Hey all. I’m installing an EBC on my evo, coming from a MBC my whole time using turbo cars. and I am reading a ton of different information on evo fourms, here, ecmlink, and other turbo tech fourms.
I want to make this thread to come up with a general consensus on how the boost plumbing should be. Seems tuners all over the country can’t agree on one set way of doing things so I’m coming here to gather information and hopefully it helps others in search of this same info.
In this thread we will be talking about the most common boost control solinoid, the MAC boost controller (MAC EBC) which also gets re branded by other people such as AEM and grimspeed.
First lets talk about how these MAC 3 ports work in the NO POWER configuration
port#1 normally closed
Port#2 common port
Port#3 normally open
so if you blow air Into Port number 2 with no power, it comes out #3 and is blocked from #1. Same if you blow into #3 it will come out #2 as there is no check valve or anything like that.
Here is where the confusion comes, at least on my end. There are two ways to hook up an EBC. You can hook it up just like a manual controller (known as the simplified method) and not use the top port of the gate and use it as a bleeder style. pretty self explanatory. Or You can use both bottom and Top ports with a T in the line of the boost source.
USING THE TOP PORT: (top of diaphragm) allows boost pressure in addition to spring pressure to keep the wastegate valve closed. When using a light spring for low boost, but targeting higher boost the exhaust back pressure is fighting the spring and the added pressure on the top of the diaphragm most likely over running the spring pressure and actuated top of the diaphragm and that is what you hear when your Wastegate chatters, running a stiffer base spring combo seems to get rid of the chatter Incase anyone was wondering.
The biggest thing I’m coming to find for uncertian information is which port the boost source enters.
I see other manufacturers (grimspeed specifically) saying to feed boost source into port #3 (normally open) leave #1 (nornally closed) vented, and connect #2 (common) to the bottom of the wastegate and VTA the top of the diaphragm. As shown below.They do not have a diagram for use with the top port at all
This is fine if you run enough base spring that the exhaust isnt over running your wastegate valve, but what if you do? Then you use the top port “Tee’d” method.
Tee’d method:
Some diagrams say to boost source into #2 (common) vent to armosphere #3, (normally open) and #1 (normally closed) is to the top of the wastegate diaphragm as seen below
Another diagram, which I personally think is correct, and I will explain why in a second, is this: boost source (and T to bottom of wastegate) to #1 (normally closed) #2 (common) to top of wastegate, and #3 (normally open) VTA
The reason the port selection of where the boost source becomes most Important is this:
one has a fail safe, and one does not.
Some of you may or may not have noticed that if you have your boost source to #2 (common) and you dont hbe BCS ebabled, that you overboost. Does this mean that if your boost controller failed, be it heat, or moisture, that your car will go boom? When these fail they fail in their off position.
If you plumb your boost source (Which is T’d into the bottom port of the wastegate to give it constant boost refrence) into #1 (normally closed) then when the solenoid does not have power, or if it fails, then the boost source will go straight to tue bottom port of the wastegate as if the lines were looped straight from boost source to wastegate bottom. And should be regulating at wastegate spring pressure. And when energized, port #1 opens to allow flow to port #2 (common) which then gives you a duty cycle based amount of psi to put on top of the wastegate diaphragm. Which also closes port #3 which is normally open VTA
So with these ways to plumb this thing, which are you using?
I want to make this thread to come up with a general consensus on how the boost plumbing should be. Seems tuners all over the country can’t agree on one set way of doing things so I’m coming here to gather information and hopefully it helps others in search of this same info.
In this thread we will be talking about the most common boost control solinoid, the MAC boost controller (MAC EBC) which also gets re branded by other people such as AEM and grimspeed.
First lets talk about how these MAC 3 ports work in the NO POWER configuration
port#1 normally closed
Port#2 common port
Port#3 normally open
so if you blow air Into Port number 2 with no power, it comes out #3 and is blocked from #1. Same if you blow into #3 it will come out #2 as there is no check valve or anything like that.
You must be logged in to view this image or video.
Here is where the confusion comes, at least on my end. There are two ways to hook up an EBC. You can hook it up just like a manual controller (known as the simplified method) and not use the top port of the gate and use it as a bleeder style. pretty self explanatory. Or You can use both bottom and Top ports with a T in the line of the boost source.
USING THE TOP PORT: (top of diaphragm) allows boost pressure in addition to spring pressure to keep the wastegate valve closed. When using a light spring for low boost, but targeting higher boost the exhaust back pressure is fighting the spring and the added pressure on the top of the diaphragm most likely over running the spring pressure and actuated top of the diaphragm and that is what you hear when your Wastegate chatters, running a stiffer base spring combo seems to get rid of the chatter Incase anyone was wondering.
The biggest thing I’m coming to find for uncertian information is which port the boost source enters.
I see other manufacturers (grimspeed specifically) saying to feed boost source into port #3 (normally open) leave #1 (nornally closed) vented, and connect #2 (common) to the bottom of the wastegate and VTA the top of the diaphragm. As shown below.They do not have a diagram for use with the top port at all
You must be logged in to view this image or video.
This is fine if you run enough base spring that the exhaust isnt over running your wastegate valve, but what if you do? Then you use the top port “Tee’d” method.
Tee’d method:
Some diagrams say to boost source into #2 (common) vent to armosphere #3, (normally open) and #1 (normally closed) is to the top of the wastegate diaphragm as seen below
You must be logged in to view this image or video.
Another diagram, which I personally think is correct, and I will explain why in a second, is this: boost source (and T to bottom of wastegate) to #1 (normally closed) #2 (common) to top of wastegate, and #3 (normally open) VTA
You must be logged in to view this image or video.
The reason the port selection of where the boost source becomes most Important is this:
one has a fail safe, and one does not.
Some of you may or may not have noticed that if you have your boost source to #2 (common) and you dont hbe BCS ebabled, that you overboost. Does this mean that if your boost controller failed, be it heat, or moisture, that your car will go boom? When these fail they fail in their off position.
If you plumb your boost source (Which is T’d into the bottom port of the wastegate to give it constant boost refrence) into #1 (normally closed) then when the solenoid does not have power, or if it fails, then the boost source will go straight to tue bottom port of the wastegate as if the lines were looped straight from boost source to wastegate bottom. And should be regulating at wastegate spring pressure. And when energized, port #1 opens to allow flow to port #2 (common) which then gives you a duty cycle based amount of psi to put on top of the wastegate diaphragm. Which also closes port #3 which is normally open VTA
So with these ways to plumb this thing, which are you using?
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