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Thread: Driver Demand

  1. #1
    Senior Tuner Higgs Boson's Avatar
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    Driver Demand

    On the Driver Demand table why would one not calculate for each throttle position row the percentage from maximum? For example, at 50% throttle you put 393*.5= 196.5.....What happens if you put that all the way across at 50% throttle and do the same for each row.
    What would happen to the throttle feel? Is this the equivalent of DBW or would this be a totally screwed up setting?

    What is the point of having say, 66% in the 30 MPH 60% pedal cell and then 68% in the next MPH cell and then 65% in the next (for example)? It looks like the numbers go up and down through the MPH range and I just want to understand why.

    Thanks for any info!

  2. #2
    Advanced Tuner yonson's Avatar
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    If that was the only table it looked at that might be a viable option. But there are a ton of coefficients that get taken into to equation, so until we know exactly how those are used it's basically going to be "spray and pray" so to say...

  3. #3
    Senior Tuner Higgs Boson's Avatar
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    Good point, maybe the next big catch phrase in tuning is going to be "Don't Rape your Driver Demand Table!" lol.

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    Quote Originally Posted by Higgs Boson View Post
    Good point, maybe the next big catch phrase in tuning is going to be "Don't Rape your Driver Demand Table!" lol.
    "As of 2013, scientists are virtually certain that they have proved the Higgs boson exists, and therefore that the concept of some type of Higgs field throughout space is proven."
    Last edited by jim2092; 04-06-2014 at 11:11 AM.

  5. #5
    Senior Tuner Higgs Boson's Avatar
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    Ok I give up. What is limiting my Driver Demand? It appears I am getting full throttle but Predicted Engine Torque is higher at WOT no matter what I set the Driver kW table to.

    Need some help, thanks.
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  6. #6
    Senior Tuner Higgs Boson's Avatar
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    Ok so what I did now, instead of maxing the peak engine torque table, I set the high number to 550hp and then put 450kw (550hp is 410kw) in the 100% Throttle area of the Driver Demand table. So now when I command 100% power with the pedal it should match up with Peak Torque and stay close. We will see.

    My throttle is not being limited so I guess I should not expect any more power than it is making now....It's weird how slow it feels since my last Vette was 850hp....

  7. #7
    Senior Tuner Higgs Boson's Avatar
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    After logging the results of Driver Demand at 600kw and Peak Torque Table at 550 (nearly stock) it is clear that the Peak Torque table directly drives Predicted Engine Torque Command value and that if you simply max out the Peak Torque table you will never go into PE unless you zero the PE Torque criteria.

    Peak Torque Table drives Predicted Torque Cmd
    Maximum Engine Torque must exceed Predicted Torque Cmd otherwise it is limiting

    So what are the effects of raising the 100% throttle row of the Driver Demand table (it doesn't raise Maximum Engine Torque).....maybe only useful when FI or more modified?
    How do you keep Maximum Engine Torque higher than Predicted Torque Cmd without actually LOWERING the Peak Torque table???

    Someone has to have some info on this.....

  8. #8
    Advanced Tuner yonson's Avatar
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    Interesting, I haven't gotten that in depth with it because of the lack of info. With FI I did have to raise the 100% area in order to make full power, other than that I've just been tweaking the table to get the desired feel. Do you have a stock read of your car, or have you compared it to 12660065 to see if there are many differences? Mainly in the DD tables.

  9. #9
    Senior Tuner Ben Charles's Avatar
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    If I get time later I may explain what I know, There is a lot too tuning these torque based systems.

    Ill say this though, it ALL starts with driver demand

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  10. #10
    Senior Tuner Higgs Boson's Avatar
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    please do

  11. #11
    Tuner in Training
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    Subscribed for more info on the Driver Demand table.

  12. #12
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    Quote Originally Posted by Higgs Boson View Post
    please do
    So post #47 in the below thread that you participated in did not produce the desired results?

    http://forums.corvetteforum.com/c7-t...omputer-3.html

  13. #13
    Senior Tuner Higgs Boson's Avatar
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    that has nothing to do with this topic. I am not interested in part throttle "feel."

    100% throttle feels the same no matter what you do to driver demand table because there is no transition left. if raising the 100% row of driver demand table does not raise horsepower then there is no point in raising it. but that is what I am looking at now.

    the peak torque table also does something quite different than what one might expect. it's not a simple tqmngmt limiter of power. the ecu uses it to know where it is with the torque request and bases things on it like when to go into pe and I am sure many other functions.

    I've been out of town. tomorrow I can start measuring the results of changing the given TM tables again.

  14. #14
    Senior Tuner Higgs Boson's Avatar
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    Here's another log and my tune for my bone stock C7.....No MAF changes yet, just trying to understand Driver Demand right now....

    Can anyone tell me why Predicted is higher than Maximum? Is the "Max must be higher" rule only applicable to modified/FI applications? I'd love to quit sweating this and put the wideband on to finish my tune.

    Any advice?
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  15. #15
    Senior Tuner Higgs Boson's Avatar
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    word on the streets is when stock, increasing driver demand 100% row won't increase your power. only when your throttle blade actual is not 100% vs commanded. usually only nitrous and super/turbo charging will necessitate elevating the values. if it is already giving all it has to give, then there is no where else to go. now at part throttle, you can increase and decrease the values and see a difference for feel.
    Last edited by Higgs Boson; 04-15-2014 at 10:22 AM.

  16. #16
    Senior Tuner Higgs Boson's Avatar
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    so I have taken to the driver demand table corrections by pasting the error between "ETC average pedal" vs "ETC position" much like one would do with afr error.

    I multiply only the positive error to open the throttle more where it is less than pedal. i multiply by the full percentage rather than half as it corrects more slowly than afr does.

    it works, the discrepancy is very small to nonexistent now and the feel is great. I have found that all of the areas that need improvement are above the 45% pedal areas so it won't affect low throttle feel like highway cruising or idling or parking lot use.

  17. #17
    Advanced Tuner yonson's Avatar
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    Interesting, I'm going to log those and see how they look...

  18. #18
    Hey guys just tuned a 14 ltz with 6.2 and played with the driver demand tables and setup a histo to get it closer and raised the peak torque numbers any of u guys have any other experience with raising the peak torque values. Or any other tables.. i matched the driver demand tables in all modes as wel

  19. #19
    Senior Tuner Higgs Boson's Avatar
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    If you raise Peak Torque too much it won't go into PE (if you use torque as a criteria). Since it uses Peak Torque to look at PE, I feel it must look at Peak Torque for other calculations as well so I basically smooth Peak Torque out and leave it alone....more 550 values smoothed to lower values at lower RPMs. Being stock and NA, it doesn't seem to be limiting anything.

  20. #20
    Guys really interesting topic please update and keep the info coming great topic if u by any chance can post the cfg file for us to test too thanks