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VBox throttle position & brake pressure

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Old 05-27-2022 | 12:13 PM
  #16  
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Thanks for the help. I am 100%/Mac and don't have parallels or whatever to run windows, but yesterday I fired up my son's old gaming PC/windows laptop and took a look at the scene file (can't edit maths channels on a Mac...) and I think I found a few minor issues (although I really only know enough to be dangerous). I made some tweaks and need to do some more testing in the car to see if the issues are resolved. Will report back after the weekend!
Thanks,
Tom
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Old 05-27-2022 | 04:47 PM
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That's GOOD (knowing just enough to be dangerous ).

The Windows VBOX Setup is a must option for setting up maths, but not the "fake brake" long g indicator. Let us know!
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Old 05-27-2022 | 11:26 PM
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Originally Posted by 924RACR
For brake apply data in an old/analog car... here's another approach I've been using in my prototype.

To go beyond mere brake switch and decel data, without the pain (and cost!) of installing a true pressure transducer to measure line pressure, I chose to measure brake pedal travel instead.

But adding a string pot is a pain. Instead, I went for a non-contact IR distance sensor:
https://www.robotshop.com/en/sharp-g...ge-sensor.html

...plus the cable:
https://www.robotshop.com/en/cable-s...ge-sensor.html

For a grand total of $12. Just stick the sensor to the firewall with good double-sided tape, feed it 5V and ground, and it spits out a nice signal 0-5V based on your actual brake application, by bouncing an IR beam off the back of the pedal/your foot. It's accurate enough to, in my experience, show the difference between warm and cold pads/different lining choices in my prototype (which, admittedly, has no booster, so much more direct pedal).

Just an alternate thought for some higher-quality data vs, recombining what you already have...

We're also using them for live, active ride height measurements... joys of aero cars...
THAT is cool stuff!
Old 05-28-2022 | 07:10 AM
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Originally Posted by Frank 993 C4S
THAT is cool stuff!


You should see the rest of the data setup on that car... two loggers (one just for the engine), 20 analog channels (still want more!)...
Old 05-28-2022 | 09:25 AM
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Originally Posted by 924RACR


You should see the rest of the data setup on that car... two loggers (one just for the engine), 20 analog channels (still want more!)...
... and I thought I was the only crazy one. I use shock potentiometers to measure ride height and therefore lift and downforce (on a 911 there is mostly lift) and from the data found out that the springs on my car were not correct as advertised by the seller (they were far off, which explained a lot of other issues). People struggle with stuff for years without knowing what they are actually chasing if you don't have detailed data logging capability and (in my case) help interpreting the data.
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Old 05-28-2022 | 11:26 AM
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Originally Posted by Frank 993 C4S
... and I thought I was the only crazy one. I use shock potentiometers to measure ride height and therefore lift and downforce (on a 911 there is mostly lift) and from the data found out that the springs on my car were not correct as advertised by the seller (they were far off, which explained a lot of other issues). People struggle with stuff for years without knowing what they are actually chasing if you don't have detailed data logging capability and (in my case) help interpreting the data.
Where is the “love” button for this post?

Seriously, the validation of baseline and verification of a given setup really helps guide progress and save incredible amounts of time.

What few people realize is that capturing data when things are working well is one of the greatest benefits, so you can see what’s happening when it’s really right. The ideal baseline.
Old 05-28-2022 | 09:59 PM
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Originally Posted by 924RACR
For brake apply data in an old/analog car... here's another approach I've been using in my prototype.

To go beyond mere brake switch and decel data, without the pain (and cost!) of installing a true pressure transducer to measure line pressure, I chose to measure brake pedal travel instead.

But adding a string pot is a pain. Instead, I went for a non-contact IR distance sensor:
https://www.robotshop.com/en/sharp-g...ge-sensor.html

...plus the cable:
https://www.robotshop.com/en/cable-s...ge-sensor.html

For a grand total of $12. Just stick the sensor to the firewall with good double-sided tape, feed it 5V and ground, and it spits out a nice signal 0-5V based on your actual brake application, by bouncing an IR beam off the back of the pedal/your foot. It's accurate enough to, in my experience, show the difference between warm and cold pads/different lining choices in my prototype (which, admittedly, has no booster, so much more direct pedal).

Just an alternate thought for some higher-quality data vs, recombining what you already have...

We're also using them for live, active ride height measurements... joys of aero cars...
I have not had good luck with those units as ride height. I have some laser units that do work really well, but they are more than $12.

Originally Posted by 924RACR


You should see the rest of the data setup on that car... two loggers (one just for the engine), 20 analog channels (still want more!)...
What channels do you find most valuable? Depending on the day, I have about 100 channels of data and really have found the value to depend no some different things. After engine health, throttle position, brake position, and steering position, I've the TPMS to give the most value, followed by tire temp, brake temp, then suspension travel.

Originally Posted by Frank 993 C4S
... and I thought I was the only crazy one. I use shock potentiometers to measure ride height and therefore lift and downforce (on a 911 there is mostly lift) and from the data found out that the springs on my car were not correct as advertised by the seller (they were far off, which explained a lot of other issues). People struggle with stuff for years without knowing what they are actually chasing if you don't have detailed data logging capability and (in my case) help interpreting the data.
Absolutely. It's way easier to measure what you want to know and make informed decisions. But then I'm preaching to a guy with a good data setup
Old 05-29-2022 | 07:49 AM
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Well, I went out once with the IR sensors, but that was Indy, and other things went wrong... so no data sets to eval. If they work, they'll save me a lot of trouble (working the ride heights through the shock pots). If they don't... yeah, I'll have to look into the laser setups. Care to share what you're using?

Most valuable - this really gets to what my focus is at the time. Engine health for sure is high; for me and my car, driver mod is relatively low in the order, driver will drive to what the car is capable of, so brake and TPS aren't so critical except occasionally in reference to other things (like monitoring engine performance, mixture during accel, that kind of thing). Shock pot data, if we're chasing that. Tire temps would be a nice add, but a big incremental bump we haven't been able to justify yet.

So then it's ride heights, since, in addition to making/keeping the engine healthy, high on our list is getting the aero optimized, and we're still trying to work on filling in our aero map data, figure out how to get the height and rake dialed at speed for optimal downforce. We were making progress, then made base chassis changes which resulted in a spring change, which screwed up all our dynamic/at speed settings, so we're trying to figure out how to get back to that point, to get the car at the right attitude when she's at speed. Would be a lot easier if we had a third spring setup, but no capability to readily engineer that in on the rear, where we really need it. Limitations of the suspension design, unfortunately...
Old 05-30-2022 | 11:31 AM
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I've run/sell a sensor from Banner. I get very good pricing and have the wiring control figured out. Ita a good setup and gives good data.
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