Uprated fuel regulator...

The fuel pressure in a smart it restricted by a regulator to 3.8bar. By up-rating the fuel pressure into the fuel rail, you can increase the amount of fuel through the injectors for the same time frame.

After a bit of research we discovered that we could use a fuel pressure regulator from an Audi A6 which has a fuel pressure of 4bar with the same fitment as the smart.

Bosch part number: 0280 160 575

We have been running these on 2 cars since June 2006, a Brabus 101 Roadster and a highly modded Fortwo and both feel a notable improvement in the mid-range power, essentially overtaking power, and firmer under acceleration.

The fuel pressure regulator is located at the end of the fuel rail next to the throttle body.