Results 1 to 5 of 5

Thread: Need help tuning gmpp intake w/ accel 1150cfm tb

  1. #1
    Member
    Join Date
    Apr 2007
    Posts
    66

    Default Need help tuning gmpp intake w/ accel 1550cfm tb

    Ok so i've decided to go with a carb intake and efi tb setup for my 383 stroker but i have no idea where to start with the tune. Should i tune just like any other vehicle or will there be specific tables that need to be adjusted for the larger tb or even a different iac then the stock ls1? Are there any tables that should be adjusted for a shorter runner? What about the alpha-n tune? I have heard people talk about it but after doing a search there doesnt seem like there is much info out there about it? Also can i do a alpha-n tune on a stock ecm? If so how do i go about doing so?

    I know there are a lot of questions here but i really am stuck on this one and cant seem to find much info on any of the efi/carb style setups

    Thanks,
    ..RJ..
    Last edited by wadesns; July 12th, 2007 at 05:20 PM.

  2. #2
    Lifetime Member 5.7ute's Avatar
    Join Date
    Oct 2006
    Posts
    1,840

    Default

    The alpha-n tune is available in COS5. Have a look from this page on where they get into the nuts & bolts of setting this option up.http://forum.efilive.com/showthread.php?t=2599&page=6

  3. #3
    Member
    Join Date
    Apr 2007
    Posts
    66

    Default

    I have read through this and was wondering is this what people are calling the alpha-n tune or is it just a modified tune where it uses part of the stock tune and what i presume is the alpha-n at lower rpms?

    ..RJ..

  4. #4
    Lifetime Member 5.7ute's Avatar
    Join Date
    Oct 2006
    Posts
    1,840

    Default

    From what I understand it is used in the lower RPM areas for cammed cars where getting a stable map pressure from reversion is an issue. However the table has resolution up to 8000 RPM so it can be used exclusively. The hardest part will be populating the table initially.

  5. #5
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Alpha-N is fueling based on throttle position (alpha) and engine speed (N).

    Speed Density is fueling based on intake charge density (calculated from manifold pressure) and engine speed.

    COS5 has both the alpha-N TP vs RPM table and the usual speed density MAP vs RPM VE table.
    COS5 has parameters for enabling the alpha-N table at specific MAP/RPM values allowing the PCM to select either table based on MAP/RPM.
    Last edited by joecar; July 13th, 2007 at 04:30 AM.

Similar Threads

  1. Accel enrichment
    By Camaro SS in forum Custom Operating Systems
    Replies: 15
    Last Post: February 9th, 2009, 08:12 AM
  2. B5208 Rev limiter accel modifier
    By XLR8NSS in forum E37, E38 & E67 PFI ECM's
    Replies: 2
    Last Post: September 22nd, 2008, 07:47 AM
  3. tuning carb intake and elbow
    By minytrker in forum General (Petrol, Gas, Ethanol)
    Replies: 1
    Last Post: July 1st, 2008, 05:25 AM
  4. RPM remains high after accel
    By madprof01 in forum General (Petrol, Gas, Ethanol)
    Replies: 2
    Last Post: March 26th, 2006, 02:55 AM
  5. Tuning a LSX intake?
    By Redline Motorsports in forum General (Petrol, Gas, Ethanol)
    Replies: 5
    Last Post: September 26th, 2005, 01:50 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •