Guide: Ferrari GTB Turbo & GTS Turbo

Oct 20

Oct 20 Guide: Ferrari GTB Turbo & GTS Turbo

Ferrari - Ferrari 208 - Ferrari 328 - 1980s Italian Cars - 1980s Supercars - Pininfarina

Background

During the energy crisis of the mid 1970s, Italy's government dramatically upped the tax rate for private motor vehicles with engines larger than two litres. Simultaneously, big tax reductions offered to vehicles with under 2000cc enticed several high performance auto makers to launch a new range of sub two-litre variants.

One firm to release a tax break model was Ferrari.

First to arrive was the Ferrari Dino 208 GT4 in late 1974. It was essentially a de-bored 308 GT4 that stayed in production until late 1980.

At this point, two-litre versions of the 308 GTB and 308 GTS were introduced: the 208 GTB and 208 GTS.

The normally aspirated 208 engine was then dropped in favour of a turbocharged motor during 1982. The arrival of forced induction meant Ferrari's home-market special was suddenly endowed with performance more or less on par with the 308 Quattrovalvole.

When 308 production ended in 1985, the 208 Turbo was discontinued.

Customers then had to wait a full year before a two-litre turbocharged version of the new 328 was introduced.

The resultant GTB Turbo and GTS Turbo were launched at the Turin Motor Show in November 1986. The GTB Turbo was a fixed-head Berlinetta while the GTS Turbo was a targa-topped Spider. They joined a Ferrari line up that included the Testarossa, 412i, Mondial 3.2 and 328.

Engine / Gearbox

The most fundamental difference between the 328 and these tax break variants was what lay in the engine bay.

At the heart of Ferrari’s latest ‘due-litri’ was a new Tipo F106 N 000 all-alloy 90° V8. Like its big brother, this small displacement unit was equipped with wet-sump lubrication and belt-driven dual overhead camshafts.

Bore and stroke was the same as on the 208 Turbo: 66mm and 71mm respectively. Engine size was 1991cc.

Although there was nowhere to go in terms of stretching displacement, Ferrari made some big power gains by fitting the latest turbo system and upping the compression ratio.

The original KKK turbo was switched for an IHI unit which ran at 1.05 bar compared to 0.6 bar beforehand.

Engine compression was increased from 7.0:1 to 7.5:1.

The intercooler came from Behr, Bosch supplied the K-Jetronic fuel-injection and the electronic ignition was Marelli Microplex.

Output rose from 220bhp at 7000rpm to 254bhp at 6500rpm. There was also much better turbo delivery and considerably more torque (242lb-ft at 4100rpm compared to 177lb-ft at 4800rpm).

The new turbocharged engine was easily identifiable on account of its high-rise natural aluminium intake casting.

Transmission was via a five-speed gearbox (with new ratios), a single-plate clutch and limited-slip differential. As usual, the engine and gearbox were mounted in unit.

Chassis

These uprated motors were dropped into tubular steel 328-style chassis with new type numbers: Tipo F106 AB/TR for the GTB Turbo and Tipo F106 AS/TR for the GTS Turbo.

Suspension was fully independent via unequal length wishbones, coil springs and Koni dampers. Anti-roll bars were fitted at either end.

As per the 328, a quicker steering rack was used than the outgoing 308-based variant.

The existing fuel tanks with a combined 74-litre capacity were retained. They were mounted either side of the engine, up against the rear bulkhead.

Ventilated discs brakes were installed all round along with 16-inch Speedline alloy wheels (7-inches wide at the front, 8-inches wide at the rear).

Most cars left the factory on Goodyear or Pirelli tyres.

Bodywork

The bodywork was largely identical to the 328 apart from some additional cooling features. Easiest of these to identify were then NACA ducts carved out from the sill ahead of each rear wheelarch and the five exhaust cooling louvres cut from the rear bumper.

Another unique feature was the engine cover which now had a bigger power bulge to accommodate the intercooler.

Like the 328, twin electric wing mirrors were fitted as standard. Also standard on the GTB Turbo and GTS Turbo was a matt black basket handle rear aerofoil.

All things considered, the 328 and its small displacement cousin were blessed with some of the most handsome bodywork of the era. Pininfarina's design was extremely popular in period and has aged better than most of its contemporaries. Extravagant use of grilles, spoilers and phoney ducts was rife at the time, but Pininfarina resisted the urge to be swayed by short-term fashion.

Interior

Much like the exterior, the interior was lifted almost straight from the 328.

The only new features were cloth seat centres as standard, Turbo script on the glovebox (instead of GTB or GTS) and a boost gauge in the main instrument binnacle.

Everything else was pure 328.

The 328 cockpit had been given a major update over the 308 Quattrovalvole. The centre console was revised, all the switchgear was revamped, a new supplementary control panel was added to the dash and orange-on-black instrumentation replaced white-on-black.

There were also new seats and door panels and the handbrake was moved from the centre console to the floor outside the driver’s seat.

Directly behind the three-spoke leather rimmed steering wheel were large read outs for road and engine speed. In between was the boost gauge, above which were additional instruments for oil pressure and water temperature.

A clock, oil temperature gauge and fuel read out were located centrally in the cockpit above the audio system and ventilation controls. The rest of the switchgear was mounted on the centre console behind the gear lever.

Options

The options list comprised leather seats, metallic paint, air-conditioning, fitted luggage, Pirelli P7 tyres and a full leather interior that extended to the dash, headlining and rear window surround.