383 cam selection

Discussion in 'High Performance Modifications' started by Brad Burris, Feb 5, 2021.

  1. jthomas

    jthomas Veteran Member Lifetime Gold Member

    Messages:
    1,631
    Likes Received:
    125
    Joined:
    Dec 5, 2007
    Location:
    NorthCentral PA
    EFI is affected by LSA. While it’s true you can make EFI work with a tighter LSA, it requires a very good understanding of tuning dynamics. It’s important to call it like it is and be clear that a 112+ LSA plays much nicer with EFI than say a 108. I’ve seen many engines with tight LSA and EFI that just don’t work like they could. I’ve seen a few that do because the builder/tuner really knew their stuff. Overlap plays a big role in how well EFI works. EFI likes minimal overlap and a steady manifold vacuum signal to really shine.

    Unless you really know what your doing and build with the parts best matched to a tighter LSA, if you plan to go EFI, you will be much happier in the 112+ range.
     
    G72Zed likes this.
  2. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

    Messages:
    16,127
    Likes Received:
    1,092
    Joined:
    Mar 25, 1999
    Location:
    San Jose, CA, USA
    [​IMG]

    Literally every OEM and experienced tuner on Earth disagrees with you
     
    G72Zed likes this.
  3. 76z28

    76z28 Veteran Member

    Messages:
    2,305
    Likes Received:
    168
    Joined:
    Jun 29, 2009
    Location:
    bakersfield
    I am amazed that most of you think you can't run a tight LSA with EFI. Many people seem to be doing it just fine without issue.

    Tight LSA has nothing to do with being able to run EFI and EFI is not affected by LSA. Get a new tuner if they can't figure out how to tune it with a tight LSA.


    OEM has absolutely nothing to do with LSA and EFI. How do I know? THEY ARE BUILD TO LAST AND MAKE CUSTOMERS HAPPY. That is why you put a cam in and pick up power.
     
  4. 76z28

    76z28 Veteran Member

    Messages:
    2,305
    Likes Received:
    168
    Joined:
    Jun 29, 2009
    Location:
    bakersfield
    I have a feeling those of you saying "can't run a tight LSA with EFI" have no idea what LSA really is.

    Based on that logic, I can run a 280/[email protected] with an LSA of 112.

    Yet I can't run a 230/236 on a 108.

    The 112 cam will have MUCH more overlap and cause MANY more issues with EFI than the little 108 cam.
     
  5. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

    Messages:
    16,127
    Likes Received:
    1,092
    Joined:
    Mar 25, 1999
    Location:
    San Jose, CA, USA
    No one said anything about running a [email protected] cam but you. Put your straw-man away.
    I'm going to go ahead and guess that you've never tuned an EFI car on a dyno. Let alone one with a [email protected] cam with a 108 lobe separation.

    You can make a narrow lobe separation work, but it's much more difficult. EFI systems take most of their reference from intake manifold pressure (the MAP sensor). When you run a narrow LSA it greatly drops manifold pressure and gives you a much smaller range of pressures to work with for reference. One can run a special MAP sensor and tune around it, but there are no gains to be had on a streetcar from doing so.

    Bear in mind here, the Chevy LS7 7.0 revs strong all of the way to 7000RPM. It runs a Hyd-roller cam with 211/[email protected] with an LSA of 120
    If I can take an engine with a 4" stroke to 7000RPM and make peak horsepower from 5500-6400 RPM (and make 440+ ft/lbs from 3000-6400) with [email protected] and a 120-degree lobe separation... why do I need a cam with a PITA narrow lobe separation?
     
  6. flht99b

    flht99b Veteran Member Gold Member

    Messages:
    832
    Likes Received:
    273
    Joined:
    Nov 28, 2014
    Location:
    Knoxville, TN
    Agree 100% with you, based on my real experience.
     
  7. 76z28

    76z28 Veteran Member

    Messages:
    2,305
    Likes Received:
    168
    Joined:
    Jun 29, 2009
    Location:
    bakersfield
    To make more power down low. You clearly have no CLUE what you're talking about LOL. I have, hell even mine (250/256 on a 108)
    LSA has nothing to do with how to tune EFI. You don't know what LSA is, a sum of numbers. It's weird, you see EVERYONE using EFI now and they don't mind what LSA their engine has. You just need to get with the times.
     
  8. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

    Messages:
    16,127
    Likes Received:
    1,092
    Joined:
    Mar 25, 1999
    Location:
    San Jose, CA, USA
    ... yes, clearly I lack experience...
     
    SPG likes this.

Share This Page