Fiat 131

The Fiat 131 used steel monocoque bodywork for its three-box design and used a front engine, rear-wheel drive layout, where the engine is longitudinally front-mounted. The gearbox is directly behind the engine, and a tubular propeller shaft, under the transmission "tunnel", transmits the drive to a solid live rear axle.

The engines were all inline-four types, derived from those used in the outgoing 124 range, with a cast iron cylinder block and aluminium alloy cylinder head. Initially the 131 was offered only with pushrod valve gear, which offered the innovation of being the worldwide first engine with OHV valve gear and a belt driven camshaft. Only later in the model's life came the well known double overhead camshaft (DOHC) engines which used a toothed timing belt. Fuel supply was via a single Weber ADF twin-choke carburettor, fed from a trunk mounted steel fuel tank. Traditional contact breaker ignition systems were used, usually with Marelli distributors.

The suspension system utilised fully independent front suspension, with MacPherson struts, track control arms and anti-roll bar. The rear suspension was quite advanced (when using a solid live rear axle), in that the rear axle was controlled by double unequal length trailing arms and a panhard rod, with coil springs and direct acting dampers. This design proved far superior to many of its contemporaries, especially with respect to vehicle stability and handling.

The braking system was also typical; the front brakes were disc brakes, using a solid iron disc and a single-piston sliding caliper. The rears were drum brakes (a technological backwards step from the 124, which used discs all round), utilising leading and trailing shoe design operated by a dual piston fixed slave cylinder. They were operated hydraulically, with a tandem master cylinder assisted by a vacuum servo using two separate circuits. A rear-mounted load sensing valve varied the bias of effort applied to the rear brakes, dependent on the load being carried (and also the pitch dynamics caused by braking effort and road levels). A centrally located floor mounted handbrake operated on the rear axle using bowden cables.

The car's interior had its secondary dashboard switches illuminated by a central bulb with fibre optic distribution to the switches.

The Fiat 131 Mirafiori was introduced at the 55th Turin Motor Show in late October 1974.[7] The 131 came with a choice of a 1,297 cc (1.3 L) or 1,585 cc (1.6 L) OHV inline-four engines, both from the engine family first introduced on the Fiat 124. Both engines were fitted with a single twin-choke Weber 32 ADF downdraught carburettor. A 4-speed manual transmission was standard, with a 5-speed manual and a 3-speed torque converter automatic optional on the 1600 engine only.

The initial range comprised eleven different models.[7] There were three body styles, all available from the start: 2-door saloon, 4-door saloon and Familiare station wagon (Estate on the British market).[8] Trim levels were two; the entry-level 131 Mirafiori (also known as "Normale" or "Standard") had single square headlamps, wheels and dished hubcap from the 124, and simplified interior furnishings. Next was the better appointed 131 Mirafiori Special (or simply "S"), which could be distinguished from the base model by its quadruple circular headlamps, specific grille, side rubbing strips, chrome window surrounds, and rubber bumper inserts.[7] Inside it added different instrumentation with triple square dials, a padded adjustable steering wheel, cloth upholstery, and reclining seats.[7] Additionally the more sophisticated options — such as air conditioning, tachometer, limited slip differential and vinyl roof — were exclusive to the Special. Each body style could be combined with either of the engines and trim levels, save for the Special estate which only came with the larger engine.

Initial sales were disappointing, since the car was launched at the height of the oil crisis and at a time of strikes and hyperinflation at home. Adding to manufacturers' woes, the cost of parts and materials all increased, while sales went down. Gradually, however, sales built up and the car also sold well in export markets. In 1975, the 131 went on sale in the United States as well. US market versions had a SOHC 1.8 litre inline-four, carried over from the earlier 124 but now with more emissions control equipment, and were available with a GM three-speed automatic transmission.[9]

Salvatore Diomante's Autocostruzioni S.D., located near Turin, offered a nearly 5-metre long "131 Diplomatic" limousine conversion.[10]

Model	Engine code	Engine type	Displacement bore × stroke	Carburetor	Power
Mirafiori 1300	131A.000[11]	OHV I4	1,297 cc (1.3 L) 75.0 × 71.5 mm	single twin-choke Weber 32 ADF	65 PS DIN (48 kW; 64 hp) at 5400 rpm
Mirafiori Special 1300
Familiare 1300
Mirafiori 1600	131A1.000[11]		1,585 cc (1.6 L) 84.0 × 71.5 mm		75 PS DIN (55 kW; 74 hp) at 5400 rpm
Mirafiori Special 1300
Familiare 1600
Familiare Special 1600
Abarth Rally[12]	n/a	DOHC 16-valve I4	1,995 cc (2.0 L) 84.0 × 90.0 mm	single twin-choke Weber 34 ADF	140 PS DIN (103 kW; 138 hp) at 6400 rpm
US version	131A1.040	SOHC I4	1,756 cc (1.8 L)	single twin-choke Weber	86 hp SAE net (64 kW; 87 PS)[9] CA: 83 hp SAE net (62 kW; 84 PS) at 5800 rpm

• 
  Fiat 131 Mirafiori Special
• 
  The "T"-shaped tail lamps are characteristic of first series cars.
• 
  Series 1 dashboard, here a Mirafiori Special's
• 
  SEAT 131 Estate
• 
  US-spec 1976 Fiat 131 four-door, showing the larger bumpers used to meet strict federal safety standards.

