Road Atlanta And Put Away Wet

Check out the Boost Brothers as they go over our various issues from the Road Atlanta race and talk about the changes to come! Needless to say, we are lucky to have these fellows in our corner as we try for an AER podium in 2017.

9 Replies to “Road Atlanta And Put Away Wet”

  1. Eric H

    Just give up with the stock float level sensor in the stock tank.
    There is no amount of filtering that will help.
    On our car (VW Fox) when I built the custom electronic dash I calibrated the system accurate to the liter. When the car is still, it’s perfect. As soon as the fuel starts to slosh the sender alternates sending full-empty-full-empty.
    With a properly baffled fuel cell, perhaps a capacitive sensor will work.

    It would probably be better to try to rig up sensing directly from the injectors and calculate fuel burn from there, if you actually wanted accurate fuel remaining.

    • Bozi

      You may be right. We are exploring all options and trying not to blow the bank in the process.

      What type of dash did you build? Based on some off-the-shelf stuff or fully custom?
      What type of sensor did you use?

      We are definitely considering tube style capacitive sensors and your idea to measure from the injectors is interesting. I am thinking of how we could accomplish this, maybe by using a measurement from the injector and VSS and making a calculation.

      We’ve tried to think of other ideas along the same path and possibly even using a couple of flow sensors. We have channels that we can use to send data to the Pista but any processing will have to be done between it and the car/sensor/device.

      Interested to hear any ideas or examples.

      • Nick D

        In one car I drive, we have a good idea of fuel burn from measuring how much we fill during pit stops, and refine that model each race. When we’re getting close, we will radio driver to BOLO for fuel starvation and have never had a problem. The car has a stock gas tank and the fuel level gauge changes by a quarter tank per minute on the track.

        In the other fuel cell-equipped car I’ve driven, a combo of knowing fuel burn and monitoring fuel pressure worked for 4 hour stints. The fuel cell has a mat inside it to help avoid sloshing-related starvation. When it is nearing empty, fuel pressure will start to drop in tight corners and you’ll feel a miss, but have at least 10-15 minutes of race time before you’re in real trouble from gas in the mat.

      • Eric H

        The dash I built for the Fox (I built a much more advanced one for a Jetta) uses an STM32F4DISCOVERY board as the CPU on a motherboard I designed. When I built it five years ago I used a monochrome 256×64 pixel LCD as the display and hooked it up to all the stock sensors on the car plus a bog-standard GM oil pressure sensor.
        The Jetta dash uses the same CPU board but a better motherboard that hooks up an 800×480 RGB touchscreen LCD. It’s amazing that in two years the cost of the RGB display had dropped to the same as the lo-res monochrome one.

        If you want to measure the injectors you need to know the cc/min rate, number of pulses and pulse length. I’d probably just fudge and assume the injector turn on and turn off delays are symmetrical and ignore them.

        When I calibrated the Fox fuel level sender I first drained the tank with the fuel pump and when the first sputter in the output happened I shut it off.
        I then measured the resistance of the sender for empty, +1l, +2l, +3l, +4l, +5l, +10l and so on in 5l increments until the tank was full. I put the data in a lookup table and did linear interpolation to get how much fuel was remaining in the tank on the display.
        Since it’s completely useless when driving we go by fuel burn rate and stint time. The car can go 2+ hours on a tank no problem, so we mostly ignore it. In the end it was a mostly useless endeavor.

        You mostly can’t see the dash in the videos but it’s quite easy to read when driving.

  2. Ronnie Schreiber

    I don’t know if you could do this and still pass safety inspections but how about some kind of sight glass with a camera? There’d be some dampening as the level in the glass would slightly lag behind what was happening in the tank/cell.

  3. ltcftc

    A Penske shock! I hadn’t pegged you for Penske material Jack!

    +1 to the Boost Brothers, I enjoyed the breakdown of the weekend.

  4. Widgetsltd

    Hmmm. Regarding the EBD/ABS issue: EBD should not affect front brake pressures, only the rears. If you want to disable ABS but leave EBD functional, you should be able to simply unplug one of the wheel speed sensors and run the system with only the remaining three WSS working. The ABS cannot operate without four properly functioning wheel speed sensors, but as long as it has a front speed input and a rear speed input it should be able to control EBD. I know that early-2000s Teves systems such as the Mk20e will work that way. I do not know which company supplied the ABS in your MX-5 though.


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