Key considerations
- Available for £55,000
- 2.0-litre four-cylinder turbo, rear-wheel drive
- Beautiful balance of power and handling
- Probably the best all-round Atom ever
- There’s nothing else quite like it
- Solid used values can mean low (or no) ownership costs
Launched at the Goodwood Festival of Speed in 2018 for deliveries starting in mid-2019, the Atom 4 was – and at the time of writing in February 2025 still is – the latest iteration of Ariel’s line of skeletal supercars. Maybe we should be calling them exoskeletal supercars but you don’t get the alliteration that way so let’s skip merrily on.
In January 2022 we put together a buying guide on the Atom 4’s predecessor, the Atom 3, which with its Honda K20 Type R engine generated 245hp in naturally-aspirated form or 300hp supercharged. The 3 was described by Ariel as ‘all-new’. The average bod on the street might have struggled to recognise that description because to them one Atom looked very much like another, irrespective of the number at the end of its name. ‘All-new’ was actually a fair description, though, because the Atom 3’s chassis had been manipulated to increase its width and stiffness and to give passengers a bit more shoulder and elbow room. The seating positions were lower, the engine mounts were modded to smooth out chassis vibes, and there was more cargo space.
So if we can accept from that list of changes that the 3 was ‘all-new’, the 4 we’re looking at today was even more all-new with lots of revisions to its chassis, suspension, steering, brakes, bodywork, aero, seating, instrumentation – pretty much everything, really. Ariel said that the only items the 4 shared with the 3 were its brake and clutch pedals and the fuel cap. Somebody else on the internet added the steering wheel to that list, but we can’t vouch for that.
The chassis used new large-diameter tubing, but it was still made of steel. We only mention that because Ariel did build an experimental car with a titanium chassis but it was too impractical to weld and too expensive to be put into production. Shame, bet that was quite a thing.
Although the 4 still had the Honda Type R engine, this time around it was the latest turbocharged version with 320hp and 310lb ft, enough in a car with a claimed weight of under 600kg to give the 4 Atom 3-beating acceleration figures of 0-60mph in 2.8 seconds, 0-100mph in 6.8, and a top speed of 162mph unleashed by a significant reduction in aerodynamic drag. It cornered hard too, subjecting its occupants to more lateral g than they would have experienced in a Porsche 911 GT3, but it was no raggedy-edged beast waiting to trip you up if you put a foot wrong. It was a beautifully balanced creation entirely at ease in its own skin, what there was of it. A big British car mag named it Britain’s Best Driver’s Car of 2020, one of numerous awards dished out for its general wondrousness.
You could get your 4 with a 350hp engine, a popular upgrade. Equally popular was a sequential gearbox option that was sufficiently well-liked for it to become a common retrofit on existing manual Atoms. Nobody needed the 406hp/369lb ft Atom 4R, but Ariel made it anyway because, well, they could. That was a triumph as well. We crowned it one of our favourite cars of 2023. The 4R started off with a base price of £77,490 but by the time Ariel had finished plastering the test vehicle with options like carbon aero, wheels and brakes, ABS, adjustable traction control, and the transformational Quaife six-speed sequential gearbox, it ended up costing practically double that at more than £152k. Seemed mad, but when you tried to find anything remotely comparable in terms of ground-covering ability you soon realised that it was still a bargain.
Back in the (vaguely) real world of the standard 4, the subject of our guide, how much will you need to get one? When we did our Atom 3 buying guide it was hard to come up with accurate pricings for used 3s or indeed any Atoms because a) they’re so rare; b) demand often outstrips supply; c) many of them were sold through Ariel who would verify and check all cars before resale, adding value; and d) customisation options meant that no two Atoms were the same spec or, by extension, price.
Whatever, back in early 2022 we chose £37k as the entry-level cost for an Atom 3, not as a result of intensive scientific calculations but because we’d only managed to find two examples for sale, both of them 310hp cars at £37k and £38k. Atom 3.5s and 3.5Rs were considerably more expensive than that and the 500 V8 was, and remains, a unicorn on the used market. The only one we unearthed in 2022 was on Ariel’s website with a price tag of £171k and a ‘sold’ sign on it.
