ApexRX7

I just looked at RP's web site and it only mentioned that it can control the fuel and ignition? What about boost control?

PSUR1

I am using the Power FC to control my boost (14PSI) and I'm having no problems at all. I believe that there are some limitations to what the Power FC can control as far as boost, not really sure what they are. I have no problems with creep or spiking though, and 14 PSI is plenty for me right now, especially on the stock turbos.

spyfish007

I think many people would agree the with following statement:

The PowerFC is the best boost controller out there for the stock sequential setup. Even with a midpipe it shows less signs of boost creep than most setups.

GoodfellaFD3S

iTrader: (213)

I've been using my Profec B to control boost...how does the Power FC interact w/the Profec? When I go w/a midpipe, it will still work well against boost creep, right?

Johnny

It controls boost up to 1bar...and very well for me I might add. anymore then that and they recommend the boost control kit.

Johnny

evot23

iTrader: (17)

It's my understanding that the Profec B will override PFC for boost control.

Is this correct?

newRX7fan

iTrader: (1)

I had problems with the PFC controlling boost- the boost level would move up and down, like from 10psi to 14psi and back. This only occurred when I increased the boost level- it worked fine when set to stock boost levels.

I installed a Profec B and things work fine now. The PFC still controls the turbo transistion, and also the primary boost (I think), but the Profec controls the boost when both turbos are going (through the wastegate actuator if I remember right).

fluxen

So, I've been using a manual boost controller, and I've just gotten my commander. Now that I have it, can I just remove the manual boost and pre-spool controllers, put in hoses w/o pills, and let the PFC control it? TIA.

atihun

You will need to have the stock pills in the hoses for the PFC to correctly control your boost. But it does control it very well.

GoodfellaFD3S

iTrader: (213)

...on the highway at about 75 or 80 mph, dropped into 4th and floored it. Revs went from ~4k to ~5k...and *no* spike at transition. None! held 12 on my boost gauge (so around 10 on my commander) the whole time.

Is this good or bad??

fluxen

Atihun - Thanks for the info.

Goodfella - That's not good or bad, that's GREAT! Are you running stock maps, and using the PFC to control your boost? TIA

atihun

Apexi did a nice job of removing the transition spike, so as you have a nice power curve and the appearance of a single turbo.

At first I didnt like it too much because it was like getting a second kick in the pants, but the car is actually faster without the drop and spike.

Leadfoot

OK, here's one for you --- when using the FC to control boost, it isn't enough to just change the boost level, but you have to change the base duty as well. ok, the manual is pretty non-existant for info, so, does anyone know what the base duty % should be to get a desired boost level?

The manual has:

#1
Pr .80kg 56% (11.428 psi)
Sc .70kg 64% (10.0 psi)

and

#2
Pr .90kg 62% (12.857 psi)
Sc .80kg 70% (11.428 psi)

(using 1psi = .07kg/cm2)

So what is the calculation to figure for Pr and Sc % numbers when wanting to change boost.

If you use #1 as a base, then 14 psi = .98kg with 68.6% for Pr.
but if you use #2 as base, then 14 psi = .98kg with 67.5% for Pr.

these figures are fairly close and the man. says that "if the base duty [%] is not exact, the unit will compensate during driving and correct the difference."

So if you wanted 14 psi, your setting would be .98kg with 68% on Pr?

and 12 psi (.84kg) with 76.8% Sc (#1), and 73.5% Sc (#2)?


anybody work this out and what #'s did you get ? (my math sucks so I could be way off)

spyfish007

Your duty numbers are going to have to go WAY up to reach 14 psi. It really comes down to your mods and how efficient/how fast your turbos make boost. To tune your boost set your boost level and then slowly start cranking up the duty cycle while making runs. To a peak and hold on the monitor page with like boost & rpm. Do this in several gears and even graph it. Look at the peak number for boost and see if it is close to what you set. I was setting mine at mid 80% when getting 13 lbs or so of boost. You can't turn it up past 90% so remember that when you can't get anymore boost. If you want more boost you will have to insert smaller brass pills in the wastegate line.

Any aftermarket boost controller will override the PowerFC. It is simply trying to act like the stock system. I gave a long write up in the 3rd gen forum not too long ago on this very topic. I took a few short cuts (meaning various explanations) when writing it, but it is very close and pretty descriptive.

Leadfoot

Spyfish,

thanks, i missed that post and it won't come up under a search. What I am really wanting is a 12-12.5 boost on the high end, or rather a 12-10-12 type of thing instead of the 10-8-10. So I guess it would be a .84-.70-.84 are you getting close to those numbers with the % on your maps?

One last one -- -- since the boost on the FC is more accurate than an aftermarket gauge(so I have been told), is the temp reading on the FC also more accurate than an aftermarket gauge? I am figuring on using just the FC to meter that info instead of installing anything else, and keep the cabin cleaner looking. what do you think?

Dolomite

Just to make sure I understand this correctly... please advise me if I am wrong:

The PFC's boost controller duty cycle has nothing to do with the injector duty cycle. From what I gather, it is a solenoid duty control cycle. It controls how often the solenoid is "actuated" in its operation? If that is the case, we would ideally like to use the lowest number possible (yet high enough so that it will properly control our boost levels)?

So, if that is the case we don't have to change the duty cycle, we just need to make sure that ends up being compatible with our boost setting, no?

Leadfoot

My understanding is that you can input any (almost) number you want into the boost level, but nothing will change unless you change the base duty %.

The manual says:

"when changing the desired Boost Level, please change the Base Duty"...because..."the selenoid valve duty must be changed in order to achiece desired boost levels"..."the duty cycle required to hit a certain boost level is usually determined by the wastegate spring".

Does that help?

Dolomite

Not really. We all know what the manual says, but I am trying to figure out what the duty cycle represents. Hopefully not just some arbitrary numbers to accompany the boost levels.

Anyone know?

spyfish007

Ok ideally you really want a 12-12-12 boost pattern meaning a perfect linear boost pattern. With the PowerFC you should get close to this pattern -- at least in feel. The discussion of boost was in this thread ..... https://www.rx7club.com/vforums/show...threadid=10616

Like I said I take a couple of short cuts in my explanations but the ideas are what count. The powerFC will try to hit the boost level you set ... 0.80 etc but you have to be near that level with the dutcy cycle. The default setup worked really good for me. I have since gone non-sequential and I am using a bleed valve and the duty cycle to control boost.

The injector duty and boost duty are TOTALLY DIFFERENT! The duty cycle for boost represents % time of solenoid open . . and that means venting boost pressure and not allowing wastegate to open.

And lastely . . stock sensors are ok, but if you add an aftermarket guage then add a new sensor and you will have a better setup. The stock sensors don't really move/respond very quick. Also maps have nothing to do with boost control. Just fuel and timing is all the maps are for . . . .

SleepR1

I'm confused because the wastegate vents the boost pressure. If the wastegate is not allowed to open, the boost pressure builds, and you get boost creep, or do I have this *** backwards?

93BlackFD

my boost gauge (autometer) is registering 10psi, and i stare at my PFC and it says .80kg/cm2, should i be replacing my map sensor?