The Maserati Biturbo (pronounced Bee-Turbo) was introduced into the United States during the 1984 model year. The Biturbo coupe featured a 2.5L V6 SOHC engine that developed 185hp at 5500rpm. The Biturbo had originally been introduced in Europe in late 1982 with a 2.0L engine. Specifications for the European cars can be found from an article in the magazine Auto Italia.
The engine was derived and heavily modified from the 2.0L Maserati Merak engine used in the Italian home market. It was an aluminum 90 degree V6 with cast iron wet cylinder liners, three valves per cylinder, with one exhaust valve and two intake valves of dissimilar sizes. The engine bore was fat (91.6mm) with a relatively short stroke of 63mm. Two IHI turbochargers sat underneath the cylinder banks and blew air through a single 2 barrel Weber carburetor housed atop the engine in a plenum chamber. Peak torque of 208lb-ft was available at a low 3000rpm, and combined with a weight of around 2700lbs, helped propel the car from 0-60mph in about 7 seconds.
The Biturbo had a 5-speed manual ZF transmission, manual rack and pinion steering, and a leather interior. The front suspension was MacPherson strut, and the rear was an independent semi-trailing arm design. Large non-ventilated ATE disc brakes were at the front and rear, with 4 piston fixed calibers up front, and 14" 4-bolt wheels.
In 1985, the Biturbo was offered in the USA with the options of power steering and an automatic transmission. The Sensitork differential began to appear during this model year, a limited slip differential which replaced the earlier Salisbury unit.
A higher performance version of the Biturbo, called the E model, was offered during 1985 only. The E model had two-tone paint, firmer and shorter springs, a stiffer front anti-roll bar, revalved shocks, larger tires (205/60-14 instead of 185), and different wheels. The Biturbo E had the options of either dual air-to-air or air-to-liquid intercoolers, the latter made by Spearco and available only on cars sold on the west coat. With the dual air-to-liquid intercoolers, the engine produced 205hp@5250rpm and 260lb-ft at 3500 rpm. The Biturbo E sprinted to 60mph in about 6.3 seconds.
For the 1986 model year, the 2 door coupe was temporarily dropped from the lineup and two new models arrived: the Biturbo Spyder, a convertible, and the 4-door Biturbo 425. All cars were equipped with automatic transmissions and power steering, and water-cooled IHI turbochargers replaced the previous oil-cooled units, which tended to improve the reliability of the turbochargers. A slightly smaller Weber carburetor was fitted. The Spyder had a shorter wheelbase than the earlier coupe and seats for only 2 people, but the mechanicals were much the same. The 4-door sedan had a slightly stretched wheelbase and increased height over the coupe.
For 1987, the coupe was re-added to the model lineup and the Weber carburetor was replaced with a Weber Marelli fuel injection system. The lineup became the Biturbo Si (coupe), the Biturbo 425i (4-door), and the Spyder. All cars were fitted with twin air-to-air intercoolers and 5-speed manual transmissions. (Some 1987 cars still had carbureted engines and automatic transmissions). Engine power increased to 187hp at 5500rpm, with torque measured at 240lb-ft at 3000rpm. The 0-60mph times dropped to around 6.5 seconds.
During the 1988 model year, no Biturbos were shipped to the United States.
For 1989, many important changes took place. The engine displacement was increased from 2.5L to 2.8L, and power was up to 225hp at 5600rpm and 246lb-ft of torque at 3500rpm (250hp in Europe). The Spyder continued, and the new 228 and 430 models replaced the previous coupe and 4-door, respectively. The Biturbo name was dropped, but the Biturbo heritage was evident in the new cars. The 228 featured a redesigned 2-door body with a stretched wheelbase over the original coupe. The 430 remained similar in appearance to the earlier 425 model.
All cars featured upgraded suspensions and brakes, including ventilated disc brakes and floating calipers, a new "Ranger" limited slip differential, dual exhaust, and larger 15" 5-bolt wheels. A 4 speed automatic transmission became an option. Other improvements included a copper radiator that replaced the aluminum unit, and automatic climate control. The intake valves in the engine were changed to be the same size.