Anyway, back to the 4. In 2018 its list price was just under £40,000 before options. At the time of writing in February 2025 that new car price had risen to around £51,500. In terms of grabbing a used one, things seem to have changed in terms of availability since 2022 because we found no fewer than 13 Atom 4s for sale, which is a lot. The cheapest one was a privately-owned 320hp car from 2022 with just over 2,000 miles on it at £52,495. The next cheapest was a 545-mile 2023 trade car of unknown power at £57,950, so we’ve assumed it’s a 320hp and split the difference between those two to arrive at our guide’s Atom 4 starting price of £55,000.
The most affordable 350hp upgrade car we found was a 2020 6,500-miler at £59,995, while the cheapest 350hp with a sequential box was a 2,500-miler (also from 2020) at £69,950. Above that, you’ll see cars at £80k or £90k, dealers obviously looking at the 8-10 month waiting time for a new 4 and trying their luck. Motorwatch price monitoring shows that these cars aren’t selling at these lofty prices, but the point about the solidity of Atom used values remains. You could buy one, have some fun with it, and come out ahead when you move it on.
SPECIFICATION | ARIEL ATOM 4 (2018-)
Engine: 1,996cc inline four 16v turbocharged petrol
Transmission: 6-speed manual, rear-wheel drive
Power (hp): 320@6,500rpm
Torque (lb ft): 310@3,000rpm
0-60mph (secs): 2.8
Top speed (mph): 162
Weight (kg): 595
MPG (estimated): 30
Wheels (in): 7 x 16 (f), 9 x 17 (r)
Tyres: 195/50 (f), 255/40 (r)
On sale: 2018 - 2023
Price new (2019): £39,950
Price now: from £55,000 (approx)
Note for reference: car weight and power data are hard to pin down with absolute certainty. For consistency, we use the same source for all our guides. We hope the data we use is right more often than it’s wrong. Our advice is to treat it as relative rather than definitive.
ENGINE & GEARBOX
If someone you trusted told you that the Atom 4’s 2.0-litre turbo engine had been installed by Honda themselves rather than by a tiny outfit in the south-west of England you probably wouldn’t argue with them. The sense of oneness between car and drivetrain was perhaps the best compliment you could pay to the Atom 4. In fairness, after 25 years in production, you’d expect Ariel to be pretty good at the drivetrain integration thing by now. The length of their relationship with Honda gives you some insight into the mutual respect between the two companies. Honda doesn’t enter into many engine supply contracts outside of F1, so it tells you something that Ariel was given access to the Honda K20C1 engine before the Type R using it went on sale. Honda also supplies Ariel with the Civic 2.4 engine for the Nomad and a 1.2-litre V4 bike engine for the Ace.
There are few poor Honda engines, but the 2.0 in Atom 4 spec is particularly fine. Most of us look at an engine’s power figure when we’re top trumping, and the Atom 4 is certainly not short in that department with 320hp in the most powerful of the three diallable settings, but it’s the torque – and the revs it’s produced at – that really make this car special. In the Atom 4 the 2.0 litre motor was churning out 310lb ft at just 3,000rpm, by which point the horsepower was coming in hard, so even though the turbo hit was softer in feel than that of its supercharged Atom 3 predecessor you were never short of face-flattening surge in standard trim.
Hardly surprising really with a power-to-weight ratio of 538hp per tonne, which was superior to that of the ballistically quick McLaren 720S. Ariel boss Simon Saunders has always considered the Atom to be a four-wheel motorcycle and there is some similarity in power delivery. It’s relentless enough to encourage you to take early upshifts in order to create the impression, in your own mind at least, that you’re sort of in control of it.
The noises it makes under acceleration, even on partial loads, are either inspiring or terrifying depending on your fear threshold. As our Matt memorably put it, ‘the Atom 4 sounds like Darth Vader’s Dyson, whooshing and wheezing in response to every throttle application’. The power dial reduced boost pressure from 1.3 bar to 0.6 bar, giving you 290hp, or to 0.3 bar for 220hp, but if your face wasn’t quite flat enough for your liking even on the high-power setting Ariel was ready and willing to take you further in the shape of a 350hp upgrade (sports cat, decat pipe and ECU reflash). Irrespective of what engine you had in your Atom, the car’s light footprint meant it was easily capable of delivering 30mpg on a cruise, so it was even politically correct.
