I'm installing a Fitech efi system and am mounting the surge tank in the left fender. Is there is any reason why I can't use the vent line on the left frame rail as a return line?

 

I was going to do that with my Sniper 2 but found Holley makes an in-tank fuel pump with the return built into it. I'm not running a return line.

 

I'm not sure if I have what you're asking is correct. One, the vent line generally isn't large enough and two, if you're the vent line as a return I'm assuming you're use the tank vent as a return. Fuel should be returned to the bottom of the tank into fuel otherwise you'll aerate the fuel.

 

Just did this last week with a Fitech 30003. The oem return line is 1/4" and Fitech specifies a minimum of 5/16" (3/8 recommended). There is also likely scale and buildup in an older line so the flow will actually be less than a new 1/4" line.

That being said I did use the original factory 1/4" line for my return for the initial install. Fuel pressure gauge shows 52 psi vs the regulator spec of 43.5 psi because of the too small return line. That is just at the range the O2 can compensate so runs fine. In my case it is a temporary solution until I can get a larger return line installed. I am just going to use a factory 3/8" feed line to replace the oem return line. Hopefully the pressure regulator doesn't die before I get a change to change the return line.

 

I did that ages ago. Worked fine. I even took pressure readings on that return line and it was not a concern at all. I reckon it would depend on how much fuel you are having to return.
I later ran 3/8" SS Braided hose all the way forward.

 

The surge tank is the number 1 reason for failure with aftermarket EFI systems. Absolutely the wrong way to do it.
the pump belongs in the fuel tank!
Using the vent line is also a really bad idea.
I am thinking that you wish to cut corners on this install. And then you will be the next one on line complaining that this aftermarket EFI stuff is garbage.
Don't be lazy! DO IT RIGHT the first time!

 

On a 78 corvette a proper fuel pump sending unit can be installed from the top. Without need to drop the tank! Although I would anyway and replace those nearly 50 year old fuel lines. There is just No reason to install a surge tank set-up. And all the problems/ issues that will follow.

 

the fuel pump at the gas station surly aerates the fuel nothing happens, most fi kits give you a fitting to drill a hole in the tank for a return , they say you could even install it in the filler neck of a tank.

 

And most of us that do it correctly have the fuel return line an inch or so off the bottom of the tank dumping directly into the fuel baffle so as to never have fuel starvation on hard acceleration or hard cornering.

 

On my 78 with a TPI set up, the original fuel line became the return line. A new line was run from the in tank pump all the way to the fuel rails, with a nice in- line filter. It was simple and easy to install. Just my $.02, which isn't worth that much any more.

 

 

Yeah, but it would be a little tough to stick a gas pump nozzle in the bottom of a gas tank. Keep in mind that it's a constant return passing through air. At the pump it's one and done. Besides my old CFI sending unit returned the fuel one inch to the side of the fuel sock. Ditto for my old Daytona Turbo Z. So the factory engineers design it that way they must have known a little something about designing a fuel injection system. Besides most aftermarket EFI systems suck .

 

I'm thinking that the above statement is a bit harsh. But it's true a number of them feature the ECU Mounted right on the throttle body.
WOW! .... OK, perhaps it aids in ease of installation. But that's where that ends.
Let's think, just a little.
What do computer's, any computer hate the very most?
How about, heat and vibration.
So on a C3 Corvette. The Hottest place on the car? Right on top of the engine! Place with the highest vibration on the entire car? Right on top of the engine!
So, dumbest place on the entire car to mount a computer?
That's right, let's put it right on top of the engine.
Seriously???
So, Holley, FiTech and others do just that!
And the internet is full of people complaining of ECU Failure!
Now of course these companies also sell units that feature remote mounted ECU's.
Oddly, I just don't see complaints of ECU failure with these systems.
I have a FiTech based aftermarket EFI system on my car. And have for several years now.
I have also been involved with a couple different FiTech help lines.
Helping out one another with tuning tips, etc.
I see a fair number of guys complaining that the systems are complete garbage and after X amount of time they still can't get it to run right and they are going back to a carburetor! This stuff is junk they say!
I basically see 3 things that are the biggest issues.
And most of this comes down to lack of knowledge.
Number 1 thing that'll throw the whole thing under the bus?
Poor installation! Thinking it's OK to run that ground wire to the engine, or its OK to pull power from any available circuit. Or it's fine to run these wires right under the distributor or next to these plug wires, etc.
Number 2. Those fuel command centers. Run my factory mechanical pump to fill a box with a electric pump in it to.......
Absolutely will give you nothing but issues. God help you if you think you will ever get it tuned with a system with fuel pressure all over the map. And constant complete shut downs.
Number 3. ECU failure on units like the sniper and a number of FiTech units with the ECU Mounted right on top of the engine!
So, yes, a lot of aftermarket EFI Systems are of questionable quality.
Do your homework before you buy.

 

[QUOTE=4-vettes;1608778721]The surge tank is the number 1 reason for failure with aftermarket EFI systems. Absolutely the wrong way to do it.
the pump belongs in the fuel tank!
Using the vent line is also a really bad idea.
I am thinking that you wish to cut corners on this install. And then you will be the next one on line complaining that this aftermarket EFI stuff is garbage.
Don't be lazy! DO IT RIGHT the first time![/QUO


Seems like a lot of anger in your response. Nice of you to assume what my character is, and that I'm just being lazy. Just asking if it'll work. There's literally a line that's right there that goes to the tank. I don't think it's an unreasonable question. If it would work I'd do it. If it wouldn't work I won't do it. The purpose of these forums is for people to is to ask technical questions so people with more knowledge in certain areas can offer help and guidance.

 

No anger mate. Truly trying to be helpful. Will that work? NO
Will the entire surge tank idea bite you in the *** hard?
YES.
Absolutely no anger, sorry, you can't hear the tone of my voice so you imagine.
Yes there are a number of us on here who have put EFI on these older cars. Yes we have learned lessons along the way.
When you open with, I'm going to put EFI on my car, and I wish to repeat every mistake possible. Your likely to get replies trying to set you straight.

 

Speaking about ecu's mounted under hood , back in the day Chrysler mounted the lean burn ecu on the air cleaner housing , Buick had a turbo ecu I think on top of the radiator, I remember replacing many of both ! Much more than inside the car ecu's. Now I have a sniper with a under hood ecu.

 

While can't speak on the Buick but the Chrysler Lean Burn ECM had a inlet and outlet scoop inside the air cleaner to allow cool air to pass through the ECM. The air was drawn into the air cleaner from air in front of the radiator as part of their cold air intake system. In later years with their front wheel drive cars ECM's were mounted on the L/S inner fender and served as the initial intake for the engines cold air intake.

 

[QUOTE=Cool95vette;1608780522]And when those with way more experience actually give you good solid advice, Say Thank You.
Don't go off in a huff because you don't want constructive criticism.
Running your fuel through a undersized, rusty old vent line really doesn't make a lot of sense if you actually think about.
And any research at all on Installation of a EFI system will net you much information on the right way to do it.
If you started out with, " I'm thinking about installing a Fitech EFI system " "What's the best way to run a fuel system in my 1978 Corvette.
You would have gotten a lot of good advice. And not one person would tell you to put in a fuel command center.
People only do that because they don't want to put a pump in the tank and run new lines. In others words. They don't want to take the time to do it right!

 

4-vettes, on your ECM that's mounted on the throttle body, does the throttle body have a cool plate that uses fuel to cool the ECM?

 

Absolutely NOT. My ECU IS NOTin the engine compartment.
Nor would I consider purchasing a EFI System that puts the ECU in the engine compartment.