in order to enable quicker spool-up of the 1HD-FTE’s relatively large turbo. The small, standard factory intercooler clearly was also in need of attention. The conservative standard item does not lend itself to consistent engine performance under steady, continuous load, particularly in high ambient temperatures where a drop in power between ten and fifteen percent is not untypical. So APS designed a new, larger intercooler able to remove more temperature from the intake charge over consistently longer periods. A cooler intake charge equals better combustion efficiency and more power. |
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