Vaccum Line on the Fuel pressure regulator...

[td06hkiko]

Can someone tell me what the vaccum line is used for on the Fuel pressure regulator? I am going to upgrade to an aeromotive 13109. I keep hearing people say to set the psi at 43 without the vaccum hose. So what happens when I put the vaccum hose back on???

 

[SoonToBeDSM06]

The vac line is used to close the orfice in the FP Reg. when boosting. While your boost goes up, so does the fuel pressure so you wouldn't run lean. They are supposed to raise on a 1:1 basis as for every 1psi of boost it raises the fuel pressure 1 psi. They tell you to set it while its off because when vacuum is present in your engine, it lowers the fuel pressure a little bit but when the vacuum is gone then its fine. So set it without the hose on. Hope this helps you

 

[i'm boosted]

The AFPR is a 1:1 regulator, meaning for each pound of boost the fuel pressure will increase 1 pound. That is if the hose is hooked back up. That hose is a boost source. Without it hooked up the fuel will stay at 43psi and not increase, putting the car in very lean condition.

-Brian

 

[td06hkiko]

Hey thanks man!!! I'll do that. Just waiting for my install kit from prostreet. One more question. I know it may sound stupid but. My car should be at idle while I set the Fuel pressure regulator right???

The vac line is used to close the orfice in the FP Reg. when boosting. While your boost goes up, so does the fuel pressure so you wouldn't run lean. They are supposed to raise on a 1:1 basis as for every 1psi of boost it raises the fuel pressure 1 psi. They tell you to set it while its off because when vacuum is present in your engine, it lowers the fuel pressure a little bit but when the vacuum is gone then its fine. So set it without the hose on. Hope this helps you

 

[i'm boosted]

Sorry about that you beat me to it.

-Brian

 

[td06hkiko]

thanks for all the support.