The six-speed manual gearbox worked as well in the Atom as it did in the Civic Type R, which is to say very well, even though it occupied a different location in the drivetrain. Atom 2 gearboxes were a bit weak in the synchro department between third and fourth and between fifth and sixth but by the time the Atom 3 came out that had been sorted. Clutches were strong and replacements weren’t massively expensive either at £300 or less, although it’s worth noting that by the time you’d paid for the labour (which included dropping the engine) the bill could be four times that. Stainless steel clutch lines were available. Ariel could also enhance the existing trans with an upgraded shifter or change it up to the brilliant Quaife six-speed sequential.
Many Atom owners take their cars back to Ariel for servicing but if Somerset is too much of a schlepp for you Backdraft Motorsport in Milton Keynes is an excellent option. They developed and raced the first Atom race car in 2004 and can do you an annual oil and inspection service including suspension lubrication for £395 + VAT. Presumably you could at least try to book your Atom into a Honda dealer for mech stuff. They might quite like something other than a Jazz in the workshop.
CHASSIS
The 4’s length and wheelbase were both slightly up on the 3.5, but it was no wider than the old car which was just as well as the Atom wasn’t a skinny design like (say) a Caterham Seven. Overall it was about 20kg heavier than the 3.5. The suspension was double wishbone with inboard coilovers and new aluminium uprights.
After previous Atoms that had bordered on the hyperactive some thought that the 4’s handling was almost too benign. The revision of the geometry to provide anti-dive and anti-squat was welcome, the quality and control of the ride at higher speeds was tremendous, and oversteer was a sweet balance of provokable and recoverable, but in the final analysis there was always a disconnect between power and grip so an appropriate degree of circumspection was required on damp and/or broken surfaces. If after spending a week with one on British roads you were asked to suggest areas of improvement, you might come up with the idea of a little more feel in the brake pedal and maybe something to reduce the 4’s nerviness on cold or wet Avon ZZR tyres. Otherwise there was very little to criticise. The less extreme and more rain-suitable ZZS was the default rubber. The 4’s rear tyre section (on 17-inch wheels, the fronts were 16s) was quite a bit wider than those on the 3. The steering rack could be sped up but that was a bit like adding gold flake to the finest caviar, i.e. totally unnecessary.
As with the mechanicals, Ariel was offering scads of chassis tuning options including chrome-moly adjustable camber aerofoil wishbones and pushrods, race-grade rod ends, race needle roller bellcranks, Bilstein single or two-way MDS adjustable dampers with two-piece springs in either road/track or track bias settings, and Ohlins TTX three-way adjustable remote reservoir dampers. On the braking side, you could opt for AP Racing four-pot caliper/290mm discs, carbon ceramic brakes, stainless steel brake lines, and cockpit-adjustable remote brake bias. The 4’s one-inch bigger wheels (including forged ones) came in silver, grey or black, or you could have carbon.
The powdercoating for the chassis tubework could be silver, grey or black. As a British company, Ariel has always been well aware of the corrosive potential of weather, so Atomic rustproofing was always done to a decent standard, but it was advisable to give your car a look over after a drive to pinpoint any stone chips inviting Roger Rust in to do his thing. Crazing in the lacquer of a used car could be an indicator of crash damage. We’re not sure how much a replacement Atom chassis would cost in 2025, but back in the early 2010s they were £18k plus VAT so draw your own conclusions about the wisdom of regular checks.
BODYWORK
The intake snorkel behind your head and the new nose (concealing two small storage areas) were the biggest visual changes for the 4. The colours that were available for the bonnet and cowl were red, blue, green, yellow, orange, black, or white.
Or carbon fibre. You could spend a lot of money on carbon fibre parts – front and rear aerofoils, mudguards, lamp covers, or the whole body set. You could also change the colour of your Atom by buying new bonnet panels and air intakes at reasonably un-ruinous prices (about £700 the pair). The 4’s titchy windscreen didn’t look too hopeful for your hairdo. Wind tunnel imaging suggested it was surprisingly effective but in these uncertain times we’d stick with the helmet.
Again the factory was at your disposal with trackday-enhancing options like a bolted-in rollover bar or a welded-in roll cage. Side panels to reduce attack from flying foreign bodies were an especially useful add-on when you were passing slower traffic or, heaven forbid, ploughing through the gravel traps on a track having misjudged a pass.
For additional luggage-carrying on tour you can fit cargo nets into the spaces between the main side members of the chassis and then cable-tie waterproof kayaking bags to them (remembering to take a bag of ties with you of course).
