I run an efi pump right out of the tank to a regulator and only run a single line forward. The return like is like 8 inches long

 

You run your regulator in the rear of the car ?

 

This is a common setup

 

Regulator at rear of car? That's a bad idea imo.

 

What exactly makes it a bad idea? Been running mine this way making 500+whp for years.

 

Ok thanks

 

I should also mention i use the evap line to provide a boost/vacuum reference signal to the regulator

 

I’m a big fan repurposing factory stuff. Personally I wouldn’t run the fpr in the rear as I like to keep vac line as short as possible to it. Also not a fan of deadheading the fuel rail.

 

One thing i don't like is all the fuel sitting in that long of a line absorbing heat while driving around town. I'm not saying there will be an issue, just prefer to minimize it.

ks

 

Not quite but this thought needs clarified. Yes, the end injectors can still run lean even with a good pump b/c the first injectors will always be "steeling" fuel away from the last injectors. What helps keep the last injectors from going lean is the "reservoir" of fuel that each injector is pulling fuel from, ie the ID of the fuel rail.

Example #1: If the fuel pump was feeding a 50gal drum and this drum was being filled with a steady pressure then no matter where the injectors are located (ignoring the weight of the fuel above the injectors) all the injectors will see the same pressure due to the large volume of fuel available.

Example #2: If the fuel rail had a really tiny ID like 1/8" diameter, then there is a good chance that even with double the amount of fuel pressure the last injectors will still run lean. The last injectors can also be affected by the injector pulses from the front injectors possibly causing issues. YES, this is an extreme example but the affect still shows what is really going on and there is a difference from using fuel "pressure" vs a "reservoir" to feed the injectors

I am NOT saying that there will be an issue and won't debate peoples good luck or their system. I am merely pointing out what is happening and what to look out for.
Because of these extreme examples I create as large of a fuel reservoir for my injectors as I can to pull fuel from and I tie both rails to this "reservoir".

..and I agree 100%.. If it's working for him then leave it alone!

ks

 

It also depends on how much fuel needs to be injected into the engine based on whatever power levels are required. But it’s working for him which means it might work for others also. One way to find out right?

 

I'm loving this debate over my fuel system 😆😆

 

I thought I read at somewhere one of the points of the return was to get the air out of the line that can happen naturally because of the heat of the motor/exhaust as it travels from the tank to the front? By doing it with only a single line forward it would seem would prevent that?

 

To answer some of the questions. I run dual 340lph pumps with the 2nd coming on at 3# of boost. The volume I have is overkill. I run 58psi base fuel pressure to combat any issues with heatsoak and restarts. I have a vented cowl hood that really helped eliminate that issue. Heat doesnt really build up in the engine compartment because of the vents. Ironically, someone mentioned heat soaked fuel with this design. I went to this design to fix the heat soak issues I had. Long drives of an hour or more in my car in Colorado would result in the fuel boiling. This is because during cruising 95% of the fuel running through the lines would return to the tank after running through the engine compartment. I would make a 2 hour drive back and forth to Pueblo and the fuel in my tank would be boililng. I initially did have the rails with no cross over in the front and didnt have any issues but I did add the crossover eventually after figuring out a way to get the fuel pressure damper installed with the crossover.