How to do the bb mod
Lead Driver
Joined: Jun 2007
Posts: 6,757
Likes: 5
From: Corvallis, OR
Your fuel pressure is first regulated to 100 psig out of the HFCM, so your pump is really not increasing its pressure based on what is happening at the fuel filter regulator. The fuel pressure is first regulated at the HFCM and then further regulated by this spring loaded regulator at the fuel filter to the 45-65 psig we see with our gauges.
Fleet Owner
Joined: Nov 2003
Posts: 27,927
Likes: 3,651
I've never heard of a 100psi regulator at the pump. Are you sure its not a backup regulator to prevent line blowouts? If the pump was running at 100psi all the time with this much flow it would be one helluva pump, it would blow the socks off FASS and Airdog. There would be no reason to have a 100 psi regulator at the pump (keeping the pump at 100 psi) as it would just decrease flow rates and shorten the pump lifespan.
If a pump can deliver 65+ psig at the filter, then the pump discharge pressure will be measureably higher. As I am sure you know, the pressure is to account for the frictional losses in the fuel lines. Doesn't a FASS install bigger fuel lines? Also, the FASS is capable of delivering higher volumes of fuel.
Lead Driver
Joined: Nov 2007
Posts: 5,139
Likes: 209
I've never heard of a 100psi regulator at the pump. Are you sure its not a backup regulator to prevent line blowouts? If the pump was running at 100psi all the time with this much flow it would be one helluva pump, it would blow the socks off FASS and Airdog. There would be no reason to have a 100 psi regulator at the pump (keeping the pump at 100 psi) as it would just decrease flow rates and shorten the pump lifespan.
the biggest restrictions in a stock 6.0 fuel system are the nipple from the pickup tube where it connects to the frame rail line hose(it's a tiny little hole in that piece), and the banjo bolts at the heads.. the pump can keep up with stock tuning..
guys running strong tunes will see drastic pressure losses during WOT runs with a stock system.. I could watch my pressure drop from 50 to 12.. Instead of unreliable aftermarket fuel pumps, I installed a second HFCM and increased the fuel line size from tank to motor.. Also, an ITP RR set at 60psi and I haven't lost an injector in a year and a half.. Last racing season was very hard on my injectors and they're still doin fine..
Senior User
Joined: Oct 2007
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From: Oklahoma
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Lead Driver
Joined: Nov 2007
Posts: 5,139
Likes: 209
a fuel pressure gauge will tell you what you need to know.. you want to see a minimum of 45-50 at all times.. a fatigued spring will bleed off too much pressure from the top of the motor..