Long-term testing with Power FC single turbo boost control
 

I've discussed my Power FC single turbo boost control setup in various threads and sections of this forum. I thought I'd start a fresh thread to discuss my long term observations after having used this setup for almost a year now. For those of you who aren't familiar with my setup, here it is in a nutshell:

PFC Single Turbo Boost Control Setup/Installation

1. Hook up a boost control solenoid to the factory wastegate solenoid plug (FD) or directly to PFC pin 4U (FC). You have a lot of solenoid options as long as you know how to hook up the plumbing. You can use the Apexi/Denso solenoid which is expensive. You can use an AEM/MAC solenoid. You could probably use a GM, Perrin, etc solenoid as long as the impedence isn't too different from the factory solenoid. Speaking of which, you can use a factory 2 port solenoid on external wastegates (I am doing that right now).

2. Run the plumbing. If it is a 3 port solenoid, just hook it up like any typical external boost controller would call for--usually with the solenoid connected to the top port on an external gate. You can also use the NO (normally open) port on a 3 port solenoid for an internally gated turbo, including FD twins/BNR turbos or FC stock/hybrid turbos. A two port solenoid can be used on an external gate as long as you have a bleeder installed in-line to relieve pressure, which I won't get into at this point. A two-port can also be used on an internal gate if it is hooked up in a bleed fashion, tee'd off like the factory 2nd gen solenoid or after the wastegate like on the FD.

3. Get a Datalogit and make the setting changes depicted on the right:

https://www.rx7club.com/attachment.p...1&d=1271741167

To make a long story short, you are tricking the PFC into thinking it's controlling boost on sequential twins (something it already does pretty well). That's all I'm going to say about that for now. The settings on the left are for tuning the boost levels.

Tuning the Controller

After initial set up, the Commander can be used for tuning although a Datalogit is useful. You've got two possible boost selections: option 1 and option 2, both of which can be selected and tuned with a Commander. You can make one your high boost and the other your low boost or cold weather option. The primary and secondary values are for sequential twins only: you should make them the same values.

To tune it you use the "boost" setting as a coarse boost adjustment and the "duty" setting as a fine adjustment. And by that I mean the "boost" setting kind of puts you in the ballpark (as long as "duty" isn't too low) and the "duty" setting then gives you smaller adjustments. These are all kind of "ballpark" values. You just fiddle with them until they work, keeping in mind that the PFC will engage a fuel cut if the boost level is around .25 kg/cm^2 higher than the target. You may have boost that consistently measures higher than the target you set. That's ok; the key is keeping boost stable and consistent.

I've got a T04R with a Tial 44mm external gate (13psi spring) using the factory FD 2 port solenoid. I started out with conservative settings. I set target boost to .90 kg/cm^2 (right around what my spring pressure is) and 20% duty. This caused boost oscillations and confused the PFC. Let me list some of the combinations I have tried over the past year.

.90 boost 20% duty underboosting and oscillating
.90 boost 40% duty
.95 boost 42% duty steady at about 15psi in most weather
.95 boost 46% duty steady at about 15.5psi in most weather
1.00 boost 46% duty almost 16psi in most weather
1.00 boost 50% duty about 16psi in most weather
1.05 boost 52% duty about 16.5psi in most weather, a little bit of oscillation
1.05 boost 50% duty about 16.5psi in most weather, more stable, slight differences depending on gear

Here is a log with the settings 1.05 boost 52% duty:

https://www.rx7club.com/attachment.p...1&d=1271886591

"PIM" is actually manifold pressure, where 10000 = 0psi and 22000 = 17psi . WG% is the logged solenoid duty cycle where 255 = 100%. This is a 1st and 2nd gear pull on the street, 1/2 throttle in 1st and WOT in 2nd. You can see that the duty is flat at first. That's the PFC holding the gate shut to improve spool (similar to your "Start Boost" setting on a Profec Spec II or "Spring" on an AEM Tru Boost). Then the gate opens and duty drops down, while the PFC tries to keep boost stable by varying the duty. You can see the boost is pretty steady there in 2nd gear as I go WOT, but I did end up dropping the duty setting by 2% to reduce fluctuations. This is not a turbo setup designed for low end and spool. In third gear the boost rises slightly over what is depicted here.

