EFI Comparison (MSD Atomic vs Holley Avenger vs FAST EZ vs Powerjection III)

Discussion in 'High Tech Retrofits' started by CDesperado, May 3, 2012.

  1. Zee

    Zee Veteran Member

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    Good discussion. I don't see how that Holley throttle body is any different from those used with the pro-jection but understand the primary difference is in the ECM. Holley has been at the FI game for years if not decades and has not gained much of a foothold in my opinion. I doubt there would be either the Avenger or the MSD had it not been for FAST proving the market existed for a guy to convert over to FI without any programing background. I do have an open mind and would consider the Holley. How does the Holley fit a drop base? It appears that since the throttle body is so low that the throttle linkage would never clear a drop base air cleaner without something in the order of a 1" spacer between the throttle body and air cleaner. Moving onto the ignition issue, I did find this that may allow me to use a small cap HEI distributor on my Pontiac: http://www.davessmallbodyheis.com/ If that would work, I think that would give the Holley system a serious advantage for me.

    Newschool, with your FAST system, are you talking about clearance with the actual rails or the fittings and crossover attached to the rails. I was looking at that and was assuming the crossover would have to be swapped to the other side and different fittings used. Maybe hardline??
     
    Last edited: May 8, 2012
  2. hutchenc

    hutchenc Veteran Member

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    Zee...you'd have to ask the fellow who builds those distributors if they'd work for you. I honestly don't know. The Holley stuff is designed to work with a 7 pin computer controlled HEI found on all sorts of GM vehicles but older Pontiac motors, I dunno.

    I think FAST makes a good product yes, but I think FAST, Powerjection, and the Holley Avenger and HP stuff all came on the market around the same time. The TBI is the same yes, but as you said, the advantage is in the ECU. You can easily adapt it to an MPFI setup or run it on an LS based motor just by changing the harness and loading a different base map. The FAST EZ ecu is pretty basic in comparison and costs the same amount as the basic Avenger kit from Holley. If you just want to run NA and don't want to take advantage of timing control I guess it's fine. Simplicity does have its place in all of this and if the MSD unit turns out to be a good product, it may well give FAST a run for its money.
     
  3. Zee

    Zee Veteran Member

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    still would like to know what issues are involved using the Holley TB relative to the air cleaner. Drop base? Flat base?
     
  4. CDesperado

    CDesperado Veteran Member Lifetime Gold Member

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    I'm posting version 4, which includes the MegaSquirt option. (A tip of the hat goes to Jones20992 for putting that together. Thanks man!)

    I am still working on the more in-depth version with notes about the various sensors, etc. It may take a little longer than expected. It's a lot of detail (as I am sure many of you know) and trying to translate this into practical language that makes sense is a challenge.

    Plus, I am still doing research for my own build for other things. LOL Trying to select mufflers and exhaust today. Narrowed it down a good bit, but time is marching on!

    [​IMG]

    Edit. 15 May. Holley Fuel Rails are listed as "Not Included" on Summit website, but appear to be Internal, the same as the MSD Atomic EFI kit.
     
    Last edited: May 15, 2012
  5. PolarBear

    PolarBear Veteran Member Lifetime Gold Member

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    The Holley TB is VERY short, but it comes with a spacer that you have to use. The TB is also basically "square" so it will work with a drop base. The linkage is also VERY Holley like, basically the same as any Holley Carb.

    I can post some pictures with an air cleaner once I get closer to installing it.
     
  6. earnhardtgm3

    earnhardtgm3 Veteran Member

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    I'm interested in seeing this.
     
  7. PolarBear

    PolarBear Veteran Member Lifetime Gold Member

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    Forgive my mess :crazy: I am single and that is my kitchen counter

    Without the spacer
    [​IMG]

    With the spacer
    [​IMG]
    [​IMG]

    Here is with my drop base, I think it is a 2.5" drop.
    [​IMG]

    With my 3" air filter on it.
    [​IMG]

    I am actually going to have to use a flat base, or less drop or a taller air filter. I cant actually put the lid on the filter because the lid touches the top of the injectors
     
  8. Zee

    Zee Veteran Member

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    That was exactly my concern. I'll have to measure my base but due to the shaker, I can't run a taller filter. I assume the spacer is so the base will clear the linkage. Wonder what kind of airflow is available by the time you add the air cleaner spacer as the TB really can draw air from the sides when using the spacer???
     
  9. PolarBear

    PolarBear Veteran Member Lifetime Gold Member

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    Holley is saying it is 900 CFM
     
  10. Zee

    Zee Veteran Member

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    Yeah but is that with the goofy spacer on? I believe them with the throttle body itself but not sure by the time you cramp its style with a spacer that fits close to the injectors then cap it off with a filter lid that sits down on top of it all as shown in the pics.
     

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