Fuel pressure?

[jp]

I have just built a new fuel system to my Viper, and need to know what pressure I should start with?
50psi?
55psi?
60psi?
It's a Gen1 with large heads, cam etc etc.

 

[99 R/T 10]

Iwould guess 50psi to match the 50 lbs injectors you are(maybe) using. Just a guess though. Let's hope one of the knowledgable tuners chime in.

 

[HP]

JP, what injectors did you go with? - not stock genI I hope.

 

[Vipermed 97.01]

going by memory when we talked last with your mods and cam,Although i did not realise you were using 50lb inj.Start w/60psi....are you using a return line and what size lines are you using,also are you using a wide band a/F monitor

 

[jp]

At the moment do I use Stock Gen2 injectors.
The feed is a 1/2" and the return a 3/8" line.
I will also use a fuel and ignition management system.

 

[Russ M]

JP,

What about fuel pump? Remember the higher your fuel pressure the less volume the fuel pump can provide. So while bumping fuel pressure higher may seem like a smart thing it may not be.

 

[HP]

JP,

What about fuel pump? Remember the higher your fuel pressure the less volume the fuel pump can provide. So while bumping fuel pressure higher may seem like a smart thing it may not be.

Maybe it's my interpretation, but I can't help but see a contradiction,
in your relationship of fuel pressure vs volume. It's true that
at higher pressure, you get less of a change in flow, per change in pressure,
but your statement implies that there is an inverse relationship between
the two.

 

[Daniel Cragin/DC Performance Inc]

JP, Give me a call and I can give you some advice.

Dan Cragin
DC Performance

 

[Doug Supercharged Vipers]

JP,

What about fuel pump? Remember the higher your fuel pressure the less volume the fuel pump can provide. So while bumping fuel pressure higher may seem like a smart thing it may not be.

Russ's is right. There are many variables that effect how much flow volume a fuel pump will produce.

Fuel pumps are rated at a maximum fuel system pressure and the pumps flow volume at that pressure. Once you exceed the fuel pumps rated pressure the flow volume decreases above that pressure.

JP, I think it would be wise to consult with an experienced engine builder when estimating fuel pressures and calculations. There's no guessing, you need to be spot on.

Best of Luck!

 

[HP]

JP,

What about fuel pump? Remember the higher your fuel pressure the less volume the fuel pump can provide. So while bumping fuel pressure higher may seem like a smart thing it may not be.

Russ's is right. There are many variables that effect how much flow volume a fuel pump will produce.

Fuel pumps are rated at a maximum fuel system pressure and the pumps flow volume at that pressure. Once you exceed the fuel pumps rated pressure the flow volume decreases above that pressure.

JP, I think it would be wise to consult with an experienced engine builder when estimating fuel pressures and calculations. There's no guessing, you need to be spot on.

Best of Luck!

Sorry, I just got back to this post, but Doug, Russ's response - "What about
fuel pump" brought my conclusion that the increase pressure was coming from
'bumping up' the pressure from the pump - maybe I had 'pump booster' on my
mind. In that case you would get more flow. If the pressure adjustment is from the pressure regulator, then
of course,its a factor of constricting the flow- and that is what you get.