BREATHE FREE

The nat­u­rally as­pi­rated en­gine is ca­pa­ble of stir­ring emo­tions a tur­bocharged mo­tor can still only dream of. Here we cel­e­brate the best of the breed, be­fore look­ing at what the fu­ture holds

Evo India - - CONTENTS - WORDS by ADAM TOWLER | PHO­TOG­RA­PHY by BARRY HAY­DEN

Cel­e­brat­ing the finest nat­u­rally as­pi­rated en­gines we have driven over the years, be­fore forced in­duc­tion takes over en­tirely: from the hum­ble four-cylin­der from Honda to the glo­ri­ous V12s from Fer­rari and ev­ery­thing in be­tween

TIME CHANGES EV­ERY­THING. FORTY years ago, the ex­cite­ment and nov­elty fac­tor of the tur­bocharger was enough to prompt the con­trivance of the word be­ing plas­tered on ev­ery­thing from vac­uum clean­ers to ra­zor blades. Nat­u­ral as­pi­ra­tion? Oh yes, that more tra­di­tional ap­proach, where air en­ters the in­duc­tion sys­tem of an in­ter­nal com­bus­tion en­gine at the same pres­sure as the planet out­side be­fore be­ing com­pressed with a squirt of fuel by the pis­ton and ig­nited with the as­sis­tance of a spark? That one was sud­denly so very yes­ter­day.

Nev­er­the­less, and per­haps against the odds, the nat­u­rally as­pi­rated en­gine mounted a come­back, and for a while the tur­bocharger was as un­fash­ion­able as other forms of ’80s ex­cess, such as Fer­rari Tes­tarossas and shoul­der pads, and those weird bat­tery-pow­ered danc­ing flow­ers in pots. The nat­u­rally as­pi­rated en­gine made in­roads back into both mo­tor­sport and road cars, from For­mula 1 to hot hatch­backs. Revs and noise were once again king.

It didn’t last, though, and in more re­cent years the roles have been re­versed again – for well-doc­u­mented rea­sons rang­ing from emis­sions test­ing to the growth in ve­hi­cle weight and the sub­se­quent need for strong, low-down torque – and we now have a sit­u­a­tion where the nat­u­rally as­pi­rated en­gine is a real nov­elty, and the in­tro­duc­tion of a new one – as in the Cay­man GT4’s 4-litre flat­six – an al­most un­think­able and cel­e­bra­tory ex­trav­a­gance.

But apart from de­sir­ing what we can no longer have, the lure of the NA en­gine is ob­vi­ous. How­ever ad­vanced tur­bocharg­ing set­ups be­come, they can never hope to repli­cate the di­rect and in­stan­ta­neous re­la­tion­ship be­tween the move­ment of your right foot and the re­sponse of the throt­tle, and their use of ex­haust gases to force-feed an en­gine with air above at­mo­spheric pres­sure means an in­evitable mask­ing of in­take and ex­haust noise.

Here, then, we look at the great and the good of nat­u­rally as­pi­rated en­gines, and a few duff ones too, and try to ex­plain just what makes them so de­sir­able.

FOUR-CYLIN­DER

Just the very ubiq­uity of the nat­u­rally as­pi­rated four-cylin­der en­gine gives it a bad press. It’s hum­drum. Work­man­like. Unglam­orous. It tends to make sim­ply a duh noise, a dreary one-di­men­sional tim­bre, and while it’s hard to pin­point ex­actly why that’s dull, our ears tell our sub­con­scious it most def­i­nitely is. At its worst, a mass-pro­duced four-cylin­der en­gine is un­en­thu­si­as­tic, coarse, and just un­pleas­ant. Joy­less, frankly.

