Audi has decided that some of its S-cars are best served by diesel power after all. Is it right?

Why we ran it: To see if diesel power really can excite as much as petrol in a sporting four-door

Month 4Month 3Month 2Month 1 - Prices and specs

20 Audi s5 sportback 2020 lt static

Life with an Audi S5 Sportback: Month 4

Running this fast, red, surprisingly attention-grabbing Audi S5 for the past few months has been bittersweet. Not because of the car, which has been broadly very good, but because of what it represents: a dying breed.

Maybe I’m being a bit dramatic, but cast your eyes over the figures. Even including mild hybrids, diesel’s share of the UK new car market has dropped to around a fifth so far in 2020, continuing a steady but stark decline over the past half-decade. And the number of diesels on sale has more than halved in the same time.

I’m not sad to see the back of things like the diesel Ford Fiesta, which is now toast; small, agile cars suit responsive, higher-revving petrol engines far more. But once you get into larger and more premium echelons, it’s quite often the case that large-capacity diesels are the best all-round fit: more effortless, more frugal and, because they don’t need to be worked as hard, more refined.

Effortless is an apt term for the S5. Unexciting would be unkind. It’s one of those cars that wouldn’t blow you away on a short test drive; instead, it gradually got under my skin the more I used it in different situations: long late-night jaunts, wet-weather airport runs and, most recently, a four-up drive to Pembrokeshire for my sole holiday of the year.

I was aching to volunteer as the driver for the trip, partly because I can’t stand how my friends drive but mainly because there are few better cars for the job. The S5 is easily roomy enough for four sizeable men, its nappa leather seats are brilliantly comfortable and supportive and its hatchback boot swallowed our kit. While its 20in wheels thump a bit around town, rolling comfort and stability at higher speeds is superb. And the 19-speaker Bang & Olufsen stereo highlights notes and instruments you’ve never noticed in songs you’ve listened to 1000 times.

The cabin itself emanates a sense of thoughtful design and (so long as the front passenger seatbelt isn’t undone so bashing against the hard seat side) rattle-free solidity that I worry Audi is losing in its latest cars. Even the lane-keeping assistance, technology that I usually despise so never use, operates more slickly and smoothly than it does in many cars. And all the while, a steady 70mph yields a cruising MPG figure in the high-40s – not bad for an 1805kg car with 516lb ft of torque.

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After the end of the M4, the rest of the trip to the Welsh coast was on busy, single-lane A-roads. The S5 knocked this out the park, too. The fuss-free, relentless way it builds speed in the mid-range meant I felt little anxiety when overtaking on uphill passing points; I just planted my foot and whatever was holding me up was briskly dispatched.

Indeed, the only real concern came when I encountered some of the tight, farm-focused roads that rural Pembrokeshire has in spades. I was surprised to learn while writing this that the S5 is actually slightly shorter and narrower than the S4 saloon, because its smaller glasshouse and resulting reduced visibility makes it seem less manoeuvrable. It’s hardly an A8, though, and when parking, our car’s 360deg overhead camera view made it a cinch – and I didn’t kerb its 20in alloys once, thanks to the tyres featuring a preventative lip.

The glowing report so far suggests the S5 was faultless; although that was the case mechanically, there were some foibles. The flickering issue with the matrix-beam LED laser lights was never resolved by the dealer who examined it, who blamed Audi UK for not yet outlining a fix. I also never got on with the MyAudi app; having completed the multiple security stages to connect car and phone, I could never get the pairing to finish. Towards the end of our time, the S5 also kicked me out of my user profile, requesting a four-digit PIN that I’d never set up. Technology, eh?

But the overriding issue is one that never really softened during my time with the S5: the engine and gearbox calibration, which I’ve mentioned in every report. When trying to drive frugally it impedes by holding onto gears for that bit too long, even in the most efficient driving mode, often winding me up enough for me to take manual control of upshifts.