The lineup continued mostly unchanged in 1990, and only a few 1991 model year Spyders were shipped to the USA. Maserati left the USA market after that time, continuing to develop and sell the Biturbo model line elsewhere in the world.
|
Model Summary
|
| Transmission | Body Style | ||||||
| Year | Fuel System | Manual | Automatic | Turbos | Coupe | Sedan | Spyder |
| '84 | Weber Carb | 5-speed | Oil-Cooled | ~2000 | |||
| '85 | Weber Carb | 5-speed | 3-speed | Oil-Cooled | ~2200 | ||
| '86 | Weber Carb | 3-speed | Water-Cooled | 646 | ~300 | ||
| '87 | Fuel Injection | 5-speed | Water-Cooled | X | X | ~200 | |
| '89-'90 | Fuel Injection | 5-speed | 4-speed | Water-Cooled | X | 158 | 94 5-speed, 32 automatic |
| '91 | Fuel Injection | 4-speed | Water-Cooled | 12 | |||
| "The Biturbo zips to 60 mph in 6.8 seconds and reaches 100 mph in only 21.4 seconds, covering the quarter mile in 15.3 seconds at 91 mph in the process. ... [It] will actually run with a Ferrari 308 Quattrovalvole up to about 90 mph. Above 100, the Maserati's bluff shape attenuates its acceleration considerably, finally arresting it at 125 mph." |
| -- Car and Driver, April 1984 |
| "Twin turbos or not, there was lag; everything is relatively placid until the tach needle approaches 4000 rpm, and then -- blast off! The sudden burst of power can be dicey at the proverbial 10/10ths, as the somewhat tail-happpy Biturbo wants to switch ends. The car's powerful brakes are a bit rear-lock sensitive too. And the engine, despite its willingness to rev, occasionally hiccups on acceleration. But then, that's entertainment!" |
| -- Road & Track, August 1990 |
| "[We] found that the [automatic] does lag behind the 5-speed up to about 30 mph, but by 60 it's within a tenth of a second, and from there on up the automatic moves smartly past the manual, establishing a lead of nearly a full second by 80 mph. ... With the automatic, however, much of the peaky power characteristic of the blown 2.5-liter engine is masked, the torque converter's slippage also allowing quicker turbo response." |
| -- Road & Track, January 1986 |
| "Although the 425 [automatic] might be a slug from 0 to 30 mph, its true personality becomes evident on the freeway. At extra-legal speeds, it gives you a Superman-like sense of invulnerability; bullies could bounce off its windshield. Rolling along through knots of traffic, it feels like a mako eating its way through a school of minnows." |
| -- Car and Driver, May 1986 |
| "The two small blowers spin up to working speed quickly and deliver useful boost even below 2000 rpm. By 2500 rpm (about 60 mph in top gear), the blown V-6 can press you into your seat at the same instant the throttle is pressed. The engine generates little noise or vibration, just a trace of coarseness at low rpm and at full throttle. " |
| -- Car and Driver, April 1984 |
| "More recently the highly original twin turbo V-6 has made a significant contribution to the superb performance of the 3.2-litre engine used on the current Maserati." |
| -- Maserati Factory |
|
"The power is there in abundance, ... but it
still comes in with a bang, rather than progressively.
This means the driver has to be alert when combining
high revs and high g-forces, because the sudden change
in power available affects the cornering stability.