The four-stroke four-cylin­der will never be as smooth as, say, a straight-six be­cause it only gen­er­ates one power stroke per crankshaft rev­o­lu­tion – one bang at a time if you like, with no oth­ers over­lap­ping. But of course, we’re not go­ing to talk about hum­drum four-cylin­der en­gines here, we’re talk­ing about per­for­mance ver­sions, and of those there have been many. Sadly, they are vir­tu­ally non-ex­is­tent now. The Mk4 Mazda MX-5’s has im­proved and is now quite a free-spir­ited thing, the Toy­ota GT86/Subaru BRZ’s flat-four is still a coarse and rather gut­less com­pan­ion, and there are still lowvol­ume sports cars such as Cater­hams that use off-the-shelf en­gines such as the Ford Du­ratec. Es­sen­tially, though, that’s about it.

What a pity that is, be­cause de­pend­ing on your age you’ll no doubt have great me­mories of sim­ple but oh-so-spe­cial four-bangers. Rorty, whiny old A-se­ries-pow­ered Minis, scream­ing Ford BDAs re­ver­ber­at­ing through forests in Mk2 Es­cort rally cars, gutsy early ’80s hot hatches with eight-valve mo­tors such as the VW Golf and Peugeot 205 GTI, or the newer-age 16-valve crowd, which seemed so po­tent when 150bhp was breached, from the As­tra GTE to the Peugeot 306 GTi 6. Then, of course, there was Re­nault, with the F-se­ries en­gines stretch­ing from the Clio 16v and Wil­liams all the way to the last non-turbo Clio 200. But per­haps as we rem­i­nisce, we think of the ex­tremes most fondly, and in­evitably that leads us to Honda’s VTEC en­gines.

en­gine’s valve tim­ing to suit ei­ther low-speed econ­omy or high-rev power. It fea­tures two sets of cam lobes: the milder-pro­file ones for the ev­ery­day, and a much more ag­gres­sive set al­low­ing the en­gine to keep the valves open for much longer for en­thu­si­as­tic driv­ing. At a pre­de­ter­mined point in the rev range the hot­ter cams are en­gaged via a hydraulic mech­a­nism that shifts them into con­tact. In­ge­nious. And at its most mem­o­rable, ca­pa­ble of cre­at­ing some­thing in­stantly for­get­table and mild-man­nered one mo­ment, and as feisty, freerevvin­g and hard-edged as a tour­ing car mo­tor the next.

It’s this will­ing­ness to rev high, and with a lack of vi­bra­tion and harsh­ness that sug­gests the en­gine is en­joy­ing every minute of it, that makes VTEC so spe­cial. It hasn’t al­ways made the car faster on-road than ri­vals (on track is a dif­fer­ent mat­ter), be­cause fall­ing out of the VTEC zone through an un­ex­pect­edly tight cor­ner or poor gear choice was bad news, and an is­sue not shared by some­thing such as a Clio Wil­liams. But when the rev counter nee­dle flies past 8000rpm like it does in an EP3 Civic Type R, to be hon­est, it’s com­pletely cap­ti­vat­ing, and worth the price of buy­ing one alone.

SIX-CYLIN­DER

Jump­ing to six-pots changes ev­ery­thing. Adding two ex­tra cylin­ders brings with it not just a per­cep­tion of pres­tige, but a depth and breadth to a car’s voice, over­lap­ping power pulses, and per­for­mance ben­e­fits. Un­usu­ally, three dif­fer­ent lay­outs of this en­gine re­main in favour: the straight-six, the V6 and the flat-six.

It’s the V6 that’s en­joyed the great­est pop­u­lar­ity in re­cent years, and when tur­bocharged that of­ten makes for a very ca­pa­ble en­gine. But if we re­move the blow­ers for a sec­ond, the pic­ture is a lot less clear. When a V6 is good, it can be very good: think Honda’s orig­i­nal NSX with VTEC rel­ish sup­plied, Alfa Romeo’s Busso en­gine or the won­der­ful Fer­rari Dino V6 from the 246GT and Lan­cia Stratos.

