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Discussion Starter #1
I searched and searched and sadly cant find anything that is clear to me, and take it easy on me, i'm learning all this as I go.

I'm trying to setup the map control on the Holley Dominator in my 69 camaro.


Some background:

427LSX
Twin GT35R (62mm)
A2A intercoolers
T56 Magnum

Boost control method:
Single Solenoid
Manifold pressure reference
Dual Tial MVR (44mm) WG.

I have been running boost by speed, duty cycle based only.

I have now selected the MAP control and have taken multiple logs per the boost control instructions at 0%,10%,20%,....60%. WG spring currently is 6.5-7psi. Obviously with turbos this size it hit very early, at 0% it's VERY stable. As i increase the boost it has a spike/wave in the boost plot through a 3rd gear RPM pull.

I'm building the Map Control table but it doesn't seem to follow the same trend that the one in the example. Does anyone have any advice on this or do you have any experience with this method with single solenoid? I have plotted the "curves" for these duty cycles per the Holley instructions, as Boost PSI x Duty Cycle for each RPM.

I am planning to change the spring so understand that I will need to re-plot these duty cycles, but trying to get my head wrapped around this first while the boost is "safe" for the engine and shouldn't be any surprises.

These are the plots i took while at the track, including a couple "full passes" at the end. All the data logs were 3rd gear pull from ~2500 to 7000rpm.
0% Duty Cycle:


10% Duty Cycle:


20% Duty Cycle:


30% Duty Cycle:


40% Duty Cycle:


50% Duty Cycle:


60% Duty Cycle: Showing this one to see the steep incline in boost. I had a boost safety set at 17.5psi for 1.5s, and you can see it did it's job, and exactly 1.5s it went -100% DC and the boost came off quickly.


Sadly I didn't make any more data logs as I was starting to have some clutch slave issues (not fully disengaging).
I did log two full passes that I made as seen below:

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Subscribing so I can learn as well, but also to say that is one hell of a car! (y)
 

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Beautiful car! I don't have an answer to your spike question, but looking at how well the car is built, when Holley recommends dual boost control solenoids, why would you run a single? Are you using compressor charge to run your boost control? C02? What plugs, and what are they gapped at? I run a 7 on the street with 91 (7 psi gapped at .025) , and an 8 at the track with C16 (23 psi gapped at .023).
 

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Discussion Starter #5
Subscribing so I can learn as well, but also to say that is one hell of a car! (y)
Appreciate it and I’ll get it figured out one way or another and post up here is the answer isnt here. Seems like no one has done this. I get there are better ways to control but this is what I’m working with and unless it’s just impossible to do, I don’t plan to change the control method.

And thanks for the compliment on the car. Its got a ways to go but it’s staying with me forever so I got time.

GOT TO LOVE THAT MPH
Absolutely. More power on the table and definitely more improvements on driving to be had. Can see in the logs shifts were slow. Had one chance (turned to two back to back runs) to try and get a decent time so wanted to be sure I didn’t botch a shift or a launch.

 

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Discussion Starter #6
Beautiful car! I don't have an answer to your spike question, but looking at how well the car is built, when Holley recommends dual boost control solenoids, why would you run a single? Are you using compressor charge to run your boost control? C02? What plugs, and what are they gapped at?
When I bought all the holley stuff I had solenoids and sensors to run dual and dome pressure. I always planned to use manifold pressure as I didn’t want to rely on getting a c02 tank filled. Yes I know that’s easy, just a weird quirk in always wanting the car to be the same (like why I’ve never run nitrous. What if it’s low pressure of out).

Place that built the kit said he recommended single solenoid for all the street cars for simplification. So I went with it. Definitely an experienced person and shop so I definitely trust that recommendation. End of the day I want better control doesn’t need to be perfect. It’s a jack of all trades master of none sort of deal.

Plugs are NGK B8EFS (1049) gapped to .021”
 

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Discussion Starter #7
Also worth mentioning the car runs e85 full time pretty much. Has flex fuel sensor and tune can adjust for it, just never do.
 

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I also started out running my pressure source from the turbo, so I get the simplified street car approach. I switched to C02 when we started chasing numbers at the track. The C02 allowed for faster, more accurate tuning changes as the boost control solenoids see a constant 60 psi, not a fluctuating source. The 5lb bottle has been in the car going on 3 summers, and still has 400 psi in it. I do not run C02 on the street. Just spring pressure. It appears the "noise" seams to be consistent at the same point of the pass. I encountered a noise related issue after adding a drive shaft sensor over the winter a few years ago. The harness that was built for the sensor was made from what we had here. It did not have a drain for the ground. We remade the harness and the "noise" went away. Just a thought.
 