On motorways, the slightest incline had it drop a gear when really it should be able to use its prodigious torque in the highest gear. In spirited driving, too, it could grate, dithering about when you want it to pick a cog smartly and fire out of a junction.

Accruing miles didn’t help, either. Trying Mercedes-Benz’s equivalent straight-six diesel, which is more responsive to the throttle and quicker to select ratios, only highlighted the S5’s issue. It seems to be hamstrung by a combination of long gearing and programming that’s designed to avoid using full torque at low revs.

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It’s a pity this was such a big fly in the ointment that reduces the S5’s credibility as a sporting saloon. Sure, it’s something that you can learn to live with relatively easily. But if Audi could sort the calibration, it would remove the only real fault with what is otherwise an extremely pleasant ownership prospect.

18 Audi s5 sportback 2020 lt cornering rear

Second Opinion

Although it’s not a car that I’d set my alarm to drive on deserted country roads, I’m not surprised the S5 became an obvious choice for long-distance cruising. Audi has returned its SQ7 and SQ8 SUVs to petrol, but it would be a shame if the saloons followed; diesel suits the S5’s mien as a rapid yet refined cruiser and distinguishes it clearly from the ballistic RS5.

Tom Morgan

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Love it:

Dynamics Sure-footed handling and composed ride made the S5 a really accomplished daily driver.

Pace Once it was in-gear, acceleration was relentless. And it even sounded good for a diesel.

Efficiency As well as decent fuel economy, I never once had to put AdBlue in the tank.

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Loathe it:

Gearing A slow-witted, rev-holding automatic gearbox was the biggest gripe we had with the S5.

Technology I never got the MyAudi phone app to sync with the car and the touchscreen logged me out.

Final mileage: 3792

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Life with an Audi S5 Sportback: Month 3

Swallows more than you'd think - 21 October 2020

Everyone blames the slow demise of the traditional saloon on SUVs, but I reckon the influx of four-door coupés is also a factor. And rightly so: at no point during my time with our S5 Sportback has the S4’s fractional extra head room been needed, and the S5’s much larger hatchback boot opening has been very useful. One drawback? I’ve been told child seats are easier to fit in the A4.

Mileage: 3494

20200830 130230

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The shorter days of September have revealed a glitch in the matrix - 23 September 2020

As the days begin to shorten, I find myself spending more time behind the wheel of the S5 in the inky blackness of night.

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Here, the classiness of its cabin design, including the neat ambient lighting details and clarity of the digital instruments, makes those journeys pleasant. But something has been bugging me, and it’s not the inside that’s the problem.

You see, our car has Audi’s optional matrix LED headlights with laser light technology as part of the extensive extras tally. This tech contains two distinct elements. The first is the matrix LED adaptive beam function, using a forward-facing camera and controller to switch off individual LEDs or dim them in 64 stages to create several million possible light patterns. They also serve as cornering lights, shifting the focal point of the light along a curve.

The second element is a fairly new laser light system. It doubles the range of the high beam, it’s claimed, using a phosphor-converted laser beam to generate a light cone of several hundred metres. The laser spot, used above 43mph, automatically dims if a car enters the camera’s path.

Trouble is, something isn’t working properly. The system adjusts the beam pattern for the conditions ahead as it’s supposed to, but it has recently started to flicker and flash noticeably when switching between modes. I took the car to Basingstoke Audi to diagnose the fault, and after two days with them, an engineer had acknowledged some sort of issue.

1audi s5 sportback lt lights

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Sadly, the problem isn’t a well-known one, so the dealer needs to compare with a laser light-equipped car to see the difference. Despite the tech now being available on several models, the dealer claims to have no cars in its network fitted with the option. Audi’s UK headquarters have been informed, but there’s currently no fix for our S5. It’s clearly not performing at its best, judging by the number of times I’ve been flashed by oncoming cars in the past few weeks.