When it’s bad though… it can be a gritty, painful-on-the-ear mis­ery. Think ‘cheap Amer­i­can hire car’, the one that makes you wince when you de­cide to beast it straight out of the air­port car park. The typ­i­cal 90-de­gree V6 is not bal­anced in the way a straight-six is, ef­fec­tively be­ing a pair of in-line three-cylin­der en­gines joined to­gether. Pop­u­lar be­cause the typ­i­cally com­pact di­men­sions of the en­gine make it easy to pack­age, even in front-wheel-drive cars, it re­quires bal­ancer shafts to make it ac­cept­ably smooth.

The straight-six usu­ally has no such prob­lems, as its pri­mary and sec­ondary forces are in bal­ance; the pis­tons at the front and the rear of the en­gine move in ef­fec­tively a mir­ror of each other. This re­ally is the most no­ble of en­gine lay­outs, form­ing the ba­sis of Bri­tish sports cars for many years, in the Jaguar XK and As­ton Martins, plus the charis­matic but flawed TVR Speed Six, and is of

course syn­ony­mous with cars from the Ger­man city of Mu­nich. When those M-cars have been nat­u­rally as­pi­rated, they’ve been things of won­der, from the orig­i­nal M88 3.8-litre M1 en­gine through to the un­for­get­table S54, which, par­tic­u­larly in E46 CSL trim, has ar­guably the best in­duc­tion noise of any car. BMW now tur­bocharges its straight-sixes, and while fe­ro­cious in their torque de­liv­ery, they have noth­ing like the charm of the old NA en­gines.

Which leaves us with the flat-six, and we don’t have to go far down the A8 au­to­bahn to find the great­est ex­po­nent of this for­mat. Nicely bal­anced, com­pact, and with a low cen­tre of grav­ity, Porsche has el­e­vated the nat­u­rally as­pi­rated it­er­a­tion of this lay­out to a fine art. In­deed, whether hum­ble 986 Boxster or 991.2 GT3 RS, that smooth, rev-happy flat-six is the per­fect part­ner to the ex­cel­lence of the car’s dy­nam­ics. It’s why the com­pany clings on to them, seek­ing ever more power out of them and at rev­o­lu­tions per minute that would once have been un­think­able. When it does sur­ren­der to leg­isla­tive pres­sure, as in the 718, we all moan fu­ri­ously, as if our own grand­moth­ers have been per­son­ally in­sulted by CEO Oliver Blume, and de­mand Weis­sach sort it out. That it can, for now, with en­gines such as the new GT4 and GTS mo­tor, is some­thing to be very thank­ful for.

EIGHT-CYLIN­DER

Ev­ery­one loves a V8, don’t they? From the so­porific, mel­liflu­ous woofle of a lazy Amer­i­can V8 to the de­mented howl of some­thing high-revving and usu­ally Ital­ian, a nat­u­rally as­pi­rated V8, free from the damp­en­ing shack­les of forced in­duc­tion, is a thing of beauty. It’s also now ex­cep­tion­ally rare, out­side of mus­cle cars, age­ing Maser­atis and the un­likely, slightly weird, but still in­trigu­ing per­for­mance of­fer­ings from Lexus.

The di­chotomy of the NA V8 cen­tres on the lay­out of its crankshaft, par­tic­u­larly the an­gle be­tween the crank pins, or ‘jour­nals’ – the cylin­dri­cal pas­sages be­tween the lobes where the big ends of the con­rods are at­tached. Put those at 90 de­grees to each other and you have a cross-plane crank V8; have them at 180 de­grees and, as the an­gle im­plies, you have a flat-plane crank style of en­gine. The for­mer has un­evenly spaced fir­ing pat­terns, and it’s this, along with the man­i­fold and ex­haust de­sign, that gives the tra­di­tional V8 sound – think the afore­men­tioned mus­cle cars, and the ubiq­ui­tous Rover V8, among oth­ers.

