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Co2 boost control

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i have co2 boost control on my skyline using the fury to control it. I just use a 1kg co2 bottle with a 3 pot mac valve it works really  well however i needed to use pneumatic needle and seat valves to get it smooth which also saves co2 they were about $10 from a air plant shop. Can run a 3psi spring and achieve 40psi can do nice boost vs speed tables etc awesome for track. If you need any info let me know and ill email you pics  

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ok sounds like it is possible to some degree. looking at other platforms  they have specific co2 settings and the ecu controls two mac valves via feedback from a pressure sensor in the top of the wastegate. I want to be able to run a low pound spring and ramp the boost right up on a time base for drag racing. 

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That sounds like an expensive way to achieve the same result. That's exactly what i am doing except you dont need two mac valves just one you can run as small a spring as you like. You dont need feedback from the top of the gate you want to control boost in the manifold not specifically pressure in the waste gate top hat. You use a PID in the ecu and the co2 and you can set boost vs time, speed or whatever you like and achieve the same result maybe even better as the boost is referenced from the manifold not pressure differential on the diaphragm of the gate.  the main advantage with the system your describing i would imagine will be less co2 used. However i use the car for track work and haven't been through a bottle of co2 yet. I would think you would get years out of a drag car providing you use needle and seat valves.  

 

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18 hours ago, tarlo said:

That sounds like an expensive way to achieve the same result. That's exactly what i am doing except you dont need two mac valves just one you can run as small a spring as you like. You dont need feedback from the top of the gate you want to control boost in the manifold not specifically pressure in the waste gate top hat. You use a PID in the ecu and the co2 and you can set boost vs time, speed or whatever you like and achieve the same result maybe even better as the boost is referenced from the manifold not pressure differential on the diaphragm of the gate.  the main advantage with the system your describing i would imagine will be less co2 used. However i use the car for track work and haven't been through a bottle of co2 yet. I would think you would get years out of a drag car providing you use needle and seat valves.  

 

The drag race style CO2 control than the OP is asking for here is where you have two solenoids controlling wastegate dome pressure.  Made popular from the old AMS-1000 boost controllers.  Our boost control is currently linked to MAP rather than a separate pressure sensor which this system needs.  The idea of controlling dome pressure instead of manifold pressure is it is apparently more responsive and precise.  You only have a small static dome volume to control rather than the large volume pipework and plenum etc which is also highly dynamic.  So the control loop is much smaller and you have a much more stable target.   I have never seen any back to back testing but I suspect in most situations the final control stability probably doesnt work out much different than what you're doing.

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thats interesting.... If you were controlling pressure on either side of the diaphragm you would still need to reference map in the controller to as to see the target yeah?  Or does the controller just view/control the pressure in the top of the gate not the bottom and the inlet still acts on that?  

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As far as I remember they only control/monitor/target the dome pressure (top side).  Bottom side is still connected to manifold but not referenced at all in the control system.  Basically just like changing the spring in the dome.  If you have a 4psi spring and you add 30psi to the dome your manifold pressure will control at about 34psi.

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Oh yeah i see what you mean. The same result could be achieved by different duty cycles and a constant CO2 pressure with the link yeah? in fact that is generally how i run mine most of the time i just use a trim pot to set the duty cycle. I i don't quite see how the controller could be more precise at controlling boost without actually referencing the variable its controlling? it wouldn't be able to account for variances like pressure in the exhaust manifold that would slightly affect the waste gate valve or changes in barometric pressure. I would imagine a well tuned pid referencing inlet manifold pressure would out perform a duty cycle/pressure in top hat of wastegate based system at maintaining target accuracy. What are your thoughts Adam?  also i don't mean this in a disrespectful way i really like to discuss stuff like this and brainstorm different ways of attacking problems.

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