View Full Version : What does adjustable fuel pressure regulator do?

Turbo Trans Am
09-09-2004, 11:51 AM
How exactly does the adjustable fuel pressure regulator work in conjunction with the fuel pump and injectors? If I have a stock car with an adjustable wastegate, can I up the boost and just use the adjustable fuel regulator to increase fuel flow in order to negate any knock? I have heard the term "duty cycle" being used with injectors, which I am largely unfamiliar with. Will raising the fuel pressure with the adjustable regulator increase the duty cycle of my injectors? Is that safe and to what point? How do you check the duty cycle on injectors?

09-10-2004, 02:42 AM
The fuel pressure regulator allows you to adjust the fuel pressure up or down, in its entirety, across the spectrum. From idle to full boost. Its a crude tuning tool, but is a variable that can be used it the field. Adjusting chip parameters generally can't. That is why the 'big boys' go with programmable controllers for tuning.

'Duty cycle' of injectors is not really 'adjustable'. Duty cycle refers to the amount of time an injector is held open vs. the amount of time available at a certain rpm before the next injection event happens and is expressed as a percentage. The electrical characteristics of injectors make it undesirable to drive them at 100% duty cycle due to stress on the injector windings and drive circuitry. Maximum duty cycle can only be between 70 and 85% (theoretically).