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There are a lo lot of in depth and lengthy threads about this. Many of those threads seemed to stop short of anything definite. There Probably is no real solid answer.
I am still a bit confused of what the WG setting does. You have a target boost for primary and secondary. The PC basically spools the primary and how I understand it is the WG will be like the PC on the secondary. How the secondary will spool.
Since this is such an old topic I was just curious if there is any better understanding today than 10-15 years ago.
There are a lo lot of in depth and lengthy threads about this. Many of those threads seemed to stop short of anything definite. There Probably is no real solid answer.
I am still a bit confused of what the WG setting does. You have a target boost for primary and secondary. The PC basically spools the primary and how I understand it is the WG will be like the PC on the secondary. How the secondary will spool.
Since this is such an old topic I was just curious if there is any better understanding today than 10-15 years ago.
i just got a PFC, so i've been reading a bunch of Arghx's threads. so it works like this, we think.
the boost is the target boost, pretty simple. if you had a perfect car, turning it to 0.85 you would see boost of 0.85
the boost cut is 0.25 kgcm above the set boost. also pretty simple.
the duty value is the starting solenoid duty cycle, the ecu will take the value you set, and then it has a small window to try and get boost to the target. this one i think you just need to play with. its going to depend on the actual setup.
in theory the primary vs secondary is the pre-control vs the wg. on a twin turbo car that is probably good enough, i think in reality it may be RPM based, and or there is something else going on, as Raymond had a single turbo car running from the WG solenoid, and Banzai Racing uses the precontrol and they both work.
the PFC is kind of a weird mix of simple and complex, plus its in weird units, i made myself a little spreadsheet that does the simple calculations like kg/cm to the PIM value.
also unproven is how the PFC does atmospheric corrections. the old guys always complained that the PFC reads different than the boost gauges, but i think the PFC is correcting to atmospheric pressure, and i think it just takes a reading when you turn the key (common, like everything else), and uses that as 0. again unproven, but might explain why the logged numbers move a little vs the fixed numbers in the maps.
With traditional electronic boost controllers (like the Profec-B) you have a target boost and a duty. This is similar.
You set a target boost - say, .85 kg/cm2. That's how much boost you want to run. The duty is a start duty point for the solenoid. So, if the number was 0-100, if you set 25 it would start at a 25% duty cycle which means it's closed 25% of the time.
Typically you fine-tune that number looking for the sweet spot. If the duty is too low, the boost will take a while to hit your target and the car will be laggy. If it's too high, you will overshoot or overboost. Hit the sweet spot and you get fast response and steady control.
I can't remember how the PFC handles the primary/secondary thing with the 2 different duties. I think it just simply uses one before transition and one after, that's it.
I use an Apexi AVC-R boost controller and love it. Set up boost by gear and RPM and it self-learns the duty cycle. I also have it set so if my water injection tank runs out it basically sets boost to the minimum it can do.
While it's good the PFC can control boost I've never been super happy with how well it works. IMHO it's a very basic setup, you can make it work and work well but it's cumbersome.
i just got a PFC, so i've been reading a bunch of Arghx's threads. so it works like this, we think.
the boost is the target boost, pretty simple. if you had a perfect car, turning it to 0.85 you would see boost of 0.85
the boost cut is 0.25 kgcm above the set boost. also pretty simple.
the duty value is the starting solenoid duty cycle, the ecu will take the value you set, and then it has a small window to try and get boost to the target. this one i think you just need to play with. its going to depend on the actual setup.
in theory the primary vs secondary is the pre-control vs the wg. on a twin turbo car that is probably good enough, i think in reality it may be RPM based, and or there is something else going on, as Raymond had a single turbo car running from the WG solenoid, and Banzai Racing uses the precontrol and they both work.
the PFC is kind of a weird mix of simple and complex, plus its in weird units, i made myself a little spreadsheet that does the simple calculations like kg/cm to the PIM value.
also unproven is how the PFC does atmospheric corrections. the old guys always complained that the PFC reads different than the boost gauges, but i think the PFC is correcting to atmospheric pressure, and i think it just takes a reading when you turn the key (common, like everything else), and uses that as 0. again unproven, but might explain why the logged numbers move a little vs the fixed numbers in the maps.
