348 Challenge Non Catalyzed Cam Timing: ECU Cal Change?

Discussion in 'Challenge/GT Cars' started by Jasonberkeley, Oct 24, 2017.

  1. Jasonberkeley

    Jasonberkeley Formula Junior

    Apr 23, 2017
    261
    New York, NY
    Full Name:
    Jason Berkeley
    Hi,

    If you use the alternative holes on the drive to advance the cam timing by two degrees to the factory (Challenge approved) "non-catalyzed" work-shop specs, will the car run properly without running the 348 Challenge calibration (or some other alternative calibration?).

    Does anyone have a source for the 348 Challenge ECU calibration (is it an actual chip that gets swapped, or do you re-flash the ECU?) for a 1990 car?

    I've searched on here, but can't seem to find anything definitive on the ECU with respect to the advanced cam timing.

    Thanks,

    Jason
     
  2. fatbillybob

    fatbillybob F1 World Champ
    Consultant Owner

    Aug 10, 2002
    14,356
    socal
    There was no challenge ecu. The latest version of the 2.7 motronic was the latest spyder ecu. That had some minor tweek that was used by teams as the challenge ecu. The ecu is sealed and can't be flashed. But they can be openned and eprom replaced with what people whip up as hot chips. We used to copy the 94 ecu spyder eprom chips and retro fit them into earlier year ecus and have a defacto 94 ecu programing. When I raced my 348 I messed with cam timing. It was a pain becuase engine comes out for access each time. So combine going to track under differnt conditions and my inability (newer racer) at that time to run consistent laps within 10ths repeatedly I was unable to prove a superior cam timing with my stopwatch. Your mileage may vary. I don't have a 348 anymore but still tied into the pointy end of the crowd so we have access to "hot chips" if you want to experiment. I have been out of it for a while so I don't know how far they have gone with mapping on dyno with exhaust system changes etc. But if you are sticking to stock challenge stock 94 ecu set up is for you.
     
  3. SoCal1

    SoCal1 F1 Veteran
    Rossa Subscribed Owner

    Jun 14, 2011
    6,960
    SoCal LA/OC
    Full Name:
    Tim Dee

    What exactly did they do to the timing?

    Advance intake exhaust or retard the exhaust a couple degrees?


    :)
     
  4. Jasonberkeley

    Jasonberkeley Formula Junior

    Apr 23, 2017
    261
    New York, NY
    Full Name:
    Jason Berkeley
    Set at 14 and 53.
     
    SoCal1 likes this.
  5. itsablurr

    itsablurr Formula Junior
    Silver Subscribed

    Dec 9, 2005
    802
    Carlisle, MA
    Full Name:
    Matt
    To answer your question on timing, yes it will. Tim (aka SoCal1) in the 348/355 section is a good guy to talk to regarding his chips with revised red line and fuel/ignition mapping.
     
  6. Jasonberkeley

    Jasonberkeley Formula Junior

    Apr 23, 2017
    261
    New York, NY
    Full Name:
    Jason Berkeley
    I actually bought chips from Tim shortly after posting! Thanks!
     
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  8. itsablurr

    itsablurr Formula Junior
    Silver Subscribed

    Dec 9, 2005
    802
    Carlisle, MA
    Full Name:
    Matt
    I should add, it is assumed that you're running the cat-delete pipes in this config. Based upon my understanding, the cats of the era are quite sensitive to exhaust gas temp, especially given the proximity to exhaust ports in the configuration, and the tweak in timing was a measure to increase cat life, or decrease likelihood of burning them up.
     
  9. Jasonberkeley

    Jasonberkeley Formula Junior

    Apr 23, 2017
    261
    New York, NY
    Full Name:
    Jason Berkeley
    Correct.

    See pic below
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