Originally Posted by CrookedH
It allows you to run higher pressure on the fuel injectors so they flow more. A couple of companies have made 300whp on the stock injectors using a return line setup and higher pressure.
crooked how are you?
yes it allows higher preasure
but the main reason this should be done is the returnless does not allow for high flow and in high flow situations the preasure will drop causing fluctuations with each injector pulse causing eratic injector flow and possible detonation. some manufacturers use a pulsation damper to reduce this. if at idle you hold the fuel rail you will note the injector pulse is amplified by preasure drop at each opening this is magnified at high load wide injector openings.
we up the size of the intank pump and use returnless at over 300 rwhp for this reason.