Fuel Pressure Regulator

There are a number of fuel pressure regulators on the market, some good, some bad, some good looking, some not so good looking. Here are pictures of an Aeromotive unit on the left, and an SX unit on the right. I use the Aeromotive unit because it is cheaper. Both units are excellent quality and operate to the same high level of standards. The Aeromotive unit runs about 25.00 cheaper then the SX unit. Note that both units require the use of AN fittings, the Aeromotive unit is setup to utilize the -10 connector fittings and the SX unit is setup to utilize the -6 fittings.
Both units are rising rate regulators, a 1 to 1 rate. I tested the Aeromotive unit and it is about .95 to 1 rate and that is good enough for me.
The primary consideration on the size hose and connector is the amount of fuel need to deliver sufficient fuel to the engine at WOT. You will need to vearify the complete system to ensure the correct flow rate and maximum fuel pressure based on the injector size and the application, I.e. turbo, N/A, or super charged.
You can calculate the flow rate by summing all of the injector flow rates to come up with the total system requirements with the injectors running at 100% duty cycle. Once you have drtermined the total flow rate, you need to determine the pressure requirements of the system. My car is a turbo setup so to find the correct flow rate at the correct pressure you start with the base pressure, in most cases 2 bar or 36.6psi, then you add the additional pressure the turbo will develop, in my case 25psi of turbo pressure. Now we have 36.6psi plus 25psi for a total of 61.6 psi. To test the system delivery, you then would set static pressure to 36.6psi apply the 25psi of pressure to the regulator and start the pump. The flow rate required for six 500cc/Ml injectors would be 3000cc's/ml per minute. Disconnect the return line and run it into a measuring container and run the pump for one minute. Take the measurement and you should have at least 3000cc's/ML to be ale to provied enough fuel at WOT. This is the very most the system will flow through the injectors at 100% duty cycle. It is useful to realize most systems will not run the injectors at 100% duty cycle, but you need to have the head way designed into the system, and there are systems out there that are getting to 100% duty cycle of the injectors. I have a Jim Wolf setup that does run 100% duty cycle at WOT.

NOTE: when you test the system, keep in mind that when the vehicle is running, the supply voltage to the fuel pump will be 13.8 volts. I realize this in most cases will not matter, but when you get into running a system and pump to is't maximum flow rate like my car, the voltage change at the pump is significant. I tested my system at 12.6 volts, there is a .4 volt drop from the fuel pump relay to the pump, the system flowed 3000 cc's/ML. I then put my battery charger on the battery and brought the voltage up to 13.6 volts and the pump was seeing 13.2 volts and the pump flowed 3300cc's/ML of fuel. Just something to keep in mind, because the last consideration for your delivery system is its ability to return fuel to the tank. So if you have a great delivery and a bottle neck in the return, you will not be able to run the minimum fuel pressure at for instance, negative manifold pressure at idle. If you cant return the fuel to the tank correctly, then you run into a situation of excessive pressure at idle which will make the car run rich at idle. The really radical 4 cylinder cars have this challenge, becaues the injectors are so large to get the Hp from the engine. You stop to consider a four cylinder car running 4 720cc/ML injectors and at 750RPM, you really need to shut down the duty cycle to get the engine running correctly and not be throwing raw fuel out the tail pipe. You get what I am saying right.
So make sure the mechanical part of the system will do exactly what your application is and then go for the electronics, because that is a challenge all in itself, and if you dont think so ask some guys who tune DFI, TECHII, type systems.
I have noted that both units will leak down fuel pressure after about 12 hours. This is not a issue if the fuel pump runs for abour 5 seconds before the engine is turned over. The only thing you will find is hard starting if you do not pressureize the system before trying to start the car, however, for the most part the leak down is a non issue for most applications.
I was at one time having starting problems with my stock system because the rubber check valve in my fuel pump got hard and really drained the system. I will also add that there was not an air issue I was dealing with, but a rise time on the fuel pressure of the system because of the defective check valve. There is a good article on IZCC regarding the fuel pressure you may want to check out and read also.
My final suggestion for selecting a pump and the accessories for the system is ask questions, try to find a guy running a similar system and get accurate information. I found that a number of shops that sell pumps, regulators, and all that, really cant answer definetly a question about flow rates, hose size and the best setup. I spent about 350.00 of wasted money on parts for my system that would not do what I need them to to for a variety of reasons, and I still am not to happy about that. I did ask the hard questions and got wrong answers, so if you dont know, make darn sure of what you are buying and that it will fufill the system requirements for your particular application. Guess work in this area can cost hundreds of dollars for a wrong, say pump selection.These components get very expensive when you need some real flow for performance applications.