If you run the pump up the regulator like a holley, the return feed will come off there and go back to the tank and run the pressure you need
CK5
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Where to place regulator
- Thread starter centexk5
- Start date
The bracket came with the regulator. I made a small piece of angle to mount it to the intake where there is a threaded boss for I assume an accessory bracket I didn't need.
Mine just has a single feed to the passenger rail and loops around back and out the front of the driver rail.
What I typically do is run the fuel line along the frame rail to the front of the engine and Y it to the fuel rails, then put the regulator on the firewall and T into the regulator from the each fuel rail. From there it's easy to run the return line down the firewall back to the tank. You can put the 10 micron filter in the single line either along the frame or up front before you split it with the Y. Whatever you prefer. I typically put it in back by the frame away from the heat.
If I may, I’d like to slightly hijack this one.
So I know the discussion has mostly been for EFI applications, but what’s the general consensus for a carb’d application?
In my case, I’m running a factory fuel tank and lines, but my vortec block does not have the provisions for a block mounted pump for my quadrajet. I’m going to run a lower psi frame mounted pump therefor I’d like to run a pressure regulator. Would this be an application where you run it on the feed side as to not over pressurize the carb?
It depends on the style of pump you select. Some style of low pressure pumps like certain vane pumps you can run a dead head regulator and no return line just like a mechanical pump, in that case it's pretty simple, just a pump in series to the regulator, and from the regulator to the carb. These pumps usually run hotter because there is no constant flow to keep them cool.
If you are running a higher pressure pump like a gearotor or any pump that requires a return line, than you need a bypass regulator with a large enough return line not to restrict the pump. It also needs the correct spring to turn the pressure down to carb pressures. With this style you have the same options as the EFI (and could switch springs and run EFI, some regulators come with both carb and EFI springs). So you could run a fuel log or T the supply line off to the carb before the regulator, or you could put the carb after the regulator. But you can't dead head the pump to the carb without a regulator, that would cause major issues including flooding the engine and fire hazards. These styles of pump generally run cooler and last longer, but require a return line for installation.
So you run the feed lines for the rails up the front of the motor?
Yes, thats just one option. Stay on the framerail just like the factory lines for a mechanical pump. Then go up the front of the engine, and Y it into both rails.
You can also put both supply and return up the firewall in back, it's just personal preference, either way works.
You can also put both supply and return up the firewall in back, it's just personal preference, either way works.
Here you can see in my Regal, the "Y" is behind the alternator, into each rail, then from each rail it "T"s into the regulator, then out the bottom of the regulator back to the tank....
You can go from the firewall to the rails, then back to the regulator, but then you have more than just the rails going over the intake manifolds, you have the supply lines too.
Or you can Y into the back of the rails, T into the regulator in the front, and then out the bottom of the regulator back to the tank. Works the same and you have slightly shorter high pressure supply line, then the regulator is in the front, which is a personal preference if you prefer that or not.
You can go from the firewall to the rails, then back to the regulator, but then you have more than just the rails going over the intake manifolds, you have the supply lines too.
Or you can Y into the back of the rails, T into the regulator in the front, and then out the bottom of the regulator back to the tank. Works the same and you have slightly shorter high pressure supply line, then the regulator is in the front, which is a personal preference if you prefer that or not.
@GWeakland620 Im running a factory tbi pump in my 91, the feed line runs to the regulator, cutting it to 3.5psi, then to the carb, the return is from the regulator to the factory line and back to the tank.
Have you thought about using a tbi pump and sending unit? You would have to run a return line, but it would be quiet and dependable in the tank.
Have you thought about using a tbi pump and sending unit? You would have to run a return line, but it would be quiet and dependable in the tank.
That's a good idea, in tank pumps generally run cooler and last longer.
Also, if you go to that trouble, and there is any chance you might want EFI down the road, I would put a Walbro pump in there. Then when it's time for EFI, you just swap the regulator spring. My best selling regulator from Holley has both EFI and carb springs so it can work for both. The return line should be as big as the supply line when running a EFI pump with carb pressures (the little portion in the sending unit is fine).
Also, if you go to that trouble, and there is any chance you might want EFI down the road, I would put a Walbro pump in there. Then when it's time for EFI, you just swap the regulator spring. My best selling regulator from Holley has both EFI and carb springs so it can work for both. The return line should be as big as the supply line when running a EFI pump with carb pressures (the little portion in the sending unit is fine).
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Do the fuel lines from the Y to the fuel rails and from the rear of the fuel rails to the regulator need to be of equal lengths?
Thank you,
Ed
No, splitting them through the rails and "T-ing" back into the regulator after the rails insures equal pressure, which is what matters in the fuel rails for equal flow to the injectors.