The flat-plane crank V8 is more like two in-line fours joined to­gether, and its even fir­ing or­der gives it a com­pletely dif­fer­ent sound, along with a propen­sity to be more suited to higher revs – as you’ll find in a Fer­rari 458 Spe­ciale, for ex­am­ple.

Both types have dif­fer­ing chal­lenges when it comes to bal­anc­ing the forces gen­er­ated within, and with­out turn­ing this into an engi­neer­ing text­book, the cross plane needs heav­ier crankshaft coun­ter­weights to negate its rock­ing mo­tion, but on the move it’s in­her­ently much smoother than the flat-plane unit as each bank can­cels out the sec­ondary forces of the pis­ton strokes. That’s why

I’D FOR­GOT­TEN JUST HOW AP­PEAL­ING THE S65B44 EN­GINE IN THE E92 M3 GTS RE­ALLY IS

you’d never find a buzzy, hard-tim­bred Fer­rari V8 in a lux­ury car, or if you did, as in the case of Maserati , it’s been re­worked to have a cross-plane crank, along with, in­evitably, a lower rev limit.

Of course, there are al­ways the ex­cep­tions to the rule. The cur­rent Mus­tang GT350 is a true blue mus­cle car with a flat-plane V8, and the old E90/92/93 M3s revved to blazes but had a cross­plane V8; the fir­ing or­der of the cylin­ders in the M divi­sion’s S65 mas­ter­piece gave it a dif­fer­ent sound again to the typ­i­cal Amer­i­can V8 rum­ble, a smoother, lighter, more sonorous blare, but still with the bass notes am­pli­fied. The E92 M3 GTS is a per­fect case in point.

Be­fore the pho­to­shoot for this fea­ture it had been a while since I’d last driven a GTS, and in truth I’d for­got­ten just how ap­peal­ing the S65B44 en­gine (the suf­fix de­not­ing the GTS’s ex­tra 362cc over the stan­dard 4-litre S65B40 unit in the reg­u­lar M3) re­ally is. We live now in an era when the over­rid­ing emo­tion is sim­ply grat­i­tude that in­ter­nal com­bus­tion-pow­ered per­for­mance cars ex­ist at all, along with a nag­ging sense of trep­i­da­tion that time has al­ready been called on the party. As such, a tur­bocharged V8, usu­ally backed by a man­u­fac­turer claim­ing ever more out­ra­geous power and torque fig­ures, feels like some­thing it would be sac­ri­le­gious to moan about. We do just that, of course, in this mag­a­zine, and I some­times think there must be those who won­der what we’re con­stantly bang­ing on about, or that we’re merely a group of grumpy, age­ing men, al­ways look­ing over our shoul­ders. But the un­com­fort­able truth is that just a few sec­onds back be­hind the wheel of a car pow­ered by the S65 shows it is more than enough to quash any­thing that BMW M cur­rently makes. The S63 twin-turbo found in the cur­rent M5, for ex­am­ple, and de­rived from the reg­u­lar N63 turbo V8, has noth­ing on this old-timer in terms of ap­peal. But what do we ac­tu­ally mean when we say that?

I think it’s some­thing to do with that word that’s key across so many ar­eas of a great car: con­nec­tion. If you ap­pre­ci­ate how an en­gine works, revel in its op­er­a­tion, get a kick out of the raw­ness of sound that comes with each metic­u­lously timed ex­plo­sion hap­pen­ing within, love the ex­cite­ment and con­trolled ag­gres­sion – even artistry – of driv­ing for en­joy­ment, then you can con­nect with a great NA V8 on an emo­tive level. It goes be­yond merely op­er­at­ing a de­vice to make an inan­i­mate ob­ject move very quickly. It’s why some of the best me­mories I will take away from our Fast Fleet Mus­tang are of driv­ing it slowly, let­ting the en­gine haul from low rpm, dur­ing which it felt as though each in­di­vid­ual ig­ni­tion at topdead cen­tre could be felt: thud, thud, thud, thud.