Conclusion

What I've figured out over the past year is that

1. PFC boost control works, you don't need to buy the kit, you just need someone to make those sequential turbo settings changes in your map with a Datalogit

2. The boost and duty settings are "ballpark" values. You just have to fiddle with them until the boost is relatively steady, being mindful to set target boost high enough that you're not easily tripping fuel cut in higher gears. Fuel cut is a way to protect your motor should your wastegate fail, but I would still try to avoid hitting it.

3. Boost will rise when it's cold outside--the PFC can't completely stop this but few boost controllers are smart enough to do that. You can manually lower the boost and duty settings to correct this or just have one of your boost options be for cool weather.

4. The Datalogit is a powerful way to improve your boost control tuning, but I wouldn't consider it necessary for tuning boost. I have made plenty of adjustments with the Commander only, just by using the up key in monitor mode for peak/hold display. You can also look at a separate boost gauge.

5. Keep in mind that the default calibration for the stock FD MAP sensor tends to read the boost as a little low, perhaps 1psi too low depending on boost level, altitude, etc. The log above was taken using a calibrated GM 3 bar sensor.

Hope this helps.

I have been using the MAC valve to control the external WG on FD with T04E and thus far the valve is inconsistent. There are times that the valve will work great and times that it won't work well at all. The MAC valve may be getting stuck. Perhaps it is not taking the heat very well. Again, I suspect that the issue is in the MAC valve and not in the PFC control system. The flaw in using the PFC is the lack of gear dependent vent duty. I see very different boost peak readings between 5th gear (highway) and 2nd gear (autox) at a given vent duty. 64% will keep 5th gear at 1 k/m2. The vent needs to be raised to 86% to reach 1 k/m2 in 2nd gear (keep in mind the 2nd gear load is reduced because I have 4.77 gears).

how do you have it hooked up? is it going to the top port of the gate? I actually have a dedicated hose to the side port of the gate and then the solenoid runs to the top port. I don't tee them off one source.

Some Datalogit logs would help determine what exactly is going on. Looking at rpm, boost, and solenoid duty can tell you a lot. I've been under the impression that these are fairly reliable solenoids. I haven't seen one screw up on the AEM Tru Boost for example.

The lack of gear-based control is certainly a limitation, but it's a limitation found on most aftermarket EBC's anyway. To get gear-based you need to buy an AVCR (there may be some other obscure external ebc that can do it) or use an ECU that has gear-based maps. On my car I have a difference of .75psi at most between the peak boost levels in 2nd through 5th gear. This is acceptable to me.

Please ignore this issue. The BOV venting made the MAC valve wires rub against some other items in the engine bay and wore right through. Fixed. The gear dependent peak boost variation is still prevalent.

If possible post some Datalogit logs that illustrate the variation

I don't have a logger.

WIth a Datalogit you can log the actual wastegate duty cycle curve (see image in 1st post) and you can change the rpm at which the wastegate opens in the settings 1 tab of the software. It's a lot easier to tune.

on my previous car a s13 with sr and t04e and tial 44mm wg. i setup the pfc to control boost using an apexi/greddy solenoid. it worked better than any previous separate controller. no fiddling it just worked and held boost consistently. i differ from you guys though. i dont like using the top port, if the wg spring is strong enough its not necessary imho

damn, i thought you were dead? ^^

i did have death threats on my life. none came through though

thanks for the info. i'm going to be trying this today/tomorrow.... i'll report back how it goes!

