Adjusting a fuel pressure regulator

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cudajames

cudajames

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I am new regulators, just finished installing a Holley 12-879 to help lower and balance the pressure from the electric fuel pump.

To help knock down the pressure I have connected vacuum line to manifold vacuum.

My questions, when adjusting the regulator
1. Adjust when the engine is at operating temperature?
2. Adjust with the vacuum disconnected?

I am seeing mixed information when I search
 
What kind of boost are you running?

And if the answer is "none" then don't even cap the vacuum line, just leave it open to the atmosphere

(That is in fact a "boost reference port" which increases fuel pressure when boost increases, no boost, no need to reference it)
 
diymirage said:
And if the answer is "none" then don't even cap the vacuum line, just leave it open to the atmosphere

(That is in fact a "boost reference port" which increases fuel pressure when boost increases, no boost, no need to reference it)
Click to expand...

No boost, initial start up without vacuum connected put pressure at 10.5 psi. With vacuum connected, i am inbetween 5-7 psi.

So, if I understand what you are saying, leave the vacuum port open and run it like that?
 
Nothing to do with your question ! I watch some Chevy boys at the track burn up pistons like they are free ! They are smacking the motor with 350-450 shot ! Their carburetors are to fat ! So instead of jetting the carburetors down they go to their regulators and turn the pressure down ! I made the comment to one of the guys, you still need the fuel pressure to be there when you smack it ! So why wouldn’t you jet the carburetor ! The guy did answer me ! So I carry on about my business ! The next run the guys tears up some pistons ! About two hours later I walked back by this guys pit ! He is putting two pistons in this dude ! The guy pitted beside him was helping him and telling him don’t turn your fuel pressure down ! You still need fuel pressure ! You need to put smaller jets in your carburetor to get rid of your fat condition ! I just kept walking ! Then I find out a buddy of mine did the same thing the next weekend ! He got 3 pistons ! Not sure what I’m not understanding, or not sure what they are not understanding ! Seems elementary to me ! I’ve never ran the smack ! If your fat without the smack ! Why wouldn’t correct that problem before you spray it ! I did my buddy, if you don’t want to jet the carburetor and your fat ! Don’t pull as much timing ! But he would have to be careful with that! It would be easier and safer to just fix your fat condition, pull the correct amount of timing and go race ! Just saying !
 
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