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I'm working on installing a BP kit on a HR. I have the Profec controller and a AEM wideband/boost gauge. This question is likely due to me missing some detail on the pressure/flow behavior but I am wondering the proper routing of the pressure sensor for the EBC. I have included a diagram to better show my question with the dashed lines being the two possible options. Conventionally the pressure sensor is connected to the plenum and that is the end. There are some factory turbo cars that use a pressure sensor before the throttle body to control the wastegates/boost pressure behavior and that is what caused me to wonder.
Currently to be tuned with UPREV. As soon as a boost map could be made with a standalone controlling the boost behavior this is a mute point also.
The concern is absent under full throttle and the charge pipe pressure and manifold pressure are nearly identical, but on partial throttle there is concern.
-If the EBC(@10psi) pressure sensor was connected to the chargepipe and the throttle bodies are 75% open the manifold pressure would be ~7psi with the charge piping at 10psi if the EBC pressure sensor was connected to the charge pipe.
-If the EBC(@10psi) pressure sensor was connected to the manifold and the throttle bodies are 75% open the manifold would be at 10psi but the charge piping could be much higher at 20psi, meaning a large boost spike if the throttle was quickly opened from 75% to 100%.
It seems to me that if the EBC pressure sensor was connected conventionally (to the manifold) the throttle response would be worse, with full torque arriving at the point where the turbo can produce 10psi in the manifold (60%,70%,80% throttle) rather than at the point where the throttle is completely open to the chargepipe pressure at 100%.
Obviously the intercooler, exhaust, wiring, and dual intakes are removed from the diagram for simplicity.
EBC's (and all the Wastegte/boost control components for that matter) only need pressure, so connect it pre TB, and you are good. Might be overthinking it there a bit. You can also connect it to the turbo compressor port.
Can I ask?? I'm confused? You say a pressure sensor for the electronic boost control ... is this a traditional 0-5v sensor that reads 0-100 (or whatever pressure)?? Or is this a vacuum line style pressure sensor?
Originally Posted by GreyZ
If the EBC(@10psi) pressure sensor was connected to the chargepipe and the throttle bodies are 75% open the manifold pressure would be ~7psi with the charge piping at 10psi if the EBC pressure sensor was connected to the charge pipe.
I think this is a bad assumption ... if you charge pipes are at 10psi and your TB is open beyond 5%-10% for more than a fraction of a second than pressure is equal between your charge pipes and your manifold ... you wouldnt have pressure differences between the two.
Originally Posted by GreyZ
If the EBC(@10psi) pressure sensor was connected to the manifold and the throttle bodies are 75% open the manifold would be at 10psi but the charge piping could be much higher at 20psi, meaning a large boost spike if the throttle was quickly opened from 75% to 100%.
still a bad assumption ... for the sake of simplicity, if your TBs are open more than 5%-10% for longer than a fraction of a second than the pressure is equal ...
Gotta remember that boost does not equal airflow -
Originally Posted by GreyZ
It seems to me that if the EBC pressure sensor was connected conventionally (to the manifold) the throttle response would be worse, with full torque arriving at the point where the turbo can produce 10psi in the manifold (60%,70%,80% throttle) rather than at the point where the throttle is completely open to the chargepipe pressure at 100%.
Obviously the intercooler, exhaust, wiring, and dual intakes are removed from the diagram for simplicity.
this statement makes my head hurt...are you new to turbo-charging?
Typically electronic boost control is 'conventionally' referenced pre-throttle body ... furthermore, should never see vacuum.
So yes, the throttle response would be horrible if it wasnt seeing constant positive boost pressure and/or connected to a source that saw positive pressure and negative vacuum.
I dont know how invested you are in the AEM / Greddy / Uprev ... but your life will be significantly easier if you can go standalone and bring all these features into one device ... simplify everything!
You will benefit from a vacuum block ... install a vacuum block.
I'm overthinking it, but I am also interested in it.
Originally Posted by bealljk
Can I ask?? I'm confused? You say a pressure sensor for the electronic boost control ... is this a traditional 0-5v sensor that reads 0-100 (or whatever pressure)?? Or is this a vacuum line style pressure sensor?