Most of Arghx's info passed on was based on single from what I saw.
The transition portion is what interests me. The WG setting for the secondary. I am pleased with my #1 setting. I just need to play with my #2.
This is why I was curious how some others have theirs set.
Everyone's pfc needs to be calibrated from my understanding. Without doing so it will never read the proper pressure.. I am sure most are within a very close proximity so it isn't much of an issue.
I AGree Dale. I think I would be best off logging it and looking at graphs, but I am not sure how to set it up yet, but I will find out.
Just curious as to how others have handled this.
My car is night and day now compared to before. Speaking of turbo transitioning, but I know there is still room for improvement.
BTW there are 2 boost control settings in the PFC you can toggle between, that's the 2 settings you see. Basically you can set one up for low boost/everyday driving and one for high boost/race track. Whichever one is highlighted in the Commander is the one the PFC is currently using.
The turbo transition points can be lowered. IMHO Mazda designed the car with the transition dip solely for marketing - you test drive the car, feel the power ebb then the second turbo hit, the sales man says "boy, feel that 2nd turbo kick in!" and you buy the car.
I lowered my transition points ages ago and I have ZERO dip at changeover, just solid boost from 2000 RPM to 8000 RPM. That's the way it should be. It doesn't take much, just a few hundred RPM.
Everyone's pfc needs to be calibrated from my understanding. Without doing so it will never read the proper pressure.. I am sure most are within a very close proximity so it isn't much of an issue.
i think this is why, although some testing is needed. i think the PFC (like most stock ecus) take the pressure reading with the key on engine off, and uses that as barometric pressure, really common. i do wonder if the PFC just makes this number zero, which would make the it look like the calibration is off. its the only thing i can think of that makes sense,
just as a for instance, the manual says absolute pressure is 1.033 kg/cm. so that would be 10000 PIMs, but if today its only 0.98 kg/cm then the whole thing is off by 0.05 in the map, but all the other values, like the boost are the same. if that makes sense
The turbo transition points can be lowered. IMHO Mazda designed the car with the transition dip solely for marketing - you test drive the car, feel the power ebb then the second turbo hit, the sales man says "boy, feel that 2nd turbo kick in!" and you buy the car.
Dale
It's also going to be hard to share settings. It's going to be very dependent on what exhaust you have, the health of your ignition system, the health of your turbos, etc. etc. A whole lot of factors tie in here.
Best bet is to start low, like 40, and go up in increments of 5. May want to dial one turbo in first then the other.
Come to think of it, I don't know if anyone has really done this level of adjustment with the PFC. Most times I think people may just stick with the defaults or something.
I was getting spiking on #2 setting so that's what prompted me to start playing around.. Makes sense that mods would play a huge role. Not sure why anyone would keep the factory settings unless it is where they want it obviously.
I like a bit of spike on the #1 as said before it hits hard then settles back. #2 was making me a little nervous as I am getting the boost up there a bit more and don't want it spiking into 16+, but I don't mind it touching 15. I will keep playing with it until I get it dialed in the way I like it.
# 2 hits around 14.6 settles on 14 dips to about 13 and slowly climbs back into low 14. I will try and see if I can get it to get back to 14 a little faster.
I've been on this forum so long I basically have to google myself to see what I wrote x numbers of years ago on these kinds of topics
Originally Posted by arghx
Here are the transition settings I recommend for most applications of the stock sequential twins:
The "High" values are default values in the Apex'i map. The "Low" values have been raised 500rpm based on my real-world testing.
FYI, "High" is the rpm at which the charge control and turbo control valves switch (also charge relief and precontrol) during acceleration. "Low" is the rpm at which the values go back into operation for primary turbo only operation. "Low" could also be called a hysteresis value. As far as tuning the target & duty settings, make sure you log each change. The TPS(V) refers to the Full range TPS voltage, also called VTA1.
You need to log TCN, CCN, (sensors/switches under monitor window) as well as PC % and WG% (Advance). Look at what the two boost control solenoids are doing and whether they are overshooting or unstable in their control. That varies which each car because everybody has a different level of exhaust restriction, intake restriction, porting, etc. You have to try different combinations of "Primary" and "secondary" target boost / duty cycle settings to see what works best.
Thx Arghx, I never saw that thread, but I found a godzillian others.
