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I am looking for a Winter project and thought going EFI would be a good one.
So what I am looking for.
1. Gas tank with internal fuel pump / baffle's etc. and is the standard fuel capacity for the 78 corvette (24 gal)
so first question can I use the existing fuel lines ?
as for the EFI unit.
everything must be programmable the ECU must control fuel delivery and ignition timing and adapt to different climate conditions.
The cars use is mainly track days, so safety of the fuel lines etc is a must.
So is there a system / manufacture that does this very well.
Last edited by cagotzmann; 10-22-2018 at 12:42 PM.
The aftermarket EFI tank options for the late C3s are limited; one really simple solution for the 78 is to buy an 82 vette sending unit and install a Walbro in-tank pump and a Holley "Hydramat" that mates to your particular pump -the hydramat will prevent fuel starvation under cornering without having to have baffles installed in the tank -as long as fuel is touching the hydramat ANYWHERE it will still pull fuel. Whether you can use the stock fuel lines or not depends upon your HP peak. (There's 3 different Walbro 255l/hr in-tank pumps, 2 will allow the connection to the hydramat and only one of those will work with the stock sending unit hangar bracket (I bought the wrong one and had to cut off the stock hanging bracket).
-I just did this conversion on my 79 and I went with all new fuel line and return line using Earl's Vaporguard EFI hoses as my old steel line had been cut in a couple of places and had some rubber lines installed between sections of steel and I just didn't want to deal with it. If you go with new hoses, you'll want 2 12' or 13' lengths. (I bought 20 feet thinking that 2 10' lengths would be enough.... it wasn't...
The 82 sending unit uses 3 wires and the 78 only has a basic ground and the ohms signal for the Fuel level gauge in teh dash- you'll want a GOOD ground going to the sending unit for the EFI pump and then you'll run the hot wire off of a relay from the Sniper EFI back to the tank.
Adam
P.S. The Hydramat has an estimated lifetime of 10 years; if you go this route instead of a baffled tank or a sump tank you'll need to drop the tank and replace the Hydramat 10 years from now again...
P.P.S. If you're going to pull your stock tank it's a good time to wire brush it up and paint it with Eastlake "Tank Tone" paint; it looks pretty spectacular; buy two cans.
Last edited by NewbVetteGuy; 10-22-2018 at 01:31 PM.
I am looking for a Winter project and thought going EFI would be a good one.
So what I am looking for.
1. Gas tank with internal fuel pump / baffle's etc. and is the standard fuel capacity for the 78 corvette (24 gal)
so first question can I use the existing fuel lines ?
as for the EFI unit.
everything must be programmable the ECU must control fuel delivery and ignition timing and adapt to different climate conditions.
The cars use is mainly track days, so safety of the fuel lines etc is a must.
So is there a system / manufacture that does this very well.
How much horsepower are you making?
I just converted to FAST EFI on my 79. I am making somewhere around 400 hp, so I needed a 3/8 feed and 3/8" return line. The stock feed line is 3/8", the stock return is 1/4" (too small). So I used the current 3/8" feed line as my return, and I ran a new 3/8" feed line.
You didn't say what kind of budget you're working with. For the fuel tank there's Rock Valley. All stainless steel, in-tank pump, and baffled. Very pretty, but it's over $1K.
You didn't say what kind of budget you're working with. For the fuel tank there's Rock Valley. All stainless steel, in-tank pump, and baffled. Very pretty, but it's over $1K.
You didn't say what kind of budget you're working with. For the fuel tank there's Rock Valley. All stainless steel, in-tank pump, and baffled. Very pretty, but it's over $1K.
No budget just need a system that works like it was factory installed. Not looking for making modifications. If this tank just fits and is 24 gal same as the factory this looks good.
I just converted to FAST EFI on my 79. I am making somewhere around 400 hp, so I needed a 3/8 feed and 3/8" return line. The stock feed line is 3/8", the stock return is 1/4" (too small). So I used the current 3/8" feed line as my return, and I ran a new 3/8" feed line.
Stock ZZ383 ~ 400HP so installing 1 line should be fine. Did you run steel line or all rubber. I don't think my local track for track days allows more than 2 ft of rubber lines total.
No budget just need a system that works like it was factory installed. Not looking for making modifications. If this tank just fits and is 24 gal same as the factory this looks good.
Rock Valley will build you anything you want. So if you want stock 24 gallon they'll make it. On mine I had them add an extra fitting in case I wanted to add a vent line later and also some studs for mounting the bracket holding the lines. They didn't charge anything extra for that which was nice. They also offer stock steel tanks converted to in-tank pump but you don't get all the baffling the stainless tanks have.
Stock ZZ383 ~ 400HP so installing 1 line should be fine. Did you run steel line or all rubber. I don't think my local track for track days allows more than 2 ft of rubber lines total.
