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Old 10-04-2010, 01:41 PM   #376
02RexWI
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What do your turbo dynamic's tables look like?
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Old 10-04-2010, 02:19 PM   #377
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Got it working.I increased turbo dynamics burst and continuous to 90% everywhere in positive correction. Now I get perfect boost control.12 psi on the IWG and 21 on the EWG.
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Old 10-04-2010, 02:49 PM   #378
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snapshot: glad to hear! i think you may have the first known application of the dual wastegate setup on a subie.
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Old 10-04-2010, 04:00 PM   #379
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I really love the way it drives. Pretty quiet, but 12 psi worth of pep to get around tow, and it stays a rock solid 12 until ~80% throttle.

Does that make it a hybrid-hybrid boost controller?
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Old 11-12-2010, 12:35 AM   #380
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ok so as i have found without much avail people are not using like me a greddy profec b spec 2 bcs. im running the hybrid setup kinda like what is posted (i think)...

pic:


i hit both on high and low 22psi which is above my 19 goal. using opensource tune and that all works so i think its within the controller or i have something hooked up wrong.

any ideas?

josh
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Old 11-12-2010, 06:42 AM   #381
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why BOTH solenoids?
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Old 11-12-2010, 08:17 AM   #382
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^what he said
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Old 11-12-2010, 08:55 AM   #383
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Quote:
Originally Posted by ride5000 View Post
snapshot: glad to hear! i think you may have the first known application of the dual wastegate setup on a subie.
Then let's add one to this list that until now was unknown for a little under 2 years.

Basically, I tune the internal gate with my EBCS up to about 90% throttle. Then, when I enter a tunnel and notice a fat old dude sitting on a perpetual whoopie cushion (aka Harley), I increase TPS to 100%. The ECU shifts focus to the extreme right column of my 'Max Wastegate Duty Cycle' table while the 'Turbo Dynamics' table notices the large boost error and ramps WGDC to 100% with impressive fervor. The MBC's internal spring is futile against the incoming pressure wave that continues past to hit the external wastegate's internal diaphragm. The combusted air/fuel mixture in cylinders 1, 3, 2, and 4 screams its way to the atmosphere bypassing all superfluous restrictions such as catalytic converters, resonators and silencers. Fat old dude will now require hearing aids for the remainder of his journey.
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Old 11-12-2010, 08:55 AM   #384
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reason was from what i was talking to the guy who helped me tune it said that if the car got into a high knock situation the ecu will take over. the greddy in theory will do all the "boost controlling" and the factory is still there as a saftey back up so to speak.

josh
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Old 11-12-2010, 09:08 AM   #385
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The stock BCS has no path to the wastegate if its run the way drawn except through the other BCS, so the only thing it could do is increase your boost by bleeding off some of the pressure that would go through the other BCS.
If you wanted a fail safe for over boosting you should T in an MBC where the stock BCS is and T it into the line going to the wastegate.

LOL @ harley story We've got tons of those f@gs in WI
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Old 11-12-2010, 11:56 PM   #386
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Quote:
perpetual whoopie cushion


Awesome.
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Old 11-22-2010, 11:27 PM   #387
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Will a tinyrex opensource Launch Control patch still work with this setup? I know it cuts fuel but does changing the boost tables in the map effect the function of the LC?
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Old 11-23-2010, 01:02 AM   #388
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Will a tinyrex opensource Launch Control patch still work with this setup?
Works just fine.
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Old 11-24-2010, 02:06 AM   #389
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Thanks
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Old 12-06-2010, 02:12 PM   #390
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it is possible, IF you flip the electrical/pneumatic phase.

to interrupt we need closed when energized, not open, as in the oem bcs.

if you wanted to, you could rig up a state inverter with a transistor... flip the electrical phase. then use the oem.