What car do you have now?

an fd with pfc and greddy solenoid

thank for the info arghx. it works perfectly only weird that happened to me was. i used my datalogit to change the turbo transition and then enable twin turbo control but twin turbo control didn't actually turn on for some reason. i just had to enable it in the commander while i was driving.

glad it's working out for you. you are using a Greddy solenoid, so that plugged right into the factory harness right?

yes... should have been plug and play. i got it free so i had to replace the connector on it back to stock. someone had already hacked it up. so i fixed it to make it plug and play

yeah the Greddy, Apex'i, and HKS (only HKS EVC-S) solenoid all plug into the factory harness because they use the same AMP Econoseal connector as the factory precontrol and wastegate solenoids.

the car is going to get retuned for more boost and i'll report back how it goes but i already know it was awesome in my old car. i'm sure i will be happy again

are you still using the oem solenoid ?

^ yeah I am. no problems for the past year and a half

i thought about trying it but i just don't trust it... that is awesome to know it works though

raised the boost to a little over 17 pounds. current settings are 1.10 boost 56% duty

i've been fixing lots of other issues. have not had a chance to retune with more boost on my car... fun stuff

Hey Jon, I am surprise that the car is still twins, by now I thought u setting it up for big single or not yet?
Khris

when did i ever say the car has twins....

my fault dude i read this from above (i used my datalogit to change the turbo transition and then enable twin turbo control but twin turbo control didn't actually turn on for some reason) and i thought u were twin.

I always thougth that the boost value is actually for the fuel cut and the duty is what actually controls boost; is this not true?

What happens if you leave your duty unchanged but increase the boost value?

IIRC Fuel cut happens when your actual boost > Set Boost Level + 0.1 kg/cm^2. Duty is what controls boost.

tuned my car last night. pfc was able to control boost up to 1.2kg. worked pretty damn well

Generally speaking it will go up but the best way to know is to log wastegate duty cycle and boost to see what happens. You've just got to play with it a little bit like any other kind of tuning. It's not really that complicated.

Technically it's supposed to be .25 kg/cm^2 higher than the set value, but I've seen it kick in lower or higher than that at times. There has to be some other calculation being performed behind the scenes that affects it. I think there might be a delay timer or other logic based on the rate of change of boost. Subaru for example uses a delay timer for overboost fuel cut on their factory ECU. Boost has to exceed a particular value for a particular amount of time.

On the PFC I have tried many combinations of different settings in different weather conditions. I have noticed that if there is a very very sudden spike the measured boost may exceed the target by more than .25 kg/cm^2 for a split second the fuel cut may kick in. On more sustained pulls in high gears it will kick in lower.

Anyone know which wires you would tap into on the ECU for the solenoid assuming the originally wires for the solenoid have been eliminated form the harness?

thewird

I have wired this up before. FD pin 4U is the pulsewidth modulated ground output for the wastegate solenoid and then you need a 12V power wire. FD pin 1B comes from the main relay so that's one option if you want to tap power from there. Don't tap into a 5V reference voltage wire for a sensor by mistake.

https://www.rx7club.com/attachment.p...1&d=1314494101

Awesome thanks :)

thewird

good to know that the pfc can control boost, will try this on my friends fd.

anyone has a picture of the boost control selonoid? ( I never had a chance to play with stock twin went straight to single turbo :(

http://www.mazdatrix.com/pictures/c-...-2850-N3A1.jpg

those are the stock FD 2-port boost control solenoids, if that's what you are asking. FC also has a 2 port solenoids; most turbo cars use that style, but there are some cars that come with a 3 port solenoid (like on an aftermarket controller) from the factory

Does the PFC utilize feedback at all, or is it strictly duty cycle. I am currently running the AEM Truboost and cannot get it to hold boost so I am looking at other options.
Thanks,
Dan

It utilizes feedback, but you do not have direct control over it (there is no actual "feedback" or "gain" setting). An AVC-R does, but it has a bigger learning curve and you do not have data logging integrated with your engine management system. On the AVC-R you set a target boost and a baseline duty cycle. You set a "feedback speed" which is basically a gain parameter. The AVC-R will add or subtract solenoid duty in an attempt to achieve the target boost--higher F/B speed increases this sensitivity, which means you are more likely to hold boost up top but also more likely to spike. The same idea carries over to other controllers.