It’s a small fly in the S5’s otherwise very appealing ointment. The engine is well run-in now and performance is stronger than ever, although the sometimes hesitant gearbox can irritate. I recently had a brisk, late night airport return run during which its blend of comfort, efficiency, pace and high-speed stability were so strong that it’s hard to think of much else better suited to the job.

Love it:

Light fantastic Leaving/coming home lighting animations are showy but very cool nonetheless.

Loathe it:

Seatbelt buckle The passenger seatbelt buckle rattles against the side seat plastic, so I click it in even if it’s not in use.

Mileage: 2295

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Dig deep for weather reports - 16 September 2020

A few years ago, you would get a new car and spend a while pressing every button to find out what it did. In the touchscreen age, I’ve not been doing the same, oddly. Which is why, four months into my stewardship of the S5 Sportback, I’ve only just found out that the car has a live radar display in its weather app to show cloud cover for the coming hours. Handy.

Mileage: 2051

Audi s5 sportback lt radar

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Life with an Audi S5 Sportback: Month 2

The right way to coast - 19 August 2020

I use the S5’s mild-hybrid engine-off coasting function on almost every drive. As any hypermiler will confirm, it’s much better to get up to speed quickly and then coast than continually accelerate slowly. I’ve discovered that you can tell the S5 to coast precisely when you want it to by lifting off the throttle and briefly pulling the upshift paddle. Handy.

Mileage: 1254

Coasting paddles

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How does our £69k fully loaded test car compare with a £41k Kia Stinger GT-S? - 12 August 2020

By sheer luck (and the kindness of Kia UK), I found myself in possession of a Kia Stinger GT-S the week after picking up the S5. Although the Kia is a relatively niche product unlikely to be cross-shopped by many Audi customers, it was interesting to compare the brands’ very different approaches to sporting saloons.

First, the price. Our S5 is just over £50k as a base price but knocking on the door of £70k with all our options added in. The Kia? £41k. And that’s before haggling, which is well worth doing given Stingers haven’t exactly flown out of showrooms. And don’t think the Korean car is sparsely equipped. It can’t match the Audi’s perceived finish or vast array of tech, but all the main niceties – sat-nav, Harman Kardon sound system, wireless phone charging, electric and heated nappa leather seats, LED headlights and the like – are thrown in. It even gets ventilated front seats and heated rear seats as standard, which the Audi doesn’t. It’s enough to make you wonder what Kia’s profit margin is on it…

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Performance is comparable, too. In outright terms, the S5’s 516lb ft of diesel punch monsters the 376lb ft of the Kia. But both quote the same 0-62mph time (4.9sec) despite the Stinger being two-wheel drive only. Most of that is down to engine and transmission response: the Audi takes longer to hook up, find a gear and hit its stride, while the Kia’s eager twin-turbo V6 and snappier ’box mean it fires off the line with verve. The petrol car sounds nicer, too. And it turns more heads, being far rarer and (I reckon) more distinctive.

Kia meets audi

So buy the Kia, then? Hold on, I haven’t finished. The S5 remains the better cruiser – not just in refinement terms. It’s also vastly more frugal. You’d be lucky to crack 30mpg in the Stinger on a run, whereas 40mpg plus is within easy reach in the Audi. And while the Stinger is an entertaining steer (and quite tail-happy in the wet), the S5’s all-weather composure and agility mean it’s more confidence-inspiring.

However, a quick look at leasing reveals that while a base S5 is around £140 a month more than the Stinger, the Vorsprung spec is approaching twice the monthly PCP cost on a similar three-year deal.

Anyone set on a fast four-door from the Germans would do well to seek out a Stinger and keep the substantial wad of leftover cash for the extra fuel, spare rear tyres and some flyers to hand out to people asking what on earth it is.

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Love it:

Smart wheels The 20in wheels look great and don’t ruin the ride and the tyres have a hard lip to prevent kerbing.

Loathe it:

Fake exhaust tips The exhaust is a single outlet, but Audi has stuffed on another set of obviously fake tips. Boo.

