MSD Atomic LS EFI anyone run one?

[Solid LT1]

Looking for feedback on users of the MSD Atomic LS EFI systems. Would like to know real world experience with system, type of motor...LS1, LS3....any mods on motor...cam? Intake type. There was a Trans Am at SEMA a few years back with a single plane and 4bbl throttle body running the Atomic LS EFI, that's the exact set up I would like to build. Thanks for the info.

[jwcarguy]

A buddy of mine tried running that setup on a 408 stroker in his sandrail
Neither of us was impressed, especially at a base price of $2500
The car would lean out and not run correctly after numerous times out on shake down runs with it "self-tuning", it comes loaded with stock GM settings and from what I remember that you can only "adjust" settings so far (unlike HP Tuners, EFI Live, etc)

He finally got in contact with MSD and they stated that that system was designed for a "street rod" running a mild engine mods" , not for a stroker or "highly modified engine"
We pulled that system off, went back to a proven GM Gen III pcm and aftermarket harness (it was either a Speartech or Affordable EFI) loaded a base tune, then off to dyno, the sand rail preforms great now, no lean out conditions, etc

Hope this helps

[TheJDMan]

Take a look at this recent video on youtube where they were actually testing the difference between a Holley 750 double pumper carb vs a throttle body EFI on an LS7 engine. In the process of testing they encountered some interesting results with respect to the intake manifold.

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[gnx7]

I run the Holley EFI (HP and Dominator) on a bunch of LS motors between myself and friends. Making anywhere from 600hp to 1400hp.

The software is very user friendly is the great part. Other aftermarket fuel management systems are not as easy to learn or navigate. You can run a composite style intake with standard style TB.... it can also be configured to run a single plane style intake with 4150/4500 series TB with injectors in the runners near the port. As long as the computer receives the data it needs.... the motor can be tuned (self tuning feature is very nice on it), data logged, etc.

Read up on the Holley features. It just came out with Flexfuel. For a naturally aspirated motor on lets say 91 octane and 11.25:1 compression it would make 500rwhp for example. Drain the tank and add e85 (with enough injector/pump) and it will gain 10-15rwhp from timing alone.... which the computer will recalculate the fuel changes for you! On a forced induction car you can add 500rwhp+ from the octane/timing/boost e85 allows.

Traction control, 2 step launch, data logging, up to 100% added automatic fuel enrichment (if a regulator or pump goes bad), lean cruise, low oil pressure auto shutdown.... many other cool features.

I don't run the Atomic EFI version of the Holley.... it's probably bang for the buck cheaper than the HP/Dominator.

My new LS motor is a 4.190" bore resleeved 5.3 with 4" LS7 crank and Titanium rods making 13.5:1 compression with AllPro LS7 430cfm heads and single plane AllPro intake running a 4500 series throttlebody on e85. It should be alive in April/May timeframe. Goal is 700rwhp all motor and 8000rpm when needed (road racing). It will be using the Holley HP efi.

[supremeefi]

The software is very user friendly is the great part. Other aftermarket fuel management systems are not as easy to learn or navigate. That's your opinion, some others would argue that. And that would be their opinion. You can run a composite style intake with standard style TB.... it can also be configured to run a single plane style intake with 4150/4500 series TB with injectors in the runners near the port. As long as the computer receives the data it needs.... the motor can be tuned (self tuning feature is very nice on it), data logged, etc.

Read up on the Holley features. It just came out with Flexfuel. Which others have had for years, AEM and FAST come to mind. For a naturally aspirated motor on lets say 91 octane and 11.25:1 compression it would make 500rwhp for example. Drain the tank and add e85 (with enough injector/pump) and it will gain 10-15rwhp from timing alone.... which the computer will recalculate the fuel changes for you! On a forced induction car you can add 500rwhp+ from the octane/timing/boost e85 allows.

Traction control, 2 step launch, data logging, up to 100% added automatic fuel enrichment (if a regulator or pump goes bad), lean cruise, low oil pressure auto shutdown.... many other cool features. Again which other systems have and/or have had for years.



My point? Simple, download the various software packages from the manufacturers you're interested in and navigate them for yourself. Then call their tech depts. and ask all of them the same questions, i.e. what are systems biggest attributes etc. It'll help in making an informed decision, I guarantee it.

Hope this helps. Thanks.

[gnx7]

If you think AEM Infinity is easy to use you must be a rocket scientist.

[supremeefi]

If you think AEM Infinity is easy to use you must be a rocket scientist.

It is, and so is the Accel DFI, FAST XFI as well as the BS3 to name a few others. The Holley is cumbersome to me vs those others. Just sayin.

But I'm still a proponent for guys to download the respective software packages from each manufacturer and decide for themselves. From there they can decide if the features and benefits of any given system are right for them and their own application.

[hifi875]

i had a performer rpm intake with my holley terminator and it didn't run right till i went back to a single plane intake from holley.

[NOPANTS68]

I ran an Atomic on a warmed over ZZ502 in my 67 Chevelle a couple years ago. I loved it. It started every time, kept a great idle, plugs looks great, and the car made stupid power. I ran a second O2 sensor with a FAST monitor in each bank just to keep tabs on things for the first 100 miles and the system was dead on. Tough to beat for $2500. Was it making every last HP? no. I beat it was 995 there though. With 19 inch wheels and 30 series tires, it didn't matter anyway.