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Thread: Chop tune

  1. #1
    Potential Tuner
    Join Date
    Apr 2023
    Posts
    4

    Chop tune

    Hello everyone I was reading online how to do a tune that would give the car more of a wop wop wop sound at idle. The 408 I have does it and I like the sound. But my new 421 doesn't. Someone told me to change the over/under speed tables to something like -18/18 from 0 up to 300 rpm which I did and it kinda sounds like it but it's not the same. Any ideas at what to do? The cam is a 244/248 112lsa and idles at 950 anything lower its not happy

  2. #2
    Senior Tuner
    Join Date
    Mar 2022
    Location
    Indiana
    Posts
    2,780
    Think about it. -18 at 0 rpm and 18 at 0 rpm? Try factory settings then multiply by about 2.5. Something like 0 3 5 7.5 10 10 10... for underspeed then same, but negative, for over. Mess with different settings and see what happens. A little goes a long way.

  3. #3
    Advanced Tuner
    Join Date
    Jan 2015
    Posts
    563
    try this for the overspeed table. leave under speed stock.
    Screenshot (96).png
    That is by no means proper but it does give the steady chop chop chop chop chop without interruption. Give it a lot of idle airflow to exacerbate the issue and fool around with the idle speed. All this is for sound, no guarantees for drivability or rev recovery