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Discussion Starter #9
I also started out running my pressure source from the turbo, so I get the simplified street car approach. I switched to C02 when we started chasing numbers at the track. The C02 allowed for faster, more accurate tuning changes as the boost control solenoids see a constant 60 psi, not a fluctuating source. The 5lb bottle has been in the car going on 3 summers, and still has 400 psi in it. I do not run C02 on the street. Just spring pressure. It appears the "noise" seams to be consistent at the same point of the pass. I encountered a noise related issue after adding a drive shaft sensor over the winter a few years ago. The harness that was built for the sensor was made from what we had here. It did not have a drain for the ground. We remade the harness and the "noise" went away. Just a thought.
Yea definitely appreciate the comments and info on c02. I agree it’s a superior system, my car sees the track so infrequently that I just don’t see it making sense (In 3 years I’ve been to the track 4 times and only once on a drag radial). I can see getting caught up in chasing numbers for sure. Thats why I made my second pass, “I’m so close to 9s let me try again!” Ultimately however it’s just a fun street car.
What is your advice for the “noise?” Appreciate that comment as I’ve noticed it has the roughness in the data log on other passes and has been on my “to do” list for a while. Can’t feel that noise in the pull, either by my own inexperience or how minimal it is. My harness is straight from Holley, I modified for everything. The VSS is an added wire to the factory t56 magnum VSS.
 

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Yea definitely appreciate the comments and info on c02. I agree it’s a superior system, my car sees the track so infrequently that I just don’t see it making sense (In 3 years I’ve been to the track 4 times and only once on a drag radial). I can see getting caught up in chasing numbers for sure. Thats why I made my second pass, “I’m so close to 9s let me try again!” Ultimately however it’s just a fun street car.
What is your advice for the “noise?” Appreciate that comment as I’ve noticed it has the roughness in the data log on other passes and has been on my “to do” list for a while. Can’t feel that noise in the pull, either by my own inexperience or how minimal it is. My harness is straight from Holley, I modified for everything. The VSS is an added wire to the factory t56 magnum VSS.
This is what I changed to on my "suspect" harness's. It is 4 wire, but the 5V sensors only require 3. The braided drain with the eyelet (eyelet gets removed) gets connected to your holley ECU ground wire. Once I encountered this issue, I switch any sensor I had made a harness for, to this style wire. That would be FPR sensor, pressure sensor on the gate, and the driveshaft sensor.
88035
 

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Exactly how do you have the gates/solenoid plumbed ?

IMO do one solenoid per gate, and blow into the bottom chamber only for simplicity

The spike you see each time shouts to me like a gate control plumbing issue, or far too long hoses to the gates, which is why a solenoid per gate with very short hose runs is preferred.

And stick with a simple boost table until you have it doing what it should.

But building any base table is simply trial and error.
 

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Discussion Starter #12
Exactly how do you have the gates/solenoid plumbed ?

IMO do one solenoid per gate, and blow into the bottom chamber only for simplicity

The spike you see each time shouts to me like a gate control plumbing issue, or far too long hoses to the gates, which is why a solenoid per gate with very short hose runs is preferred.

And stick with a simple boost table until you have it doing what it should.

But building any base table is simply trial and error.
Currently i have a single solenoid pressure referenced off the back /bottom of the intake manifold:


Has a line that runs to front of valley cover and tee's to each Waste Gate BOTTOM:
Seen here the longer stainless line from the intake. That goes to the solenoid above.


Top of the gate is left vented, solenoid adds/removes pressure on bottom of the WG via the manifold pressure source.

The waste gate flow is setup:


I agree with simple boost table, using boost by speed and solenoid duty cycle, but trying to use the base duty cycle to help control that spike. If i'm understanding correctly that's what it SHOULD do, and seeing the 60% log above where it has boost safety triggered, it shows me that it is capable of bringing the boost back, and quickly.
 

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It's a beautiful install...but functionally poor.

The solenoids should be as close to the gates as possible. Hose runs should be as short as possible. IMO, take the supply port from the compressor housing, the intake is the least ideal place IMO whether others like it or not.

As said, the spike you are seeing is classic symptoms of everything I've said.

As for any perceived safety measure, overboost protection needs to be in the form of a fuel/spark cut. It's pointless having overboost protection, that is reliant on the boost control system actually working, because if some aspect of it fails, then it would be rendered useless.

