Fuel Pressure
#1
MBWorld Fanatic!
Thread Starter
Fuel Pressure
Did some testing today with the Kenne Bell Boost A Pump that I thought I would share.
Back story is engine has 60lb injectors in it and fuel pressure and injector duty cycle where just not playing well together meaning the IDC was too high and if I brought it down with a tune I could not get enough fuel pressure to keep AFR where I wanted it. I know I am safe where I am at as per Hulk's recommendations right now but here is what I did/have.
My system is a looped fuel rail return system with an Aeromotive boost reference regulator,3/8 steel line to the rails, 3/8 return line,modified fuel tank outlet hat and in tank fuel filter removal, filter is close to the rail now and I have stock replacement pumps.
Max fuel pressure under boost was 62-64psi and ID in the 29-33 range....way to high to get the AFR where I wanted it.
So I added a Kenne Bell Boost a pump that when under boost the unit will step up the voltage to the pumps to 17v. Now fuel pressure can be set anywhere I want it, presently holding 75psi at 16 IDC and 11.8 AFR. It was real easy to set up and wire in and sits under the rear seat near the pumps. Real easy to do if anyone ever looked into one of these units and they are used on some of the fastest cars around for years...just go on Kenne Bells web sight for more info.
Back story is engine has 60lb injectors in it and fuel pressure and injector duty cycle where just not playing well together meaning the IDC was too high and if I brought it down with a tune I could not get enough fuel pressure to keep AFR where I wanted it. I know I am safe where I am at as per Hulk's recommendations right now but here is what I did/have.
My system is a looped fuel rail return system with an Aeromotive boost reference regulator,3/8 steel line to the rails, 3/8 return line,modified fuel tank outlet hat and in tank fuel filter removal, filter is close to the rail now and I have stock replacement pumps.
Max fuel pressure under boost was 62-64psi and ID in the 29-33 range....way to high to get the AFR where I wanted it.
So I added a Kenne Bell Boost a pump that when under boost the unit will step up the voltage to the pumps to 17v. Now fuel pressure can be set anywhere I want it, presently holding 75psi at 16 IDC and 11.8 AFR. It was real easy to set up and wire in and sits under the rear seat near the pumps. Real easy to do if anyone ever looked into one of these units and they are used on some of the fastest cars around for years...just go on Kenne Bells web sight for more info.
Last edited by SICAMG; 05-27-2019 at 10:25 AM.
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drothgeb (05-28-2019)
#2
MBWorld Fanatic!
So you are boosting the voltage to the pump from what metric (output from ECU, boost pressure, etc).
Stock pumps?
I was under the impression the ECU was increasing boost pressure from ECU?
Stock pumps?
I was under the impression the ECU was increasing boost pressure from ECU?
#4
MBWorld Fanatic!
Thank you. So the ECU is affecting input voltage (the second pump does not already run, is that correct?) - and he is taking that input voltage and "boosting" it further when he chooses per another signal (boost was mentioned).
#6
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Thread Starter
Yes when the boost sensor sees 10psi voltage will ramp up tp 17v from the 13.8. If you go on kenne bells web sight and read their fuel documents. There is a lot of great info and much to learn.
#7
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The tuning side is where the info would be appreciated. You were finding that with your system redesign, which was to return style, adj FPR, no fuel filter at pump, and a looped rail, you were not seeing the fuel pressure you need to see for the boost level. And you were increasing the injector duty, or as you state "ID") of the injectors opening time - to compensate for this delta.
So you put the boost-a-pump on and increased the pressure (when you need to only) and you can now keep the duty cycle at a lower rate.
So you put the boost-a-pump on and increased the pressure (when you need to only) and you can now keep the duty cycle at a lower rate.
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#8
MBWorld Fanatic!
Thread Starter
Yes. You did it for me !! LOL. But yes that is where I was at and what I did. I still can't see this engine making more than 650-700 flywheel to justify needing that much injector but who knows. Keeping duty cycle down for long runs is important. It is right on the money and some clean shake down runs at the next 1/2 mile event june 29 before the big 1 and 1.5 mile event this year will tell me where everything is at data wise. Hope the crank stays in it !!! LOL