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Lambda and back pressure


randolph
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I’ve got this engine running 4 lambda pre turbo(runners) and one set as lambda 5 in the downpipe. I’m using exhaust back pressure on this set up too, is there a way to stop the ecu from calculating the back pressure for lambda 5 as this is not in the pressure zone. Tia

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Hmm, good question - im not sure if anyone has raised this point before and we may have over looked a situation like this.  I will talk to the firmware engineers tomorrow to see if we can come up with an idea.

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Yes, in the mean time i will carry out two runs, one with ex back press on and one off, and workout the approx compensation. Let us know when you get something out with the engineers.

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Can you attach a copy of your tune.  There is a way we can do this, but we will need to set up quite a few custom streams so we may not be able to depending what else you have set up in CAN.  

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Hi, just a note, the 5th lambda is on analogue and not on can bus yet, if can bus is easier for you then it’s a balenger afr500c(can version) i can connect to can bus if needed, just that we had another lambda that was already to an v so i’ve just used the same wires at the time of installation 

file attached

 

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3 hours ago, randolph said:

just a note, the 5th lambda is on analogue and not on can bus yet, if can bus is easier for you then it’s a balenger afr500c(can version)

In that case your setup will be working correctly as is and needs no changes.  Except I'm not sure how you assigned an analog input to lambda 5.  

FYI, the exhaust pressure compensation is done inside the CAN lambda devices.  The ECU sends calibrated pressure to the CAN lambda, they take it into account in their O2 calculation and send compensated Lambda back to the ECU.  The AFR500 does not have any of this functionality so will always assume exhaust pressure is at sea level atmoshpere.

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10 hours ago, Adamw said:

In that case your setup will be working correctly as is and needs no changes.  Except I'm not sure how you assigned an analog input to lambda 5.  

FYI, the exhaust pressure compensation is done inside the CAN lambda devices.  The ECU sends calibrated pressure to the CAN lambda, they take it into account in their O2 calculation and send compensated Lambda back to the ECU.  The AFR500 does not have any of this functionality so will always assume exhaust pressure is at sea level atmoshpere.

I didn't know that was being done inside the CAN Lambda :D

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