So.... my pfc used to control boost pretty well. Not so much lately. Today I read through the commander guide and adjusted my boost setting and wastegate cycle. boost was set to .75kg/cm on all marks. duty cycles were 58, 66, 64, and 72%. on a third gear WOT pull fully warmed up my boost went to .94kg/cm. (boost gauge indicated 14+ and the moment i looked) Thats not quite right.

so i set my boost down to .75kg/cm and 54, 62, 60, and 68% 4th gear WOT pull .82 but not stable.

mods: PFC, cheap *** intake mod, poor mans nonsequentials, downpipe, 3" cat, cat-back.


how do i need to set up boost control for stable boost at .8-.85

 

Start with boost setting 1:
You keep playing with the "%" for #1 and #2 turbos untill you get it like you want.

Then start on boost seting 2.

If your transistion from #1 turbo to "#1 + #2" turbo dips or spikes, then you need to place a pressure control valve in the line between the #1 turbo outlet nipple and the pre-control actuator. This will require you to also remove the jet in the same hose (older FD) or drill out the hole in the nipple (newer FD).
This jet/hole acts like a fixed pressure valve.

I recommend just going with a good EBC which a feedback circuit to kepp boost constant between seasons.

 

I'm on poor mans so i don't have any transition. does the % go up or down to control boost? The PFC commander manual states that you raise it when you raise the boost. I did that and boost went to .2kg/cm higher than i wanted it (and it was set).

Ultimately i will be going with an EBC, but i want to get some other things first.

 

Really, the boost amount is how much boost you want to run, and the percent is the starting duty cycle. If you're overboosting your target boost, you need to bring the duty cycle down.

Basically, when you get on it, the percentage is how "closed" the boost controller will be to spin the turbos up. The PFC will then adjust the duty cycle to try and maintain your desired boost level. But, if your duty cycle start is too high, it will overshoot and the PFC can't put boost where you want it. You have to bring it WAY down from there.

By the same token, if boost takes forever to hit your target, you need to bring the duty cycle up.

Long-term, a real boost controller is the way to go, but you should be able to get some life out of the PFC's boost control. At a certain point, it's possible you'll get secondary turbo spikes that won't go away - that's when you have to either drill the precontrol pill out or play with a manual boost controller. That's the sign that you need a better boost controller .

Dale

 

Sorry, I did not read your mods list for this HIDDED info.

Have you turned the SEQ TURBO CONT switch off, and tried it that way since you are non-seq? I do not know which duty cycle % will control non-seq, so set both of them to the same value and EXPERIMENT.

I never liked the stock OEM boost control system and went manual BC and also non-seq before the PFC was available, then went seperate EBC with the PFC.

 

Well that explains it. The manual says to increase the duty cycle when you increase boost (i can understand why- i guess). But when I increased the boost target and the duty cycle i was setting my car up to overboost quickly.

Btw- i'm on poor mans nonsequentials.

 

One last thing- what are the Primary 1 & 2 and Secondary 1 & 2 settings? Or rather how do they work?

 

Pages 27 & 28 of the PFC manual and Section F of the Mazda manual.

Two boost control settings. That allows a click of the button to run two predetermined different boost levels.

Primary and secondary: it was designed for seq turbos. #1 turbo is primary, #1 & #2 turbos together is secondary.

 

What button?

 

"metaphor"

 

In theory, you can actually hook a switch up to the Datalogit to switch between the two boost settings. It's in the Datalogit manual - dunno if anyone's actually tried it. If you're at the point where you're looking to hook up a button, you've probably already got a real boost controller .

Dale

 

^ Dale, do you know if it's possible to do this with a single setup? I don't have a datalogic and would like to have a valet boost mode switchable on the fly. I know there are 4 settings for the twin sequestial setup but i'm not shure if it's still posiblle to use the second boost setting with a single. What would be even better would be to switch maps then I could go to race boost on the fly.

 

Man, the PowerFC's boost control is just a poor idea with a single. With an external wastegate, use a real boost controller that can properly control it.

External wastegates have 2 vacuum line ports for full control of the wastegate. If you just use the bottom nipple, you're throwing out a lot of the functionality of the external.

That said, if you have a good electronic boost controller, it's easy to wire up a switch to kill power to the boost controller. With it off, you get whatever boost the wastegate's spring is at. Not to mention most electronic boost controllers will let you switch between 2 boost settings pretty easily.

Dale

 

Set your rev limit to 3000 and take the commander with you. Takes like 10 seconds.


External Commander Connector

 

^ that's an idea, thanks.

