Vaporization chamber
 

My cousin and I were looking at his 240SX as it idled and the motor trembled back and forth. At first I thought one of his plugs might be out, but decided to check fuel instead. We got a gas can out of the garage and poured about 8oz into the airbox, then closed it back up. Within a few seconds the engine quieted down and sat perfectly still as it idled. It seemed his injectors were unbalanced.

On my car, which is now a turbo sleeper, I'm using a fifth injector to provide the additional fuel, but the injector sprays right up against the charge pipe like a laser beam. By the time those vapors get to the engine, the fuel is very well distributed. The manifold is almost always coated with fuel, but despite the performance mods, I can still touch 40 MPG highway. Even without the extra injector, the manifold was designed to run wet, so that the runners are at its highest point, therefore any fuel drippage collects at the bottom until it can enter the engine as a vapor.

If I had another car like mine to ecomod, I'd use a hot air intake, then run the intake tract through a chamber filled with steel wool or scotchbrite pads, or something else with a lot of surface area, with a fuel injector aimed at it.

Since the fuel distribution would be very good, you could probably run at 20:1 or leaner. I believe the reason I lose economy above 18:1 is that a significant amount of fuel ends up in pockets inside the chamber which are just too lean to ignite. If the vaporization chamber ensured that no part of the air charge was leaner than say, 25:1, a greater portion of the fuel the injectors sprayed would burn.

Any thoughts?

I know that the more homogenous the mix, the better.
 

how do you run that extra injector?

With a piggyback controller.

How would you meter the fuel effectively on a naturally-aspirated car? It seems you'd run super-lean for a fraction of a second before the extra fuel had time to mix with the incoming air due to the very short length of the intake tract on many naturally-aspirated cars.

Also, you'd run into plumbing issues on cars there is no turbo aftermarket for, or that have sensors mounted in the throttle body.