Quote:
Originally Posted by thejeremyman9
Quote:
Originally Posted by johnung
I think that you are making an incorrect assumption which is causing you to think that the engine will run rich.
The Turbosmart BOV Dual Port is venting some, but not all, excess boosted air to the atmosphere which makes that whoosh sound. But the fuel mixture is determined by sensor measurements just before air enters the engine, which is after the BOV. BOV has no disruptive effect on fuel mixture ratio.
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What do you mean the sensors are after the BOV? The MAF is in the very beginning of the intake track.
Any vent to atmosphere BOV that vents air that has already been read by the MAF is going to cause a rich condition when that air is vented to the atmosphere instead of going into the engine. Having said that, whether or not this affect is negligible on a modern car/engine like this has not been determined to my knowledge. The DME can probably correct for it using STFT, etc.
An apples to oranges comparison is my 3000gt. It came factory with a recirculated BOV and runs based on a MAF (no closed loop fueling on WOT). When i got the car 12 years ago it had a vent to atmosphere BOV. If you were to do a hard pull and immediately push the clutch in and go to neutral at the end of the pull the wideband would read extremely rich, the idle would dip, and sometimes the car would stall. I converted it back to recirculating. Now again were talking about 1991 ECU versus 2013+ with additional sensors, etc, but the concept is the same - the MAF thought a certain amount of air was going into the engine and fueling was determined based on that, but some of that air was vented, leading to a temporary rich condition. |
I'm no expert on this. Obviously there's a lot of computer calculations going on with algorithms developed based on information from many sensors. MAF is at the beginning of a very long intake air road where air is compressed, heated and cooled before it enters the actual engine to be mixed by fuel. There is no way that MAF information is being used to fine tune the mixture. Too much happens to that air after it goes past the MAF sensor.
IMO it is more likely that the MAF information is being used almost as a ballpark range check. Then the mixture fine tuning occurs from sensor information as the air continues towards the engine. What convinced me of this was when I was investigating Inlet Pipe options.
Guys voiced concerns that the connection from the air pipe to the turbo Inlet wasn't really secured and subject to leaks, yet it didn't seem matter to engine performance. Guys installed the first version of the Pure Turbos Inlet that didn't really have a fastening system like a sleeve. It just kinda fit into the opening. It didn't even have a bolt hole like the stock plastic Inlet Pipe. A leak there obviously changes the amount of air that the MAF already measured. But doesn't severely effect how the engine runs. That's the experimental evidence that tells me that the MAF sensor reading isn't critical to fine tuning the mixture.
Not sure if I'm explaining myself well but that's where my opinion is coming from.