PFC w/boost kit IS a "real" boost controler and as a matter of fact it's an electronic boost controler. Electronics are in the PFC itself. Works the same as AVCR and Greddy which both use the exact same Nipondenso solenoid. I don't remember there being two vacuum lines on my Tial, will have to check it out.

The only thing i'm loosing out on is dual boost settings but I still wouldn't be able to switch maps on the fly, so I guess it still wouldn't work out. What I need is a mini laptop in the glove with datalogic.

 

Check out the new t-5 toughbooks. We're getting them at work and they are secks! You can also get used tablets on E-bay for dirt cheap. You won't get switch on the fly but you could change it at a stoplight or have a passenger do it.

 

Ah, no it's not a real boost controller . It's damn close, though, but there's no setting as far as I know to control an external wastegate. Every electronic boost controller I've seen required you to change something (flip a dip switch, set up in the menu) that you were using an external.

I guarantee your Tial has two nipples. This gives you very fine control of the wastegate - you can introduce pressure above and below the diaphragm to give much better control of the wastegate's actions.

Not to mention the boost control kit costs about as much as a Profec B!

Dale

 

The settings to change are on the PFC. Twin turbo setting is internal gate and single turbo setting is external gate. There's also some optional boost kit settings. The solenoid uses the OEM wastgate plug. The charge/pre control plug is left unpluged. There's no dip switches. It's controlled by the commander and datalogic software. You change change the boost level with the commander. But that's assuming you have tuned to the higher of the two levels. It's certainly slow to do compaired to fliping a switch though. The optional boost kit cost about $350. I would imagine other electronic kits are > $500, no?

 

I have a somewhat related question; apologies to the original poster, if you think this is inappropriate, mods please move it.

I use the Apex'i 3Bar MAP sensor but *not* the boost control solenoid on my 1JZ Soarer, which natively has no factory boost control.

I found that in order to select Apex'i Pressure Sensor in PIM Voltage and have the idle, etc running properly, I had to concomitantly set Boost Control Kit to ON in the Options menu, even though I don't use the solenoid. If I try to set Boost Control Kit to OFF, then the idle goes to absolute **** until I return the PIM Voltage option to Normal.

Is this normal behaviour (intuitively I think it is) ? If so, are there any detrimental effects to letting the PFC think it has boost control, when in fact it does not ? If it ISN'T normal, are there any other settings that I need to alter in order to use the 3Bar MAP sensor on its own ?

Thanks for any advice.

 

Would the optional boost control kit worth with non sequential? (sorry if the question is dumb)

 

"work" with non-sequential? probably. though for the price of the boost control kit you could get a stand alone EBC that would probably perform better. My pfc is notorious for inaccurate boost readings. it'll display .60kg/cm when my DEFI gauge is reading 10lbs- that's a difference of nearly a pound and a half.

 

^ I think that's misleading. It's possible your expensive Defi gauge are off. My autometer reads 1.5lbs too high. Mine is easy to know this because when the car is off it rests at 1.5lbs. Your Defi should recalibrate if it's electronic but being expensive doesn't ensure it's more acurate then the PFC.

The only reason to get the kit with the twins in parallel would be if you were over 16lbs which is the limit for the 2-bar map sensor. Unless you have BNR or Knightsports twins, then there is no reason to go over oem efficiency of 14lbs.

People for some reason say they had problems with the kit but never had the kit, only the solenoid. Some people think the GM map sensor and the solenoid = Apexi kit but it does not either.

Alot of people keep mixing up the PFC boost control with the optional boost control kit.

 

^If you search it has proven that the PFC reads low, when it reads boost. Chuck, I believe, actually found out the voltage read from the MAP sensor is correct but the output on the commander/datalogit is lower than the given boost. He has tested more than one guague and they read basically the same thing. My boost also gauge reads between 1-1.5psi higher at 15psi than my PFC.

Trust the Boost Gauge not the PFC, that was a major point he made in his thread.

I think this is the thread. I didn't reread it totally but from what I did it looked right.

https://www.rx7club.com/showthread.p...fc+boost+gauge

 

Yeah, i've read the old thread before. No updates on it. I know on my last tune the datalogit showed .9 and my commander shows .89. Not much difference to me. Is everyone in that thread using a mechanical gauge? I know my Autometer is off since it rests on almost 2psi. Has anyone compared with a digital boost gauge? What about comparing with an electronic boost controller? Are you using a mechanical gauge as well?

 

I'm using a mech. Autometer gauge also, mine reads 0 at rest, it's fairly new. From what I can tell it seems the more boost you run the more difference you get between the gauge and the PFC.