Divergence

We compare the evergreen 328 GTB to its little-known Italian-market counterpart: the GTB Turbo.

Divergence 1
July 19, 2018

When examining the wave of turbocharging that has swept through Maranello over the last several years, most enthusiasts look back to the 1980s and the mighty F40, the last blown Ferrari offered for sale before the arrival of the California T. The F40 wasn’t a one-act play, though; it was a grand finale to a composition carefully orchestrated throughout the entire decade, a performance that included more than just supercars.

Initially, as in recent times, Ferrari didn’t really want to move to turbos. Although the company’s period PR efforts tied the change to its success in Formula 1—the turbo-charged 126C-series cars won back-to-back World Championships in 1982 and ’83—and the 288 GTO and F40 arose from the factory’s plans to enter Group B racing [We told that story in last issue’s “The Rally Years”—Ed.], the most significant motivating factor was likely an Italian tax law introduced in mid-1970s that imposed a 38-percent luxury tax on all new cars with an engine capacity greater than 2 liters.

Ferrari reacted to the new tax, in 1975, by refitting the 308 GT4 with a 1,991cc V8. Based on the model’s 255-hp 3-liter Tipo F106 V8, the 208 GT4 version reduced both the bore and stroke and produced 170 hp. Five years on, the company introduced a similar 2-liter version of the new 308 GTB (and later GTS). Despite the introduction of Bosch K-Jetronic fuel injection, these cars never caught on with Italian clients: During their two years of production, just 300 208 GTBs and GTSs were sold.

Divergence 2

The 308’s underpowered companion soon made way for a much more suitable model: the 208 GTB Turbo. Introduced at the 1982 Turin Motor Show, the Turbo’s 2-liter V8 enjoyed a significant boost to 220 hp courtesy of a single, non-intercooled KKK blower. Although much quicker than its predecessor, the turbocharged 208 didn’t sell much better, with only 687 examples built over four years.

There was clearly room for improvement. It came in 1986, one year after the introduction of the 328, when Ferrari once again released a sub-two-liter derivative. This time, the Italian-market model was simply called the GTB (or GTS) Turbo, eschewing the numerical part of the name which would indicate inferior engine size.

During these years, Ferrari’s naturally aspirated and turbocharged V8s continued along separate paths of development. The 308’s 2,927cc naturally aspirated F 105 CB 000 engine started with Weber carburetors, then switched to Bosch fuel injection; later, the original two-valves-per-cylinder heads were replaced with four-valve versions. After a few years, the 3-liter 308 Quattrovalvole smoothly transitioned into the 3.2-liter 328 with no significant engine changes bar the small increase in displacement and the addition of a new Marelli electronic ignition system. With 9.8:1 compression, the 328’s 3,186cc V8 was good for 270 hp at 7,000 rpm. Top speed of the GTB version was 163 mph.

Divergence 3

In the parallel 2-liter universe, the F 106 N 000 V8 also moved from carbs to fuel ignition but never adopted four-valve heads, meaning the 1986 GTB Turbo was still propelled by the 208 Turbo’s two-valve 1,991cc curiosum. However, the turbocharged engine did receive some significant external improvements, like Marelli electronic ignition, a water-cooled IHI blower (the same Japanese supplier that provided a similar unit for the F40, which was in production at the time), a wastegate with pneumatic control, and a Behr air-to-air intercooler.

With 1.05 bar of boost, the GTB Turbo achieved 254 hp at 6,500 rpm (then a record specific power output of 127 hp per liter) and 157 mph, the first time a car from this small-displacement lineup offered performance so close to its bigger-engined counterpart. Plus, since it was taxed at a low 18 percent, the GTB Turbo could lure clients with a 78,116,000 lire price tag, a significant drop from the cost of the 91,425,000 lire 328.

In addition to the tax discount, Ferrari’s turbocharged models offered a few visual improvements compared to their naturally aspirated counterparts. The 208 Turbo featured a pair of NACA ducts deployed just in front of the rear wheel arches (relegating the Pininfarina signature badge from its usual location to a spot behind the wheel) and a standard roof aerofoil that was otherwise optional. The 328-based Turbo went two steps further, receiving five slim vents in the rear bumper to aid air circulation under the engine cover, which itself now featured a hump that housed the intercooler. While these differences don’t leap out, they definitely add a bit of visual drama.

