Stretch Limousine

Overview

A stretch limousine is a coachbuilt vehicle: a production sedan or SUV that a specialist builder has cut in half and lengthened, turning the rear seat area into a passenger lounge. The donor car arrives complete, and the builder removes the centre, splices in a fabricated section, and re-skins, re-wires, and re-trims everything that crosses the cut. The result keeps the donor manufacturer's front and rear styling but adds a lounge in between. Almost every system has to be modified to suit: the Stretched Chassis is spliced, the Driveshaft lengthened, the Suspension System uprated, the Body Electrical doubled, and a Passenger Lounge built where the boot floor used to be. Reputable builders work to manufacturer coachbuild programmes such as Ford's Qualified Vehicle Modifier scheme so the modified vehicle still meets crash and emissions rules.

Stretching the chassis

The structural job is the hardest part. The Stretched Chassis is cut behind the front seats, and the donor Front Frame Section and Rear Frame Section are rejoined by a fabricated Stretch Frame Insert of box-section steel rail. The splices are fish-plated and continuously welded, never simply butted, because the long frame sees far higher bending loads than the original. A stretch removes torsional stiffness, so the builder welds in extra Frame Crossmember bracing and boxes the Rocker Reinforcement sills to put it back. The propeller shaft cannot simply be lengthened as one piece at these spans, so a two-piece Driveshaft is fitted with a Centre Bearing supporting its midpoint, keeping the shaft below its critical whirl speed. A floor section, the Floor Insert, and a welded Roof Insert close the body over the new frame.

Powertrain and cooling

A finished limousine can weigh 3 to 3.5 tonnes, well over the donor's gross rating, so the Powertrain is chosen for torque rather than outright power. The V8 Engine is a 5 to 6 litre naturally aspirated petrol unit, with its Crankshaft, eight Piston assemblies, and two Cylinder Head castings, delivering strong low-rpm pull for a heavy vehicle that mostly cruises. The Automatic Transmission is a multi-speed torque-converter automatic; its Torque Converter lockup and Valve Body are calibrated for smoothness. Because a limousine spends long periods idling with full air-conditioning, the Cooling Pack pack is oversized, pairing a large Radiator with a dedicated Transmission Cooler. The Fuel Tank is usually relocated and enlarged to clear the new floor and restore range.

The passenger lounge

The point of the whole exercise is the Passenger Lounge. Where a sedan had a rear bench and a boot, the limousine has a salon. Seating runs around the perimeter as a J-shaped Perimeter Bench Seat facing inward, often with forward-facing Seat Assembly jump seats so eight to fourteen passengers face each other. A Bar Console with glass holders and an ice well sits along one side. The roof carries a padded Headliner, frequently with a fibre-optic starlight pattern, and the floor is laid with thick Floor Carpet over the Floor Insert. Upholstered Trim Panel sections cover the doors and sides. A glazed Privacy Partition separates the lounge from the driver, its powered Privacy Glass raised by a Window Motor and backed by an Intercom so passengers can isolate themselves or talk to the chauffeur.

Suspension, brakes, and ride height

Adding two-thirds of a tonne over a longer wheelbase changes how the car sits and stops. The Suspension System keeps the donor Suspension Corner units at the front but replaces the rear coils with Air Spring air bags. An Air Compressor and a Levelling Valve hold the rear at a set height whether the lounge is empty or carrying a full party, so the headlamps stay aimed and the long body does not drag. Braking is uprated through the Brake Corner assemblies, and the larger Wheel Assembly units spread the load. The long overhangs and soft rear give the deliberately gentle ride a limousine is meant to provide.

Electrical, climate, and entertainment

The donor wiring was never designed to feed a lounge, so the Body Electrical system adds an Auxiliary Fuse Panel and extra Wire Bundle looms, backed by an Auxiliary Battery and a higher-output Alternator. The factory air-conditioning cannot cool a cabin this large, so the Climate System system adds a rear Rear Evaporator, extra Blower Motor units, and a PTC Heater Core with its own HVAC Ducting runs. Finally the Entertainment & Lighting package is what passengers remember: LED Accent Lighting accent strips, LCD Panel screens, a multi-channel Audio Amplifier feeding the Speaker array, and a Control Panel that puts lighting, audio, climate, and the partition under passenger control. These loads, not the engine, are why the limousine carries a second battery and a beefed-up charging system.