That is very re­lax­ing, in a ther­a­peu­tic kind of way, which is not some­thing you could say about the Dino V8 in a Fer­rari 360 Chal­lenge Stradale, or the last-of-the-line F136 V8 in the afore­men­tioned Spe­ciale. Their raw, ra­bid in­ten­sity, the in­tim­i­dat­ing sharp­ness and pre­ci­sion of their throt­tle re­sponse, and the ag­i­tated howl em­a­nat­ing from their tailpipes – and that makes those of us who love cars feel a bit pe­cu­liar – is the very essence of the op­er­atic Ital­ian su­per­car ex­pe­ri­ence. It just con­jures up highly strung beauty, pas­sion, speed and spirit. That’s why how­ever fast the 488 Pista, or its successors, they’ll never quite eclipse the vi­brant Spe­ciale.

TEN-CYLIN­DER

Bar odd­i­ties such as the Dodge Viper, the V10 lay­out in road cars has been a more re­cent phe­nom­e­non. Much of the inspiratio­n for this trend came from mo­tor­sport, specif­i­cally F1, when it re­turned to nat­u­rally as­pi­rated en­gines for the 1989 sea­son. Most teams took the tra­di­tional Ford Cos­worth V8 route, while Fer­rari au­to­mat­i­cally re­verted to its clas­sic V12 con­fig­u­ra­tion, but Re­nault and Honda opted for the V10, fig­ur­ing it of­fered the best com­pro­mise be­tween the V8’s meaty midrange and the V12’s high-rev ex­u­ber­ance, but with­out the lat­ter’s added weight, thirst and fric­tional losses. Strangely, Honda would switch to V12 power in 1991, but soon all man­u­fac­tur­ers set­tled on the V10, which held sway un­til the rules changed and de­manded small-ca­pac­ity V8s from 2006.

The Porsche Car­rera GT’s pierc­ingly in­tense V10 started life as a racing en­gine for a Le Mans con­tender that never was, and it’s doubt­ful BMW would have pur­sued its won­der­ful – and won­der­fully in­ap­pro­pri­ate in many ways – nat­u­rally as­pi­rated V10 for the E60 M5 (and E63 M6) had it not been for the lever­age of its noughties F1 pro­gramme, nor Lexus the LFA’s stel­lar V10 with­out Toy­ota’s largely ill-fated F1 era.

Yet the brands most as­so­ci­ated with the type must surely be VW group bed­fel­lows Audi and Lam­borgh­ini, who have made the big V10 a cor­ner­stone of their re­spec­tive su­per­cars, start­ing with the orig­i­nal Gal­lardo back in 2004. At birth, the Lambo-de­vel­oped unit dis­placed five litres and made 493bhp, in­stantly set­ting the car apart from its Maranello op­po­si­tion purely by of­fer­ing such a uniquely ap­peal­ing char­ac­ter. Flex­i­ble, punchy, but with an ex­u­ber­ant top end, it truly was a thump­ing Bologna heart.

Its 5.2-litre suc­ces­sor was an Audi en­gine, which would go into the R8 as well as the Gal­lardo facelift, the LP560-4 (and the S6 and RS6 of pe­riod), and sur­vives in up­dated form in the Mk2 R8 and Hu­racán Evo mod­els. The spac­ing be­tween the cylin­ders is greater, there’s di­rect fuel in­jec­tion, and while it re­mains a 90-de­gree V, it has an un­even fir­ing or­der with shared crankpins, which gives it a more gut­tural note, with less of the typ­i­cal V10 wail; it sounds more like a clas­sic five-cylin­der Quat­tro mo­tor in stereo gor­geous­ness.

Whichever gen­er­a­tion, the V10 is larger than life, and while the R8 and later Hu­racán have be­gun to lag be­hind ri­vals from the likes of McLaren in other tech­ni­cal ar­eas, the V10-pow­ered ma­chines usu­ally end up main­tain­ing their rel­e­vance purely on their abil­ity to gen­er­ate such an emo­tive re­sponse from a driv­ing en­thu­si­ast.

