MSD Atomic EFI

[sunsetdart]

Was out at SEMA and got to check out some of the new stuff. Talked to FAST and Holley about their EFI systems. Then I went into the MSD booth.........they got this new EFI called the Atomic EFI.
You don't need a regulator or a return line and you only need to hook up an O2 sensore and a temp sensor.Everything else is contained in the unit.
Check it out on their site............it aint cheap, but none of them are but as far as simple goes, this one is.
And no, I don't work for MSD...........just wanted to pass on some very cool stuff.

[Bakaruda]

Not bad. I have installed 2 fast systems. No real differance here. The install kit is on the cheap side in my opinion.

[qkcuda]

Very simple kit, but I don't understand why they run the injectors thru the boosters. Doesn't the FAST system inject the fuel below the throttle blades?

[bremereric]

I have studied the Holley setup and I would like to give it a try someday. It has the learning/tunning computer.

[jamesdart]

yes the fast ez efi has the injectors below the throttle plates.

[Bakaruda]

The fast system has the learn feature as well.

[Joe-Dokes]

It is a throttle body injection system which greatly simplifies installation and wiring. I actually like the idea of using booster for the injectors. It makes the throttle body appear more like an old school carburetor. Also since the injectors actually reside in "float bowl" area of the throttle body you don't have a giant injector blocking airflow into the motor. Thus the "injector" is simply a spray nozzle that directs the fuel into the intake manifold.

In a throttle body injection setup you want the injectors spraying fuel down and directly into the manifold. The OEMs all pretty much placed the injector above the throttle plates spraying directly into the intake manifold.

Here's a typical GM throttle body.

The FAST EZ EFI system places the injectors on the sides of each barrel of their four barrel setup, with the injectors aiming into the incoming airflow at a 45 degree angle. Thus, all four injectors are firing at the same time towards the center of plenum, which would also provide good atomization. Considering the generally positive reviews of the FAST EZ EFI system, it appears that this system works well as well.

Several DIY setups have tried placing the injectors at a 90 degree angle to the airflow with poor results. Lean cylinders, overly rich cylinders, and fuel puddling have resulted. Thus, proper injector placement is critical to an effective efi setup. However, this doesn't correct placement is rocket science, simply that awareness of air and fuel flow is an important consideration in EFI.

If you look at the way port injectors are setup, you'll find that they are aimed at the back of the intake valve. Thus when the injector fires it hits the back of the hot intake valve which helps with fuel atomization well. Contrary to popular belief in a sequential port fuel injection setup you time the fuel injection pulse for when the valve is closed not open. Of course as engine speed increase and the injector approaches 80% to 90% of its duty cycle it's pretty much spraying all the time.

As far as price goes, it appears as though the system runs around 2k which puts it in the same price range of FAST EZ EFI. You could do system a lot cheaper with Megasquirt, but the learning curve is more like a vertical assent.

The more interesting fact is that while carburetors have been climbing in price these stand alone EFI setups have been either staying the same or been decreasing. For example a New Holley Ultra Carburetor has a list price of between $665.99 and $778.96. Thus, it won't be too long before the choice between EFI and a carb will be made without reference to price.

Regards,

Joe Dokes