You're over-complicating the entire situation...

1. It doesn't matter which BCS nipple you use... the WGDC controls how much the two nipples flow to each other

2. Changing the MBC boost source with the BCS is not going to give you reliable results... the BCS is not meant to send boost to the WGA, it's meant to bleed away small amounts of boost.

3. Just put the MBC first in line and you will be able to accomplish the same thing with reliable results!

 

Thank you both for your input.

EAG: The spike I got was because I had:
A. added restriction (pressure drop) from having the BCS in line
B. added restriction (dP) from having MBC in line
C. added initial spring force due to spring mod.

Since I've taken off the spring I can now get anywhere from 22psi (MBC cranked all the way down, and BCS in line) The spike is not an issue. The new issue is now the fact that my taper is WORSE than before.

cookie: I suppose we need to define terms here. When I hear "bleed" I picture the GM 3port, where it is actually bleeding airflow away from the WGA. Since this BCS only has 2 ports (in and out) the only way it can effectively raise boost is for it to add restriction to the air that is trying to get to the WGA by causing a pressure drop at the BCS... correct? In effect, it controls how much pressure can get to the WGA without actually diverting air anywhere... right?

You're saying it will be inconsistant... but why? I'm thinking of it this way. I have the BCS set up as basically an on-off switch stopper. Below 5500RPM it is set to allow air to pass through to the MBC. I understand that the BCS even being in-line causes some restriction, but that only makes me have to lower my MBC setting. Then, between 5000RPM and 5500RPM (interpolation between cells), I'm trying to use the BCS to TOTALLy cut off all pressure possible to the WGA (and consiquently the MBC).
Say there were no interpolation between cells and the BCS went right from 0%DC to 100%DC at 5500RPM (obviously not the case):
A. MBC would control boost curve like it always has until 5500RPM
B. BCS would cause large pressure drop in line after BCS at 5500RPM and greater
--MBC's internal spring pressure would overcome the now very low boost pressure applied to it meaning it would snap shut and bleed off all air between MBC and WGA, therefore closing WGA entirely.

The way I see it if I put the MBC before the BCS:
A. Before 5500 boost should be a bit higher than the other config because the added restriction of the BCS between the WGA and MBC will cause more air to go out of the MBC's bleed hole. Other than that, it should work the same.
B. After 5500 where BCS 'closes' the pressure in the line between the BCS and WGA will lower more predictably, but with less effect.

See... the issue here isn't reliabilty, its whether this will even work. Heck, if I just put some sort of on-off valve in the line somewhere so that above 5500rpm the airflow were totally cut off from the WGA, it would serve my purpose. Boost above 5500rpm is NEVER going to be out of hand. The turbo simply cannot make "too much". If I see 22psi I'll be happy. There's no way it will spike after 5500, but that's not to say that this setup will actually stop the taper either. I'm expecting the worst case scenario to be that this does absolutely nothing and that I am left with my old MBC boost curve in the end.

I am going to try to reverse the 0%s and the 100%s before I physically switch the lines, just for giggles because the lines are harder to get to (especially at work).

Noone has addressed the fact that this idea is WORKING, except in the opposite way that I want it to. How can that be explained? If its not because the lines are backwards then what else can cause a 180* incorrect response? Yes, the BCS controls the flow between the two nipples, but what are the mechanics behind it? Isn't it likely a plunger? If so what if one port is on the side of the plunger and one port is on the face of the plunger (like a BOV/DV)? We all know that, yes, a DV installed backwards will work, but not nearly as well and its reaction is poor. Perhaps this is a small electronic equivalent? I don't know, I'm hypothisizing.

 

Okay, lunchtime tuning results:

Cookie: You were absolutely right, nipple orientation doesn't matter.

Other interesting finds:
(remember, when boost is high I can adjust the actual value w/ the MBC. When it is low it is WG pressure and no adjustment helps)


With values set like I think they should be the outcome is always backwards, MBC boost until 5000-5500 where I get WG boost!




With values set backwards I get WG boost UNTIL 5000-5500 where I see MBC boost.


So..... I'd really like to stay with my MBC making my boost curve until 5k-5500 where the BCS settings take over... but how do I do it? lol, I reaaaalllly gotta get back to work so leave your thoughts and I'll ponder this later.

Revisited: Plan of action: turn up MBC with WGDC = 100<5500ROM and WGDC = 0>5500RPM. See what happens.

 

I tried for a good 20 minutes to understand how you even have the lines run, and you have totally confused me...

It's so simple to accomplish what you want, I don't understand why you've made it so complex by trying to put the BCS before the MBC.

All a manual boost controller is, is an adjustable restrictor pill.

 

Wouldn't this be the same if you added a male to male fitting (Nylon) with a hole drilled thru, after the MBC, but before the Wastgate? Help bleed of more air before hitting the Wastgate.

 

Nice diagram and yes that is 100% correct.

With this setup the MBC is a adjustable restrictor. Instead of changing the restrictor by using a pill with different hole sizes, you are now doing it on the fly with the mbc.

