So you’re sold on doing an EFI conversion, perhaps one of the easy self-learning systems profiled elsewhere in this issue. Pretty much any company marketing conversions will have you taken care of with everything needed from the engine to the fuel system upgrades, but what about the fuel tank?
While you can technically run an EFI system with any factory fuel tank, the problem is that older tanks, typically pre-1980s, don’t feature any sort of baffling or sump; it’s just a big open chamber for the fuel to slosh around in. Such is the case with the fuel tank in Project EcoNova, our ’76 Nova project car and its LS3 E-Rod conversion. With the low pressure and flow associated with mechanical fuel pumps, that’s not too much of a problem for daily driving situations. EFI pumps, however, flow much more fuel at around 10 times the pressure—something our Nova’s E-Rod conversion would demand. If the tank is below half to a third full, just exiting a freeway ramp could be enough to create a fuel starvation issue that could damage the pump, or even the engine. If you’re planning to do any sort of performance driving like autocross or open track (that’s us!), forget about it, you absolutely need a baffle of some sort to keep fuel around the pump.
For our baffle we just grabbed a scrap piece of sheetmetal left over from a failed experiment on a previous project. If you need some, hit the metal scrap yard for something cheap; this needs to be functional, not pretty. Working with advice from the fuel experts at Aeromotive for the dimensions, our grid lays out a box with an 8x9 floor and 5-inch high walls.
…the problem is that older tanks, typically pre-1980s, don’t feature any sort of baffling or sump…
There are some great ready-to-go EFI-prepped tanks on the market, but they tend to be pricey, and model-specific applications will only be the usual suspects, Camaros and Mustangs and so on. So what do you do if you’ve got a project with no direct-fit option—such as a ’76 Nova—and you’d rather avoid a universal fuel cell? No worries, we’ve got the solution. There’s a quick, easy, and cheap way to prep just about any tank for EFI. Even with a killer pump like the new Aeromotive 340, we still came in around $350 total. Not bad at all considering we didn’t reuse anything from the car, and we finished it off in a day. Better yet, all the work is on the top and inside the tank so it retains its stock looks, and with an in-tank pump there’s no telltale whine either.
Note of Caution:
The first problem with vintage tanks is the size of the fuel sending unit; there’s barely enough room to slide in an electric pump, much less the full sending unit assembly. Our pump of choice is Aeromotive’s brand-new 340, which is a direct drop-in for most standard in-tank pumps.
We recommend using a new reproduction tank that has never been filled with fuel of any kind for this mod. If you choose to reuse an old tank, do not attempt to cut or weld on it until it has been professionally cleansed and rendered inert. Some fuel tank or radiator resto shops can handle this, but ask first and tell them what you’re planning to do. Don’t try to clean it yourself, and don’t trust advice on the Internet—old fuel tanks can, and do, explode!
No worries, we’ve got the solution. There’s a quick, easy, and cheap way to prep just about any tank for EFI.
