A90 A91 Supra B58 STG1 Fuel System Upgrade

Stage 1 fuel system upgrade designed to increase fuel delivery capacity for high horsepower B58 applications.

This system is designed specifically for Toyota A90 and A91 Supra platforms where additional low pressure fuel supply is required to support upgraded turbos, port injection, and higher ethanol blends.

Our STG1 Fuel System Upgrade adds a second in-tank fuel pump while retaining factory style plumbing and fuel routing. This allows the system to maintain stable fuel pressure even under high horsepower conditions.

During extensive testing it was found that the factory low pressure fuel pump begins to experience pressure drop around 750 WHP. This issue becomes more severe when running higher ethanol blends. Tuners often compensate by increasing injector open time, but this creates inconsistent fueling and makes true flex fuel operation difficult.

This upgrade provides the additional fuel volume required to maintain proper fuel pressure and support higher power levels.

What’s included:

Walbro 525 fuel pump  
Visconti fuel pump bracket  
Visconti fuel pump Y quick connect fitting  
Visconti replacement in-tank fuel line kit
Visconti sealed wire pass-through  
Holley fuel mat  

Advantages over other solutions:

Keeps the second fuel pump inside the fuel tank  
Does not require additional fuel lines in the engine bay  
Maintains proper fuel pickup even at low fuel levels

Wiring:

If you are not running our ReFlex Sequential Port Injection Kit, you will need to activate the fuel pump relay using our non-ReFlex harness and a Hobbs switch.

(Hobbs switch not included)