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Rick
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« on: February 28, 2011, 04:09:22 PM »
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I'm getting very close to the 1.5 bar limit of the MAP sensor, so soon will have to go open loop on the N75. I'm thinking that requested load should be left alone, as otherwise you will run into problems of setpoint being unreachable. Question is, what to do with PID maps? I will add duty with the linearisation map, but do you zero out the PID settings or leave them as they are?
Rick
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Tony@NefMoto
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2001.5 Audi S4 Stage 3
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« Reply #1 on: February 28, 2011, 05:40:05 PM »
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I would leave them as they are so that you have a smooth transition between "open loop" and "closed loop" control.
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judeisnotobscure
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« Reply #2 on: March 01, 2011, 01:52:30 AM »
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Which map do you change to go open loop?
Kfldimx, do you set this to 100 for open loop?
Kfldrl, would guess needs to be adjusted.
Once the pid maps are changed do you leave ldrxn alone as well as requested load?
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« Last Edit: March 01, 2011, 07:08:19 AM by judeisnotobscure »
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I have a b5 s4
but i just want to dance.
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Tony@NefMoto
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« Reply #3 on: March 01, 2011, 11:26:56 AM »
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For the record, there is no such thing as open loop boost in the ME7. What we are discussing, is how you control boost pressure once you exceed the limit of the MAP sensor.
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judeisnotobscure
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« Reply #4 on: March 01, 2011, 05:21:10 PM »
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thanks, I will look up open loop then, I thought that's what it referred to... no wastegate duty as prescribed by the ecu.
I'm under the impression the ebc or mbc would need to be used if you are boosting past 22 psi. I would like to write a ko4 tune, so I will be keeping an eye on this topic.
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I have a b5 s4
but i just want to dance.
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Tony@NefMoto
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Posts: 1389
2001.5 Audi S4 Stage 3
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« Reply #5 on: March 01, 2011, 05:40:55 PM »
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If you boost past 22psi the ECU doesn't know, because it can't read higher than that. Past 22psi the ECU will be unable to control boost, because it can't detect when actual boost exceeds desired boost. The ECU will think desired boost is 22psi and actual boost is 22psi, so everything is perfect, when in really actual boost higher than 22psi.
The only way around this is to use the ECU PID to control boost up to 22psi. Above 22psi you can tune the N75 linearization table to fake control based on RPM, or you can use a MBC or EBC.
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aef
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« Reply #6 on: February 24, 2015, 07:42:38 AM »
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alot of dust on here  Do i need to touch the PID if i plan to go over 1,5 anyway? in other words: is it necessary to redefine the PID from square one for 1,45 bar in the first step to have a good closed loop boost control. The result of this would be a smooth transition from <1,5bar to more boost, at least in my brain. I dont know  Or is it just not necessary if i aim for 1.8bar ? |
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prj
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« Reply #7 on: February 24, 2015, 10:29:51 AM »
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The solution is not to run it in open loop, and rescale the pressure in ECU.
Open loop with a bleed valve does not work right, it will overboost horribly in winter and underboost in summer.
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ddillenger
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« Reply #8 on: February 24, 2015, 10:45:09 AM »
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The solution is not to run it in open loop, and rescale the pressure in ECU.
Open loop with a bleed valve does not work right, it will overboost horribly in winter and underboost in summer.
And if you change altitude......... Shit goes bad. |
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Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience!
Email/Google chat:
DDillenger84(at)gmail(dot)com
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vwaudiguy
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« Reply #9 on: February 24, 2015, 04:27:48 PM »
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And if you change altitude.........
Shit goes bad.
Is this in reference to re-scaling the pressure? |
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"If you have a chinese turbo, that you are worried is going to blow up when you floor it, then LOL."
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ddillenger
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« Reply #10 on: February 24, 2015, 04:32:50 PM »
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Is this in reference to re-scaling the pressure?
More-so atmospheric density and running fixed DC over the map. Agreeing with prj. |
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« Last Edit: February 25, 2015, 12:02:30 AM by ddillenger »
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Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience!
Email/Google chat:
DDillenger84(at)gmail(dot)com
Email>PM
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vwaudiguy
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« Reply #11 on: February 24, 2015, 04:42:11 PM »
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Copy that. Thanks
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"If you have a chinese turbo, that you are worried is going to blow up when you floor it, then LOL."
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aef
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« Reply #12 on: February 24, 2015, 11:45:56 PM »
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Are you pointing me to the 5120hack or what does rescale the pressure mean here?
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ddillenger
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« Reply #13 on: February 25, 2015, 12:02:01 AM »
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Are you pointing me to the 5120hack or what does rescale the pressure mean here?
That is exactly what prj was doing-lol. |
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Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience!
Email/Google chat:
DDillenger84(at)gmail(dot)com
Email>PM
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aef
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« Reply #14 on: February 25, 2015, 01:22:48 AM »
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thx sometimes its hard for the non native english users  |
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