Single Turbo Boost Control Options

shushikiary

Corporal
Jun 4, 2018
160
Ok so get this... I put a check valve on the top of the waste gate and it still did it, no changes what so ever.

So now I can be confident there is not a vacuum on the top of the waste gate...

Maybe my diverter valves are opening and staying open and dumping pressure or something?

I'm at a loss.
 

shushikiary

Corporal
Jun 4, 2018
160
Changed out the diverter valve springs (they are the turbosmart kompact plum back, and I just have them open to atmosphere with filters on the end)... no change.

I can even get on it, let the PID timeout (which the tuner made happen on purpose to try to figure this out), then get right back on it, it builds boost no problems, then get back off it, and every time it just goes right back to 7-8 PSI.

Darndest thing... I have no idea.

I tried moving the boost box ground just in case too. I'm really starting to think that perhaps this is a "feature" of the hypergate version V waste gate.
 
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WOT808

Specialist
Aug 7, 2017
78
I'm seeing something very strange and would like some input from you guys. During tuning I'm seeing that after a PID timeout the boost pressure going below spring pressure while staying WOT, and we can't figure out why.

This is with the speed tech twin scroll bottom mount kit with a GTX3582R gen II (at a mile of altitude and no spool increases yet), with a turbosmart hypergate Gen V. Boostbox with the proper 3 port mac valve. Boost signal is coming from the throttle body, 1/4 inch silicone tubing used for boost signal with a T to the bottom of the waste gate and the right side port of the MAC valve (when facing it's front) and the left side of the mac valve goes to the top of the waste gate. Aka it's properly plumbed.

Log: https://datazap.me/u/shushikiary/pi...w-spring-pressure-118-psi?log=0&data=3-4-6-24
Weird issue. I don't see PID timeout in this log but maybe the IJE DME has a different time out strategy than my I8A ?
Looks here for PID timeout examples
I see a drop in load/boost target before that craziness happens even though pedal/throttle are max the whole time.

Do you have a log with a flat boost target? If not, maybe try targeting ~20 flat and see what it does.
 

shushikiary

Corporal
Jun 4, 2018
160
I can't change the tune it's locked.

Tuner told me he was trying to tease out the issue and thus was forcing a PID timeout.

I have run tunes with WGDC logic disabled and on those it holds a flat 11.8 PSI from spool to flatline.

Remember too that with boost box gen 3 the WGDC base and WGDC after PID make sense, but the WGDC Bank 1 will be inverted (aka 100 - (WGDC after PID)).
 
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Cruizinmax

Specialist
Jul 18, 2018
75
I didn't see if you were getting throttle closures in the log but if you were is it possible your BOV is opening, causing your drop in boost pressure? If the throttle closed too much the pressure differential between the intake manifold and charge pipe would cause the diverter valve to leak all your boost out.
 

shushikiary

Corporal
Jun 4, 2018
160
Yea that's why I tried changing the spring pressure, but in the log the throttle never closes, so I don't think that's the issue. I did think along those same lines though. Sadly no change with changing the spring on the BOV's.

I've ordered a Tial MVR so we'll see what happens with that too.
 
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Cruizinmax

Specialist
Jul 18, 2018
75
What about the 3rd port on the MAC solenoid? Is it plugged or have the "muffler" in there? Can you freely blow in and out of the port on the left side of the mac solenoid? (the one going to the top port?)

My thought was if the mac solenoid was trapping a vacuum in there from after the wastegate had opened it could cause it to run less than the wastegate spring. Air should flow freely in and out of that port through the port on the front port when the solenoid is not energized.

1600915336592.png
 

Cruizinmax

Specialist
Jul 18, 2018
75
Another way you could test plumbing your MAC solenoid which would eliminate the theory of vacuum on the top of the wastegate. If you still had the same issue I think the issue would be with the diverter valves somehow.

1600916366093.png
 

shushikiary

Corporal
Jun 4, 2018
160
So I put a check valve that lets air into the top of the waste gate, so it's not possible for the waste gate to have a vacuum on the top port.

I have not tried to breath through the filter, and used the same filter on both MAC valves I've tried.... Ok I verified that the mesh filter is working fine, I can move air through it just fine.

I really am starting to think that it has something to do with the waste gate valve not being able to close under ambient top pressure when the pressure drops or something. We'll see what the Tial waste gate does.
 

Cruizinmax

Specialist
Jul 18, 2018
75
So I put a check valve that lets air into the top of the waste gate, so it's not possible for the waste gate to have a vacuum on the top port.

I have not tried to breath through the filter, and used the same filter on both MAC valves I've tried.... Ok I verified that the mesh filter is working fine, I can move air through it just fine.

I really am starting to think that it has something to do with the waste gate valve not being able to close under ambient top pressure when the pressure drops or something. We'll see what the Tial waste gate does.
That's fair. There was one other thing I seemed to recall. If you take your wastegate off the manifold there is a divider separating bank 1 and 2 in the wastegate port. On some of the first manifolds that divider was made too tall for some wastegates. Can you see if your wastegate valve is making contact with that and not closing all the way?

Also full disclosure I'm not a tuner so I'm super familiar with this platforms factory boost control logic. But in your log after PID drops off you continue higher in the RPM's and it comes back and shows wgdc after PID is 100% but the boost stays at 8 psi. If I'm reading that correctly that's saying the ecu is trying to shut the wastegate with everything it has available. Either you're loosing exhaust energy because the wastegate isn't closing or boost is escaping out the charge pipe somehow. I could be misreading the log though.
 

shushikiary

Corporal
Jun 4, 2018
160
Yea looking at the log it really is more like the tuner used the boost request offset table to change boost requested for the same load, thus the drop in boost request, but the PID does seem to be still active as the post PID value is not just pegged to the base value.

