NOMADz28

I'm near done with my carbed LT-1 swap into my wifes 88 V-6 car. I've gotten the Inlet and Return line figured out on the stock electric fuel pump.
I have what I assume is a 2 port fuel pressure regulator. It has a T shape to it, one hole on each end of the T so it actually has 3 ports. I'm not sure if this is what I need honestly. It's a Holley brand, don't know the Model #.
I am running a Fuel Log with the inlet at the front and also a outlet in the back for fuel return.

Is a 3 port necessary since I have the ability to run it directly through the fuel log and out the back?
With the regulator near the inlet, wouldn't it just simpley regulator to 7 PSI and not allow the excess to go through the outlet on the log ?

I'm confused

-Shannon

PhilM

well, the high pressure has to be reduced before the carb, and if you are mounting the regulator before the log and carb, you'll have trouble with this type. mounting the regulator after the carb, in the return, won't solve anything either as the pressure will go right to the bowls. does this make any sense?

deadheading the pump without a return will burn it up. having tried a holley regulator like this, i can tell you that it doesn't work well.

five7kid

iTrader: (14)

You can run a orificed return (such as an adjustable needle valve) so that there is always some fuel circulating and not dead-heading the pump. You have to have enough restriction at the log so that pressure is maintained in order to push some fuel into the carb fuel bowls. However, you have to keep the flow low enough so that pressure doesn't drop too low under maximum demand conditions. That's a balancing act that may not be ideal under all conditions, which is why the reg that maintains pressure by returning the excess is preferred over the typical dead-heading type.

You could also put a relief valve in the return that pops at 6 psi. Getting one that opens at 6 psi reliably and repeatedly is the issue there.

NOMADz28

Well, it does make sense. I was thinking pretty much everything you guys said. I know I can't dead head it or the pump will burn up because of excess heat

The regulator i've got is a Holley, it has one in port and 2 out ports. The instrucions say it can be used to regulate 2 carbs, is only using one carb, the other port should be blocked off. Would it be possible to use this other port as a return ?

-Shannon

RWB____s

Well I would get another T fitting and install it between the fuel line from the pump just before the regulator. Hook up your return line to the extra port on the "T" fitting. Then run a line from the "T" fitting to the regulator. Use both outlets from the regulator
and plumb them to the carb if its a DBL pumper carb or block one outlet from the regulator and plumb the remaining out let to the carb if it is a single outlet. I hope this helps and works for you

five7kid

iTrader: (14)

Whether you do it the way either one of you suggest, you have to provide some restriction in the return line, or you won't have any pressure at the carb.

Personally, I'd tap the return off of the log so that the fuel stays as cool as possible when the flow is slowed going into the carb (slow moving fuel has more time to pick up heat).

RWB____s

I removed the drawing till I can come up with something else(IF I can). 57 you are correct in what you say as usuall I wonder if the holley regulator can deal with the pressure from a F.I. pump?
If it can, Why couldn't you just run the fuel line to the regulator and let the regulator reduce the pressure (6-7 psi)for the carb. Then run the return line off of one of the regulator ports and the other feed it to the carb? Na that won t work .

five7kid

iTrader: (14)

It would work if you controlled the amount going through the return.

A "3-port" regulator does that because it controls pressure by how much flow it allows to the return. That is why it is more desireable, and also why it is more expensive.

NOMADz28

I think i'm gonna have to buy a damn 3 port

-Shannon

five7kid

iTrader: (14)

Here's my "dream" setup:

Electric pump at/in the tank. Both sides of each fuel bowl inlet tapped - the "passenger" side for the feed, the "driver's" side for the return. A check/relief valve that opens at 6 psi and doesn't chatter.

With this setup, the pump would flow a constant volume. The fuel would pass right up to the float needle, what is needed would go into the bowls, what isn't would go back to the tank. This would have the effect of keeping cool fuel at the inlets, and actually cooling the fuel bowls as the relatively cool fuel from the tank, which hasn't had much time to pick up heat as it passes by the engine.

At the track, I also run a cool can, so I could keep the fuel pump running and it would cool down the carb as the engine cools down between rounds.

And so I continue to dream on...