Question: 1:1 Boost referenced adjustable FPR w/ return or Static 72PSI(or other PSI) regulator with a return? Just curious from people's actual experiences with both. Pros/Cons etc. Please chime in.
This is my low pressure fuel system set up:
525 & 535 in stock bucket
BMP4 fuel pump controller
Driver's side top hat restrictions removed via PR top hat
Aftermarket FPR(adjustable or static TBD) w/ return to bucket located in engine bay
Aftermarket fuel filter
6x Bosch EV14 750 CC injectors
Stock 'V2' HPFP
The EV14 fuel injectors we use for PI are supposedly good up to 8bar fuel pressure or 116 PSI so says the internet. However, Black Market Parts claims they work up to 10 bar. I will assume 8bar as that is what I have seen most often as the max psi. As I probably don't want to run them at the limit, 100PSI should give 'enough' headroom in my opinion, almost 20%. With a Boost refenced 1:1 FPR targeting 72 PSI LP then add in + 30 PSI of boost = 102 low pressure fuel psi required for PI to inject at 72 PSI. Max would be 44 PSI of boost which would hit the EV14 limit of 116psi not that I want to touch that or get close. I can lower my fuel pressure below 72psi to keep the combined fuel pressure + boost below 100 PSI, this just eventually starts to limit the flow of the injectors which is not a problem, can always go 1000cc.
The internet tells me this:
Tested Static Flow Rates for the EV14 750cc fuel injectors:
750 cc/min at 3.0 BAR (43.5 psi)
818 cc/min at 3.5 BAR (50.8 psi)
885 cc/min at 4.0 BAR (58.0 psi)
970 cc/min at 5.0 BAR (72.5 psi)
Black Market Parts claims this:
750cc @ 3bar (43.5 PSI industry standard)
900cc @ 4bar (58.2 PSI)
1050cc @ 5bar (72.5 PSI)
The numbers don't match but they are close enough, I will use the lower numbers to be on the safe side.
The Walbro 285 pumps fall off flow wise around [email protected]. At 13.5Vdc and 100psi still plenty of flow for my needs(I have a 525 and 535 in my bucket and will have a return):
For a static FPR I would likely be using one of these: https://precisionraceworks.com/products/in-line-micro-regulator?variant=42398655840449
So what would you use, target, and why?
This is my low pressure fuel system set up:
525 & 535 in stock bucket
BMP4 fuel pump controller
Driver's side top hat restrictions removed via PR top hat
Aftermarket FPR(adjustable or static TBD) w/ return to bucket located in engine bay
Aftermarket fuel filter
6x Bosch EV14 750 CC injectors
Stock 'V2' HPFP
The EV14 fuel injectors we use for PI are supposedly good up to 8bar fuel pressure or 116 PSI so says the internet. However, Black Market Parts claims they work up to 10 bar. I will assume 8bar as that is what I have seen most often as the max psi. As I probably don't want to run them at the limit, 100PSI should give 'enough' headroom in my opinion, almost 20%. With a Boost refenced 1:1 FPR targeting 72 PSI LP then add in + 30 PSI of boost = 102 low pressure fuel psi required for PI to inject at 72 PSI. Max would be 44 PSI of boost which would hit the EV14 limit of 116psi not that I want to touch that or get close. I can lower my fuel pressure below 72psi to keep the combined fuel pressure + boost below 100 PSI, this just eventually starts to limit the flow of the injectors which is not a problem, can always go 1000cc.
The internet tells me this:
Tested Static Flow Rates for the EV14 750cc fuel injectors:
750 cc/min at 3.0 BAR (43.5 psi)
818 cc/min at 3.5 BAR (50.8 psi)
885 cc/min at 4.0 BAR (58.0 psi)
970 cc/min at 5.0 BAR (72.5 psi)
Black Market Parts claims this:
750cc @ 3bar (43.5 PSI industry standard)
900cc @ 4bar (58.2 PSI)
1050cc @ 5bar (72.5 PSI)
The numbers don't match but they are close enough, I will use the lower numbers to be on the safe side.
The Walbro 285 pumps fall off flow wise around [email protected]. At 13.5Vdc and 100psi still plenty of flow for my needs(I have a 525 and 535 in my bucket and will have a return):
For a static FPR I would likely be using one of these: https://precisionraceworks.com/products/in-line-micro-regulator?variant=42398655840449
So what would you use, target, and why?
Last edited: