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Thread: Tuning out cam-surge?

  1. #1
    Fuel Injected!
    Join Date
    Jun 2015

    Tuning out cam-surge?

    I have a 95, 383, TFS heads and LE cam. 224/230 .560/.544 112, 3.42 gear with Yank 3k stall. Tune was done by Moe Bailey.

    The car has pronounced cam surge when cruising at 45+. I've tried a few different things like increasing lockup speed, lowering shift MPH to keep the r's higher, adjusting timing, etc. Nothing appears to be working, but I am admittedly a n00b when it comes to tuning. Are there any tips anyone can offer to point me in the right direction?

  2. #2
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Check to see if AE is going active in the data log.

    dave w

  3. #3
    Fuel Injected! steveo's Avatar
    Join Date
    Aug 2013
    is it still the same LT1 you had before?

    lets see a log of when the event is happening so we can pinpoint what vss/tps/map/rpm/spark is doing at the time.

    if you get eehack running and with a friend driving, try manipulating ignition timing to see if you can get rid of it that way.

    cam surge occurs outside the normal operating range of the cam so what you're experiencing might be something other than 'cam surge'. usually things like cam surge smooth out at high speed like that - you have a lot of flywheel action with all of that heavy metal spinning at such a high RPM.

  4. #4
    Carb and Points!
    Join Date
    Jun 2016
    45 mph lets you get into OD if the shift tables command it, which is just under 1400 rpm when locked up. If the "cam surges" smooth out around 60 (1850 rpm) then it could be a cam surge since your cam should be smooth by 1800 rpm. You could also verify by seeing if has the same problem when the shifter is in 3 (to keep it out of OD) and going 45+.
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    Last edited by Yesterday; 12-10-2019 at 02:45 AM.

  5. #5
    Fuel Injected!
    Join Date
    Jan 2018
    I suspect this can be tuned out because I have a slightly bigger cam (232/234 @ 112) in a slightly smaller engine (346) and it only surges in first gear. At cruising speeds it's totally fine.

    My first thought is to try adding a bit more timing in the area where you get the surge. At 1400 RPM I'm running about 23 degrees of timing from 0-0.44, tapering to 7 at 0.84.

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