🏷️ Basic Information

Make:

Maserati

Model:

Biturbo

Model Variants:

425, 430, Spyder, Karif, E, II, III, Racing, Gransport

Engine Variants Covered:

2.0L, 2.8L, 3.5L

Years Covered:

1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993

Chassis Codes:

AM331, AM331C, AM331E, AM332, AM450

👋 Introduction

Positioning:

The Maserati Biturbo represented a significant shift for Maserati, aiming for a more accessible luxury sports coupe segment, competing with German and Italian rivals like BMW 3 Series, Mercedes-Benz 190E, and Alfa Romeo GTV.

Rivals:

BMW 3 Series (E30), Mercedes-Benz W201 (190E), Alfa Romeo GTV (Type 116), Porsche 944.

Distinctive Elements:

Twin-turbocharged V6 engines, sophisticated Italian styling, luxurious interiors, rear-wheel drive, often featuring sporty chassis tuning.

Target Audience:

Enthusiast owners, independent mechanics, and restoration specialists working on Maserati Biturbo models.

📋 Manual Details

Manual Scope:

Comprehensive workshop and service repair

Estimated Pages:

500+

Type:

Workshop Manual / Service Manual / Repair Manual

Languages:

English, French

Format:

Digital (PDF)

📖 Manual Coverage

Powertrain:

Engine mechanical, fuel injection (Weber Marelli, Bosch), ignition systems, cooling systems, exhaust systems, turbocharging (IHI, Garrett AiResearch) and intercooling systems.

Transmission:

Manual gearbox (Getrag 5-speed), Automatic gearbox (ZF 3-speed, 4-speed) repair, overhaul, and adjustment procedures.

Chassis:

Suspension (front independent, rear independent), steering (hydraulic power steering), brakes (ventilated discs, ABS), wheels, and tires.

Electrical:

Wiring diagrams for all models, lighting, instrumentation, power accessories (windows, seats, mirrors), HVAC controls, and engine control unit (ECU) diagnostics.

Body:

Body panels, doors, windows, locks, interior trim, and convertible top mechanisms (for Spyder models).

Maintenance:

Scheduled maintenance, oil changes, filter replacements, tune-ups, fluid checks and changes.

Repair:

Engine rebuilds, gearbox overhauls, turbocharger replacement, brake system repairs, suspension component replacement, electrical component troubleshooting and repair.

Diagnostics:

Troubleshooting guides for common and uncommon issues, diagnostic charts, error code interpretation (where applicable).

Specifications:

Detailed torque specifications, clearances, timing settings, fluid capacities, electrical resistance values, and component tolerances.

Depth:

Extensive, covering from basic routine maintenance to complete engine and transmission rebuilds, including advanced electrical diagnostics and bodywork repair.

📊 Manual Specifications

File Type:

PDF

Searchability:

Searchable text for quick information retrieval.

Printable:

Printable pages for workshop use.

Image Resolution:

High-resolution scans of original diagrams and illustrations.

Binding:

N/A (Digital Format)

Paper:

N/A (Digital Format)

Version:

Likely compiled from original factory service manuals for various Biturbo iterations.

⚙️ Engine Specifications

Engine Family:

Maserati Tipo AM572 (V6)

Configuration:

90-degree V6, DOHC, Twin-Turbocharged

Displacements:

1996 cc (2.0L), 2790 cc (2.8L), 3491 cc (3.5L, primarily for US market models like 430)

Power Output 2.0L:

Approx. 180-220 hp (depending on specific version and market)

Torque 2.0L:

Approx. 250-270 Nm

Power Output 2.8L:

Approx. 225-255 hp

Torque 2.8L:

Approx. 320-350 Nm

Power Output 3.5L:

Approx. 250 hp

Torque 3.5L:

Approx. 370 Nm

Induction:

Twin Weber Marelli or Bosch electronic fuel injection (EFI) with twin turbochargers and intercoolers.

Fuel Type:

Unleaded Petrol (Octane rating typically 95 RON or higher)

Type:

Pressurized liquid cooling system with engine-driven fan or electric fan assist.

🔧 Transmission

Gearbox Standard:

Getrag 5-speed manual transmission

Gearbox Optional:

ZF 3-speed (early models) or 4-speed automatic transmission

Clutch:

Hydraulically operated single dry plate clutch

Rear Axle:

Limited-slip differential (LSD) often standard on performance variants.

