(sorry im new to this whole pfc thing, and rx7 in general)
My boost percentages are all set different, I dont know what any of the numbers mean or where they should be or if they even matter because I dont have an eletric boost controller anyways. Any input would be appreciated. thanks.

 

Rtfm

 

what? ive been reading through this section of the forum all day trying to learn more but its not very easy.

 

RTFM = Read The ******* Manual

Your question would be easily answered by reading the PFC owner's manual. You can download it from several places, including www.fd3s.net, if you didn't buy an authorized US PFC.

Do you have a separate boost gauge or just the PFC Commander?

 

I read the manual myself at least 5 times. It helped a lot, more every time but it still left me clueless on most things. Not to step on your toes...at least I learned what RTFM means...lol

 

lol i got the RTFM right away wen i saw it too haha

 

the boost percentages refer to the cycling of the wastegate and turbo pre-control wastegate and the time they are open to bleed off boost. The first number is for the primary turbo and the second for the wastegate for the 2nd. The higher the number, more boost.

Tim

 

The PFC manual leaves a lot to be desired so lets see if I can help...

I assume your looking at the Boost Setting screen of the commander. All the info that is displayed here IS used even without the addon boost controller kit. The addon boost controller is used for single turbo conversions and NOT with the stock sequencial turbo setup. The PowerFC by itself can control the boost based on the data in the Boost Setting screen. The first column of this screen has a 1 and a 2 which are two different settings that can be switched easily by highlighting the number you want to use. When 1 is highlighted you select to use the data on that row as well as the data on the next row. The Pr is for the primary turbo and the Sc is for the secondary turbo. The boost pressure is how much boost the primary and secondary turbo uses and is in kg/cm^2. Here is a chart of approximate conversions to psi...

kg/cm^2 psi
-------------------
.70 9.96 ~stock boost
.75 10.67
.80 11.38
.85 12.09
.90 12.80
.95 13.51
1.00 14.22

The PFC has a pressure sensor that reads how much boost your turbos are producing and trys to match this pressure to the desired boost setting automatically. It does this by opening a door that bleeds off excessive boost. There is a door for the primary turbo and one for the secondary turbo. They should be opened all the way with a 0% duty cycle and closed all the way with a 100% duty cycle. The PFC starts with the Base Duty cycles specified in the Boost Setting screen to help it get close to the desired boost setting. If a Base Duty cycle is set too high then the boost can spike above the set boost level before the PFC can react fast enough to control it. If the Base Duty cycle is set too low then the boost will be slow to get to the desired level. Changing the Boost Pressure or Modding an RX-7 makes the desired Base Duty cycles different and setting this allows a similar boost pattern to the stock 10-8-10. If lightly modded this may not need to be changes at all. The Base Duty percentages are all set different even in a new PowerFC.

I hope I got all that right . It's difficult to be non technical and still get something across.

 

Also,note that by changing the values for the Pr.turbo,you affect the transition.That was the cause for my low transition(10-5-10).

 

awesome guys thanks. So to make a long story short (not saying I didnt read it all but pretty much my main question is..) YES i can change my boost settings with JUST the pfc? and Im reading my boost by the pfc and a boost gauge that goes by lbs.

 

so I should go to about .80 or .85 if I want just a slight increase in boost. and with just that I shouldnt have to mess with the base duty percentages?

 

Short answer is probably. Try it and watch your boost guage closely for spikes. Get off the throttle quick if it starts to spike. Don't forget to watch the road every once in a while too . You feel the need for more boost already? Didn't you just get your car and aren't you like 17? I feel like I'm breaking some kind of law here

One last thing to mention is that the PFC boost reading is not very accurate and may not agree perfectly with your boost guage. Then again some boost guages aren't very accurate either.

 

Correct, except your changing the PFC with the optional Commander (handheld thingy with buttons and screen) . Don't get carried away with raising the boost no matter how tempting it is. There is data in the PFC (fuel maps) that may not be set (tuned) very good for your car which can make raising the boost dangereous.

 

ok so I thought I was running stock boost, and always felt the 2nd turbo was stronger than the 1st.. and now that we got into numbers i found out Im not running stock boost. the numbers go as follows
1st turbo: .80
.75
2nd turbo: .90
.80

and with the pfc will I still have fuel cut?
So i think Im running around 13lbs on my 2nd turbo which is where i wanted to be.. is it safe to turn the 1st turbo to the same numbers as the 2nd turbo? and are the % numbers after the .80 or whatever number.. the "base duty cycle" you guys are talking about?