the 3 port solenoids are easier because they allow you to pick which pneumatic phase you want.
i have a question about using the factory BCS instead of a 3 port. are you referring to a regular WRX BCS or an STI BCS? reason i ask is that i have n 04 STI and after reading this thread a few weeks ago i have started experimenting with the idea. after taking apart a few things i found that my factory BCS is normally closed and energized open. that and if you look at how the factory vacuum lines are ran and how the WGDC tables are set up makes me believe that there isn’t anything wrong with my factory BCS. i have my car setup right now as hybrid using the manual BCS that is off my talon. but cant test it out until i get the clutch replaced in my car.
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Old 12-06-2010, 03:13 PM   #391
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both wrx and sti solenoids are functionally equivalent: both are normally closed at rest, and pneumatically open when current is applied to the coil.
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Old 12-06-2010, 03:29 PM   #392
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Quote:
Originally Posted by ride5000 View Post
both wrx and sti solenoids are functionally equivalent: both are normally closed at rest, and pneumatically open when current is applied to the coil.
alright i just wanted to make sure i didn’t miss something. so as long as i have it connected like the diagram in the first pic just replacing the 3 port with the factory BCS then it should work fine.
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Old 12-07-2010, 12:15 AM   #393
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like the diagram in WHICH first pic?

you cannot use the factory BCS in an interrupt topology*. it will only work as a bleed setup.


*without inverting the electrical phase
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Old 12-08-2010, 01:06 AM   #394
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Quote:
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like the diagram in WHICH first pic?

you cannot use the factory BCS in an interrupt topology*. it will only work as a bleed setup.


*without inverting the electrical phase
pic in the very first post...

call me stupid if you want but could you please explain why i would need to invert the the electrical phase. from what i can tell there really is nothing different in the way it operates compared to how you would set up the 3 port BCS. from messing around with the factory BCS and with conformation from another member the factory BCS is normally closed. if you were to blow into one of the ports while no electrical signal is ran through it then you wouldn't get any airflow out of the other port.

from what i see in the diagrams, when you setup the three port solenoid that everyone uses for this mod, by caping off the middle port and running the lines to ports 1 and 3 then you are making the solenoid block all airflow until there is an electrical signal ran through it. then it opens and allows the air to pass through it just as the factory BCS would.

like i said, call me stupid if you want, but with the exception that the 3 port BCS's that everyone uses has a faster response time, i am failing to see any other difference between the two in how they operate for this application.
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Old 12-08-2010, 01:57 AM   #395
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The computer increased wastegate duty cycle in order to achieve more boost, so think of it this way:

You floor it and manifold pressure is at 0 psi (atmospheric), in order to get the best boost response the ECU starts to increase wastegate duty cycle (energizes the solenoid more and more rapidly) until it gets close to target boost. (It does this because in stock setup the solenoid would be allowing pressure to bleed off and not reach the wastegate actuator, thus allowing boost pressure increase beyond wastegate spring pressure)
The way you are running it the computer would effectively always be increasing the supplied pressure to the wastegate actuator to try to achieve a higher boost pressure and you would be stuck at whatever your wastegate spring pressure is.

If you inverted the electrical phase it would work because it would be doing the process in the opposite manner.
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Old 12-08-2010, 12:51 PM   #396
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Quote:
Originally Posted by mike96 View Post
from what i see in the diagrams, when you setup the three port solenoid that everyone uses for this mod, by caping off the middle port and running the lines to ports 1 and 3 then you are making the solenoid block all airflow until there is an electrical signal ran through it. then it opens and allows the air to pass through it just as the factory BCS would.
this is where you're mistaken.

for an interrupt mode system to work, it needs to be normally OPEN (allowing pneumatic signal to reach the wastegate) with no current applied.

no current is the failsafe mode if there were to be a wiring open or short circuit, or if the ecu triggers limp mode or high det maps.

during operation, current is applied by the ecu to RAISE boost. in the interrupt mode system this CLOSES the valve and BLOCKS the pneumatic pressure signal from reaching the wastegate.

in the factory system, the application of current OPENS the valve and BLEEDS pressure from reaching the wastegate.

got it?
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Old 12-08-2010, 01:37 PM   #397
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I don’t mean any disrespect, but I am having a hard time understanding why you claim that I would need to basically invert the signal. See, the way I understood how the system works is this. If you were to take and remove the vacuum lines and run a straight piece of tubing to the WGA then you would only achieve boost pressure equivalent to the spring pressure in the WGA (I.E. if the factory spring in the WGA is 10 pounds then you would only get 10 pounds of boost). Now if you were to interrupt the source of pressure running from the manifold/turbo compressor/or where ever you were getting it from, for example disconnect the vacuum line or add in a “T” to allow the pressure to bleed off, then one of two things would happen. Either you would eventually build up enough exhaust pressure to blow the WGA open or you would build enough boost to make your motor would go POP!!!

