Fast cars generally look like they're fast cars. These don't. Today we're taking a look at some of the best undercover heroes, the ones your friends and family will think of as nothing more than a sensible daily driver - until you plant the throttle.
The Rover 620ti
Lets start with Rover, the humble British car maker that's loved by grandparents all across the nation. At one time Rover were one of the top manufacturers in Britain, compared with the likes of Jaguar. They were cool, classy and perfectly British. Unfortunately by the 1990s, plagued by an industrial crisis and poor reliability, those glory days had long since passed and Rover were seriously struggling.
In 1993, Rover released the 600 which was aimed at competing directly with the BMW 3 series and based on the Honda accord, it came in various trim levels but most people seemingly opted for the wood and beige combination. Most of the Rover 600s weren't really anything to get excited about and certainly weren't thought of as high performance machines.
Are we interested in most Rover 600s? No. We are interested in one Rover 600. The 620ti.
Released in 1994, the 620ti may well have looked old and dated by the 2000s but don't let that fool you. If you encounter one of these on the roads, prepare to collect your jaw from the floor as it takes off from the lights and reaches 60 in just under 7 seconds. This is all thanks to Rover sneaking a 197hp/236nm turbocharged inline 4 engine under the hood as well as upgrades to suspension and a fresh new interior.
Volvo S40 T5
Another manufacturer that you wouldn't expect to be tearing up the local roads is Volvo. It's a little known secret that Volvo have some legendary cars to their name but to anyone who isn't a fan of cars they're usually associated with the caravan club (count how many XC90s you see pulling a caravan this summer). Volvo have released a few sleepers in their time, the Volvo 850R springs to mind, but my favourite is the S40 MK2, probably because I own the one in the picture.
The S40 to the naked eye looks like any other compact motorway cruiser, destined to a life of business trips to and from London and most of them probably are. But what if Volvo decided to take that office on wheels and drop a 2.5 litre, inline 5, turbocharged engine from a Focus ST where the diesel lump should be? well that's exactly what Volvo did. Making a punchy 220hp and 350nm, these cars can really shift and thanks to their strong engines and turbocharger they're easy to tune to make even more power, mine currently sits at 240hp/420nm (conservative figures) and its unbelievable fun.
The GMC Syclone
Lets take a break from saloon cars and talk about trucks, specifically the GMC Syclone. While the previous two names on this list are fairly quick, the Syclone would make them look like they'd left the handbrake on at the drag strip. Released back in 1991 the Syclone is one of the best examples of a sleeper around.
Looking at this truck you can obviosuly tell it's no ordinary pickup but would you really expect it to outrun the supercars of its day? because with a turbocharged V6 making 280hp/475nm and AWD it could sit with the likes of Ferrari and Lambo all day long in the quarter mile. its 0-60? 4.3 seconds IN A TRUCK.
Any list of sleepers without the Lotus Carlton is quite frankly not a complete list. A Vauxhall Carlton on steroids, the Lotus variant was an absolute monster in its day. On the outside, differences included a wider body kit, spoiler and vents. If you hadn't heard about the Lotus, you'd be forgiven for thinking someone crashed their Vauxhall into a Halfords at first glance.
But take one look under the bonnet and you'd see this was more than just a body kit. The Lotus used a 3.6 litre straight 6 with two turbochargers bolted on for good measure meaning it would see 60mph in 5 seconds and had a top speed of around 180mph.
Another working class hero that could take it to the supercars, The Lotus caused quite a stir when it launched with the Daily Mail even asking for it to be banned. One of the reasons the Lotus was so fast was it's lack of a speed limiter. Whereas most of the super saloons of the time, like the M5, were limited to 155mph the Lotus Carlton was absolutely not.
VW Passat W8
The VW Passat is another fairly regular motorway runner but back in the early 2000s VW wanted to change that. Nobody asked for this car, no traditional Passat buyer needed one either but here we are anyway marvelling over its nonsensical glory. One evening at a board meeting in Germany a group of mostly middle age businessmen in suits agreed unanimously that dropping a 4.0 litre W8 engine into their trusty motorway cruiser was a good idea.
The Passat range truly had an engine for everyone, starting at just 1.6 litres all the way up to the W8 we have here. Aside from some subtle hints like the wider tyres and twin exhausts there wasn't a huge difference visually from one to the other, especially once those W8 badges were ripped off.
The W8 Passat was a sort of test for the viability of VWs W engine that later found its way into the Veyron in the form of the W16. The 4.0 lump made around 275hp and lots of people rub their eyes in disbelief as it hammered into the distance with a 0-60 time of around 6.5 seconds and a limited top speed of 155mph.
VW Phaeton W12
One step up the insanity staircase and we're presented with VWs luxury barge, the Phaeton. This car was a hefty £70,000 or thereabouts when it dropped in the early 2000s but can now be picked up for a fraction of that price.
The Phaeton, as with all good sleepers, doesn't immediately scream out 'race car' but that perception changes once the pedal hits the metal. With 450hp wedged into place this was one seriously quick barge hitting 60 in 6 seconds with a limited 155mph top end.
The Saab 92-X aero (Saab-aru)
The Subaru Impreza is about as far away from a sleeper car as you can get, with a reputation the world over for being the car of the fully grown child. They're loud, they're fast and they're almost always modified. But what if you wanted all the rally inspired fun a Subaru brings without actually having to drive one? well, you're in luck.
The Saab 9-2X Aero is based on the Impreza wagon with a more upmarket styling, it has the same 2.0/2.5 litre turbocharged engine as the lary Japanese car as well as the all wheel drive system but comes with a more refined interior and the face of a Saab superglued onto its front end. These cars could reach 0-60 in just under 6 seconds thanks to their 230hp with plenty of room in the back for the dog.
The Honda accord (V6)
The accord is visually quite a boring car and can usually be found pottering around town or doing 35mph in a clearly signed 60mph road, so it makes a very good base for an unassuming sleeper car.
Surprisingly, Honda actually offered the Accord with a near 280hp V6 a few years ago that could propel the Japanese family saloon to 60 in under 6 seconds. Sadly you're unlikely to see this version on British roads as it was never released over here but you never know what someone's willing to import.
When most people think of BMW performance, they think M. The M division has long built a reputation for putting out some seriously fast cars and thanks to a power war with rivals, Mercedes and Audi, have become synonymous with performance vehicles. From super straight 6's to the infamous V10 M5, No ones expecting any BMW to be slow slow.
When looking for a fast car, many people overlook diesels. They are somewhat brushed aside and considered to be below the performance standard of their petrol counterparts and, although they can look pretty mean in M sport trim, this is one of those cars that's all too often overlooked.
With the most recent 335D however BMW offer two very good reasons to opt for the 'lesser' option. Those reasons are 308hp and 630NM from a straight 6 that can jump the 335D to 60 in just 4.5 seconds (and thats before a remap). To put that Torque figure into perspective, the M3 of the same era has just 550NM although it was obviously the quicker car.
So there's your introduction into the world of the sleeper cars. Some look plain boring, some offer little hints of performance and some are just completely overlooked and underestimated. One thing they all have in common? nobody ever expects them to be as fast as they are. There's plenty more out there to find if you know where to look - just don't go telling everyone or you'll ruin the fun.