TWELVE -CYLIN­DER

The big, nat­u­rally as­pi­rated V12 re­mains the true thor­ough­bred of en­gines. It fol­lows that two straight-sixes joined to­gether will be ex­cep­tion­ally smooth, while small pis­tons keen to rev and or­nate ex­haust man­i­folds usu­ally guar­an­tee a sonic ex­pe­ri­ence as spe­cial as the power de­liv­ery and num­bers. But there’s more, so much more: a cer­tain majesty, an ex­trav­a­gance verg­ing on rude­ness, an op­u­lence that, nowa­days in par­tic­u­lar, feels so spe­cial. Fer­rari and Lam­borgh­ini recog­nise this, which is why they push ma­te­ri­als and tech­nol­ogy to the limit to not only un­leash in­creas­ingly lu­di­crous lev­els of power and torque, but to keep their en­gines within in­creas­ingly strin­gent emis­sions laws. That won’t al­ways be pos­si­ble, but these fab­u­lous di­nosaurs will be the last to bow to ex­tinc­tion be­cause those brands know their well-heeled cus­tomers ac­tively choose these cars for the qual­ity, the­atre and emo­tion of a nat­u­rally as­pi­rated V12. When changes are in­evitable, ex­pect some form of elec­tric in­ter­ven­tion be­fore there’s even a men­tion of a tur­bocharger.

For all a Lambo’s blood and thun­der, no one makes a V12 quite like Fer­rari. The way the 812 Su­per­fast’s enor­mous 6.5-litre V12 gains revs in the up­per reaches of its op­er­at­ing range is more akin to a 1-litre su­per­bike en­gine – it just has to be ex­pe­ri­enced to be be­lieved, and even then the thought of all those com­po­nents ro­tat­ing and re­cip­ro­cat­ing in mi­cro-mil­lime­tre pre­ci­sion, at im­mense speeds, time af­ter time, sim­ply makes the head spin. And then there’s the noise – that yowl, con­stantly evolv­ing in tex­ture in the way a tur­bocharged en­gine’s never could, the use of the throt­tle of­ten like play­ing a mu­si­cal in­stru­ment. This is the stuff of su­per­car dreams, the un­ob­tain­able thrill.

It’s also the rea­son why po­ten­tially the two ul­ti­mate cars of our age, the As­ton Martin Valkyrie and Gor­don Mur­ray Au­to­mo­tive T.50, both use be­spoke nat­u­rally as­pi­rated V12s from Cos­worth with star­tlingly high rev lim­its and surely a blood-cur­dling shriek. They prom­ise to be al­most primeval in the awe-in­duc­ing ex­pe­ri­ence they recre­ate, and their de­sign­ers Adrian Newey and Mur­ray – two of the most in­flu­en­tial au­to­mo­tive en­gi­neers of the last 50 years – recog­nise that to achieve this, only a V12 will do, and a nat­u­rally as­pi­rated one at that. ⌧

Top: Man­ual shift was a per­fect match for the Honda en­gine

Above: The E92 BMW M3 GTS used the larger 4.4-litre ver­sion of the S65 V8, pro­duc­ing 444bhp and 439Nm of torque; the E92 would also be the last nat­u­rally as­pi­rated M3, the 2014 F80 switch­ing to straight-six twin-tur­bocharged power

Right: 5.2-litre V10 found in the back of the cur­rent Audi R8, and its Lam­borgh­ini Hu­racán rel­a­tive, is cru­cial to the ap­peal of those mod­els

Left: Fer­rari’s V12 was hon­oured at last year’s In­ter­na­tional En­gine Awards, fin­ish­ing run­ner-up in the ‘best per­for­mance en­gine’ cat­e­gory

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