Tech Torque FRASER STRONACH

4 x 4 Australia - - Front Page - FRASER STRONACH

IN RE­CENT years, road test­ing at 4X4 Aus­tralia has in­volved a near con­stant stream of turbo-diesels, with the odd petrol en­gine in the mix. But this sta­tus quo was re­cently un­done, with no fewer than three petrol ve­hi­cles – in a row – to road test, which has got to be some sort of record.

You may think: “Well, so what?” But there’s more to this tale than that. Two of those three petrol en­gines were small-ca­pac­ity tur­bocharged fours rather than larger-ca­pac­ity nat­u­rally as­pi­rated fours, sixes or eights, all of which says much about where au­to­mo­tive en­gine de­vel­op­ment is head­ing right now.

First up was the Haval H9, a Chi­nese take on a Toy­ota Prado, save for its 2.0litre tur­bocharged four-cylin­der petrol en­gine. Other­wise, the H9 mim­ics the Prado in ev­ery way: six-speed auto; same body di­men­sions; seven seats with 150-Se­ries fold­ing, side-hinged sin­gle rear door; sep­a­rate chas­sis; in­de­pen­dent/coil front sus­pen­sion; live-axle/coil rear sus­pen­sion; and dual-range, full-time 4x4.

All that means the Haval H9 shares its weight with the Prado and in the case of the test ve­hi­cle, 2236kg would seem a lot for a 2.0-litre petrol donk – even one with a turbo – to haul around. Af­ter all, the Prado comes with a 4.0-litre petrol V6 or a lat­est-de­sign 2.8-litre turbo-diesel.

Truth is, the Haval’s 2.0-litre four does very nicely. With its max­i­mum torque on tap at an al­most diesel­like 2000rpm, and then re­main­ing undi­min­ished for the next 2000rpm, it makes very use­able and per­fectly pro­gres­sive power in that much-used rpm range.

The Haval’s en­gine bears an un­canny tech­ni­cal re­sem­blance to Volk­swa­gen’s cur­rent 2.0-litre TSI en­gine, a tur­bocharged petrol four that serves in a range of VW mod­els how­ever Haval says the de­sign is “in-house”.

The en­gine has all the lat­est tech­ni­cal fea­tures you’d ex­pect from a pre­mium Euro­pean brand, not from a Chi­nese – or even a Ja­panese – man­u­fac­turer. Those fea­tures in­clude high-pres­sure di­rect fuel in­jec­tion, a low-in­er­tia dual-scroll tur­bocharger and an un­der­square bore/stroke re­la­tion­ship de­signed to op­ti­mise the com­bus­tion cham­ber shape.

If the Haval’s small 2.0-litre en­gine did an ex­cel­lent job of haul­ing more than two tonnes of heavy-duty Prado-like 4x4, then I was even more im­pressed by the sec­ond, and even smaller, turbo four, which boasts just 1.4 litres.

This en­gine was sam­pled backto-back with a 2.4-litre nat­u­rally as­pi­rated petrol four, both of which are avail­able in Jeep’s new baby wagon, the Rene­gade.

The Fiat-de­signed 1.4-litre turbo is the de­fault en­gine in the Rene­gade range, with the off-road-pitched Trail­hawk be­ing the only model us­ing the Chrysler-de­signed 2.4-litre.

In­ter­est­ingly, the 1.4-litre turbo claims a max­i­mum of 230Nm, the same as the 2.4 but where the 1.4-litre’s peak torque is avail­able from just 2500rpm, the 2.4 needs 4400rpm to achieve the same peak. Ul­ti­mately the 2.4-litre makes more power than the 1.4-litre (129kw ver­sus 103kw), but it needs an ad­di­tional 1000rpm to do so.

With its stronger torque at much lower en­gine speeds, the 1.4 is more ea­ger and re­spon­sive than the atmo 2.4, and it does that with just six speeds inits dual-clutch se­quen­tial gear­box – the 2.4-litre has nine speeds to call on via its ZF auto trans­mis­sion.

Be­ing a much smaller-ca­pac­ity en­gine, the 1.4-litre is no­tice­ably smoother than the some­times buzzy 2.4, due to the less than ideal dy­namic bal­ance of an in-line four, es­pe­cially in big­ger ca­pac­i­ties and at higher revs.

The les­son here is if turbo-diesels fall over due to emis­sion reg­u­la­tions, then the small-ca­pac­ity turbo-petrol en­gine is ready for more wide­spread duty.

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