TECH TORQUE

4 x 4 Australia - - Contents - FRASER STRONACH

I’VE been driv­ing a cou­ple of dif­fer­ent vari­ants of the new Suzuki Vi­tara range this month. Un­for­tu­nately with mono­coque con­struc­tion and no lowrange or fully in­de­pen­dent sus­pen­sion this new Vi­tara isn’t a tough 4x4 like pre­vi­ous Vi­taras, but it’s in­ter­est­ing nev­er­the­less thanks to two very im­pres­sive en­gines: one rep­re­sent­ing the present, and one that looks very much like the way of the fu­ture.

The au­to­mo­bile’s rise from cu­rios­ity to ubiq­uity in the last 100 years has come off the back of free en­ter­prise. How­ever, in more re­cent times that free en­ter­prise has been sub­ject to in­creas­ing gov­ern­ment in­flu­ence and con­trol. For ex­am­ple, the fact the vast ma­jor­ity of new 4x4s sold in Aus­tralia to­day are diesel- rather than petrol-pow­ered is a re­sult of po­lit­i­cal de­ci­sions made in Eu­rope in the 1990s.

A broad frame­work of gov­ern­ment poli­cies (ve­hi­cle and fuel taxes, etc.) that sup­ported diesel en­gines as a key strat­egy in the EU’S push to lower ve­hi­cle ‘green­house gas’ emis­sions led to a huge in­vest­ment and con­se­quent rapid ad­vance­ment in diesel-en­gine tech­nol­ogy. Car com­pa­nies quickly trans­formed the diesel en­gine from dunger to su­per­star in just a few years, thanks largely to elec­tronic high­pres­sure fuel in­jec­tion sys­tems and so­phis­ti­cated tur­bocharg­ers.

The knock-on ef­fect is that mod­ern diesel en­gines are so good com­pared to petrol en­gines that few new 4x4s are now petrol pow­ered – and when a petrol en­gine is of­fered it sells in tiny num­bers.

Still, while one hand gives, the other takes away. The very Eu­rope that in­sti­gated the rise in diesel pop­u­lar­ity is now mov­ing in a di­rec­tion that could see diesels con­signed to his­tory – ev­er­tight­en­ing ex­haust emis­sion stan­dards risk putting the ky­bosh on the TDI party.

Aus­tralia has moved to line up with ex­haust emis­sion stan­dards de­vel­oped in Eu­rope un­der the so-called ‘Euro’ stan­dards. These stan­dards ad­dress many things, but crit­i­cal to diesel’s fu­ture are par­tic­u­lates (soot) and the var­i­ous ox­ides of ni­tro­gen col­lec­tively known as NOX.

Right now the car in­dus­try is deal­ing with Euro 5, which tar­gets par­tic­u­lates with manda­tory use of a diesel-par­tic­u­late fil­ter or equiv­a­lent tech­nol­ogy. From 2018, Euro 6 tar­gets NOX and will need se­lec­tive cat­alytic re­duc­tion (Ad­blue) or equiv­a­lent tech­nol­ogy. With new en­gine de­signs and spe­cific tech­nol­ogy, car mak­ers have E5 and E6 cov­ered for diesels.

By around 2020 even tighter pro­posed stan­dards in Eu­rope and the USA will make the game even tougher for diesels – so much so that many car com­pa­nies are now say­ing enough is enough and they won’t be able to build diesels that com­ply with fu­ture reg­u­la­tions.

There is good news, though, and it’s plain to see be­hind the wheel of this new Vi­tara and its tur­bocharged petrol en­gine. Most telling was driv­ing this tur­bocharged petrol en­gine back-to­back with the op­tional tur­bocharged diesel, a mod­ern Fiat de­sign backed by a so­phis­ti­cated six-speed dual-clutch se­quen­tial gear­box (GSG) – ef­fec­tively a con­tem­po­rary ‘best-prac­tice’ diesel pow­er­train.

Both en­gines are fours, the petrol a 1.4-litre and the diesel slightly big­ger at 1.6 litres. The diesel claims 88kw at 3750rpm, while the petrol claims 103kw at 5500rpm. As ex­pected the diesel of­fers far more peak torque, 320Nm against the petrol’s 220Nm.

But there’s a qual­i­fier: the petrol’s 220Nm is de­liv­ered over a spread of en­gine speeds from 1500rpm to 4000rpm; while the diesel’s 320Nm peaks at 1750rpm and de­clines there­after. That the petrol en­gine makes good torque at higher en­gine speeds than the diesel is why it ends up mak­ing more power.

On-road the diesel is grunty, while the petrol is zippy and ul­ti­mately quicker. It’s also more re­fined, smoother and qui­eter than the diesel. On give-and-take un­du­lat­ing roads the diesel’s DSG holds onto the taller gears bet­ter than the petrol’s six-speed torque-con­ver­tor auto, but there’s not much, due in part to the torque con­ver­tor’s abil­ity to un­lock and ‘slip’ – which the diesel’s DSG can’t do.

Af­ter more than a week in iden­ti­cal con­di­tions the diesel used a thrifty 5.5L/100km, while the petrol used 6.5L/100km. An ex­cel­lent re­sult, even if the petrol does ask for 95RON.

If diesels fol­low the di­nosaur there’s much to be said for new-gen petrol tur­bos, de­signed for broad torque rather than high power.

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