INTERIOR
Not sure you can say an Atom has an interior as such, unless you went for one with all those infill panels. They could rattle a bit if you didn’t bother inserting something squidgy between them and the chassis. Panelling-in your Atom could also make the cabin (let’s call it that) quite warm on sunny days, those typically being the days you would take the car out for a spin, so it’s worth thinking carefully before going for the panels.
One advantage of not having any panels was the extra ease of parking that came from being able to see the road past your legs. There was a reversing camera on the option list and that was a sensible thing to have on an Atom given the amount of hardware between your cricked neck and the supermarket’s concrete post lurking behind you. The 4’s dash panel was new. It included a TFT colour digital display/PDM system with readouts for speed, revs, water temperature, fuel level, oil pressure, gear position, odometer, trip and time. Everything that you might reasonably need and no more. Any inconsistencies with speedo or tacho readings would normally be due to out-of-position sensors rather than the display itself.
Logically for a car with no doors, the 4 was fitted with a keyless immobiliser. A quick-release steering wheel added an extra layer of security and eased the driver’s entry and exit. Spacers of up to 100mm allowed you to fine-tune the driving position. The shell seats might be perfect for your body shape, but if they weren’t you could get custom moulded resin inserts from firms like Indi Seat or pad sets for your bum, shoulder, back and head from firms like JK Composites.
Track day options included lap timing with brake pressure overlay on video, a battery master cut-off switch, a fire extinguisher that could be standalone or plumbed in, and a raft or belt/harness/crotch strap alternatives.
PH VERDICT
In comparison to other earlier Atoms, the 4 seemed almost civilised. Don’t jump to the assumption that it was a more boring experience, though. It was a big step on from the 3.5 in just about every respect, including – perhaps most importantly – driveability. The bod behind the wheel didn’t need to be a driving god to score great track day laps, and that was a huge point in its favour. It was always the car to beat in Autocar’s annual 0mph-100mph-0mph test. In fact, Ariel’s domination of that was instrumental in the magazine’s decision to drop the feature.
While we’re on the subject of comparisons, the one that matters is the one between the Atom and other cars. That’s a very hard one to make as there are so few genuine rivals in the same galaxy, let alone the same ballpark. What is there, actually? Well, from a visual point of view, the nearest would be something like a Lotus 2-Eleven or a KTM X-Bow, but both of those would be slower than an Atom 4 and are more conventional in terms of the amount of bodywork they’re lugging around. Plus they’re even less common on the used market than the Atom. We found no 2-Elevens for sale in the UK at the time of writing and just one X-Bow, a 2008 model with 240hp (so quite old and relatively underpowered) at £47,500.
A used Seven 420 S or 420 R is going to cost you at least £40k and would be left for dead by the Atom. A new Caterham Seven 620 with the 310bhp supercharged 2.0 Duratec would be comparable in performance but again is relatively conventional in its design. Plus it’s nearly £60k new now, and you’ll have to wait for the same sort of time as an Atom to get one.
If you read our Matt’s views in this matchup between the two cars you might come to the conclusion that the Ariel has no real rivals. No Seven offers quite the same interaction not just with the car but also with nature. Caterhams feel cramped and, from a design perspective, old. Atoms (from the 3 on anyway) feel open – literally – and notably more spacious, partly as a result of them being so skeletal.
Atom prices have gone up somewhat since the heady days of 2000 when the Atom 1 with the K-series 120 engine started at under £17,000, but the solidity of used Atom values actually makes it one of the cheapest cars you can get, as long as you have the liquidity to buy one in the first place anyway. Ideally, you’d want a garage to keep it in too as it’s not the sort of car you’d want to leave outside for various obvious reasons. Earlier Atoms did have foibles – for more information on the 3 and on the Atom timeline generally check out our buying guide here – but reliability on the 4 seems very good. We found no recalls for anything.
Pleasingly, there is a good selection of Atom 4s on PH right now. This is the privately offered version at £52,500, complete with the 350hp upgrade, AP Racing brakes and full roll-over bar; for a couple of thousand more this dealer-offered Atom comes in Aston Martin Racing Green; and at £60k there are cars with barely more than a thousand miles available.
1 / 14
![](data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 4 3"%3E%3C/svg%3E)
![](data:image/svg+xml,%3Csvg xmlns="https://www.w3.org/2000/svg" viewBox="0 0 1 1"%3E%3C/svg%3E)