I ran Nickel Copper line for the main length of the car, and then used braided nylon lines with AN fittings for the connections to the tank and throttle body. That way there is some flex in the system (important so the hardlines don't crack when the engine is vibrating and moving around a bit).
I ran Nickel Copper line for the main length of the car, and then used braided nylon lines with AN fittings for the connections to the tank and throttle body. That way there is some flex in the system (important so the hardlines don't crack when the engine is vibrating and moving around a bit).
Did you add the lines with the body-off, or did you do it in sections with the body-on the car, and use braided lines to inter connect the sections ?
Similar to Zwede, I had Rick’s tanks build me a stainless tank to stock 69 tank dimensions. It uses an in tank Aeromotive A1000 pump and pre filter. Also has a vent. Work of art and uses extensive internal baffling. Expensive, but well worth it in my opinion. I am going to use braided Teflon fuel feed and return lines.
I'm using the stock pickup with an inline walboro 255. All braided -8 feed hose and -6 return with AN fittings. Car made 490/540 to the tire. I was also able to run the tank COMPLETELY DRY (by accident). Stock fuel level sending unit is also functioning properly.
I'm using the stock pickup with an inline walboro 255. All braided -8 feed hose and -6 return with AN fittings. Car made 490/540 to the tire. I was also able to run the tank COMPLETELY DRY (by accident). Stock fuel level sending unit is also functioning properly.
They don’t. Both Holley and Tanks Inc stop providing Corvette tanks after model year 1974. There are very few options for late C3s. Stock tank, 82 sending unit and Holley Hydramat.
I have a 383 with approximately 436 dyno'd hp.
I have Holley Terminator EFI. Sniper wasn't out yet when I did my conversion.
Used the stock tank with Aeromotive Phantom 340 in tank fuel pump. in the pic you will see that I mounted on the high side of the tank, so needed the extension kit also.
the Phantom uses a foam and rubber boot as a baffle around the pump. Only issue I had was when I was down to less than a quarter tank of fuel. on the second clockwise lap around autocross G-circle and I starved for fuel, as the pick-up is on the passenger side. This was a test & tune day and we had been running all day. normally wouldn't have so little fuel in the tank.
Ran braided stainless supply and return lines from tank to engine. they tucked in nicely along the frame rails, on top of the section on the passenger side rear wheel well.
I have the Fitech fcc, which I recently modified as a surge tank (now rather than using a float like a carb, it just overflows when full and runs back to the main tank). Has the advantages of not needing to run new lines or drop the tank, will run until the tank is dead empty without issues. Has the disadvantages of an extra component to mount with associated (minimal) extra weight, and the additional complexity of requiring both a standard carby fuel pump (to feed the surge tank) and the high pressure efi pump. Will never starve due to g forces when the main tank is low though - it holds a couple of litres/quarts in a tight vertical cylinder directly around the high pressure pump.
Edit: I used my factory lines, used a mechanical pump without a return fitting and used the factory return line as the return for my surge tank.
Last edited by Metalhead140; 10-25-2018 at 01:24 AM.
I have a non-vented cap- and from what I have read just changing over to a vented cap (designed for a carbs) could cause venting issues- not to mention that gas smell.
The vent on the Aeromotive Phantom Pump - manual said the vent should be 6" above the tank and use a roll over valve. In a Vette to do this the vent would have to be a couple of inches above the rear deck!!!
So I added a roll over valve- connected it to a charcoal canister ( used in GM cars for the brake vacuum line) and then a vent used in marine applications placed in the antenna hole. I also ended up going w/ Russel Synthetic rubber hoses to hopefully stop the permeation of the ethanol in the gas - and gas smells.
I also uses the ni-copper lines on the frame and covered it with the spring guard.
roll over valve
Vent for boat hulls-
Vent in the antenna hole-
The other thing I did was putting a fuel cooler on the return -a few OEM new cars have it- can't imagine it would hurt ...
So my thoughts- no gas smell- have a roll over valve if I am ever unfortunate to roll the car. I am also adding a Ford inertia switch to shut the fuel pump from an impact. Has a reset and mounted it in the battery compartment -for easy access.
I had gas in my tank for two years- it dissolved the foam baffle.....
I just couldn't put foam back in the tank- knowing it could dissolve.
I went with the Holley Hydromat and have two pumps in the tank now. A primary and a secondary- just in case the primary one goes down. The Aeromotive system is designed to handle two pumps-
Here's the fuel rails with the return- and running a billet fuel pressure regulator with Bosch internals
I just removed the old fuel tank and replaced with a fuel cell, made a custom frame to hold it, straps to stop it moving upwards and run teflon braided hoses upto engine, 2 x walbro in tank
10-22-2018, 12:41 PM
EFI Complete conversion