Now if you install a solenoid that is normally closed, as the factory solenoid is, then the boost control system would revert back to only being able to run waste gate pressure until the solenoid was commanded to open. Think about the way the factory setup is. As the turbo starts to make boost the ECU increases WGDC to keep the turbo from making boost or decreases the WGDC to allow the turbo to make more boost. As the WGDC increases it allows boost pressure to “bleed off” and reduces the pressure in the line that runs to the WGA. The faster the BCS actuates the more pressure is bled off resulting in more boost because the turbo now has to work harder to make up for the pressure loss. This is why the factory WGDC table increases in duty cycle percentage as the requested boost pressure increases and when you increase the boost settings on the factory setup you must also increase the duty cycle in the appropriate WGDC tables (a higher WGDC = more boost).

Now if the system had been designed with a solenoid that was normally open and allowed air flow through it when there was no electrical applied to it, then tuning would be backwards. What would happen is that the WGA would not see any pressure what so ever until the BCS was commanded to shut. Then the WGA would open keeping the turbo from making any more boost. Here is where tuning would be backwards. In order for the ECU to regulate boost at lower pressures (for example partial throttle or you just wanted to run 12 PSI as opposed to 19) the ECU would have to command the BCS to close at a much faster rate in order to keep more pressure in the line running from the compressor housing to the WGA. As you tuned the boost up you would need to decrease the WGDC in order to allow the BCS to “bleed off” some of the pressure used to open the WGA. So basically your WGDC would be larger numbers in the lower boost settings and as you wanted more boost over factory WGA spring settings the WGDC would decrease.

This is why I am confused as to why you say the signal would need to be inverted. I do like fully understanding a system before making modifications to it, and as I said in my explination I think I have a good grasp on how the system works. After all every other turbo car i have worked on is setup to operate in the same way as a Subaru. If i am wrong please let me know, i would appreciate it greatly.
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Old 12-08-2010, 03:08 PM   #398
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Quote:
Originally Posted by mike96 View Post
Now if you install a solenoid that is normally closed, as the factory solenoid is, then the boost control system would revert back to only being able to run waste gate pressure until the solenoid was commanded to open. Think about the way the factory setup is. As the turbo starts to make boost the ECU increases WGDC to keep the turbo from making boost or decreases the WGDC to allow the turbo to make more boost. As the WGDC increases it allows boost pressure to “bleed off” and reduces the pressure in the line that runs to the WGA. The faster the BCS actuates the more pressure is bled off resulting in more boost because the turbo now has to work harder to make up for the pressure loss. This is why the factory WGDC table increases in duty cycle percentage as the requested boost pressure increases and when you increase the boost settings on the factory setup you must also increase the duty cycle in the appropriate WGDC tables (a higher WGDC = more boost).
The part that isn't in bold is correct, running a line directly to the wastegate actuator would cause the turbo to run at wastegate spring pressure, but I think you are thinking that the factory boost control system regulates boost by creating a sort of "boost leak" which isn't correct.
The factory setup bleeds off pressure to INCREASE boost pressure- read this very carefully and make sure you understand it before you post again:
With the stock BCS un energized the pressure is not being bled off through the BCS and the wastegate actuator see's 100% of the pressure coming out of the turbo.
When the wastegate duty cycle is at 50% then we'll say that 50% of the pressure is being bled off (this isn't true, but we'll pretend it is) so if the turbo is creating 18 psi boost the wastegate actuator will only see 9 psi pressure, and thus will remain shut. Now if the target is 18 psi the duty cycle will decrease until there is enough pressure in the wastegate lines to open the wastegate actuator (usually around 12 psi for internal wastegates on subaru's).

