Results 1 to 5 of 5

Thread: Question about ECT-IAT bias

  1. #1
    Advanced Tuner angrygoat's Avatar
    Join Date
    Oct 2008
    Location
    New Baltimore, MI
    Posts
    358

    Question about ECT-IAT bias

    Maybe I dont completely understand this but I wanted to ask anyway. This is stemming from a post I read about placement of the IAT sensor and I have seen some posts on here about tuning this table. If I understand correctly, this table is dependent on IAT sensor placement. Is that right? So the manufacturer has set up this table based on the location of the IAt sensor and the distance from the intake. It would seem to me that this table does not need changing unless you have changed your IAt location, i.e. moved it farther from the intake or TB. Would it also be true the closer the IAt is to the TB the less the bias range would be.

    Does any of that make sense or am I missing the boat completely?
    Joe
    2006 M6 GTO
    APS TT
    10.76@131

    "The goal of tuning is for the tune to run well enough you dont need any corrective mechanisms"

  2. #2
    Advanced Tuner
    Join Date
    Apr 2006
    Location
    western NY
    Posts
    339
    it only moniters heat in the intake tract does not care about the distance from the motor,but if it is mounted in a position that is prone to heat soak then your inlet air temp will be higher than if it was mounted in the correct location that gives you proper actual inlet air temperatures.
    2000 Firebird,2002 O.S.,LQ4 370,Borg Warner S475,truck mani.,Eagle crank,Callies Compstar Rods,Wiseco-11 4.030 pistons 9.4:1 comp.,LS3CNC heads,LS3 intake,NW92mm throttle body,ID1000 injectors,BTR trunion upgrade,LJMS STG3 cam,LS7 Lifters,ARP Studs-bolts,Frozen Boost A to W intercooler,JGS 60MM BOV,2 40mmJGS Wastegates,4L80E trans wth segment swap,CircleD 3400 single disk,MOSER 12 3.31gears ,BMR K-Mem.,2 Walboro 450 pumps,Returnstyle fuelsystem MAGNAFUEL regulator.
    LS1Tech sig KRAZY K 2000 TA

  3. #3
    Advanced Tuner angrygoat's Avatar
    Join Date
    Oct 2008
    Location
    New Baltimore, MI
    Posts
    358
    Let me see if I have the basics right. The unit of measure in the bias table is gr/sec. The computer is biasing the IAT to either the ECT reading or the IAT reading depending on how much air ( read how fast) the air is being drawn into the engine. Obviously the slower the air, less gr/sec, is being drawn in the more time it has for the IAT to increase more towards the ECT. Obviously it would never reach the ECT or there would be a whole new slew of problems. And conversely, the faster the air is being drawn in, more gr/sec, the less time the air has to heat soak and the Bias would be less and more reflect the IAT reading.

    If all the above is true, I would still think location plays a great deal. Is the sensor is not taking a reading until just prior to the TB the temp isnt going to change much due to heat soak. However if you have 10ft of intercooler piping and you run the IAT down by the air filter prior to the s/c or turbo, bias plays a much larger effect because there is so much more time for the IAT to change based on ECT.

    Am I overthinking it? Please comment
    Joe
    2006 M6 GTO
    APS TT
    10.76@131

    "The goal of tuning is for the tune to run well enough you dont need any corrective mechanisms"

  4. #4
    Advanced Tuner
    Join Date
    Jun 2008
    Location
    Charleston, SC
    Posts
    969
    you just want the iat to give accurate reading of whats going into the motor now. and yes, your overthinking it.

  5. #5
    Senior Tuner
    Join Date
    Dec 2004
    Location
    Laurel, MD
    Posts
    1,020
    this is the shortest explanation that I think covers all the major points:

    http://www.ls1gto.com/forums/showpos...36&postcount=6