I think that my aeromotive fuel pressure regulator for my LT1 is acting up the pressure does not seem to adjust properly. If I adjust it to say 55 psi with the vacuum off then put it on and it runs at 50 psi it will then drop to say 47 over time. Should it hold a vacuum off of the vaccuum port, mine bleeds right off? I heard they sometimes leak out of the threaded adjustment bolt?

If I need to replace my afpr with an other adjustable one which brand is better?

 

Why are you using an adjustable?

The Aeromotive is probably the worst quality wise.

 

Update: I pulled the threaded adjustment out and plugged it with my finger and it does hold a vacuum.

But I am using an adjustable just for tuning, what other brand would you recomend? Accel, Jet, holley?

 

How are you using it for "tuning"?

 

What kind of setup are you running? The LT1 won't benefit from adjusting the fuel pressure unless you are running forced induction or have high compression - correct me if I am wrong here on some are all of this, guys, I learned this fairly recently.

 

I use the adjustable to because my lt1 is 12.8:1 compression and my direct port nitrous system is calibrated to use ~50 psi of fuel pressure running off of the schrader valve.

Should I throw the stock one back on and re calibrate my nitrous? I also have been using it to lower my air fuel ratio, I know I need to put the car on a dyno and tune it, its in the works. But as the car is now with a mail order tune it runs lean unless I up the pressure.

 

The regulator should be treated as a fuel system component NOT a tuning tool.

 

All you have to do is put it back to stock and switch the fuel jet in the nitrous system.

If your engine is running lean without the nitrous, you need larger injectors, or you need to get the flow constant in the PCM corrected to match the flow of the injectors at 50psi. You're injectors are flowing 7.2% more than the PCM thinks they are if it wasn't tuned based on the 50psi fuel pressure. Diddling the fuel pressure is a band-aid.

 

I agree adjusting the fuel pressure is not the answer. Now the car is going to be dyno tuned here shortly. Should I buy a new Holley AFPR and leave the nitrous as is @50psi? Or do I throw a stock one on and by bigger fuel jet2 for my nitrous system @43.5lbs?

I also think that I threw my stock one away.

 

There's nothing wrong with running a higher fuel pressure if everything is tuned for it.... I run Bosch 64's at 58psi (= 74 #/HR), but the ECU is set up for them. Some types of injectors do not respond well to higher pressure. The factory RP ball & seat injectors don't like high pressure. Pintle style injectors are better for high pressures. But 50psi isn't a problem with either type.

I would find a reliable adjustable, if you want to run at higher pressures. As good as Aeromotive products normally are, the LT1 AFPR appears to be a problem. I run a Weldon AFPR, but its not LT1-specific, and does not mount on the end of the fuel rail.