 

Using my diagram, 0% WGDC = MBC pressure... as if the solenoid isn't even there.

Start adding WGDC and you start bleeding away boost from the actuator and start holding more boost. This is something you should do in SMALL INCREMENTS until you find the WGDC % that gives you the boost amount you want.

Don't start at 100% because you will overboost! With MBC acting as a pill, use 0% WGDC and adjust the MBC until you are spiking where you want it to spike to... then start adding WGDC after the taper begins in increments of 10 or so until it no longer tapers

 

lol... I see the miscomunication here... I did not use the BCS like it was set up OE. I did not use it as a bleeder. I had the hose come out of the turbo nipple into nipple A on the BCS, out of Nipple B on the BCS to the MBC inlet and from the MBC outlet to the WGA. I was effectively using the BCS as a variable restrictor. I now understand why when I use it in this arrangement it works backwards... because it IS meant to be a bleeder. lol... this is what happens when you uninstall something and try to reinstall it 3 years later.

That diagram is fantastic by the way, it should be stickied in my oppinion.

Just as a note, when I had it hooked up as I described above and my WGDC being 100 up too 5500 rpm after which it went to 0 I effectively got the same curve as I had with only the MBC. It did not help taper much at all. Apparently the BCS is not an effective restrictor since it was designed for bleeding.

Thank you very much for your patience with me. I knew I was misunderstanding something, and in this case it was the nature of the BCS's function. I'll try the configuration that you've suggested, it is the natural next step anyways.

 

That would raise the whole curve. I only want to isolate the taper area.



Also, Bryan or Cookie: Could someone please post a shot of the modified activation/reactivation table for when you use the GM solenoid? I know why its only scaled for the GM, but I'd really just like to have control up to 8K since I rev there.

 

lol, I'm posting up a storm now... Cookie, I ask you this: Why are you concerned with an overboost situation above 5500RPM? Do you really believe that can happen? I don't think there is any way to "overboost" beyond 5500RPM on the stock turbo... at least there is no way for it to go beyond what your peak boost at ~4K is. The point is to make AS MUCH as humanly possible after 5500.

I propose this:
If I put the BCS as you show in your diagram it will likely effectively raise boost from 5K up. Now... this raised boost increases pressure on the MBC, so the MBC lets more air through, right? Now that extra air (on top of the air you were trying to bleed before) needs to be bled out to maintain the gain from the BCS. Does this make sense? The MBC's spring will allow more air to get past as boost is raised, thereby diminshing the bleeding by the BCS.

BUT, what if you put the BCS (still in bleed mode) before the MBC?
Hear me out: Wouldn't this effectively lower the pressure that is put on the spring in the MBC, thereby making the MBC snap shut? If the ball in the MBC is in its fully closed position then all air between the MBC and WGA will bleed out of the MBC's bleed hole which takes ALL force off of the WGA. Wouldn't this be the method used to attain maximum boost after 5K?
(remember, I'm not looking to have a "tuned" boost curve after 5K, I just want as much boost as possible because I'm fairly certain that I won't make too much)

And there should be no concern with points before 5K, since if what you say is true about 0%WGDC = MBC boost then it should be true if the BCS is before or after the MBC... right?

 

I get it now, and this set up is path I'm going down for my next tune. Would this route be ideal with the GM map sensor as well or would stock be best?

 

Let me figure out if this works before you plan on it. If you have the patience and stomach for it, 100% ecu controlled boost is the way to go. I track my car a lot and stuff breaks all the time. I need to make sure my boost is where I want it, and I can only be positive when the control is mechanical (MBC). This is why I opt to do it this way. I want to get this going before I hit CMP next weekend and I'll let everyone know how it works.

And yes, the GM is better in every respect, no matter the application... although not always necessary.

 

Heh, reading through the thread I got the impression pretty quickly that you weren't using the stock 2 port to bleed.

Of course you are going to spike with it just being a passthrough before the MBC because you are blocking all airflow to the MBC at 0% cycle with it set up as a passthrough. (aka freewheeling!)

I like the idea, but unfortunately, I think, an MBC is not as directly variable as you would like it to be. Temperature and other factors will play a pretty serious role in how consistent it is, and I think that is the inherent problem here. I think a pill might do what you want to better, but I would definitely use shameless' diagram if you are going to continue using this method...

 

Alright, set it up as bleed and ran the "piping" exactly like cookie's diagram. The red plot below uses the WGDC map w/ "RED" on it, and the green plot uses the WGDC map w/ the "GREEN" on it. As you can see this didn't work at all... Gotta get to work, but I'll ponder this a bit more soon.
Please forgive the size.

 

ok im kinda shy with 100% ECU controlled boost but here goes my verbal vomit, is it possible to set the BCS to open 100% then vary from there, cause i would think you would want to run it open 100% so as to control the boost with a MBC then when you begin to see boost fall off, start varying the amount that the solenoid lets thru so you can maintain a steady boost pressure throughout the entire RPM band....my only problem with this logic is that you would have to account for the MBC's spring pressure and adjust accordingly....this thread makes me think alot lol