Posted: Sep 30, 2013 7:53 PM
Dayum. 
Page 3 of 3
Posted: Oct 01, 2013 1:45 AM
Looks like you know what you are doing!
Posted: Oct 05, 2013 7:32 PM
Looks great! My m102 recirc/blow off is actuated by manifold vacumn. How does yours work when throtlle closes?
marc
marc
Posted: Oct 15, 2013 6:26 PM
Marc
The goal of the BOV is to stop that boost back pressure created when slamming the TB shut from reaching the turbo compressor and causing surge. So the closer to no back-pressure surge the BOV can be tuned to, the less wear there is on the turbo and the better off you are.
To your m102 question, I would think my BOV probably works like your BOV. From the information I dug into before deciding how to set up the BOV/Recirc pipe, the BOV functions along the following lines:
• The BOV psi rating manages the pressure difference between the charge-pipe and the intake manifold
• The BOV vacuum hose connected to the intake manifold is to give the BOV a manifold pressure reference feed
• When the engine throttle is open and there is boost in the system, the pressure in the charge pipe and the pressure in the intake manifold are pretty much balanced (e.g. 5psi pressure in the charge pipe before the throttle body is 5psi pressure in the intake manifold). When under boost the BOV pressure setting can be pretty much 0 psi as it has 5psi on both sides of the relief valve
• When the engine throttle is slammed shut, there is an increase in pressure in the charge pipe and the pressure in the intake manifold reverses to a vacuum. Let’s say the 5psi boost pressure in the charge pipe goes up to say 8psi and the intake manifold goes down to negative 4psi. the difference being 12psi
The BOV psi pressure should be set to manage that pressure difference. The BOV should not open when the boost is in balance but it should open when you slam the TB shut and it should stop the back pressure surge on the compressor. So in the example above (5psi normal boost and -4psi of vacuum when the TB is shut), we want to stop the additional 3psi surge on the compressor:
• TB slammed shut -- if you want to stop the pressure surge on the compressor then the BOV psi pressure should be set about 9psi. The extra 3psi surge will cause the BOV to open
• TB closed at idle and no boost pressure – You don’t want the BOV to open so the negative 4psi of manifold vacuum is a difference that has to be allowed for by the BOV. That means you can’t set the BOV psi to less than 4psi otherwise it will open under normal idle vacuum
• BOV pressure should be adjusted between 4-9psi in this example. Reality is those numbers will deviate a bit due to higher vacuum/pressure conditions of your car and if you recirculate the boost vs. vent it to atmosphere. It’s probably a repetitive process to get the adjustment correct
The goal of the BOV is to stop that boost back pressure created when slamming the TB shut from reaching the turbo compressor and causing surge. So the closer to no back-pressure surge the BOV can be tuned to, the less wear there is on the turbo and the better off you are.
To your m102 question, I would think my BOV probably works like your BOV. From the information I dug into before deciding how to set up the BOV/Recirc pipe, the BOV functions along the following lines:
• The BOV psi rating manages the pressure difference between the charge-pipe and the intake manifold
• The BOV vacuum hose connected to the intake manifold is to give the BOV a manifold pressure reference feed
• When the engine throttle is open and there is boost in the system, the pressure in the charge pipe and the pressure in the intake manifold are pretty much balanced (e.g. 5psi pressure in the charge pipe before the throttle body is 5psi pressure in the intake manifold). When under boost the BOV pressure setting can be pretty much 0 psi as it has 5psi on both sides of the relief valve
• When the engine throttle is slammed shut, there is an increase in pressure in the charge pipe and the pressure in the intake manifold reverses to a vacuum. Let’s say the 5psi boost pressure in the charge pipe goes up to say 8psi and the intake manifold goes down to negative 4psi. the difference being 12psi
The BOV psi pressure should be set to manage that pressure difference. The BOV should not open when the boost is in balance but it should open when you slam the TB shut and it should stop the back pressure surge on the compressor. So in the example above (5psi normal boost and -4psi of vacuum when the TB is shut), we want to stop the additional 3psi surge on the compressor:
• TB slammed shut -- if you want to stop the pressure surge on the compressor then the BOV psi pressure should be set about 9psi. The extra 3psi surge will cause the BOV to open
• TB closed at idle and no boost pressure – You don’t want the BOV to open so the negative 4psi of manifold vacuum is a difference that has to be allowed for by the BOV. That means you can’t set the BOV psi to less than 4psi otherwise it will open under normal idle vacuum
• BOV pressure should be adjusted between 4-9psi in this example. Reality is those numbers will deviate a bit due to higher vacuum/pressure conditions of your car and if you recirculate the boost vs. vent it to atmosphere. It’s probably a repetitive process to get the adjustment correct
Posted: Nov 11, 2013 12:48 AM
Added the Charge Pipes from each Turbo to the intercooler
Then added the intake pipes from the MAF to the Turbos
Then added the intake pipes from the MAF to the Turbos