Monday 16th March 2015

Let turbos be turbos: Tell Me I'm Wrong

If we're stuck with turbocharged cars why not make them feel turbocharged?

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The humble turbocharger is the saviour of the modern performance car. So why hide it?

PH Explains: what is a turbocharger and how do they work?

Obviously we'd love to keep hold of our fizzy, high-revving four-pots, sonorous straight-sixes and spine tingling Vs, all of them boasting fulsome cubic capacities, sucking through individual throttle bodies and uncorrupted by charisma-sapping forced induction. But a few die-hards aside it ain't going to happen. 'Torque filling' electric assistance is surely going to trickle down from the hybrid supercars. But in the meantime our downsized engines need their turbos to make up the shortfall in performance.

'Turbo' was something to be proud of once

So let's celebrate the fact!

Back when turbocharging first became commonplace it was a badge of honour, literally. BMW even wrote it, ambulance style, on the nose of the2002 Turbo so when glimpsed in the mirror you knew the baby Beemer was on a charge.

Flatter to deceive
It's different these days. Manufacturers are doing their damndest to pretend the turbos aren't there, disguising them behind piped-in engine noise, carefully massaging power and torque curves to mask lag and generally doing everything to convince us 'turbo' is a dirty word.

Don't believe me? Listen to AMG's Tobias Moers in our (shameless plug alert!) latest episode of PHTV, talking about the new 4.0-litre V8 in the C63 and asserting that disguising the forced induction was a key development goal. AMG has managed this better than most and Moers is correct in identifying driveability as the reason for wanting his turbo engines to feel like normally aspirated ones. He's got the luxury of - relatively speaking - more cubic capacity than most to fall back on too.

AMG has mastered switch to turbos

But as engines get smaller and turbos get bigger manufacturers are seemingly desperate to use every trick in the book to hoodwink us into thinking the turbos aren't there. Why bother? Let's enjoy them for what they are!

Jump to hyperspace
Back in the turbo's glory days the technology was a lot more crude, meaning there was no choice but to make sudden eruptions of boost a defining characteristic. I'm possibly a product of my age here but in my formative years turbos and Star Wars both figured prominently on my list of cool things. And even the Millennium Falcon had lag. Hell, that pause between Chewie pushing the throttles and the stars going all streaky is, in my head, the same as that one ... two ... WHOOSH sensation you get in an old-school turbocharged car.

I like that tingle of anticipation as the boost builds and then erupts into proper thrill-ride acceleration. To the point where I constantly drive modern cars a gear or two up to deliberately provoke a sense of lag, just for the hell of it.

When men were men and turbos were TURBOS

When it's done well, as it has been in the C63 and GT, the modern technique of managing and playing with boost to balance out the more dramatic peaks in power delivery is effective. Indeed, as AMG's engine man told me with the M177/M178's variable valve timing and boost at his disposal he could make it 'feel' any way you'd like.

But too many modern engines are so fixated on eliminating lag that they forget to manage the power delivery once the engine is on boost. Meaning you get everything up front and steadily diminishing returns beyond. It's almost like reverse lag - back in the day you had nothing, nothing, nothing and then - WHAM - a massive spike of boost. Which, if it happened mid-corner or just as you wanted to back out of the throttle, could cause you significant problems.

M3 does this very easily; not always wanted

Back to front
These days it all happens immediately and then tails off, meaning theM3/M4 syndrome of instant boost that overwhelms the tyres and leaves you dependent on the electronics to mitigate the resulting traction loss. Sure, you can disable the DSC and rely on your god-like reflexes to tame the beast. And it's great for hacks looking to bank the essential fully lit cornering shot for film or photo glory.

But the amount of flashing DSC light you get on a moderate throttle on a dry road is revealing of how hard the electronics are working to manage that power delivery. Indeed, as an experiment on the M3/M4 launch I did an at-pace lap of Portimao with everything fully on and there was so much intervention to stop the wheels spinning up it felt at times like the thing wasn't going to get up the inclines. For all the undoubted cleverness the engineers put into making the engine rev, maintain its boost for optimum throttle response and the rest the cruder, boostier 1 M Coupe's engine is more 'fun' and charismatic.

The all-pervading hot MQB platform cars from the VW group - Golf GTI, Golf R, Leon Cupra, Octavia vRS, Audi S3, et al - don't quite have the same traction problems. But the attempt to mask the forced induction has left a dull, one-dimensional power delivery that gives you everything up front and then leaves the party early. Sure, the rev counter reaches beyond 3,000rpm. But there's little incentive to go there, beyond fake engine noise on the speakers the CIA may want to look at for future 'enhanced interrogation' techniques.

Dan's Subaru makes a virtue of its turbo

Maybe I'm just old-fashioned. But one of the things I love about 'my' SubaruWRX STI long-termer is that it feels turbocharged. The peak power and boost are just as short-lived as those MQB cars and you need to be busy with the gear shifts to keep it on the boil. But at least it's higher up in the rev-range, giving you something to work for. And Subaru isn't shy of letting you hear the whine of the turbo spooling up, the rush of the air going through the induction system or the distinctive chuff of the dump valve as you come off the throttle. And I love the fact this varies according to the weather and climactic conditions.

Porsche has seemingly learned this too. The 997 Turbos were epic cars and brutally fast and efficient. The variable vane turbos made for a broader operating range than most too. But even 500hp-plus felt a little soulless. The991 seems to have rediscovered its love for feeling - and sounding - like a Turbo and is so much more entertaining for it.

Turbo McLaren beats atmo Ferrari? Really?

See also the McLaren 650S and its relatives. I'm more interested by the hissing and cooing of the induction system than the 'augmented' Intake Sound Generator and much more entertained by it than the binary quiet/LOUD game played by the 458's exhaust system. At civilian speeds it even feels more fun, the boostiness more exciting than the Ferrari's linearity in those sneaky little squirts of acceleration you get to enjoy in everyday driving.

So, manufacturers. Don't be scared. Make our turbos sound and feel turbocharged again. Please!

Punch it, Chewie!

 

 

[Sources: BMW M-Power.com; tonynibbles, via YouTube]

 

 

[Sampaio]

I drive a naturally-aspirated MX-5 on a daily basis and my father's turbo-diesel Volvo S60 every once in a while. I love driving both cars precisely because of the completely different way the power is delivered.

The Volvo has the famous 5-cylinder diesel engine and it feels properly turbocharged. Certainly not 80's/90's turbocharged but you'd be surprised how strong the sudden boost is for a family saloon. The Mazda has to be pushed to its (rev) limit, but when your at 6k-7k rpm the buzzing feeling is heavenly.

Anyway, just wanted to say I don't think you're wrong in your analysis. Engine character comes from the two extremes: immediate response at high revs or wait-for-boost-and-GO!

Anything in the middle will always feel like a boring compromise.