MGB Turbo Kit by Moss
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Transform your MGB's power and drivability with a comprehensively engineered, bolt-on turbo system delivering up to a 76% horsepower increase.
The Moss MGB Turbo Kit brings reliable forced induction to your classic British sports car. Featuring a modified water-cooled turbo, based on the original Borg-Warner design, and a specialized SU HIF 44 blow-thru carburetor, this kit offers an immense leap in low-end torque. Experience aggressive acceleration without sacrificing OEM-like drivability or managing complex cool-down periods.
Key Highlights
- Direct-Fit Performance Upgrade: A comprehensively engineered, bolt-on forced induction solution designed specifically for the MG MGB.
- Proven Components: Features a modified turbocharger based on the original Borg-Warner design and a specially-prepared SU HIF 44 Turbo "Blow-Thru" Carburetor.
- Massive Power Gains: Delivers a 57% to 76% increase in maximum horsepower and a 40% to 95% increase in maximum torque, depending on the addition of optional intercooler upgrades.
- Complete Hardware Kit: Includes a bespoke cast iron exhaust manifold, aluminum intake manifold, Walbro electric fuel pump, Malpassi fuel pressure regulator, 2.5" downpipe, and silicone hoses.
- Reliable Thermal Management: The water-cooled turbo design utilizes engine coolant to keep temperatures in check, eliminating the need for long cool-down periods.
Product Overview
The Moss MGB Turbo Kit represents a massive leap in performance for the classic B-Series engine. This comprehensively engineered forced induction system is designed to spool up quickly with minimal lag, providing exceptional low-end torque and continuous power throughout the RPM band. At the base 6 PSI of boost, this kit achieves a 57% increase in maximum horsepower and a 40% increase in torque over a stock, naturally aspirated engine. By integrating a reliable, water-cooled turbo design, the system preserves OEM-like drivability and avoids the complicated cool-down periods traditionally associated with aftermarket forced induction.
Engineering & Material Spotlight
At the core of the system is a modified turbo based on the original Borg-Warner design, but specially modified for use with the MGB and equipped with a custom wastegate securely pre-set to 6 PSI. Fuel management is expertly handled by a sophisticated "blow-thru" setup, utilizing a ported boost reference signal to pressurize the float bowl of the specially-prepared SU HIF 44 carburetor. To guarantee precise fuel delivery under boost, the kit utilizes a high-capacity Walbro electric fuel pump capable of 20 PSI, paired with a Malpassi rising rate fuel pressure regulator. This regulator flawlessly increases fuel pressure at a 1:1 ratio with boost to maintain the proper pressure differential, entirely preventing flooding while ensuring ideal air-fuel ratios. The hardware foundation includes a bespoke cast iron exhaust manifold and a specialized aluminum intake manifold with a carburetor inlet elbow. Based on thousands of miles of real-world testing, the system operates efficiently and safely without the added complexity of blow-off or diverter valves.
Installation & Tech Notes
This system is engineered as a direct-fit, bolt-on upgrade, requiring only basic permanent modifications. The primary modification requires drilling and tapping a hole in the side of the oil pan to accommodate the turbo's gravity oil drain. The included 2.5" downpipe bolts directly to Moss exhaust systems; if running the Moss Tourist Trophy Exhaust (459-075), the short downpipe section (459-081) is required to bolt up, whereas those with the header kit (459-085) must discard the header and bolt directly to the downpipe. A power brakes check valve kit (150-071) is strictly required for any vehicle equipped with power brakes. To manage the additional thermal load from the turbocharger, thoroughly flushing the engine block and upgrading to a new aluminum radiator is highly recommended.
Fitment & Technical Specifications
Vehicle Application Matrix:
| Year(s) | Make | Model | Submodel / Trim | Chassis / Engine Code | Notes / Exceptions |
|---|---|---|---|---|---|
| 1962-1980 | MG | MGB | Base | B-Series | Stage 1 (Cold Air Intake) and Stage 2 (Intercooler) optional kits do not fit 1977-up cars with forward-mounted radiators. |
Technical Specifications:
| Brand / Line | Moss Motors |
| Manufacturer Part # | 150-250 |
| Turbocharger Model | Custom based on Borg-Warner Design |
| Carburetor | SU HIF 44 Turbo "Blow-Thru" |
| Base Boost Pressure | 6 PSI |
| Fuel Pump | Walbro High-Capacity Electric (20 PSI capable) |
| Fuel Pressure Regulator | Malpassi "Rising Rate" (1:1 ratio) |
| Manifold Construction | Cast Iron Exhaust Manifold / Aluminum Intake Manifold |
Frequently Asked Questions (FAQ)
Will this Moss MGB Turbo Kit fit my MG MGB?
Yes, the base kit (150-250) is engineered as a bolt-on solution for MGB engines. However, if you plan to add the Stage 1 Cold Air Intake or Stage 2 Intercooler upgrades, be aware that those specific add-on kits do not fit 1977 and later MGBs equipped with forward-mounted radiators.
Do I need any additional parts or modifications to install this?
While the kit includes all essential plumbing, manifolds, and fuel management components, you must permanently drill a hole in the side of your oil pan for the turbo's oil return line. Additionally, if your vehicle has power brakes, you are required to install the Power Brakes Check Valve Kit (150-071).
How does this compare to the stock naturally aspirated engine?
The base turbo kit at 6 PSI delivers a 57% increase in maximum horsepower (up to 103.7 HP) and a 40% increase in maximum torque (up to 128.8 lb-ft) compared to a stock naturally aspirated MGB. It significantly improves low-end torque and acceleration without sacrificing everyday drivability.
What maintenance or special care is required?
Because the included turbocharger is water-cooled by the engine's coolant, you do not need to observe long "cool-down" periods after driving. However, the turbo introduces additional heat into the cooling system; therefore, flushing the engine block to remove rust and upgrading to an aluminum radiator is highly recommended for maximum cooling reliability.
The Longest in the Business
- All Classic British products are warrantied to be free from defects in material and workmanship for 2 years from the date of invoice.
- All superchargers, supercharger components, and supercharger hardware are warranted to be free from defects in material and workmanship for 1 year from date of invoice.
- Moss Motors, Ltd. will, at its discretion, repair or replace any part that fails in service within the warranty period. This warranty does not cover labor, failure of related components, normal wear of brake or clutch components or failure resulting from alteration, misuse, accidental damage, faulty installation, or faulty repair.
- Warranty requests should be submitted to our sales department and must be supported by the original Moss Motors purchase invoice and documentation of the failure.