BOV and the rich/lean ecu condition. my theory

Aaron91RS · 03-03-2004, 11:17 AM

It seems everyone on here says to recirculate the BOV air because the ECM has already measured it.
I definitly disagree with that. The ECU reacts to the MAS immediatly. It doesn't remember that this air came in and now went 3 feet but then the BOV opened so the air is starting over but still in the system. This seems to be the logic every thread on the board has.
My opinion is the BOV drives a wedge of air in between the MAS and the turbo. Essentially this stops the flow of air going through the MAS immediatly for a split second. MAS sees little air and leans stuff out.
The outcome is the same as the other theory but the way you get there is different.
Now my question would be, what kind of tables does the ECU have. On my camaro there are tables that add fuel when there is a change in pressure such that would occur on a shift. Right after a shift the engine is under high load low RPM'S and extra fuel can be a good thing. It wards off detonation and shift recovery is usually at a lower RPM where there is higher torque that requires more fuel.
Does the 1g ecu have any tables like this? If it didn't I could see some cars (especially autos) running faster with a better shift recovery with the BOV disconnected.
Thoughts?

heavyD · 03-03-2004, 01:06 PM

Ha! Ha! The trials one will go through to justify venting. Nice try but no thread of truth to your theory.

There is no such thing as "split second" in a pressure loop. Pressure is the fastest acting loop there is. Recirculating doesn't momentarily stop any new air from passing through the MAS. Venting is bad! End of story.

Aaron91RS · 03-03-2004, 01:17 PM

My BOV is the stock crushed one so I really am indifferent on the matter.
I'd have to run some time trails both ways to see the effects. My car is also not an auto.

Creating a rich condiditon could be a good thing depending on how the
tables are set up. I know GM code not DSM code.
Your saying that the same amount of air comes in through the MAS by vacum even when ~14psi air is being forced in. This would mean the air coming in the MAS is suddenly getting much denser because thats the only way more air can fill the same amount of space.

heavyD · 03-03-2004, 01:33 PM

Quote:

Originally posted by Aaron91RS
My BOV is the stock crushed one so I really am indifferent on the matter.
I'd have to run some time trails both ways to see the effects. My car is also not an auto.

Creating a rich condiditon could be a good thing depending on how the
tables are set up. I know GM code not DSM code.
Your saying that the same amount of air comes in through the MAS by vacum even when ~14psi air is being forced in. This would mean the air coming in the MAS is suddenly getting much denser because thats the only way more air can fill the same amount of space.

Dude. As soon as the air exits the BOV, it isn't at 14 psi anymore. You would only be pressurizing the intake tube if it was closed to atmosphere and it isn't as it is open to atmosphere at the air filter. Quit trying to re-invent physics.

GoFastTSI · 03-03-2004, 01:59 PM

Thoughts? Yes, you're dumb. Perhaps they had this round wheel thing all wrong for the better part of a century too.

98spydert · 03-03-2004, 02:09 PM

The amount of air coming into the system, the amount of pressure in the system, and the amount of pressure/vacume AFTER the T-body are all different things. You can't just throw them all together and make up a new theory

Here's something to think about. If the turbo is spooled at all, it's pushing air whether the BOV is open or closed. If the BOV is open and recerculating the turbo is pulling in minimal air through the MAF. If not, whatever is getting drawn in and pushed out that BOV into the atm. is being compensated by the ECU with fuel no matter how small it is. Obviously not a huge amount of air but significant none the less.

Defiant · 03-04-2004, 08:07 AM

O, we're sorry, but you don't win this lovely dinette set, and a trip to romantic Hawaii. But do play again.

boostedinaz · 03-04-2004, 11:17 AM

I understand what you are try to say but bottom line is that it doesnt work that way. All this "stuff" that you are saying is going on doesnt happen until after the MAF so it doesnt see any of it. Once it has gone through the MAF it is metered and will be burned at somepoint no matter what direction it goes.

Sorry, but there will be lovely parting gifts at the door.

Michael