It is the integrated pressure sensor for the Profec controller.
Originally Posted by bealljk
I think this is a bad assumption ... if you charge pipes are at 10psi and your TB is open beyond 5%-10% for more than a fraction of a second than pressure is equal between your charge pipes and your manifold ... you wouldnt have pressure differences between the two.
still a bad assumption ... for the sake of simplicity, if your TBs are open more than 5%-10% for longer than a fraction of a second than the pressure is equal ...
Gotta remember that boost does not equal airflow -
From my current understanding, a throttle body is a restriction that controls flow by creating a pressure drop. With an ideal gas, flow is a correlation with temperature and pressure. So unless the throttle body is controlling the flow through temperature changes, then it seems that it is a pressure drop restriction. I do realize that different turbos at the same boost level can created entirely different power levels, but that is quite different.
Originally Posted by bealljk
Typically electronic boost control is 'conventionally' referenced pre-throttle body ... furthermore, should never see vacuum.
Every EBC set of instructions on generic install that I can find recommend tee-ing in to the vacuum line that runs to the fuel pressure regulator, which is a post-throttle body measurement and will see vacuum.
Originally Posted by bealljk
I dont know how invested you are in the AEM / Greddy / Uprev ... but your life will be significantly easier if you can go standalone and bring all these features into one device ... simplify everything!
I agree. 100%. The only available off the shelf option that I have seen is running the Dynosty elite 2500 as a piggyback to the stock ecu. The alternative is the Link Thunder with a custom harness patch. Both of these options are ~$3k. I am not sure at this point the cost benefit is worth it.
Originally Posted by bealljk
You will benefit from a vacuum block ... install a vacuum block.
I am open to that suggestion, not entirely sure why it would be beneficial. Could you expand on that?
I'm overthinking it, but I am also interested in it.
I would highly encourage you to be interested and invested but overthinking it and making a system too complicated will ruin your build. Just make it simple and copy what someone else did that had success.
Originally Posted by GreyZ
It is the integrated pressure sensor for the Profec controller.
I know of Profec, I dont know much about it. So you run a vacuum line from a boost/vac source to the Profec
Originally Posted by GreyZ
From my current understanding, a throttle body is a restriction that controls flow by creating a pressure drop. With an ideal gas, flow is a correlation with temperature and pressure. So unless the throttle body is controlling the flow through temperature changes, then it seems that it is a pressure drop restriction. I do realize that different turbos at the same boost level can created entirely different power levels, but that is quite different.
A throttle body is a mechanical device that restricts air flow ... aside from the small amount of time where the TB is almost close and for a very short period of time during this transition your boost in your charge pipe and the boost in the manifold are the same - there is no pressure drop.
if your TB is closed, than yes, you have a pressure difference between the two (I concede to this) ...
youre. really. over. thinking. this ... a throttle body controls airflow becasue its a butterfly valve.
Originally Posted by GreyZ
Every EBC set of instructions on generic install that I can find recommend tee-ing in to the vacuum line that runs to the fuel pressure regulator, which is a post-throttle body measurement and will see vacuum.
It will depend on how your waste gates are setup (and there is a lot of information out there).
How I understand it:
You will have a boost/vac line coming from your manifold (this is where having a vacuum block is helpful) and this boost vac line will be routed through your EBC and sent to your bottom port of the waste gate ... the EBC will regulate (via a duty cycle) how much boost is pushed into the lower chamber of your waste gate. Its a balance ... if the EBC allows all the boost to enter the bottom of the waste gate the waste gate will dump easier, and if the EBC allows no boost to enter the waste gate than the waste gate will hold longer.
You could set it up differently ... you could plumb that same line to the top of the waste gate and the results would be opposite.
I agree. 100%. The only available off the shelf option that I have seen is running the Dynosty elite 2500 as a piggyback to the stock ecu. The alternative is the Link Thunder with a custom harness patch. Both of these options are ~$3k. I am not sure at this point the cost benefit is worth it.
