A sleeper (US English) or Q-car (British English) is a car that has high performance and an unassuming exterior. Sleeper cars are termed such because their exterior looks little or no different from a standard or economy-class car. In some cases the car appears worse due to seeming neglect on the owner's part, typically referred to as "all go and no show". While appearing to be a standard or neglected car, internally they are modified to perform at higher performance levels. The American nomenclature comes from the term sleeper agent, while the British term derives from the Q-ships used by the Royal Navy.
The earliest known reference to the term 'Q-car' is in the February 1963 edition of Motor Sport magazine. The editor, Bill Boddy, said of the Lotus Cortina: "...the modifications carried out by Lotus have turned it in to a 'Q' car par excellence...". In the 1956 British film "The Long Arm" (aka "The Third Key") there are references to a Q car (unmarked)patrolling the city by night which indicates that the term was in use among UK law enforcement at least a decade earlier.
In July 1964, British magazine Motorcycle Mechanics carried an announcement from editor Bill Lawless of the use of two police 'Q–cars' – a black Daimler SP250 sports car and a green Farina Austin A40 – patrolling the A20 between London and Maidstone, Kent.
The Chrysler 300 letter series began in 1955 with the Chrysler C-300. With a 331 in³ (5.4 L) FirePower V8, the engine was the first in a production passenger car to be rated at 300 hp (220 kW), and was by a comfortable margin the most powerful in American cars of the time. By 1957, with the 300C, power was up to 375 hp (280 kW). These cars were among the first sleepers, marketed as high-end luxury cars from the traditional luxury marque Chrysler, but with a high-end homologation racing engine. However, these cars lose their "sleeper value" due to both their rarity (this series was highly luxurious; it was made in limited numbers and examples are very expensive), and the well publicized successes of Carl Kiekhaefer in NASCAR racing (1955–1956); though the car can be one of the creditors of the creation and popularity of muscle cars.
The Mercedes-Benz 450SEL 6.9 was a powerful sedan with an intentionally subdued exterior, and a popular choice on the options list was a removal of the '450SEL 6.9' badging from the car's trunklid. Without this badge, the car is visually identical to any other period Mercedes saloon and belies extreme performance. This trend of overtly powerful saloon cars with subtle body modifications is exemplified by the work of Mercedes-AMG and Brabus on unassuming Mercedes saloons. However, the brand Mercedes Benz itself is associated with high quality vehicles so even though these models have helped to start the trend, this car still loses out on its "sleeper" value even though some cars within the same body layout Mercedes-Benz W116 may not have matched the Mercedes-Benz 450SEL 6.9. Also some other car's performance brands have become so iconic that they too lose out on their sleeper status such as an "AMG" badged Mercedes-Benz or a "M" badged BMW.
The car which is most often credited as the start of the production Q-car trend in Europe is the Lotus Carlton/Omega; a car which started out as an Opel Omega/Vauxhall Carlton (which by public opinion, are considered to be non-high performance brands) but was handed over to Lotus engineers to create a 177+ mph 4-door saloon (at its time of release it was the fastest 4-door saloon available to the public and it remained in that position ten years later) with the exact body of the car it was created from despite its Imperial Green colour (British Racing colours), discreet Lotus badging, and flared body pieces. This supercar-rivalling speed was never advertised however due to both protests jointly by Mercedes-Benz and BMW (they had agreed to limit their cars to 155 mph; yet this car can easily go 20 mph faster) and by police who believed that it was a generally unsafe car and an invitation to speed. However the car was released at the oncoming of a recession so it never gained much popularity due to costs (insurance for example). The fact that its top speed was never advertised as well also lessened its potential sale figures and helped to boost the car's reputation as a sleeper.
Other vehicle owners create sleepers by swapping more powerful engines or other performance modifications like turbochargers, leaving the external appearance exactly the way it came from the factory. Sometimes hints of the car's true nature show if one looks and listens carefully: wider tires, a lower stance, or a different engine tone or exhaust note. Gauges and instrumentation are often kept to a minimum. Some owners go as far as to use weight reduction techniques employed by other performance enthusiasts, such as removing items not fundamental to street racing, such as rear seats, interior trim, spare tire, air conditioner, power steering, or even the heater.
In some countries, customized sleeper vehicles (as with other heavily modified street cars) may be considered illegal for road use because the car's level of performance is higher than intended by the vehicle manufacturer; if the owner has focused only on straight-line performance, the existing braking, steering, tires, and suspension systems may have been rendered inadequate. The emissions control system (such as intake and exhaust restrictions or the EGR system) is often bypassed or removed entirely in customized sleeper vehicles.
Owners sometimes reduce the evidence that their high-performance car is such by removing characteristic badging and trimmings. Sleeper cars often contain stock body work and wheels found on their less-capable brethren to better blend with other traffic and appear unassuming. Some owners simply like having performance without show, but a more predatory use of the sleeper is in street racing, where it is used to fool an opponent into underestimating a car's performance for the purposes of "hustling". Some have even gone so far as to leave their cars' exteriors banged up and rusting and sometimes even causing additional rusting with the use of battery acid. Often older cars from the 1930s to 1970's could look like restored stockers but with uprated drivetrains, including suspension and brakes as well as engine swaps . These are closely related to resto rods and rat rods.
Sometimes sleepers will be cheaper to insure when compared to an equally fast sports car, but some insurance companies may refuse insurance to owners of heavily modified vehicles. Successfully and intentionally performing this feat may be considered insurance fraud.
The term "sleeper" is sometimes used in the PC gaming community as well to refer to a powerful computer that has been built into a plain-looking and rather unassuming chassis. Also known as "Sleeper PC".
- Rodrez. "1994 Honda Accord EX - Sleepers: A Modern Day Wolf In Sheep's Clothing". Honda Tuning Magazine. 2010-09-07. Retrieved 2011-05-25.
- "Sport Compact Car Terms & Phrases - Information". Modified. Retrieved 2011-05-25.
- Motorcycle Mechanics, July 1964, p.3. To deter or detect? "If you drive down the A20 between London and Maidstone, keep a careful eye on the four–wheel boys...Because there are several police patrols in the area disguised as normal vehicles. Watch out particularly for a black daimler SP250 sports car and a green Farina A40...I've no doubt that these police 'Q-cars'—the Daimler particularly—pick up dozens of offenders every day...Everyone concerned in any way with motoring should clamour against 'Q-cars' and hidden radar traps, too". Accessed 2014-02-16
- Hasson, Randy (April 2010). "Hybrid How-To: CB/CD (4G/5G) Accord Chassis with H22 Engine". Modified. Retrieved 2011-05-25.