Acquired in Formula 1, the turbo-charged 2-litre Ferrari V8 was developed further. The results were very good: specific power was raised to a record value of 127 bhp per litre and maximum torque was not only increased, but was now also available at a lower engine speed, substantially improving the car’s flexibility. Turbo boost came in gradually from as low as 3,000 rpm, making the car much more manageable.
In 1986 the Italian market “tax break” model, the GTB Turbo, together with its targa roof variant, the GTS Turbo, became the final developments of the transverse V8 engine 2 seat Ferrari series.
Essentially the GTB Turbo was, as the name implies, a turbocharged variant of the 328 GTB, but fitted with a 2 litre engine. Like the 328 GTB, the GTB Turbo model presented a softening of the wedge profile of its predecessor, the 208 GTB Turbo, with a redesigned nose that had a more rounded profile, that was complimented by similar treatment to the tail valance panel. The revised nose and tail sections featured body colour bumpers integral with the valance panels, which reflected the work done concurrently on the Mondial 3.2 models, with which they also shared a similar radiator grille and front light assembly layout.
Thus all the eight cylinder cars in the range shared fairly unified front and rear aspects, providing a homogeneous family image. The exhaust air louvres behind the retractable headlight pods disappeared, with an increase in the size of the front lid louvre introduced on the “QV” series, and a new style and position of exterior door catch was provided. The interior trim also had a thorough overhaul, with new designs for the seat panel upholstery and stitching, revised door panels and pulls, together with more modern switchgear, which combined to reflect the external updating details.
The GTB Turbo model had some differences that differentiated it from its normally aspirated cousin, notably a different engine lid louvre and raised central panel arrangement, a NACA duct forward of each rear wheel arch, and a row of five slim exhaust air slots in the rear valance panel. It also featured the rear of roof aerofoil, which was optional on the 328 series, as standard equipment.
The engine retained the Bosch K-Jetronic fuel injection system of its predecessor, but was fitted with an IHI turbocharger with a Behr intercooler operating at a boost pressure of 1.05 bar, with a Marelli MED 807 A electronic ignition system, to produce a claimed power output of 254bhp at 6500rpm. As with the earlier models the engine was mounted in unit with the all synchromesh five speed transmission assembly, which was below, and to the rear of the engine’s sump.
The GTB Turbo model continued in production for three years, during which time 308 examples were produced in the chassis number range 63277 to 83137. The early part of the series was numbered in the Ferrari odd number road car chassis sequence, and later examples in the continuous number sequence.