Results 1 to 7 of 7

Thread: Need Help: Cammed LS3, light load & cruise surge

  1. #1
    Lifetime Member
    Join Date
    Jun 2010
    Posts
    240

    Default Need Help: Cammed LS3, light load & cruise surge

    Hello,

    I'm looking for some help in dialing in a cammed LS3. The car runs and drives well. Trims look great. Plenty of power, dyno'd strong, 450hp. It's always had a light load/cruise surge. It's felt under 2500 RPMs at light acceleration and cruise, as if the car is moving back and forth with steady throttle application. It's minor, but it is there, some less sensitive people might not feel it.

    The build is the following:
    Corvette LS3
    Stock Heads
    G6X3 cam (big street cam)
    1 7/8" long tube headers and high flow cats

    I've attached the tune and a log if someone could take a look at it and offer some pointers. Thank you!

    LS3 Cam Tune.ctzLS3 Cam Data Log.efi
    2002 Z06
    Vengeance Racing Stage 5, H/C/I/3.90 diff, 575 hp
    2016 Chevy SS M6 (daily driver)
    Roto-fab Intake

  2. #2
    Lifetime Member Tre-Cool's Avatar
    Join Date
    Feb 2006
    Posts
    827

    Default

    try zero'ing out B1206. then changing b1205 to 430 across the board. - This will probably richen the idle up as it'll be injecting closer the right valve timing.

    Also make sure your minimum idle airflow is not too high, this can cause the bucking feeling.

  3. #3
    Lifetime Member
    Join Date
    Jun 2010
    Posts
    240

    Default

    I will give your recommendations a shot.

    Could it also be timing related? I'm seeing around 40* advance timing at cruise. Although with some light acceleration/larger load timing drops and the surge is still felt.
    2002 Z06
    Vengeance Racing Stage 5, H/C/I/3.90 diff, 575 hp
    2016 Chevy SS M6 (daily driver)
    Roto-fab Intake

  4. #4
    Lifetime Member Tre-Cool's Avatar
    Join Date
    Feb 2006
    Posts
    827

    Default

    nope, would put money on it being too much air, rather than spark.

    Is there a hole in the Throttle blade too?

  5. #5
    Lifetime Member
    Join Date
    Jun 2010
    Posts
    240

    Default

    Quote Originally Posted by Tre-Cool View Post
    nope, would put money on it being too much air, rather than spark.

    Is there a hole in the Throttle blade too?
    The throttle is factory untouched, there are no holes.

    I checked the minimum idle airflow table (B1829). It looks to be a bit high. Do you think the factory settings will be OK, or do I need to find a happy medium? The modified table looks nothing like the factory stock table.
    2002 Z06
    Vengeance Racing Stage 5, H/C/I/3.90 diff, 575 hp
    2016 Chevy SS M6 (daily driver)
    Roto-fab Intake

  6. #6
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    27,777

    Default

    Try this (what Tre-Cool said above):

    Quote Originally Posted by Tre-Cool View Post
    try zero'ing out B1206. then changing b1205 to 430 across the board. - This will probably richen the idle up as it'll be injecting closer the right valve timing.

    Also make sure your minimum idle airflow is not too high, this can cause the bucking feeling.

  7. #7
    EFILive Reseller ringram's Avatar
    Join Date
    Oct 2005
    Posts
    1,412

    Default

    Also look at base spark, high octane spark and coast down spark. If the numbers at the load point you get the issue are too different to each other you can get racing and surging as the ECU moves between the tables. (Mainly high octane and coastdown)

    Likely your MAP and g/cyl is different from OEM so the delta between the tables at near zero load will be out.
    Get EFILive in europe (http://www.efilive.eu).
    2007 Escalade ESV L92 6.2L VVT.
    2014 VF SV LS3 Maloo.

Similar Threads

  1. Looking For a Cammed LS3 File for reference
    By n8dogg in forum Gen IV V8 Specific
    Replies: 1
    Last Post: July 9th, 2013, 12:28 AM
  2. Looking for a cammed LS3 tune file
    By n8dogg in forum E37, E38 & E67 PFI ECM's
    Replies: 2
    Last Post: July 8th, 2013, 03:26 PM
  3. light throttle surge.
    By activity233 in forum Gen III V8 Specific
    Replies: 11
    Last Post: November 25th, 2012, 11:14 AM
  4. Excess Timing in low load areas causes surge/buck issues, and how I fixed it.
    By ArKay99 in forum General (Petrol, Gas, Ethanol)
    Replies: 14
    Last Post: August 5th, 2008, 11:08 AM
  5. Surge at cruise
    By Dlong in forum General (Petrol, Gas, Ethanol)
    Replies: 2
    Last Post: March 25th, 2006, 02:45 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
  •