Mileage: 1224


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Life with an Audi S5 Sportback: Month 1

Great economy in the right situation - 29 July 2020

Our ongoing office shutdown means no motorway commute, so town driving had held the S5’s average economy down at 35mpg. Convinced it could do far better, I took it to Milton Keynes with the cruise rigidly at 70mph and hit a journey average of 48.5mpg. Very respectable for the performance, weight (1800kg) and four-wheel drive, I reckon.

Mileage: 1012

Touring economy

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Welcoming the S5 Sportback to the fleet - 22 July 2020

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Petrol power and sound versus diesel torque and fuel economy: the debate has raged for years. And despite the decline in popularity of cars fuelled via the black pump, it seems, given Audi’s recent internal flip-flopping, that the argument is alive and well.

Ingolstadt’s S-car saga began in 2012, when it introduced the diesel-only SQ5. It was the first oil-burning Audi S model, and the logic of pairing a two-tonne, four-wheel drive SUV with a well-endowed diesel V6 was undeniable. Then Dieselgate became the portmanteau of the decade, and with Audi’s 3.0-litre unit under the microscope, its future looked untenable.

The brand responded with the second-generation Audi SQ5 in 2017, adopting the 3.0-litre petrol V6 found in the S4 and S5 of the time. That lasted all of, well, a year, as the introduction of the WLTP testing regime and looming CO2-based European fleet average legislation led to the SQ5 disappearing until a new version arrived last summer with (yep, you guessed it) a diesel V6.

Audi’s indecision continues to this day – the Audi SQ7 and Audi SQ8 have just switched from diesel to petrol – meaning there’s now roughly a 50/50 split between petrol and diesel in the S model range. Experience has told us that performance diesels such as these aren’t cars that wow you from the outset, instead taking a while to get under your skin. The perfect excuse to run this Tango Red S5 Sportback for a few months, then.

As we’ve come to expect from premium German brands, this isn’t ‘merely’ a £51,000 base S5 Sportback. Audi has gone to town a bit on the options. For starters, it’s effectively a Vorsprung model, with upgrades including 20in alloy wheels, a panoramic roof, adaptive Sport suspension, a Bang & Olufsen stereo and all the LED lighting cleverness you could possibly need. We’ve also got Audi’s super-bright laser lights, which aren’t seeing much use in the midst of summer but will surely be welcomed as the nights close in.

More superficial additions include red brake calipers and gloss carbon cabin inlays. Practical boxes ticked include the larger 24-litre AdBlue tank (the cheapest option at just £60) and the ‘Tour’ Driver Assistance Pack (the most expensive, at £2700), bringing a suite of active safety systems too numerous to list here. All in, this is a £70,000 car – well into RS4 Avant money. So, as the months tick by, I shall aim to provide some consumer advice and tell you which boxes are worth ticking and which aren’t.

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Back to the car itself. I was hoping for a subtler colour to really sell the diesel S5’s Q-car status, but flash Tango Red will do; with the big wheels, quad tailpipes and other S details, it certainly distinguishes itself from the fleet-spec Audis dominating every motorway in the land. You’d think the illusion would be shattered once that TDI V6 is awoken, but the S5 gets an exhaust sound actuator that (largely) drowns out the diesel clatter with a faux-V8 burble at idle and low revs. I’ve yet to make my mind up; inside it adds a little theatre, but outside it’s a touch more narrowboat than sports car.

10 Audi s5 sportback 2020 lt dashboard

There’s no questioning the motor’s smooth yet formidable shove, however. I’ve put around 300 miles on it since it arrived but, since there are only about 500 miles on the clock, I haven’t been overindulging in fullbore launches. Thankfully, with more torque on tap than a Lamborghini Aventador, there’s no need to wring out every gear, but I’m interested to see if the rather laggy engine and gearbox calibration improves as the miles pile on. Far from a major flaw, it’s something you have to drive around a bit: wind in some throttle and it dithers for a second or two before finding the right gear and firing you towards the horizon.

