The Fiat 131 is a mid-size family car manufactured and marketed by Fiat from 1974 to 1984 after its debut at the 1974 Turin Motor Show. Available as a two-door and four-door saloon and 5-door estate across a single generation, the 131 succeeded the Fiat 124.
The 131 was also marketed as the Fiat Mirafiori, after the Turin district where the cars were manufactured. Initially, the 131 was offered with 1.3 L and 1.6 L overhead valve engines and the range received revisions in 1978 and 1981. Production reached 1,513,800.
Specifications 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.
Series 1 (1974–1978) The Fiat 131 Mirafiori was introduced at the 55th Turin Motor Show in late October 1974. The 131 came with a choice of a or 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. 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). 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. Inside it added different instrumentation with triple square dials, a padded adjustable steering wheel, cloth upholstery, and reclining seats. 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 DOHC 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.
Salvatore Diomante's Autocostruzioni S.D., located near Turin, offered a nearly 5-metre long "131 Diplomatic" limousine conversion.
{| class="wikitable" style="text-align:center; font-size:90%;" ! Model || Engine code || Engine type ||style="line-height:1.2em;"| Displacementbore × stroke || Carburetor || Power |- |style="line-height:1.2em;"| Mirafiori 1300N |rowspan=2| 131A6.000 || rowspan="9" | OHV I4 ||rowspan=5| || rowspan="2" | single twin-chokeSolex C32 TD1||rowspan=2| (Germany-only version for low octane fuel use) |- style="line-height:1.2em;" | Familiare 1300N |- style="line-height:1.2em;" | Mirafiori 1300 |rowspan=3| 131A.000 ||rowspan="3" | single twin-chokeWeber 32 ADF 1|| rowspan=3| |- style="line-height:1.2em;" | Mirafiori Special 1300 |- style="line-height:1.2em;" | Familiare 1300 |- |style="line-height:1.2em;"| Mirafiori 1600 |rowspan=4| 131A1.000 || rowspan="4" | ||rowspan="4" | single twin-chokeWeber 32 ADF 3 || rowspan="4" | |- style="line-height:1.2em;" | Mirafiori Special 1600 |- style="line-height:1.2em;" | Familiare 1600 |- style="line-height:1.2em;" | Familiare Special 1600 |- | Abarth Rally ||131AR.000 | DOHC 16-valve I4 || || single twin-chokeWeber 34 ADF || |- |US version |132A1.040 |DOHC I4 | |single twin-chokeWeber 32 ADFA 1 | CA:
Special Performance Models Fiat 131 Abarth Rally In 1976, 400 examples of the Fiat 131 Abarth Rally were built for homologation purposes. These cars were built in a cooperation between Fiat, Bertone and Abarth. Abarth and Bertone had the strict order to stay as close as possible to the base model, both in parts choice and in physical appearance. Bertone took part-completed two door standard bodyshells from the production line in Mirafiori, fitted plastic mudguards front and rear, a plastic bonnet and bootlid and modified the metal structure to accept the rear independent suspension. The cars were fully painted and trimmed and then delivered back to the Fiat special Rivalta plant where they received the Abarth mechanicals.
The street version of the car used a DOHC 4 valves per cylinder derivative of the standard twin cam inline-four engine, equipped with a double downdraught 34 ADF Weber carburetor, producing at 6400 rpm and of torque at 3600 rpm. The street cars used the standard gearbox with no synchromesh (Rally type regulations required the use of the same type of synchromesh on the competition cars as on the street versions) and stock front brake discs, which performed better because the redesigned Bertone front and hood allowed for more air to cool them. The rear wheels had brake discs instead of the stock drums. Competition cars used dry sump lubrication and eventually Kugelfischer mechanical fuel injection. In race specifications, the engine produced up to in 1980, being driven to World Championship status by Walter Röhrl.
Fiat 131-2000 Racing Not to be confused with the European-spec 131 Racing, the Fiat 131-2000 Racing was a South African-built performance model that competed in the South African Group 1 standard car racing in 1978. The regulations of Group 1 racing required competing vehicles to be of a similar specification to their road-going counterparts. Before the 131-2000 Racing, the two-door Mirafiori coupé with a 1.6-liter pushrod engine and its twin-cam performance derivatives, namely the 131 Rally and 131 Rally-S, were the ideal road-going candidates for race tracks. Like its "131 Rally" cousins, the 2-liter 131-2000 Racing has a five-speed gearbox instead of the 4-speed unit of the Mirafiori coupé.
Some 200 imported component kits for 131 Racing reportedly perished when a cargo ship sank off the Kenyan coast, thereby thwarting Fiat's bid to meet the obligatory 100 units required for the Group 1 standard car contest. The lost parts reportedly consisted of Weber carburetors, camshafts, pistons, and limited-slip differentials. Fiat South Africa's motorsport division still completed 16 road-going models and a small number of racing and rallying cars from parts purchased on a trip to Italy, where Luigi Fincati, then the head of the division, allegedly hand-picked Fiat 131 Abarth components. Out of the 16 completed "street" cars, at least 12 known units remain roadworthy today. Pop Diedericks, one of the original racetrack drivers, retains possession of the racing unit he made famous back in the day.
The 131-2000 Racing benefited from the tweaking of the 2-liter, twin-cam Lampredi engine used in the recently launched Fiat 132 saloon. Engine modification involved the installation of two twin-choke 40 IDF carburetors to match a locally engineered inlet manifold, redesigned "banana-branch" exhaust manifolds, hot camshafts, high-compression pistons with a compression ratio of 10.2:1, modified air filters for the carburetors, and a special Abarth-developed air-intake system. The 131 Racing has a power output of and boasts a top speed of either , depending on the source. On the road-handling front, the car benefited from reinforced dampers and front and rear coil springs, a front stabilizer bar, and a limited-slip differential. The revised suspension system reduced the car's ride height by 30 mm. The redesign of the wheel camber reportedly gave the car "exceptional stability."
Inside, the rear and "sporty" front seats of the 131 Racing resembled the dark-red velvet units used in the lower-spec 131 Rally, which were notable for their color-coordinated vertical stripes. The Abarth "sport" steering wheel came with an adjustable steering column. On the exterior, the distinctive features of the 131 Racing included a black fiberglass bonnet and boot spoiler, an air scoop on the front bonnet, imported 6J Abarth alloy wheels mated to 185/70 SR13 tires, four quad headlights instead of the rectangular units of other two-door models, and "2000" badges on the rear fenders. According to the January 1979 edition of CAR Magazine, Fiat South Africa's initial objective was to release approximately 20 road-going 131-2000 Racing units per month to dealerships for a limited time.
Series 2 (1978–1981)
The 131 got a minor facelift in 1978. New DOHC, or "Twin Cam" (TC) engines arrived, and these models were badged as Supermirafiori. Mechanically, the steering geometry was changed which resulted in less understeer and lighter steering at low speeds.. 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. This interior design by Rodolfo Bonetto was awarded with a Compasso d'Oro in 1979.