The Tru Boost has only two settings: the pressure at which the wastegate is allowed to open, and a basic duty cycle. It is a dumb solenoid driver. Many other external controllers function like a Tru Boost + a gain function; a Greddy Profec Spec II and a Turbosmart are almost exactly like a Tru Boost except they have a gain option.

https://www.rx7club.com/attachment.p...1&d=1304450799

Check out my full boost controller comparison thread. https://www.rx7club.com/3rd-generation-specific-1993-2002-16/electronic-boost-controller-comparison-chart-952767/ The Tru Boost is one of the non-ebay EBC's available without feedback. I ultimately chose the PFC boost control for these reasons:

1) direct integration with engine hardware including use of the MAP sensor; lack of redundant hardware such as extra pressure sensors and boxes; integration with overboost fuel cut

2) direct integration with data logging (FC-Edit software)

3) low cost

4) ability to use the Commander to switch boost levels and monitor peak boost or quickly see the boost curve with the Commander chart display

when choosing the PFC I gave up the following:

1) boost-by-gear capability

2) the more intuitive control available with the simplest options of external controllers, like the knob-based units (Greddy Profec S)

3) direct control over feedback and wastegate opening pressure (no direct way of setting these, PFC decides indirectly based on other settings)

I'm interested in doing this to replace my Greddy Profec-B (don't like how bulky the solenoid is in the engine bay and like the datalogging/overboost protection capabilities of the PFC), but can't decide what solenoid would be best to use. Being plug and play doesn't matter to me since I am planning on rewiring my harness. Any opinions?

What is your setup?

Currently: Power FC with Datalogit and stock MAP sensor, street ported engine, T04Z (0.84 A/R) at 1kg/cm^2, 46mm Tial wastegate, 4" exhaust, HKS V-Mount
In Process: new ignition setup (IGN-1A's), water injection, rewire engine harness

http://www.ebay.com/itm/Boost-Soleno...923#vi-content this solenoid will work fine... MAC part# 35A-AAA-DDBA-1BA . It is the same as the AEM/Haltech/Grimmspeed solenoid without the markup. You can cut off the wastegate solenoid harness plug (hope you didn't "simplify" this and completely cut it out) and hardwire the new solenoid to it.

Or instead of cutting anything you can buy this plug pigtail as an adapter to put on the solenoid: http://www.bmotorsports.com/shop/pro...oducts_id/1674 then it will plug into the stock harness

Thanks, wasn't sure if the standard MAC solenoid would be good enough.

In strict terms of controlling boost, do you think that going to the PFC with the MAC solenoid will work as well as my Profec B? The OG Profec B really does work awesome, just quite bulky and doesn't have logging capabilities.

Also, what do you mean by "Hope you didn't 'simplify' this and completely cut it out"? How is this different than "cut off the wastegate solenoid harness plug and hardwire the new solenoid to it"?

If you have a working boost controller, why would you be debating switching to the powerfc? By using the powerfc to control boost, you lose the ability to have a tight fuel cut above your target boost since it will be forced to be 0.25 bar above your target boost. I have also found that boost is less similiar between pulls for some reason especially 2nd gear stuff.

thewird

The main reason I am thinking about switching is because of engine bay real estate. I am planning on installing a water injection system and a new ignition setup, so space is going to get tight. The Profec B solenoid box is quite bulky and has to be mounted so that the two vacuum ports are facing up, which really limits mounting options. Also, you have to run a vacuum line into the cabin to the back of the Profec B controller, which is less than optimal in my book. Here's a picture of how big the GReddy's solenoid box is...

http://www.floridasupras.com/attachm...yprofecb-1.jpg

I'm not dead set on doing this yet because like I said, the Profec B works great, but the smaller solenoid and additional mounting options, the capability of logging, and keeping all vacuum lines in the engine compartment sounds really nice. That's why I'm asking questions and want to be 100% positive I will be happy with my decision. The issue with boost being different in each gear is what scares me about the PFC control.