I am open to that suggestion, not entirely sure why it would be beneficial. Could you expand on that?
The link isnt quite $3k but I understand your point and if you can't run a standalone for emissions or whatever I get it.
At the end of the day, it will be your build that is subjected to multiple systems ... three components that are subject to failing versus one ... cost:benefit? I'm not sure how to value this.
Just google Vacuum Block ... they're inexpensive and important. Essentially its a single source where you should hook up anything that takes a boost/vac signal ... a vac block will provide a consistent signal to all your devices.
What turbo setup are you running? Do you have pictures of your build? What kind of power are you putting down? What are your power goals and goals for the car?
I think we will just disagree on how a throttle body works.
I have read through your build thread quite a few times and actually referenced your diagram when I made mine. My boost solenoid and wastegates will be plumbed identically to yours and I agree that is the best method. I am only questioning the location for the boost controller to read reference pressure, not any of the lines that go to the WG or solenoid.
I currently only have two items going to the manifold, but I like the vacuum block idea.
It is a BP kit on a stock HR. I have only done cooling and fuel pump changes so far. I have to wait for the COVID situation to settle before I can bring it to the dyno, and I am still waiting for the turbo itself to arrive from COMP. I will be making a build thread of the process when the time comes. I am currently planning on a 5ish psi and <=10 psi tune. It is a DD dyno so hopefully 400whp.. maybe. I really have no power goal in mind and am more concerned with response and reliability (within reason). Car is daileyed at the moment with 5-6 track days a year at NMSP.
I think we will just disagree on how a throttle body works.
ok... I really have to read your post (on how a TB works) with a colorful imagination. The throttle body doesnt create a pressure drop (possibly do you mean pressure difference? the TB doesnt create it, the engine, which is consuming air creates the difference) ... ahhhh f-it!!! I dont care ... But I'll let someone else chime in and explain it to me!
Originally Posted by GreyZ
boost controller to read reference pressure
anywhere between the blower and the throttle body ... you only want to provide the EBC positive pressure ... no vacuum.
not any of the lines that go to the WG or solenoid.
I currently only have two items going to the manifold, but I like the vacuum block idea.
Are you getting an oilless turbo?
Vac blocks arent my idea - they've been around for decades ...
I am currently planning on a 5ish psi and <=10 psi tune. It is a DD dyno so hopefully 400whp.. maybe. I really have no power goal in mind and am more concerned with response and reliability (within reason).
Originally Posted by GreyZ
with the 1.15 a/r.
damn man ... a 1.15ar for a 400hp 5psi daily tune? and a 500-550hp ~15psi track tune? is your block built? Do you intend to build the block?
damn man ... a 1.15ar for a 400hp 5psi daily tune? and a 500-550hp ~15psi track tune? is your block built? Do you intend to build the block?
Its a single twin scroll, so the ar is going to be higher than twins. Based on others with this kit the boost threshold is sub 3k rpm and should hit 10 psi around 4k.
I am thinking a 5psi and 10psi tune, definitely not planning anything over 10psi for a high boost tune. Its not currently built, but I realize that that time may come.
I dont want to sound like I'm 24/7-******* on you but a 1.15ar for a 5psi and a not-more than 10psi tune 'seems' big ... I run a 1.01 and Im pushing high teens/low 20psi, 600 to 700hp (god willing!)
Your threshold and 10psi at 4k rpms will also be a function of how much exhaust volume you have between the exh valves and turbine wheel and the intake volume you have between the compressor wheel and the intake valves.
if your AR is too big the exhaust gas is just gonna flow past the exhaust turbine and not spin the compressor side, right?
If you're committed, if you've already bought your blower than more power to ya! I'd love to see your build and see your progress! Prove me dumb!!!
EBC Pressure Sensor Pre or Post Throttle
. I will be making a build thread of the process when the time comes. I am currently planning on a 5ish psi and <=10 psi tune. It is a DD dyno so hopefully 400whp.. maybe. I really have no power goal in mind and am more concerned with response and reliability (within reason). Car is daileyed at the moment with 5-6 track days a year at NMSP.
