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My mind is forged
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Discussion Starter #1
What is the max fuel pressure for stock injectors?

What is it on stock fuel rail - looking like fuel dampener but I am not sure.

Thanx
 
Z

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fuel pressure regulator is connected to the end of fuel rail (right behind throttle body). fuel damper is connected to the beginning of the fuel rail (towards the firewall) actually it is between the line that goes from beginning of fuel rail and fuel filter.

I learned to keep stock fuel pressure for stock system, it is plenty of fuel for BPU. dont even bother with aftermarket FPR like I did. stock fuel system is so well designed and balanced, there is no need to play with it. trust me, I "know" stock fuel system:)
 

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My mind is forged
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Discussion Starter #3
Thanx, but I need more fuel, I am BPU ++++++++etc:D I have bought Bosch fuel pump and fuel damper bypass - I need more fuel but I can't spend extra $$$$ for 720 injectors now:mad: That's why I have to get max from stock injectors - I have profesionally cleaned them thru = they are like new, I hope:D

So, what is max pressure they will hold? I mean be able to work...
 
Z

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you can dial in maybe 10 more PSI and see if that helps your fuel problem. make sure you keep fuel pessure under 70PSI becuase after that stock pump is pretty much maxed out. but I know Bosch pump flows better at higher pressure, so you can try to add 10psi and see what happens.
again, when you increase fuel pressure you are trying to push more fuel thru the injectors, not sure if it will effect the duty cycle, but if I were you I wouldnt go above 10psi extra.
 

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Discussion Starter #6
What is stock psi?
 

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Peter,

Don't worry about the fuel system until you exceed about 490rwhp. Unless your going single or using a NOS dry shot the stock system will serve your needs fine even with BPU+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ :rolleyes:

Later, Steve
 
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Steve,
for what are this many ++++ standing for? additional screws or questions? just joking
 

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My mind is forged
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Discussion Starter #9
OK. I will explain... I have put very big FMIC (from Truck) I have made alcohol injection straight to FMIC. I have upgraded stockers – now they can safely make over 20 psi and I need as much fuel as possible (with stock injectors). I also have put NOS.

Please answer my question - what is max pressure for stock injectors?

Thank you:)
 

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Peter,

That will still not get you more than 490rwhp (without the NOS). You will only need to upgrade the fuel system if you are doing a dryshot.

Later, Steve
 
Z

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stock base pressure at 0 boost should be 40.5psi (2.8 bar) eventhough repair manual calls for 36psi(2.5bar) above intake manifold pressure at all time with stock FPR.
 

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Discussion Starter #12
Steve, when I set boost at 25 psi I was lean = I need more fuel.

Zerosoul, what pressure should be with max boost?

Anyone knows what is the max pressure limit for stock injectors?:)
 
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if both your injectors and fuel pump are in top condition, at 25PSI you should still have enough fuel. your fuel pressure at 25psi of boost should be around 68psi...with your Bosch pump it should be no problem to flow enough fuel for your stock injectors.
did you try runing higher octan fuel and see if it effects your A/F?
how are you monitoring your A/F?
 
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Peter Poland said:


Anyone knows what is the max pressure limit for stock injectors?:)
I guess no one is able to answer that becuase it takes precise calculation. you can have as much pressure as you want, but stock injector and only spray that amount of fuel at the highest duty cycle (should be around 90% max). the higher the fuel pressure, the less flow of the fuel pump.
trust me, dialing up your fuel pressure isnt gonna sqeez too much fuel out of stock injectors. it will just overload the injectors and overheat the pump.
 

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Discussion Starter #16
My K&N a/f monitor is showing me good readings but at Dyno - it was lean (at 25 psi), should I set fuel pressure at 68 psi - that is a lot:)
 
Z

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how lean were you at the dyno?
you know K&N is not wideband moinitoring, so dont bother.
68psi at full boost I meant. 43 static+25bppst.
 
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it was not for u zerosoul...
i`m just wonderin` that peter would like to kill his own car in any way :D
cu
mac
 
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