Getting on the power earlier solves it, but even then you sometimes find that the gap in traffic you were aiming for has gone because it took that little bit too long to select a cog. Other things of note so far? Gone are the days when ride comfort seems to be a forgotten criterion for fast Audis with big wheels.

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Granted, the 20in rims do induce some thumping and jarring over really pockmarked roads, but by and large the S5 Sportback is a well-resolved cruiser. It handles with more agility than you might expect, too, and while the four-wheel drive system detracts from any sense of playfulness, the security and stability is a worthy trade-off in everyday driving.

One thing I’m also hoping to see as the engine loosens up is an economy improvement. The first tank of fuel has delivered an indicated 34mpg figure – respectable for a performance car in mixed town and country driving but not remarkable for a diesel. A sole commute to the office has shown it can get well into 40mpg territory on a run, however.

Second Opinion

While the four-door coupé silhouette of this S5 Sportback makes me think back to the Kia Stinger GTS we road testers ran in 2018, a glance at its spec sheet shows just how drastically those manufacturers differ when it comes to extras. Our Kia didn’t have a single option fitted; everything was included as standard.

Simon Davis

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Audi S5 Sportback 55 TDI specification

Prices: List price new £53,625 List price now £53,930 Price as tested £69,310

Options:Tango Red metallic paint £675, larger AdBlue tank £60, quattro with Sport differentials £1400, front and rear-view camera £1180, head-up display £1025, red brake calipers £350, matrix LED headlights with Audi laser lights £870, storage package £195, extended LED interior light pack £125, ‘Tour’ Driver Assistance Pack £2700, dynamic power steering £1025, Sport suspension with damping control £1000, panoramic glass sunroof £1400, black styling package £570, 20in alloy wheels £2460, gloss carbon inlays £475, Bang & Olufsen 3D sound system £850

Fuel consumption and range: Claimed economy 39.8mpg Fuel tank 58 litres Test average 35.8mpg Test best 37.9mpg Test worst 35.2mpg Real-world range 457 miles

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Tech highlights: 0-62mph 4.9sec Top speed 155mph Engine 6 cyls, 2967cc, turbo, diesel Max power 342bhp at 3850rpm Max torque 516lb ft at 2500rpm Transmission 8-spd automatic Boot capacity 430-940 litres Wheels 9Jx20in, alloy Tyres 265/30 ZR20 Kerb weight 1805kg

Service and running costs: Contract hire rate £798 CO2 186g/km Service costs None Other costs None Fuel costs £539.14 Running costs inc fuel £539.14 Cost per mile 15 pence Faults Flickering LED headlights

Screenshot 2020 12 03 at 09

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Join the debate

Add a comment…
spqr 11 November 2020

Autocar are making excuses for the economy figures

The update on 22 Jul 20 where the driver raises his average mpg from 35 to 48.5 is telling. My own car, a larger BMW four cylinder petrol saloon with 250+ bhp, not quite as fast 0-60 5.9 secs, but same top speed gets an average of 34mpg with urban driving and an average of 47mpg on a 70mph cruise controlled motorway run. If there are the usual 50mph "Smart Motorway" sections in the journey it will regularly hit 51.5mpg. It seems Autocar have not realised that smaller petrol turbos these days can be every bit as economical as a diesel with a larger capacity and still be entertaining to drive. The case for diesel has been lost for mainstream cars and makes no sense at all in a "sporting" car. 

Maddness 13 August 2020

Diesel and fun!

I'd a fast diesel for a while (435d) and they are just not fun to drive. Brilliant for a big comfortable executive car but in something with sporting pretentious it's just wrong. I suppose people who buy Audi's aren't too worried about things like handling anyway

artill 13 August 2020

In isolation, probably an OK

In isolation, probably an OK car (Should be for £70k!), but i do feel Audi are playing king Canute, The tide has turned against Diesel cars especially anything desirable. This thing should be Petrol (without the dim gearbox) or Electric