Supra Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
882 Posts
Discussion Starter #1
I am just curious as to what my Fuel pressure should be set to at idle?? I am BPU++++++ including cams just to show how ++ I am, and have a -6AN fuel line system tapped into the factory rail and through a SX Pressure regulator. I do have a fuel pressure guage to reference my pressure. What should the pressure be at during idle? I read somewhere else that it should read 40-45psi when the ignition is on but car not running (I think they called that static??) and the vacuum hose detached from the regulator. Is this correct and should the psi remain the same once the engine is actually started?? If the psi changes after the car is started, what psi should it change to?? Thanks and I hope that made sense...lol. Peace!
 

·
Registered
Joined
·
103 Posts
Sounds about right, and when the boost kicks in it should rise, correct??
Other than that it's 3 bar fuel injection system.

Later
Dimitri;)
 

·
Registered
Joined
·
882 Posts
Discussion Starter #3
Ok let me try this. I will make these statements which are kinda questions also. Correct me if I'm wrong please!

1) With ignition ON, engine OFF, and vacuum line to regulator DISCONNECTED, I should read 40-45PSI????

2) With ignition ON, engine OFF, and vacuum line to regulator CONNECTED, I should read 40-45PSI????

3) With engine ON and running at IDLE, I should read 40-45PSI????

Are these accurate statements? I always thought that idle should be set to about 28-32PSI??? Just want to get the facts straight before I hit the dyno this Saturday. Thanks for all replies! Peace!
 

·
Registered
Joined
·
103 Posts
1) Correct, you pump just worked when you turned the key in order to get 3 bar pressure to the system, vaccum/no vaccum doesn't matter since your engine is off.


2) Correct

3) Sometimes the pressure drops some psi at -20 to -15 vaccum, and get to 3 bar at 0 again(transition moment from vacuum to boost, So you might since around 39-40psi at idle

4) At boost it cranks up.
 

·
Registered
Joined
·
882 Posts
Discussion Starter #5
Thank you!!

Thank you VERY much for the info, i appreciate it greatly. Does this pertain to all setups like single or twin pumps??? Should it be the same on all setups?

PS - Does everyone else agree with these statements?? I'm putting my car on the dyno this Saturday and want to make sure my fuel is as goos as I can get it. Thanks again!!
 

·
Registered
Joined
·
103 Posts
"Does this pertain to all setups like single or twin pumps??? Should it be the same on all setups?"

Even if you had 3 pumps, the pressure that you should operate the system would be 3 bar. Now if you have really big injectors and you can't cut down form duty cycle (ecu,safc, etc.) then you gotta lower the line pressure, but that has the disadvantage of NOT homogenious flow and good atomization of fuel. That means the injectors are not spraying very well if they are under 2.5 bar of line pressure.

my 2c.

Dimitri
 

·
Registered
Joined
·
882 Posts
Discussion Starter #8
Cool

Thanks for the info yet again!! I'll check it out when I get home. Take it easy. Peace!
 
1 - 8 of 8 Posts
Top