Is200 Upgrade Fuel Return Kit - Adjustable Regulator

• Upgrades the returnless fuel system to a return loop fuel system.
• Adds a fuel pressure regulator in the front, vacuum actuated 
• Deletes the factory in-tank fuel pressure regulator
• Retains the factory fuel pump, jet valve and level sender.

When boosting the 1G-FE engine on the Lexus IS200/Altezza AS200, the returnless fuel system can be a serious bottleneck - the fixed fuel pressure nature of this system means that the higher the boost, the lower the injectors can flow. Even with larger (1ZZ) injectors, there's a limit of about 0.5 bar (7 psi) where the injectors can't cope. And swapping for larger ones isn't an option without extensive electronics upgrades.

This is where this upgrade is essential - by adding a return line and converting the returnless fuel system to a return loop, we're able to install a fuel pressure regulator in the front where it can be vacuum actuated. This allows the fuel pressure to follow the boost pressure, so the difference in pressure between the injectors' feed and tip is constant (differential pressure). This way the injectors can flow well at idle (for calm idle with no overfueling) and also have enough flow under high boost for good fueling.

An added bonus is the ability to act as a failsafe on turbo setups with spikes - any spike will cause the fuel pressure to spike too, allowing for at least a bit of a correction in the AFRs to save the engine.

The rising rate FPR in this kit has a adjustable differential pressure so at idle the fuel pressure is close or just under the standard 1G-FE level and gets to 4 bar at 0.5 bar of boost. This allows the 1ZZ-FE injectors to feed the engine at boost levels of up to 0.8-0.9 bar.

This is a DIY version of our kit and includes everything needed to upgrade the fuel system to a rising rate return loop. You need to modify your fuel pump hanger (drill on top) and install the included fittings,