2nd Gen R55 Clubman WOT Question

Discussion in '2nd Generation: 2007+ R55 through R61' started by Minidave, Aug 4, 2010.

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  1. Minidave

    Minidave Well-Known Member
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    If this belongs in a different forum, please feel free to move it....

    Having gotten my new Garmin 1490T and the Eco dongle that lets me watch the OBDII info, one interesting thing has popped up....

    No matter how hard or how long I have the throttle planted to the floor, I never see more than 75% on the throttle position.

    Why do you all suppose this is?

    Does that mean I'm only getting 75% of what's there in power as well? Or does the throttle positioner restrict the throttle based on boost or something?

    Seems like if I'm asking for WOT, I should get it - and the turbo waste gate should handle the overboost if there is any.....

    OK braintrust, chime in please! 'Splain me what's happenin here.....
     
  2. lotsie

    lotsie Club Coordinator

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    We have the same Garmin rig, and I have the same question.

    I wonder if the fact it shows 15 or so % at idle comes into play?

    Mark
     
  3. lotsie

    lotsie Club Coordinator

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    Sure is fun watching all those gauges dance around though, eh.

    Mark
     
  4. Metalman

    Metalman Well-Known Member
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    Is there a change when you hit the "Sport Button"?

    Probably doesn't change WOT, just allows boost to build higher for a short period of time
     
  5. Minidave

    Minidave Well-Known Member
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    No difference in Sport Mode, I tried it just in case......
     
  6. BThayer23

    BThayer23 Well-Known Member

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    It goes to 100% on Toyotas... :lol:
     
  7. Nathan

    Nathan Founder

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    I've hear the On-Horizon one goes to 111%.
     
  8. lotsie

    lotsie Club Coordinator

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    :lol:

    Would that be the gauge, or the sensor:confused5: If you get both, does it read 222%:idea:

    Mark
     
  9. goaljnky

    goaljnky New Member

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    Actually it reads 12321%. You don't add, you multiply.
     
  10. Minidave

    Minidave Well-Known Member
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  11. BThayer23

    BThayer23 Well-Known Member

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    Sorry for the 'jack, couldn't resist.

    It's an electronic throttle, so there's no way to check the cable position. But if you were only getting 75% throttle, you'd probably feel that, no? Any chance you've driven other MINIs to compare? My point is, trust your butt. Don't believe everything the computer tells you.

    I'd be willing to guess that the ECU dumbs down some of the information it gives to the OBD to make it compatible with the standard system, or maybe there's something lost in translation between the OBD and the Garmin.

    If you want to verify, pop the intake tube off the throttle body and rev it in neutral. See what happens. (Although now that I think about it the engine might get confused - somebody else chime in here.)
     
  12. Dr Obnxs

    Dr Obnxs New Member

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    I havent looked at the scaling on this...

    but a couple of points... On a drive by wire system, there are a couple things to look at.

    Driver demand is the gas pedal position. And while there is no cable, there are two signals that are proportional to pedal position. This is done so that they can be checked against each other, and they better match or you'll get one of those "signal plausibility errors", thow a code and go into limp mode. Same thing for throttle body position (for the cars with throttle bodies). For the variable valve lift stuff like in the Prince Cooper engine, it's something else as well.

    I'm just guessing here, but if this really is the case, I'm guessing that the full allowable voltage range isn't used by the system, even when at WOT. What I guess is being reported is % of max voltage range of the sensor input.

    Another thing to keep in mind is that these scaling numbers are nice, but don't really matter. For example, I was logging what the ECU thought my injector duty cycle was in milliseconds, and I found that it was open for about 115% of a cam revolution! How's that for going to 11! The scaling factors are nice to have correct, but I don't think that's what is really used inside the ECU. Probably something more mundane like some number of oscillator counts for time. Or bits thrown out of a couple of bytes or whatever.

    Matt
     
  13. Minidave

    Minidave Well-Known Member
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    I was afraid it might be something complicated like that.....

    My buddy had an '06 R53 JCW and we're going to install the exact same system on his car, it'll be fun to see the differences.

    I'll report back after he's had a chance to play with his.
     
  14. Dr Obnxs

    Dr Obnxs New Member

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    First step...

    assume that WOT is WOT. Log throttle body position, and see what % you get at maximum. Define this as all the way open. Scale the data to that when you're doing analysis.

    The hard stuff is to actuall monitor the position voltages directly with Analog-digital converters. Then compare this to the % throttle reported.

    If you have an extra throttle body lying around, take it apart and look at the voltages based on butterfly position.

    If it were me, I just wouldn't worry about it.

    Matt
     
  15. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    I've always wondered if, on the 1st gen cars at least, if the TPS reading was degrees, not %... the readings I get seem perfectly rational IF that is the case.
     
  16. lotsie

    lotsie Club Coordinator

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    I don't think the Garmin logs data, at least I have not figured out how to.

    Mark
     
  17. BThayer23

    BThayer23 Well-Known Member

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    :Thumbsup:
     
  18. Minidave

    Minidave Well-Known Member
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    Not really worried about it, as long as my engine is doing what it's supposed to and what it's capable of.....just learning about my new toys.
     
  19. Dr Obnxs

    Dr Obnxs New Member

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    Keep in mind

    that none of this is really first principles design stuff. Yes, there are preferred units for reporting data out of the OBD port, but the manufacturers all know how they're reporting and how to interpret, and really don't care what any one else wants.

    Matt
     
  20. Minidave

    Minidave Well-Known Member
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    True enough, since this thing is designed to work with any car, who's to say how the data read out to a third party like Garmin.
     

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