Some knowledge on aftermarket TBI systems. (FiTech, Sniper, etc,)

Discussion in 'High Tech Retrofits' started by UnseenZ28, Apr 27, 2018.

  1. UnseenZ28

    UnseenZ28 Member

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    Hey all i figured i would share this piece of information that i wish i knew years ago. I've been messing with aftermarket TBI systems for a few years now. My first was the MSD Atomic EFI TBI system when it first came out on my built '87 trans am. And on my '79 Z28 I've had the Holley Sniper TBI and Atomic EFI.

    Now that the systems are in the $1,000 range more and more people are using them. Me personally i was never able to get it to run 100% on both engines. Messing with all settings i still had lean spots where the motor would fall flat or not respond correctly off idle. That is consistent across both motors on my built 87' and 79' camaro which has a stock motor and with both EFI systems.

    After doing some research i figured out the problem. Dual Plane Intake Manifolds. I recently switched to a single plane on my '79 and the difference is amazing, no more lean stumbles and extremely smooth throughout the whole band. I've seen many others report the same results.

    Engine Masters on youtube even ran into this problem with their Intake Shootout on the Dyno. They couldn't get the dual plane to run right with FAST EFI. They switched to a single plane and no issues.

    From what I've read the issue stems from the MAP sensor not being able to get a correct read because of the intake divider on the dual planes and/or how the dual plane is designed isn't the best for TBI.

    So if you're running one of these systems it may be a good idea to switch manifolds if you're having issues.
     

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  2. AllensaurusRex

    AllensaurusRex Veteran Member

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    This is really good info to us looking into this. Thanks buddy!
     
  3. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    Wondering how well a dual plane with divider cut down, like the RPM, or with an open spacer, will perform. Appreciate info on you real life experiences instead of "it should work".
     
  4. NotUniqueEnough

    NotUniqueEnough Veteran Member Lifetime Gold Member

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    Getting ready to finish the sniper install on my 80. (if all the parts come in today). Currently running a dual plane intake.. I will report back if I notice this issue. I do have a knock off single plane intake around here somewhere I can swap in to validate...maybe do the data logging and see what the numbers say
     
  5. redriderjf87

    redriderjf87 Veteran Member

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    That's good info, thanks for posting it. I kind of regret swapping out my Weiand single plane with that info, and really regret selling it. That being said, which dual plane did you have? I have an Edelbrock Air Gap and I'm curious if the little opening in the divider helps with that compared to other dual planes.

    I'm VERY curious on that, as I've been fighting similar issues with getting enough fuel on tip-in in some situations and some other inconsistencies for quite a while since putting in my FiTech. I am going to be starting a new thread in regards to this, with some unlocked settings I just discovered with the new software that solved this, but I'm wondering if the intake has been hurting me the whole time as well...

    I can't believe I haven't seen that Engine Masters video yet, one of my favorite series on youtube.

    EDIT: Just saw Corky's comment, agree with that.
     
    Last edited: Apr 28, 2018
  6. UnseenZ28

    UnseenZ28 Member

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    Hey guys, yeah i actually had a 1/2 Open Spacer on the dual plane, it did help but didn't totally eliminate my issues. To answer your question redrider i had an older Performer that was a straight divider all the way up. I could see the little opening helping but i think how the dual plane distributes fuel affects it as well.

    I just got done taking the car on a 120 mile trip and i am actually blown away at how good it's running. Red there's plenty of second hand single plane intakes floating around you can grab one for cheap off craigslist, letgo or ebay. Let us know if you swap it what results you have.
     
  7. redriderjf87

    redriderjf87 Veteran Member

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    Sounds good, thanks for the info. Which single plane do you have on it now if you don't mind? Mine was a Team G 7530 high rise, but I'm wondering what other single planes are out there that would potentially be a little more street friendly.
     
  8. UnseenZ28

    UnseenZ28 Member

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    Supposedly the Edelbrock Torker 2 is a more street friendly single plane, i was originally going to go with that one. But a buddy of mine gave me a Victor Jr. for free so couldn't pass up on it although i had to buy a different alternator bracket. You can grab a brand new Torker 2 for $188.. so not a bad price.
     
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  9. Green hornet

    Green hornet Veteran Member

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    Really good info. Thanks.
     
  10. dailycruiser81

    dailycruiser81 Veteran Member

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    I'm running an edlebrock air gap without any issues. Just hood clearance.
     

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