📐 Dimensions

Body Styles:

2-door Coupe, 2-door Spyder (convertible), 4-door Sedan

Wheelbase:

Approx. 2550 mm (Coupe/Sedan), varies slightly for Spyder

Length:

Approx. 4200-4400 mm (depending on variant)

Curb Weight:

Approx. 1300-1500 kg (depending on engine and transmission)

Gross Vehicle Weight:

Varies by model

🛡️ Safety Features

Crash Safety:

Limited formal crash test data available from the era; design focused on torsional rigidity for its size.

Braking System:

Front ventilated disc brakes, rear solid disc brakes. Optional Bosch ABS (Anti-lock Braking System) on later models.

Steering System:

Recirculating ball with hydraulic power assistance.

Seatbelts:

Three-point inertia reel seatbelts front and rear.

Lighting:

Halogen headlights, aerodynamic front turn signals and parking lights.

💡 Technology Features

Audio System:

Factory fitted Clarion or Blaupunkt cassette radio/player, often with amplifier and speaker upgrades available as options.

Climate Control:

Manual or automatic climate control systems (HVAC) with refrigerant typically R12 (now phased out, requiring conversion).

ABS:

Optional Bosch ABS system on later models, providing enhanced braking control.

Early Tech:

Basic analogue instrumentation, power windows, central locking, optional electric seats, and adjustable steering column. Early ECU management for fuel injection and ignition.

🔧 Maintenance

Oil Change Interval:

Typically every 5,000-7,500 km or annually, whichever comes first. Refer to manual for precise intervals based on driving conditions.

Spark Plug Replacement:

Every 30,000-50,000 km, depending on spark plug type (e.g., copper vs. platinum).

Timing Belt Replacement:

Crucial; typically every 40,000-60,000 km or 4-5 years due to interference engine design. Manual specifies precise interval.

Engine Oil Type:

API SG/SH or higher, SAE 10W-40 or 15W-50 (synthetic recommended for turbo engines). Check manual for exact viscosity and type.

Coolant:

Ethylene glycol-based antifreeze, typically a 50/50 mix with distilled water. Specific Mopar or Ferrari coolant may be recommended.

Brake Fluid:

DOT 3 or DOT 4 brake fluid, high-temperature synthetic.

Transmission Fluid Manual:

API GL-4 or GL-5, SAE 75W-90 or 80W-90 gear oil (e.g., for Getrag 265).

Transmission Fluid Auto:

Dexron III or equivalent ATF fluid (for ZF transmissions).

Power Steering Fluid:

ATF Dexron II/III or specific hydraulic fluid as per manual.

Common Problems:

Rust (especially around wheel arches, sills, and chassis outriggers), electrical gremlins (faulty relays, wiring harness issues, dashboard warning lights), carburetor/fuel injection tuning, turbocharger wear, aging rubber components (hoses, mounts), cooling system leaks, interior trim degradation, and differential whine.

Preventative Maintenance:

Regular underbody rustproofing, diligent electrical system checks, consistent fluid changes, and meticulous attention to the cooling and turbo systems are crucial for longevity.

📚 Vehicle History

Heritage Summary:

Maserati, founded in 1914, has a long history of producing high-performance luxury and racing automobiles, with a focus on sophisticated V8 and V6 engines and elegant Italian design.

Development Context:

The Biturbo was developed under the ownership of Alejandro De Tomaso, with the goal of producing a more affordable and mass-producible Maserati than its predecessors like the Bora or Merak. It introduced the twin-turbocharged V6 formula that would define Maserati for years.

Variant Timeline:

Launched in 1981 with the 2.0L engine. Subsequent years saw the introduction of the longer-wheelbase 4-door sedan (Biturbo 425/430), the open-top Spyder, and higher-performance variants like the Karif and Racing.

Production Period:

1981-1994 (with the last models effectively being successors like Ghibli II and Shamal built on the same platform).

Manufacturing Location:

Maserati factory, Modena, Italy.

🏆 Awards & Recognition

Awards Summary:

While the Biturbo itself didn't receive many specific awards in the way modern cars do, it was recognized for its performance and styling, and its success was crucial for the survival and resurgence of the Maserati brand in the 1980s.

Press Reviews:

Contemporary reviews often praised its spirited performance, unique styling, and luxurious interior, but also noted its temperamental nature and build quality issues, which the manual aims to address for owners.