I haven't messed with the "Turbo transition" as I really like how mine is working. Now you have my focusing on it.
Arghx if I am tuned nice and pretty right now will I have to re-tune afr by messing with these transitions? I would assume no, but assumptions get me into trouble sometimes. My TPS settings are identical I would just need changing the RPMs.
I only ask because since I have been dicking around with this I had a 30 knock. Maybe that's just being paranoid, but I haven't seem over 23 wirh my current tune.. could have been road noise or something. I wasn't logging I just saw it as a max on the commander.
This is all very interesting. I wish I knew more about what ArghX is looking for. I have my logs that show the PC% and WG%. Assuming that is the % that it is opened. Should it be represented as an average, minimum or Max? And it looks like our transition is not far off on the low, but ~200rpm on the High side. Does this mean the primary will start the hand-off at X "low RPM" and shut off at "High RPM"?
This is all very interesting. I wish I knew more about what ArghX is looking for. I have my logs that show the PC% and WG%. Assuming that is the % that it is opened. Should it be represented as an average, minimum or Max? And it looks like our transition is not far off on the low, but ~200rpm on the High side. Does this mean the primary will start the hand-off at X "low RPM" and shut off at "High RPM"?
the WG and PC are a number out of 255, so to get a duty% you need to divide the number by 255.
so if the logged number is 100. you divide 100/255 and then if you want multiply by 100, and you get 39%
i set up a little spreadsheet with a line to do the calc for me, along with a couple of the other calculations the PFC makes you do. (boost to PIM for example)
the WG and PC are a number out of 255, so to get a duty% you need to divide the number by 255.
so if the logged number is 100. you divide 100/255 and then if you want multiply by 100, and you get 39%
i set up a little spreadsheet with a line to do the calc for me, along with a couple of the other calculations the PFC makes you do. (boost to PIM for example)
So maybe I can send over a recent log and you can explain a little more? I have tried to research the old threads, but might be beneficial to all for an updated conversation?
the PFC is weird, the setting is in duty percent, but then the log is in a random computer number, so you need to do math to go from the log to the setting. its a simple math, but still the two things should have been the same unit.
I am looking at this and trying to better understand what you guys are saying. In looking at a few other threads, I have seen completely different Low/High RPM transition numbers. Wondering if lowering them will help get into boost faster for both primary and secondary. Here is a screenshot of me not know what I am looking at and have attached a few recent logs as well as my current map. I am using Xaviers FC tweak to help me along with auto tuning the car, but curious as to the boost settings. Appreciate any feedback.
This shouldn't be too hard. 10 minutes of driving around and playing with those values on the commander will tell you all you need to know. Shouldn't have to get some crazy test method going.
the thing that jumps out at me is that the WG duty is 88%, so boost is just about as high as its going to get.
also notice that you have it set to 62 and 70, but its actually ending up at like 88 and 90+ percent?
the thing that jumps out at me is that the WG duty is 88%, so boost is just about as high as its going to get.
also notice that you have it set to 62 and 70, but its actually ending up at like 88 and 90+ percent?
So then do I need to adjust the settings higher than 62/70? The car came with these settings. Am I also able to adjust the Low/High RPM to get into boost faster for the primary and secondary. A few old threads I saw had significantly lower RPM numbers compared to mine.
So then do I need to adjust the settings higher than 62/70? The car came with these settings. Am I also able to adjust the Low/High RPM to get into boost faster for the primary and secondary. A few old threads I saw had significantly lower RPM numbers compared to mine.
so boost can't go up much more, if duty is already at 90%.
the Duty number is, in theory the duty the solenoid starts at, then it looks at the current boost, and your boost target and adjusts. theoretically having a starting duty that is low would have a slower boost onset, so it'll go to whatever boost 70 get you, and then ramp up. if you set it to 90, it might spike and then come down.
you might try lowering the target to like .9 or .95, and then raising the duty and see what happens. make small changes, and then you can bring it back to 1.0. i guess with the duty too low its a little laggy, and with it too high it get spikey. so you need to adjust, and see what it does.
if you change the rpm points, i think it does change what the pri/sec does (or i should say when), but it also changes when the turbos switch, so its a separate thing to tune.
10-05-21, 03:32 PM
