Torque PIDs...Take 2
- Thread starter ecoboostsho
- Start date
Sure why not. If you have two values and you are watching the increase/difference between the two readings, I thought it would be easier to have the gauge do the arithmetic. In my case I wanted to see the total heat gained by ambient air as it went through the process of being delivered to the intake manifold so I used the sensors at each extreme. I'm sure it would work just as well using the values of the two middle sensors.
Just adding to your post above and more questions lol. I have also noticed on torque during the day the ambient temp is always higher than the dash reading. Sometimes by 10C. The dash reflects the current weather data without humidity. For example today it's 27C feels like 32C. The dash reads 27 and the ambient on torque is 34C The ambient is closer to the current weather data plus humidity? Is it possible that it's taking humidity into effect? Or could there be another explanation.
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ecoboostsho
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If you downloaded it I suggest you do it one more time...I ended up typing a few additional things. I need to find a better CSV editor than Excel. It keeps converting my PIDs to scientific notation and breaking them...I fixed the Catalyst temp but it is exactly the same as Torque from what I can see. The equation for "Desired Boost" is definitely wrong as well...still working on it.ShoBoat said:
I don't have a favorite theory yet. There are times where I see the two temps a good 10 degrees apart and others where they are within one or two degrees. My first excuse was two sensors in different locations. That's a weak theory though I think. The averaging theory for the dash display is certainly interesting and it might be the reason.....just don't know. I hope by observing eventually a solid theory will emerge. Never heard any mention of a humidity sensor.....on the car or in the tablet. The car and the tablet each have GPS sensors and inertia sensors I think? ? ?
ecoboostsho
New member
I've been messing with the "Desired Boost" PID and it has been driving me crazy, but I think I've finally figured it out for anyone that cares! It was never matching the boost gauge in Torque and didn't seem linearly related at all so I couldn't figure out the equation. Then I stumbled on a PID called "Throttle Inlet Pressure Sensor". If you remember our cars have (at least) two pressure sensors (there is an additional one for barometric pressure as well someplace) - one sitting on top of the manifold (also combined with IAT2) and one right before the throttle plate. I figured out the throttle plate PID (22033E) and watched that and sure enough that is what tracks to "Desired Boost". It makes sense actually since there would be a pressure drop across the throttle plate depending on how far it was open (and max is only 80% anyway). So bottom line is the MAP sensor on top of the manifold will probably never match "Desired Boost" - although it should get close at WOT. I'm also guessing manifold pressure will be lower since air is being sucked out of the intake manifold and in to the valves - that and the combined larger volume of the manifold.
Application: You could create a differential gauge as discussed previously to see if your turbos were keeping up with the requested boost - could be useful to discover boost leaks etc...
Desired Boost (This won't read vacuum but does vary slightly with barometric pressure)
PID: 220466
Equation: ((256*A)+B)/128*.145-14.7
Deg: PSI
Throttle Inlet Pressure Sensor
PID: 22033E
Equation: ((256*A)+B)/128*.145-14.7
Deg: PSI
Intake Manifold pressure (already in Torque)
PID: 22F40B
Equation: A*.145
Deg: PSI
Application: You could create a differential gauge as discussed previously to see if your turbos were keeping up with the requested boost - could be useful to discover boost leaks etc...
Desired Boost (This won't read vacuum but does vary slightly with barometric pressure)
PID: 220466
Equation: ((256*A)+B)/128*.145-14.7
Deg: PSI
Throttle Inlet Pressure Sensor
PID: 22033E
Equation: ((256*A)+B)/128*.145-14.7
Deg: PSI
Intake Manifold pressure (already in Torque)
PID: 22F40B
Equation: A*.145
Deg: PSI
Great work! For anyone using the TB map sensor, keep in mind that you will see some spikes in the reading. If the TB snaps shut at a high boost level there is a slight lag before the BOVs kick in. I have seen readings on mine as high as 30psi in FORScan.
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ecoboostsho
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ShoBoat said:
Yep!
Larry - as for any difference between Torque and the MAP sensor I don't know just yet. I will have to track it for a bit and see. Actual boost should take in to account the barometric pressure as well (the sensor above probably doesn't). I don't know if Torque does or not. Either way it would only change the values slightly unless you live in Denver/mountains etc...
I updated the file on the first page and included a differential pressure gauge for anyone that wants to mess with it. As long as I didn't typo anything it should be good to go.
Yup this one sounds like the most promising. Just the fact that you can tell at a glance is something is wrong with the car sounds really interesting. This might even work for detecting flow restrictions. In my case with the S&B filter or a dirty one?
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ecoboostsho
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Larrylu said:
Agreed! It has been fun and I honestly like that we keep finding new things to play with.
ecoboostsho
New member
Larrylu said:
Almost...the only subtle difference is that it is subtracting the delivered pressure BEFORE the throttle plate (not the intake manifold) from the desired (PCM) pressure. Same concept but intake manifold pressure (i.e. boost gauge pressure) will be lower due to above stated reasons.
If you've got a leaking hose this would show up as a differential pressure loss (number would be positive on the gauge though since it's desired minus actual). It would be best to baseline your car with known good hoses and then compare it later if you think you have a boost leak to look for differences.
Here is a find I made a month or so ago through pure blind luck. If I had had a working "Boost Leak" gauge I might have been suspicious enough to look harder sooner.
This O ring has been broken all the time I've had the car as far as I know. It's located in the "noise maker".
This O ring has been broken all the time I've had the car as far as I know. It's located in the "noise maker".
That would do it. Good that you found it!Larrylu said:Here is a find I made a month or so ago through pure blind luck. If I had had a working "Boost Leak" gauge I might have been suspicious enough to look harder sooner.
This O ring has been broken all the time I've had the car as far as I know. It's located in the "noise maker".
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ecoboostsho
New member
Good you found that! When I had my turbo going bad the hose on the front turbo was "Porous" according to the dealer and had to be replaced. I'm not sure how bad it was as I never saw it but I'm pretty sure I had a boost leak as well...this potentially would have helped both situations!
ecoboostsho
New member
Just a heads up that I tweaked the formula's and the file a bit...I am subtracting 14.7 psi (atmospheric barometric pressure) from the pressure sensor equations so Desired boost is actually 0 when you aren't on the throttle. Same for Throttle Inlet. I also corrected the Intake manifold pressure equation...it's just "A" multiplied by .145 for PSI. You will get weird numbers when it is a vacuum reading but it should be useful to reference against the Torque Boost gauge.
