Fueling a HybridZ

[rudypoochris]

My brother and I have laid down the fuel and brake lines and the motor is in! Now we are wondering how to configure the fuel system. This setup is to feed a Holley 4150 Double Pumper. We put a 5/16" fuel line and added a 3/16" return in case we needed it.We have decided against using a mechanical pump simply because we are afraid of vapor lock. The fuel line runs pretty close to the cylidner heads and has a rather high spot. Basically we were wondering a couple of things:

 

-What pump would serve us well, it is a stock 5.0L HO (but we would like room to grow)? I was thinking a Holley Electrical, external 110gph 14psi pump.

-How should we regulate it? Do we put a fuel pressure regulator right before the Carb?

-How do we return vapors and excess pressure (so we are not just heating the fuel between the regulator and pump when it is not needed)? Can the fuel pressure regulator be used to return the excess?

 

I have come to ntoice there are two types of regulators. Ones that return and ones that do not. The ones that do not return have 1 inlet and two outlets, the ones that do, have three outlets and one inlet. I don't understand how a non return regulator should have two outlets... One goes to the carb and the other goes where? Or are the two outlets used to power seperate carb bowls? Also when people say 6-8psi is the maximum the floats can block, do they mean 6-8psi per float bowl or the entire carb. If it is 6-8 psi per bowl does that mean a 14psi pump does not need regulation?

 

Thanks for anyhelp guys.

[Trevor]

I have see fuel systems diagrammed in Hot Rod magazine several times, and they always plumb in the fuel pressure regulator AFTER the carb, before the return line. I don't know exactly why, but it may be to maintain consistent pressure vs.volume.

 

I have read articles that advocate a returnless route for carb systems because every trip through the piping adds friction, heat, and agitation bubbles to the gasoline which allows it to evaporate at the tank.

[Pop N Wood]

I have see fuel systems diagrammed in Hot Rod magazine several times' date=' and they always plumb in the fuel pressure regulator AFTER the carb, before the return line. I don't know exactly why, but it may be to maintain consistent pressure vs.volume.

 

I have read articles that advocate a returnless route for carb systems because every trip through the piping adds friction, heat, and agitation bubbles to the gasoline which allows it to evaporate at the tank.[/quote']

 

All of what you say contradicts everything I have read.

 

Here is a good link that grumpyvette once posted. Their suggestions on fuel line sizes are a step larger than any other recomendation I have seen. But other than that they do a good job of describing the differences.

 

http://centuryperformance.com/fuel.asp

 

I have read bad things on this site about Holley fuel pumps. I have read good things about the Walbro pump and the Mallory Comp 110.

 

I am going with this Mallory pump regulator set up with my carb'd 6L LS2 (est 450 HP)

 

Comp-140 High Performance Electric Fuel Pump with 650-4207 Regulator

 

More pump than I need but the package price of the Comp 140 pump and regulator is cheaper than buying the Comp 110 and regulator separately. I will use a 3/8 supply and return line. I would think your line sizes should be fine for the 5.0