The boost is regulated by the wastegate actuator opening the wastegate and allowing exhaust gas to bypass the turbine. I belive you are thinking that it is regulated by the boost pressure being bled off and thus making the turbo work harder, but this is not the case because it would cause the turbo to become less efficient just to decrease boost pressure, and thus would lead to less power being made.

Please read this carefully and make sure you understand this, because this IS how the factory boost control system works.

Thanks!

Last edited by 02RexWI; 12-08-2010 at 03:17 PM.
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Old 12-08-2010, 03:20 PM   #399
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I don’t mean any disrespect, but I am having a hard time understanding why you claim that I would need to basically invert the signal. See, the way I understood how the system works is this. If you were to take and remove the vacuum lines and run a straight piece of tubing to the WGA then you would only achieve boost pressure equivalent to the spring pressure in the WGA (I.E. if the factory spring in the WGA is 10 pounds then you would only get 10 pounds of boost). Now if you were to interrupt the source of pressure running from the manifold/turbo compressor/or where ever you were getting it from, for example disconnect the vacuum line or add in a “T” to allow the pressure to bleed off, then one of two things would happen. Either you would eventually build up enough exhaust pressure to blow the WGA open or you would build enough boost to make your motor would go POP!!!
ok so far.

replace "T" with NC solenoid bleed and you have EXACTLY the oem boost control system.

Quote:
This is why I am confused as to why you say the signal would need to be inverted. I do like fully understanding a system before making modifications to it, and as I said in my explination I think I have a good grasp on how the system works. After all every other turbo car i have worked on is setup to operate in the same way as a Subaru. If i am wrong please let me know, i would appreciate it greatly.
the signal needs to be inverted because you are MOVING THE SOLENOID from one place to another.

oem = shunt = OPEN reduces wga signal = more boost
this = series = CLOSED reduces wga signal = more boost

if you want to use an oem solenoid in a series config, it needs to be OPEN when it is now CLOSED and CLOSED when it is now OPEN.

dude, i appreciate you trying to learn. however, the fact remains that in order to do this mod as safely and simply as possible, you need to buy a solenoid.

i have literally done NOTHING to the topology since i installed it on the car so many years and miles ago. it just works. every day.

you are more than free to play with your car, as i did, and come up with a different or better solution that uses the oem bcs.

if you do, please come back and update the thread, or start your own, and give back to the community.
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Old 12-08-2010, 03:38 PM   #400
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this is where you're mistaken.

for an interrupt mode system to work, it needs to be normally OPEN (allowing pneumatic signal to reach the wastegate) with no current applied.

no current is the failsafe mode if there were to be a wiring open or short circuit, or if the ecu triggers limp mode or high det maps.

during operation, current is applied by the ecu to RAISE boost. in the interrupt mode system this CLOSES the valve and BLOCKS the pneumatic pressure signal from reaching the wastegate.

in the factory system, the application of current OPENS the valve and BLEEDS pressure from reaching the wastegate.

got it?
Gotcha. I wasn’t so confused as to how the system works but more so on terminology and how you have the 3port BCS setup

That said, as I have my boost control set up I don’t see why it won’t work.



as you can see I have the system set just like as you would with the 3 port BCS only I have it replaced with the factory BCS. if you think about it, with the factory BCS set this way it completely blocks the airflow from the compressor housing to the WGA until the ECU commands the BCS open which allows pressure to flow trough and opens the waste gate, much like the way a MBC operates. So essentially what I have done is turned the factory BCS into an electric version of a MBC. there will obviously need to be some adjustments made to the WGDC table but I think it should work just fine. The only down fall to the system being setup this way is the fact that there really is no failsafe. If the BSC were to go bad/the connector comes off/wire break/Ect. Ect. then the turbo would continue to make boost until the MBC kicks in and opens the waist gate. But then again if that were to happen then it would be no different than running with a MBC only...
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