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Re: Turbosmart Blow Off
[Re: branimir20VT]
#1657471
07/05/2022 09:37
07/05/2022 09:37
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Joined: Feb 2019
Posts: 323 Free State of Jones
clanger
Making a profit
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Making a profit
Joined: Feb 2019
Posts: 323
Free State of Jones
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The Bosch 2.10.4 ECU performs the majority of its fueling management based on metered air flow data from the MAF. The standard re-circ valve feeds excess air back into the intake system after the MAF - this excess air has been accounted for by the ECU via the MAF and fueling adjustments have been made accordingly.
If you fit an atmo blow off valve you waste this air out of the intake system after the ECU has made a fueling adjustment to cater for its presence. This can result in an incorrect fuel mixture.
If you examine the fuel trims using something like Multi ECU Scan you will see that they go out of spec and likewise the lambda integrator can become erratic. It not a disaster, it simply means that the engine is not working at its most efficient. The choice is yours.
E85
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Re: Turbosmart Blow Off
[Re: branimir20VT]
#1657510
11/05/2022 14:58
11/05/2022 14:58
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Joined: Feb 2019
Posts: 323 Free State of Jones
clanger
Making a profit
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Making a profit
Joined: Feb 2019
Posts: 323
Free State of Jones
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Lambda controls the fueling below 3k rpm too and drops out based on engine speed and load, its range can be altered via a map. However that is besides the point Likewise the spring rate on an atmo BOV, that relates to boost levels and is nothing to do with the ECU measuring airflow !!???
The MAF is used by the ECU across the board and many calculations are made based on its signal. When the ECU ignores lambda under heavy boost, MAF values are still taken into account. See Big Maf conversion for very highly tunes engines.
As I said in my original response, its not a disaster using an atmo BOV, the engine will just not be running at its most efficient - its really easy to see on the fuel trims.
E85
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