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amd is the best
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« on: February 28, 2018, 07:14:01 PM »
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Is the frequency of the boost control system adjustable in ME7? If so, what is the map called?
I am not using a factory N75 valve and am using a 3 port MAC solenoid and there are benefits to running it at different frequencies. See attached table below.
On standalone systems this is an setting that can be changed.
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2012 Golf TDI
2001 Audi A4 2.8 30v Supercharged
1991 Audi 200 20v
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prj
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« Reply #1 on: March 01, 2018, 01:26:08 AM »
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It is adjustable in the code where the PWM output is initialized.
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« Reply #2 on: March 01, 2018, 01:47:34 AM »
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In my experience MAC valves are complete crap. They suffer from instability due to engine bay heat.
They used to be popular among Volvo owners (thankfully that's changing) and always caused some sort of overboost issues. Factory valves always outperformed them.
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amd is the best
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« Reply #3 on: March 01, 2018, 03:52:44 AM »
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It is adjustable in the code where the PWM output is initialized.
Thank you PRJ. I think that’s a bit beyond me. I honestly haven’t even grasped how to open a binary in IDA. In my experience MAC valves are complete crap. They suffer from instability due to engine bay heat.
They used to be popular among Volvo owners (thankfully that's changing) and always caused some sort of overboost issues. Factory valves always outperformed them.
My experience has been the exact opposite. I’ve been using and recommending the use of three port Mac valves for many years. I’ve had them in cold and hot places with no noticeable difference in operation. Also, the factory valve isn’t capable of controlling an external waste gate utilizing both ports (top and bottom). It’s a great, inexpensive option that is readily available as well. I’ve found that they work best at a slightly lower frequency than the N75 valve though. At least in my applications. |
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2012 Golf TDI
2001 Audi A4 2.8 30v Supercharged
1991 Audi 200 20v
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_nameless
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« Reply #4 on: March 01, 2018, 05:11:07 AM »
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In my experience MAC valves are complete crap. They suffer from instability due to engine bay heat.
They used to be popular among Volvo owners (thankfully that's changing) and always caused some sort of overboost issues. Factory valves always outperformed them.
If you remove a valve that factory calibrated boost control valve and install one thats not calibrated for the setup you will without a doubt have issues like you listed (over boost, under boost etc). I do use 3 and 4 port mac valves on vag cars without issue. 70% of all stage 2 subarus ive tuned use grimspeed / mac valves over the crappy stock bleed valve |
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Giving your mom a tuneup
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« Reply #5 on: March 01, 2018, 05:36:19 AM »
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I guess Volvo’s factory turbo control valve is superior to VAG  |
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amd is the best
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« Reply #6 on: March 01, 2018, 05:47:44 AM »
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FWIW I’ve got the MAC valve working quite well in my setup but there’s a large deadband before any boost control happens then very small increments in duty change can make a fairly large difference in boost output. I believe lowering the frequency would give the PID more resolution. I’m assuming that the factory valve is running somewhere in the 25-30htz range where I might find some benifit in running between 15-20htz.
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2012 Golf TDI
2001 Audi A4 2.8 30v Supercharged
1991 Audi 200 20v
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_nameless
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« Reply #7 on: March 01, 2018, 06:01:59 AM »
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I guess Volvo’s factory turbo control valve is superior to VAG Hardly. You missed the whole point. Nick is trying to tune his mac valve to work with his setup. Really no reason not to use the stick n75 besides hes using a "quick spool" configuration and is fine tuning it for his setup. What you did / said is blindly changing your boost control valve without any regards to tuning the valve for the setup. Do you change injectors without tuning? No. Same point here |
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Giving your mom a tuneup
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woj
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« Reply #8 on: March 01, 2018, 06:32:00 AM »
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I have configured only one boost valve in my life so far (in fact, I fully programmed it from scratch, including PWM configuration and interrupt handling, on two different ECU architectures) and that was a MAC valve in quick spool configuration. Never had any issues with the valve itself, or boost control, even though it had to be calibrated from ground zero up. Did not use varying frequencies either, fixed 30 Hz IIRC. One thing to look out for though, IIRC, are the Chinese clones (I did that work 5 years ago, have not checked the market since then).
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« Reply #9 on: March 01, 2018, 07:04:42 AM »
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Hardly. You missed the whole point. Nick is trying to tune his mac valve to work with his setup. Really no reason not to use the stick n75 besides hes using a "quick spool" configuration and is fine tuning it for his setup.
What you did / said is blindly changing your boost control valve without any regards to tuning the valve for the setup.
Do you change injectors without tuning? No. Same point here
I was just saying that based on personal experience and quite a few others too. And of course I have first tried to tune it as it is supposed to be, but at some random point the behaviour changed. This was after it was tuned to. I know very well that you can’t just replace parts and expect it to work right. But as far as valves go, to each their own I guess. |
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prj
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« Reply #10 on: March 01, 2018, 11:40:16 AM »
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My experience with MAC valves is also a strongly negative one. Give me a N75 any day of the week.
I don't understand why people fit them, I would go as far as say they are not engineered to be used for boost control, there is no restrictor etc.
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amd is the best
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« Reply #11 on: March 01, 2018, 12:02:39 PM »
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My experience with MAC valves is also a strongly negative one. Give me a N75 any day of the week.
I don't understand why people fit them, I would go as far as say they are not engineered to be used for boost control, there is no restrictor etc.
There is no way to use an N75 valve in dual port operation seen in this attached diagrams. Valve in off state needs to be closed on port 1 and allow air to pass from port 2 to port 3. When the valve is on air passes through 1 to port 2 to hold the WG shut then pulses bleeding air away from the top port of the gate. |
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2012 Golf TDI
2001 Audi A4 2.8 30v Supercharged
1991 Audi 200 20v
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woj
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« Reply #12 on: March 01, 2018, 02:08:33 PM »
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Aren't N75s technically 3 port? The classic VAG one I had doubtful pleasure replacing on Golf TDI seemed to be so?
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amd is the best
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« Reply #13 on: March 01, 2018, 02:10:54 PM »
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Aren't N75s technically 3 port? The classic VAG one I had doubtful pleasure replacing on Golf TDI seemed to be so?
Yes it has three ports but, from my testing there wasn't the same flow patterns to allow it to work correctly. I don't recall as I did the testing many years ago on a different project. I'll see if I have an N75 kicking around to review what I came up with back a few years ago. |
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2012 Golf TDI
2001 Audi A4 2.8 30v Supercharged
1991 Audi 200 20v
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IamwhoIam
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« Reply #14 on: March 02, 2018, 07:14:06 AM »
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LOL this thread is hilarious
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I have no logs because I have a boost gauge (makes things easier)
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