Atomic EFI

chomama1 · #1 (**permalink**) 08-01-2012, 06:59 PM

Anyone use the Atomic EFI by MSD?? I am thinking of getting rid of my stock Ford EFI, it works great but I can't stand the look. I want to get a Edlebrock dual quad intake and put two Atomics on it. That would be about half what a Inglese stack EFI unit would cost me.

redchief · #2 (**permalink**) 08-01-2012, 11:54 PM

Just read through the FAQ on the MSD site and it is says it does NOT support a dual quad set up. You might talk to MSD before going down this path. I have a unit and plan to run it on a stroked 351W (405) but the engine will be in a Hot Rod (33 Ford Vicky). Plan to get about 450 HP.

Gaz64 · #3 (**permalink**) 08-02-2012, 01:25 AM

Quote:

Originally Posted by chomama1

Anyone use the Atomic EFI by MSD?? I am thinking of getting rid of my stock Ford EFI, it works great but I can't stand the look. I want to get a Edlebrock dual quad intake and put two Atomics on it. That would be about half what a Inglese stack EFI unit would cost me.

You have stock EFI at the moment, and one Atomic on a single plane intake can support 525+ hp.

Isn't that enough?

The system appears to only have capability to drive four injectors in a single four barrel carb replacement configuration, as a bolt on in place of one carb, the market that MSD has aimed at.

chomama1 · #4 (**permalink**) 08-02-2012, 04:17 PM

Well, you're right, the site says it will not work as a dual quad setup. OK, back to the drawing board.

olddog · #5 (**permalink**) 08-02-2012, 08:27 PM

If your up to a challenge, here is an idea.

Look at a company call MassFlow's website. They take a Vic Jr single plane, put on a throttle body that resembles a carb, and then drill/weld in injector bungs at each port. They use a Ford EEC4 ECU. They put a GM mass meter inside the air filter and use a signal converter. Getting a good MAF reading is the important part.

I do not see why a person couldn't extend this idea to a dual carb setup. In fact you should be able to block off the jets of some junk carbs and use them as your throttle body. If the flow on the two carbs were equal, then only one MAF meter sized to 1/2 the flow should work.

Barry R. posted that he did something similar with a dual plane and it worked well. Massflow claims it only works on a single plane, but that makes no sense to me. I trust Barry, and believe him.

bobcowan · #6 (**permalink**) 08-02-2012, 11:17 PM

Multiple throttle bodies is a little bit different than multiple carbs. Especially if you use a dual plane manifold, or individual runners.

Carbs draw and meter fuel primarily based on a vacuum signal. Twin carbs on a single plane manifold will draw fuel through a common plenum. The plenum will balance out the carbs, and self adjust for small variances. All the fuel gets dumped into the same plenum anyway.

EFI is different in that the injectors will squirt out the required amount of fuel regardless of vacuum signal. And the injector is down at the end of the intake runner. If you have multiple throttle bodies, it is really important that they be balanced correctly. Especially if you use a dual plane or IR manifold. That balance is critical. If you can't get it balanced, it will never run correctly, and no amount of tuning will fix that.

Balancing an 8 stack system is not all that difficult. The proper tools are cheap, and it doesn't take long. A good synchrometer is readily available, and is <$100 shipped to your door.

Synchronizing two large TB's would be a little more difficult. You can't use a vacuum signal below the TB, because it would be effected by the other TB. You would have to measure it above the TB plates. You could probably cobble together something, and adapt a Weber tool for to the bigger TB.