The plumbing (where you source the lines for example) and the individual characteristics of the setup (wastegate size and position) are all factors in how the PFC boost control (and any controller really) behaves. That being said, the Profec B (and Profec S) are among the simplest and most stable boost control systems out there. The Profec B uses the stepper motor as shown above. If you want something very similar to your Profec B with a smaller valve unit, just get a Profec S which uses a regular 3 port solenoid.

That really depends on what the final settings end up being. In practice they usually aren't that far apart. For example, on my own personal car my setting is 1.10 kg/cm^2 with 52% duty. My actual peak boost is usually 1.20 kg/cm^2 and fuel cut kicks in about 1.30 kg/cm^2 according to the Commander. Some people like the fact that the fuel cut will be automatically adjusted with the boost cut setting (as opposed to having to change an external boost controller and then change the fuel cut in the PFC, or eliminate the fuel cut altogether).


I can't say for sure whether you will be as happy with the PFC boost control. The Profec B (and its newer sibling, the Profec S) are basically the easiest to use controllers out there and for many people that trumps everything else. If you want the boost to behave the same way as it is now, don't switch controllers or if you do, switch to a Profec S.

I might do some experiments and try both since the cost to do so is pretty low. I already have the Profec B installed (might try and find a better mounting solution though) and it is less than $50 in parts to get the PFC boost control up and running. My gut says I will end up sticking with the Profec B though.

Also about to using the boostcontrol funtion on a S5 TII, streetport engine, BNR stage4

What would be the optimal solenoid to use? or the stock 20 year old TII solenoid, which will T in and require a restrictor of some sort to work. or a 3 port solenoid.

I have a healthy supplie to the pierburg one used mainly in VW/Audi 1.9 tdi engine with wastegate turbo. they run stock at 0.9 bar

http://www.krautwagenparts.com/images/028906283F.jpg

Or would it be better to use one with bigger hose connections, as found on newer 1.8T engines

http://imageshack.us/photo/my-images...qmokjketlk.jpg

Most people use the MAC valve which is what every aftermarket boost controller uses that doesn't use a stepper motor.

thewird

I went from a Profec S to PFC control using the greddy solenoid and have been running this way for a couple years and love it. My boost is very consistent, ive never experienced a single overboost and there is less junk inside the car. Where I live seasonal changes are very mild so Ive never even had to adjust for different seasons like some people have mentioned. I will say I never had any problems with the spec S and it was very simple and easy to use, I just prefer to keep the wires and electronic crap to a minimum inside the car.

You can make almost any solenoid with the proper voltage work. I have used an FD solenoid on an external gate. For a BNR it would be easiest to use a 3 port like the MAC valve. If you have something else, give it a shot.

Sorry I didn't get involved in this thread sooner, I remember when you were asking for some terminated wires Raymond. I figured I would update this thread with some pertinent information.

The Apexi Boost control kit uses the precontrol solenoid connection for their wastegate solenoid. What this does is allow for the sequential system to be turned off and use the "Primary" as the setting for boost level on Boost Settings 1 & 2.

Our S5 PFC Adapter has always had the Turbo Duty Solenoid (3R) going to Pre-control (4V) on the PFC for boost control and has worked very well, even with the stock solenoid.

For this same reason we have recently added the BC (boost control) wire to the 4V terminal of our S4 PFC Adapter.

I am sure that the 4U connection works, but using the 4V connection the solenoid reacts quicker and does not require the system to be tricked into thinking that the sequential system is activated. Which means there is no need to alter the transition times.

For those with the PFC in an FD just change the connection over to the precontrol and turn the sequential system off.