So I suspect it's not a PID timeout as he said it is.

In any case, you're right that it seems to try to bring the boost back but it can't.

When I ran with the waste gate lower chamber disconnected the system held 31 PSI no problem, so I highly doubt it's a boost leak. I also did a smoke test and no boost leak found. If I get off the throttle and back on it then it builds pressure just fine again. So it's possible the tuner really did disable the WGDC output even if the PID is still trying to request it.

This is why I hate using tuners and not tuning my self, because they are so bad at communicating exactly what they are doing. I just wanted this to be quick and work and it didn't turn out that way anyways, and this isn't just some run of the mill tuner, it's one of the best known tuners on the platform (I don't want to bad mouth them so I won't say who). It's also not their fault if the waste gate is defective or something.

So either I think something is strange with the boost box controller (they are supposed to have sent me a replacement board to try but it's been in USPS preshipment for almost 2 wees now), or I think the waste gate has some kind of leak that is happening when the top and bottom pressures are at a higher delta, like air leaking past the diaphragm or something.

I'll see what happens with the Tial MVR, it gets here tomorrow. If that doesn't fix it then I think it's got to be the boost box. So I'll put a manual boost gauge on the bottom port and a vaccum/boost gauge on the top port and see what's actually going on at that point.

Oh and yes I have removed the waste gate twice, and there is not evidence of it hitting like in the other thread. My manifold is the updated one that has it pre-clearanced.
 
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Cruizinmax

Specialist
Jul 18, 2018
75
It really can't be the boost box. There's no way for the Mac solenoid to do anything that would lower boost below the wastegate spring no matter what the boost box is commanding.

This has to be a hardware issue. If you've confirmed the hotside is 100% I would be look at the cold side next. Where do you have the vacuum lines to the BOV'S connected? Do they have their own dedicated 1/4" line connected to the intake manifold?

I know this is frustrating. It might be beneficial to have another set of eyes look over everything if nothing else. Just get a fresh perspective.
 

shushikiary

Corporal
Jun 4, 2018
160
Well replaced the waste gate with the Tial MVR. The MVR 1 bar spring actually holds 14.6 psi.

Cold and hot side have no leak, smoke test proves it, it would have to be a transient leak that only appears after the boost request drop.

Vacuum line goes from the manifold post throttle body to the two diverter valves.With the throttle open the diverter valves should not be open at all, and it seems to be that way. I could try to put a boost gauge on the diverter valves vaccum/pressure lines and we'd be able to tell if they were open or not for sure. But I highly doubt they are open.

There are 2 check valves in the system. I run a boost side and a vacuum side catch can. So there is a check valve on the throttle body evap port that only lets it suck air from the crank case (catch can)/ gas tank, and then a second one that is the RB turbo one that replaces the stock PCV valve. It's barb goes to the input of the vaccum side catch can. Ports in the head are blocked off. The boost side one is the BMS catch can, so it connects to the flapper valve and then to the turbo intake.

My intuition is telling me this has to be in the ECU. After the boost request drop I suspect it may be reducing the fuel added, or changing valve timing, or something such that it can't push the turbo back to boost. I suspect the boost request drop must be triggering some safety in the ECU or something.

If I had a boost leak that suddenly showed up after the boost request drop, the only think I could think of is those check valves, which then I'd be pressurizing the crank case. I don't see any evidence of that.

Here are some extra logs:

https://datazap.me/u/shushikiary/1bar-tial-mvr?log=0&data=3-6-24
https://datazap.me/u/shushikiary/6k-rpm-cut-out-mvr?log=0&data=3-6-24-27-29
https://datazap.me/u/shushikiary/tial-mvr-55k-rpm-cut-out?log=0&data=3-6-24-29

I've ordered a second boost/vacuum gauge and I'll look at the pressures on both the top and bottom of the waste gate. Even with my check valve I should prove that the boost box/mac valve are not hitting some resonance that allows a vacuum to be pulled on the top port (because of venturi effect or the like)
 
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JohnDaviz

Sergeant
Jan 6, 2019
281
People aren't adjusting it on the fly for stock turbos / upgraded twins though, so I don't see a real difference in how it is handled once you go ST. That said, on the fly adjustments are on the table for MHD :)
I would recommend keeping the DME in control of WGDC whenever possible. There's quite a few current and future things you EBC users are going to miss out on, like a separate tuneable wgdc setpoint during anti-lag / NLS / 2-step, as well as on the fly load/boost target switching.
Just curious. Is this going to happen or are there issues that killed the idea?
 

shushikiary

Corporal
Jun 4, 2018
160
Found the problem.

Thanks to Cruizinmax for suggesting what the problem might be.

I have an intake setup where I run 2 cone intakes in the bumper with an M3 style pumper. uses parts of the STETT CAI, which helped reduce my IAT's a lot in the summer as the engine bay just gets so hot. So I didn't want to run a straight filter sitting in the hottest part of the engine bay. The intake though was using string
impregnated silicone (5 layer), at 3 inch diameter for some sections of it. This tubing was collapsing under the MASSIVE vacuum this turbo creates, even though it goes to 2 cone filters that are the same as the ones people normally use but with 3 inch ID holes for the pipe.

I put a filter straight on the intake and the problem went away. So I'll be switching to aluminum tubing.
 
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