... Our skidpad figure was improved from 0.78 to 0.81g [for the Biturbo E], but the slalom speed -- down to a mediocre 55.8 mph from 60.7 for our previous Biturbo -- demonstrated the nervosita', a mismatching of engine and suspension characteristics at their extremes, plus steering, that is rather slow. In fairness, the Biturbo E performs well when driven vigorously on winding roads; it requires quite a bit of wheel-sawing, but that's part of the fun. Most drivers will find the Biturbo E entertainingly manageable in 8/10s driving." |
| -- Road & Track |
| "The convertible top looks good when it's up and great when it's down. It's not a power unit, but it goes up and down easily. ... Over irregular pavement, the chassis shows no tendency to wander. You feel the quake of big bumps through the cowl, but your line never wavers." |
| -- Car and Driver, September 1987 |
| "Interior design [of the 430] is, for the most part, delightful. The leather Recaro-look seats are supportive when you're cornering hard and comfortable when you're not; large, readable instrument faces are arranged under a hooded dash cowl and are unobscured by the steering wheel rim; and the thoroughly modern panel design is relieved by a gold-plated Swiss-made Maserati designer clock." |
| -- Road & Track, February 1989 |
| "Contemporary construction techniques aside, there is evidence of considerable hand labor inside the Biturbo. In place of the stark plastic lining of many European cars, the Biturbo has hand-stitched upholstery, wood veneers, and a suede headliner. Only the seat faces are trimmed in genuine leather, but the imitation hides look good. The parts aren't fitted with the loving care lavished on a Rolls, the stitching lacks military precision, and the veneers are rough around some edges, but the overall impression is one of regal opulence." |
| -- Car and Driver, April 1984 |
|
"There's little doubt that a series of niggling problems
with the first-edition Biturbos helped dash the model's
early popularity. Mis-set carburetor float levels caused
the engines to stumble during left turns, pickup wires in
the distributors cracked from the heat, water ran through
cylinder sleeves, fluids leaked from faulty seals throughout
the drivetrain, fuse boxes melted, and coolant temperature
warning lights came on even when engines weren't over-heating.
Clutches, timing-belt tensioners and water pumps had to be
redesigned early on.
It was quite disheartening. Nonetheless, it's amazing a small company like Maserati with no experience in volume production fared as well as it did with the Biturbo. In fact, while the Biturbo's failings were always annoying, they were usually not serious. And nearly all the car's bugs were eventually worked out with upgraded parts. ... Most notable of all, our experts wholeheartedly agree that the basic Biturbo engine -- the block, pistons, etc. -- is virtually indestructible." |
| -- Road & Track, August 1990 |
| "Maserati boss in the 1980s was none other than the headstrong Alessandro de Tomaso. He did not have the time or luxury to fully sort the early cars before launching them on the modern Maser-hungry masses. After-sales problems were considerable and together with other factors led to the Fiat takeover in 1993. ... Mechanical condition is the most important consideration when choosing a Biturbo. Oil leaks, lack of turbo boost, exhaust smoke, engine knocks, low oil pressure and differential noise are going to cost plenty to fix. ... Basic engine design is very good. The wide (90 degree) all alloy V6 motor is reliable if fed with the right fuel mixture and kept at the right temperature." |
| -- Auto Italia, Jan/Feb 1996 |
Here's a primitive VIN decoder for North American cars that I
created by decoding a list of VINs. It is incomplete and
not guaranteed to be accurate. The following VIN is
for an '84 Biturbo coupe.
The following information is incomplete and is not
guaranteed to be accurate.
Michael Dop was kind enough to allow me
to use this
technical bulletin from the Maserati factory
regarding the use of
unleaded fuel in Biturbo engines outside of the USA.
Performance Data
VIN Decoder -- North America
ZAMAL1105EB318056
^ ^^ ^^
| || ||___
| || +---- Body, 31=coupe, 32=425 or 430, 33=Spyder, 34=228
| ||
| |+------ Year, E=84, F=85, G=86, H=87, K=89, L=90, M=91
| +------- Check Digit
|
+------------ Body Style, A=coupe, B=sedan, F=spyder
Serial Number Decoding, European Cars
ZAM331B00KB119189
^ ^
| |
| |
| |
| +------ Model Year, J=88, K=89, L=90, M=91...
|
|
|
+---------- Class,
9 = Shamal and Karif
7 = Qporte IV
6 = Ghibli and derivatives, incl. GT
4 = 228
2 = 425, 430, and 4.24v.
1 = 222 and derivatives, incl. 222 4v
For more information, visit the
WMI Pages. Please note the following important statement
from those web pages:
"Note that the year code can be the calendar year in which a
vehicle is built, or a model or type year allocated by the
manufacturer."
Use of Unleaded Fuel
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