Now yes, many people do deviate from all of the above, and some can work fine. But a 427 with relatively small turbos, and very fast spool.....are even more reasons why control plumbing needs to be correct.
And although difficult to judge size on the picture, the lines to the gates also look relatively small too.

All in all, IMO you've built in the spike with the configuration.
 

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Discussion Starter #15
It's a beautiful install...but functionally poor.

The solenoids should be as close to the gates as possible. Hose runs should be as short as possible. IMO, take the supply port from the compressor housing, the intake is the least ideal place IMO whether others like it or not.

As said, the spike you are seeing is classic symptoms of everything I've said.

As for any perceived safety measure, overboost protection needs to be in the form of a fuel/spark cut. It's pointless having overboost protection, that is reliant on the boost control system actually working, because if some aspect of it fails, then it would be rendered useless.

Now yes, many people do deviate from all of the above, and some can work fine. But a 427 with relatively small turbos, and very fast spool.....are even more reasons why control plumbing needs to be correct.
And although difficult to judge size on the picture, the lines to the gates also look relatively small too.

All in all, IMO you've built in the spike with the configuration.
Although I will add further.....based on the photo of the solenoid. Is it plumbed like this ? Because I'm not seeing that it is ?

That too could be a cause of your problems. ( your gate flow itself is all good, I'm solely referring to control configuration. )

Thank you for your responses Stevieturbo, you're one of the ones whose comments/replies i've read in other holley efi threads and was hoping to get a response.

What would you consider on the solenoids to being "close." Curious where i could put it the solenoid in a proximity that would fit that definition. As for the compressor housing, i'm positive that is idea, but would that be the root of the spike issue? Understanding that the manifold sees more pressure fluctuation based on TB position.

Overboost i mentioned is just a safety i had in place to keep my "blind guessing" at duty cycle and respective boost pressure at bay. My example i gave was showing that when the safety was triggered, the DC going to -100% managed to drop the boost pressure, ie the Wastegate priority flow and response to the fast spool can be countered. Not saying that is the best method of maintaining safe engine operation or the only way. I have a cut ignition safety for a bit higher than that (24psi).

On the line size i'd have to check to be honest, been a while. What is recommended size if i end up moving things around?

As for the solenoid configuration currently. Below is how it is configured. Pressure source (manifold) is to port 3, vent is on port 1, and wastegate is on port 2.
89243

The Diagram you have above looks like vent same place but the pressure source and WG are switched from how mine is.

After your discussion and talking to a few others about this, I think i'm just going to break down and go dual solenoid. Playing with the holley a bit with this option it seems just too simple NOT to do it this way...Wish I would have from the start and could have saved some wiring time.

As I see it the resolution should be something like this:
Mind the crude drawing: Compressor discharge to bottom port of Wastegate directly.
89246


Re-plumb the solenoid "supply" line to the gate to the top port as per crude pic below(added area in RED)
89247


Run dual solenoid configuration at the front of the valley cover, with supply STILL from manifold, same location as solenoid is currently (not best but should improve my control performance greatly). I was thinking put the dome sensor in the solenoid stackup in one of the "plugged" ports. Crude drawing below:
89254
 

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A fill and vent arrangement is more for a co2 based system or high pressure air.. I'd doubt it would offer any benefit with a boost fed system.

That is not what I'm referring to with a 2 solenoid setup. I simply mean 1 solenoid per gate, so you can eliminate long pipe runs which can cause delays in response of control...one factor that can lead to spikes

And also noting Turbosmarts listing of plumbing for the solenoid ports, so yours with the MAC would be correct. That other drawing I plucked online must use a different solenoid or something

ie.
 

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stevie is offering good info.
but something to keep in mind, the duty cycle probably needs to change with rpm. I have an evo, so its a single turbo 2.0 but it has a rpm based duty cycle table and i typically will have a hump shaped table, where it comes up, peaks then starts tapering down, which results in a flat, consistent boost curve. the shape of your table will be determined by your overall combination, but i wouldnt anticipate it being flat like your logs show.
good luck, your engine bay is beautiful.
 

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Discussion Starter #19
I think after all this discussion i'm going to change it up and try something different with it. I'm going to TRY to run dual solenoid off MAP, in a top fill case, and see what that does. And if not satisfied with the results, it's easy enough to bring on onboard air system (not as efficient as CO2 i'm sure, but it stays filled).

Have the solenoid coming, distribution block, dome sensor, etc. Will look to pull intake and setup the wiring likely later this summer. Gotta wait for it to be good and miserable in my small garage to be motivated enough to do it.
 
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