As always the internet's varied opinions on everything has brang me back here to start a thread..

I have a Walbro 255 fuel pump, pushing fuel through a focus 1.8 standard rail and standard regulator with focus RS injectors.

Someone once told me this regulator would be fine, now i'm hearing things like 'the regulator won't flow enough for the pump' and 'it needs to be rising rite otherwise it won't fuel properly under boost'

Help?

 

Pretty sure your reg will be be rising rate anyway, but whether its 1:1 rising rate is another matter

 

Just looked at a few websites and cleared up the whole rising rate thing.. FSE could do a great job at selling parts to people who don't need them!

I may just try get hold of a FocRS one.. that would be 1:1 surely

 

Quick one... So if I have the standard reg and it turns out its not a 1:1 type. Will this make it more difficult to map. I'll be using megasquirt. Cheers

 

Think about it, if the inlet pressure rises by 1 bar, and the fuel pressure doesn't rise, or rises say 0.5 bar, then the differential pressure between the fuel and inlet has changed so the flow rate has changed, also affecting spray pattern etc.
Yes in theory it is possible to map around this so long as the injectors have enough spare capacity, and you are only running low boost, but it is not good practice, do it correctly and buy a focus rs regulator.

 

Delete

 

That makes sense. I didn't consider the over compensation needed of the injectors!
Can't find an Rs reg anywhere! Know of anyone breaking a car? Would consider the fiesta one but I don't want one that someone's fucked around with by adjusting the pressure!

 

use a fiesta one and set the fuel pressure yourself??

 

1.8 FPR is fine for boost as long as you've got your vac hose linked up to it. Fuel pressure will rise with boost. As stated before, even if it didn't your mapping would compensate as the injector pulse width would be higher if the fuel pressure was lower.

Matt

 

Exactly.