Hey guys,
I have a '72 Vega with '93 LT1/T56 powertrain. The engine is stock. I have it wired right now with a Painless EFI Harness. I'm far enough along now that when I bump the key the engine turns over. Yay!

I need to design a fuel system for the car. The tank is about 8 gallons and very shallow. I want to retain use of the stock pickup system. It has a feed and vent line right now. I think I can utilize the feed and vent lines for feed and return, then drill and tap a new fittings for the vent right at the tank.

My questions are:
- The stock lines were just clamped on with rubber hose. Obviously, the pressures associated with EFI won't permit hose clamps anymore. So, how do I connect the hard lines on the car side to the tank pickup? Should I flare the lines or can I buy some kind of adapter?
- I want to use a stock-style G3727 TPI-style fuel filter between the fuel pump and the injectors. What in-line fuel pump should I use? I'd love to use Aeromotive parts but it's out of my price range. What would a quality pump be and roughly what cost?
- I bought AN- fuel rail adapters. I think they're made by Russell. Anyway, how do I connect those fittings to the hard line? AN- hose? I've never used AN- hose so if anyone has a link to a tutorial that'd be great. Should I use a standard braid or is there something better suited for EFI?

Any help is greatly appreciated. My budget for the fuel system is pretty low..I'm embarrassed to say it's about $200-$250. I suppose if I could afford a 4th gen I'd be building one but I put a $1500 powertrain into $200 car. -shrug-

Here's my car: http://www.iroc-z.org/72LT1vega.jpg

Thanks for the help,
Colin

 

If you're going to use an in-line pump then the slip-on hose and hose clamps at the tank and on the inlet side of the pump will be fine.

Others will have to tackle the rest of the questions.

 

Thanks for the tip. Anyone have any recommendations in regards to pump and how to connect the hard line to the fuel rail?

Thanks for the help,
Colin

 

I think we may need a bit more info, or some clarification.
Are you saying that you will use a stock Vega fuel tank, and want to use the pickup point that is already on the tank? Or does the car have an 8-gallon fuel cell? Unclear. If its a stock tank, describe the connections, since I doubt many people here know what a stock Vega fuel tank looks like.
Again, what does the tank look like? Does it have an internal mount for a submersed fuel pump, or does it have a low-point sump with a connection for an external pump? If its a connection for an external pump, how big is it? Your later question describes using an in-line pump, so it sounds like you just have a connection off a sump.

Then there's the issue of how much fuel you need.... If the Vega tank was designed to supply the fuel needs for an economy 4-cylinder, its questionable whether the connection is properly sized for an engine that is going to consume 3 or 4X the amount of fuel. The last thing you want to do is have too small a suction connection for the in-line pump. You will cavitate the pump.
What are the end connections on the G3727?

I run a Bosch in-line pump. They are extremely reliable, and will support up to 500HP in a high pressure recriculated EFI system. Alternatively, a Walbro would be larger, and cheaper.
How much of the stock 93 fuel rail setup do you have? Does it include the rails, and the hardlines that connect the fuel supply to the rails and the return line to the fuel pressure regualtor. If so, it sounds like you have already bought adapter fittings. Are these "compression" style fittings? Are you asking how you install these fittings?

As far as the braided S/S hose, you need to use -6AN supply and return lines. Make sure the specific hose that you select is suitable for gasoline. Typically, the design pressure of braided S/S hose far exceeds the 43.5psi it will see in your fuel system.

 

You shoud put a sump on the tank.

They make quick connect adapters you can use on the rail.

Your adapters, lines, fitting etc. you can probly get with your budget. Maybe use aluminum tubing for the long runs to save money and weight. But you still need the pump and filters.

You can just get a universal filter (not sure what model uses this) with 3/8" fittings on both sides. Then you could just flare the aluminum tubing under the car and mount the filter.

Use the original supply for the return, you can just clamp that....its free flowing with not much pressure.

Need to know what pump you plan to use

 

Thanks for the help, guys..

I am using the stock Vega gas tank in the car. I believe it has a 5/16" feed and 1/4" vent. I hadn't thought about using a sump on the tank so that's a great suggestion.
The tank isn't internally baffled and uses a pickup system similar to 60s GM cars where a sock floats in the tank. Interestingly, the Vega is one of the first mass-produced cars that had an in-tank electric pump (booster, low pressure) to feed the carbureted fuel system. The system looks very similar to a ThirdGen F-Body unit but with fewer lines out of the pickup assembly.

On mdacton's suggestion, I think I'm going to sump the tank. I looked around Summit and found a sump by Competition Engineering that I weld to the bottom of the tank after drilling 2 holes. I think I'll do that.

I am using the stock fuel rails on my engine. I am using the quick-disconnect AN- fittings and will go from that to the hard lines with braided ss hose.

As for the fuel pump I was looking around the net and it seems like the Walbro GSL392 is a pretty popular pump. The good thing is it's cheap! Like $120.

The fuel filter is G3737 is the same pump used on TPI Camaros and Firebirds. It uses 3/8" fittings (http://www.sherco-auto.com/images/gf481.jpg). Basically standard issue on all mid- to late-eighties GM MPI engines. I like the fact it's available 'anywhere' and should work well for a stock engine. Later, I'll upgrade to a higher flow filter but right now it'll do well.

Injuneer, your questions made me think. Thanks for the help. I guess the essentials now are a tank sump, utilization of the stock feed line as my return to the tank and purchase an inline fuel pump (probably Walbro GSL392).

Am I missing anything else? Do you of a good tutorial page on how to make AN- hoses? I don't know how to do that.

thanks!
Colin

 

The tank needs to go to a welding shop or radiator shop to be sumped. If you try to do it it will blow up.

They will wash it and fill it with argon while welding it