Divergence 4

MUCH MORE DRAMATIC is the difference in driving experience between this blue 328 GTB and red GTB Turbo. The contrast is easily noticed from the moment you slide inside the cockpit (the Turbo’s differs only in the addition of a Veglia Borletti turbo-pressure gauge) and turn the key in the ignition.

The 328’s V8 is Ferrari as we know it: a bona-fide superstar of an engine, blending superb flexibility and a subdued mechanical nature with a fierce alertness that can come only from a naturally-aspiration unit dating back to a true competition powerplant. The car doesn’t feel all that fast from today’s perspective, its 260 hp barely enough to fight with current hot-hatches, but the way each of these cavalli vapore [literally “steam horse,” a common Italian term for horsepower—Ed.] is deployed puts it on par with today’s finest performance cars—and perhaps a touch above them in terms of purity and fierceness. Where today’s supercars produce scary levels of power and are usually far more capable than their driver, the pilot of a 328 can take huge satisfaction in fully realizing the car’s potential, thanks to its comparatively limited performance, user-friendly handling, and a linear power curve that makes accelerating at every point entirely predictable—a trait that can be enjoyably exploited in the bends.

Where the 328 willingly cooperates with its driver, the GTB Turbo must be grabbed by the horns and forced. Just like in a period Porsche 911 Turbo or Lotus Esprit Turbo, the turbo lag and the surge of torque that follows are almost unexplainable unless you experience them. To really get to know the GTB Turbo, you need to leave your comfort zone and push it quite hard.

Divergence 5

The 2-liter turbocharged V8 only reveals its talents fully after passing the 4,000-rpm mark, yet as the speed rises the differences between the two engines begin to blur—or intertwine. While the naturally aspirated 328 possesses a natural advantage at low revs, in the middle region of the rev counter the Turbo accelerates more effectively. The turbo show ends all too soon, however, while the 328 zings ever harder toward the redline. (The V8s rev to the same 7,800 rpm.)

In both cases, the chassis easily manages the available power. The photos reveal two different versions of the classic five-spoke wheels: concave on the 328 GTB and convex on the GTB Turbo. This isn’t a matter of engine variety, but of a suspension overhaul—new geometry, steering, and anti-lock brakes—given to both series early in 1988. The later car’s convex wheels bring negative offset, which was intended to reduce squat and dive.

To my surprise, the more time I spend behind the wheel of the two Ferraris, the more I decide the suspension rework makes more of a difference in the driving experience than the type of engine. The 328 and GTB Turbo share the same basic straight-line performance and noise in the cabin.

Divergence 6

Ultimately, while the 328 provides the more enjoyable experience of the two, thanks to the slightly better performance and flexibility of its V8, it’s far from a blow out. From the perspective of its contemporary rivals, it can be argued that the Turbo is reasonably civilized—the lag isn’t as huge as it could be, while period publications complimented the car for its smooth building of speed.

From an ownership perspective, the 328 also makes more sense than the GTB Turbo. The naturally aspirated V8 is a gem, as well as one of the strongest points of the model, so chucking it for a smaller engine from the pioneering days of turbocharging is a big ask. And when thinking of buying a Turbo there’s also no way around the fact that the IHI blower and its associated hardware are just more expensive items on the list that will someday break.

Still, there’s something very appealing about the GTB Turbo. Its subtle but purposeful body modifications, its fantastic sound (a bit like a fighter jet doing a low pass), its bombastic engine, even the small joy of seeing another gauge on the familiar dash…and its rarity. There were no fewer than 7,413 328s built over the course of four years, of which 1,345 were GTBs out of them. During the same period just 1,136 Turbos were made, of which 308 were GTBs. The car seen here, a post-1988.5 GTB, is the rarest of the breed: only 44 were built.

Divergence 7
Divergence 8
Divergence 9

Also from Issue 168

  • One-off SP38
  • 488 Pista first drive
  • 225 Sport
  • Market Update
  • Phil Hill's photography, Part 1
  • Miguel Molina interview
  • F1: Ferrari vs Mercedes
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