The 131 got a minor facelift in 1978. New DOHC, or "Twin Cam" (TC) engines arrived, and these models were badged as Supermirafiori. The biggest changes exterior-wise for the Series 2 were larger rectangular shaped front lights (quad round headlights in the US), new bumpers (for the Supermirafiori), new bigger rear lights, while a new interior (CL, Supermirafiori) included the dashboard and a chunky, single-spoke steering wheel.

Also in 1978, the 2-door sporting version Racing (Mirafiori Sport in the UK) with 115 PS (85 kW) twin cam engine, was launched. This car had four round headlights (the inner headlights being smaller than the outer ones, unlike any other Mirafiori model produced), different grille, spoilers and extended wheel arches, and a short-throw 5 speed gearbox. The Racing had top speed of 180 km/h (110 mph). Diesel engined versions also had four round headlights (equally sized), and a noticeable (and characteristic) bump in the hood to accommodate the taller engine. The Familiare (estate) was renamed as Panorama.

In Venezuela, the 131 Series 2 was kept in production after the Series 3 had been introduced in Europe. They were only available with the four-door sedan bodywork, as the Mirafiori L and the Mirafiori CL, and were fitted with the Panorama's OHV 1.6-liter engine with 75 PS (55 kW; 74 hp). An additional version was the sporting "131 Corsa 95", which used the 131 Racing's front spoiler, grille, rear spoiler, and other parts (still with four doors) along with the twin cam Supermirafiori engine and a sizable bonnet scoop. In Venezuela, this engine produced a claimed 95 PS (70 kW; 94 hp) at 6000 rpm.[15]

The Series 2 was marketed in the United States as the Fiat Brava (two-door only) and Super Brava from mid-year 1978 with the same 1.8 litre four as had been used in the US-market 131, but before the year was over this was replaced by the somewhat more powerful and much torquier 2 litre twin-cam four also seen in the Spider.[16] Initially, the better equipped models were sold as Super Bravas, but the base model and "Super" tag were dropped for 1979. The interim Brava version also retained the 131's interior.[17] Importantly, the air conditioning system was also upgraded to cope with the demands of US drivers. For 1980 a more powerful fuel-injected version was added (102 hp or 76 kW) while the Estate version was dropped. For 1981 the EFI engine became standard equipment and the headlamps were changed for single rectangular units, but this was to be the last year for the Brava/131 in the US.[18] The January 1991, edition of Popular Mechanics in the United States listed the 1979 Fiat 131 in the "Overall Worst" category as the most "trouble prone" car ever recorded in their Owner Report histories.[19]

• 
  Fiat 131 Supermirafiori
• 
  Series 2 dashboard
• 
  Fiat 131 Racing
• 
  Fiat 131 Marengo, van version of the 131 Panorama estate

The 131 was updated again in March 1981.[24] By this time, the car was no longer offered in the USA. Production of the Racing/Sport versions ceased, although these were sold well into 1982. The same 2.0 TC (twin cam) engine went to the Supermirafiori. The car was renamed 131 Super Brava in Australia. The car received a slightly updated interior (instruments, single-piece glovebox lid), whilst lower rubbing strips found their way onto all models up to CL specification. The Supermirafiori received larger lower door cladding. Mechanically, Mirafiori versions now received overhead cam engines rather than pushrod versions; a new 1.4 litre engine and a revised 1.6 litre. Also new were the clutch and gearboxes, a tweaked suspension was also introduced and the gas tank increased in size by three litres, for a total 53 L (14.0 US gal; 11.7 imp gal) capacity.

In June 1981, a new sport version, the Volumetrico Abarth, was introduced to some markets, with a supercharged version of the familiar 2-litre twin-cam. This car, also known as the 2000 TC Compressore, was built in a small series (about 200 units[25]) and could reach 190 km/h (118 mph).[26]

In 1983, the production of the saloon version was discontinued, but the estate, now named 131 Maratea, remained in production with two engine choices (115 PS 2.0 TC and 72 PS 2.5 D) until 1984, when they were replaced with the Ritmo-based Regata Weekend. These last versions featured four round headlights and the by-now familiar five-bar grille.

In Australia the saloon was also updated for a final time for the 1984 model year. It also received the 4 round headlight and five bar grille. Other subtle revisions were also made to the vehicles wiring with the central locking button removed and integrated into central locking motors. Wheels were upgraded to a 14-inch size with unique offset . Driveshaft universal joint size was increased . Steering rack ends and tie rod ends were sizing was also changed. Brake master cylinder bore size was increased to 20mm and brake fittings changed to a metric fine thread size.

• 
  Profile of a 131 Supermirafiori Diesel 2500
• 
  Fiat 131 Supermirafiori, rear view
• 
  Fiat 131 Volumetrico Abarth

Wikimedia Commons has media related to Fiat 131.

• 131mirafiori.com
• 131abarth.com
• Italia.Haven: Irish and European forum for Fiat owners

• Fiat Marengo