 

Oh im almost forgot.
those numbers are what its set at BUT when im monitoring in while im driving, if I take it 1st-4th wot my peak boost will only be like .57 or somewhere around there.. does that mean I have a boost leak?

 

I guess this would answer my question from another thread. Im at about 5600ft above sea level so maybe thats why the number is so low?

 

It's more like this...

__________________boost__base duty cycle
1st setting: 1st turbo .80 56 %
....................2nd turbo .75 64 %
2nd setting: 1st turbo .90 62 %
....................2nd turbo .80 70 %

The PFC comes set for higher boost than stock. If the 1st setting is highlighted when you go to this screen then you are .80 boost on the first turbo and .75 boost for the second turbo. If the 2nd setting is highlighted you are .90 boost 1st turbo and .80 boost second. Get it? Maybe you *should* read the manual. It's not the greatest but at least you can read the pictures .

http://www.fd3s.net/power_fc_manual.pdf

My tutorial I guess wasn't the greatest either as I was trying to keep things simple and non-technical. The 2nd turbo feels so much stronger than the first because the second turbo is actually the 1st turbo and the 2nd turbo combined at the same boost. Also the secondary turbo is a little larger than the first. You're running less boost when the 2nd turbo kicks in but forcing a lot more air into the engine making a bunch more horsepower.

You really don't need to worry about fuel cut with the PFC. The stock computer (ECU) doesn't have fuel maps for very high boost levels so it cuts fuel if it boosts too high. The PFC has these higher pressure fuel maps. The only time the PFC will cut fuel is if your boost goes above what it's set at far enough. This would likely be from boost creep resulting from a midpipe without porting the wastegate.

I really haven't watched my PFC boost guage much so I can't tell you much there. I believe the PFC will still try to reach the set boost level regaurdless of altitude and boost leaks. The turbos will work harder, take longer, and not quite produce as much power. The atmospheric pressure (as opposed to pressure in manifold) is read once at startup and that's why driving in the mountains could change your boost. Your 2nd turbo is kicking in so I would guess your turbo system is working correctly for the most part. Your power is likely just zapped because of the altitude.

 

awesome thanks so much. I printed out like 40 pages of the manuel but than my printer ran out of ink lol. Its hard learning about the PFC when I hardly know much more then the basics of the rx7 or any turbo cars for that matter. But im learning, or trying to at least.

 

You want to learn more about the mechanicals of the RX-7? :o You must be the coolest girl ever 8). Why aren't there any girls like you around here? Since your interested in how the RX-7 twin turbos work you might check out the following link and click on the 2 PDF files at the bottom of the page. Lots more pretty pictures to read :roll: ...

http://www.davidgeesaman.com/

 

awesome.. thanks. Your a lot more help than the jerk who told me "rtfm"

 

Just because I didn't hold your hand doesn't make me a jerk. I gave you a link to the PFC manual and then asked you a question you didn't answer.

You really shouldn't be playing with PFC settings if you know nothing (by your own admission) about turbo setups or the PFC. I don't say that to be a jerk, but to prevent you from blowing a motor through not knowing better.

 

I don't think rynberg is a jerk. He's actually been a lot of help to a lot of people including me. He really knows his stuff too. Look at his postcount. Part of the problem is newbies come along and post the same questions over and over again before they learn how to search and what to search for. No offense Candy but I thought his "rtfm" was kind of funny in a dry humor kind of way . It could have been more helpful though.

 

ya the thing is I HAVE rtfm and didnt understand 1/2 of it.. and Im not "playing with my pfc" im just trying to figure out what all of it does THANKYOU. if he knows his stuff and is a lot of help he should have gave me some help instead of just "rtfm" i just thought it was rude. In your case you told me to read the manuel but you told me what to look for and a little once over about what it all means, which was a lot more helpful. Oh well.. so now I understand most of the boost stuff but im on to wondering what all the maps mean and stuff.

 

Want to know more huh? With knowledge comes power. Hopefully lots of horsepower . Here is another link...

http://www.zeroglabs.com/rx7/rx7_tuning.pdf

It's a manual about the data in the PFC. It uses a Datalogit to edit the data and is specific to a single turbo in places but alot of the info here is still applicable. Here are a few tuning tools you should know about...

Datalogit: A little box that connects the PFC to a laptop with software to edit the settings and data in the PFC. It allows more to be edited than the Commander and has other features not available in the Commander like datalogging. The bigger screen makes it much easier to use.

WBO2: A wideband oxygen sensor is used to measure the amount of oxygen in the exhaust and outputs an air fuel ratio. The air fuel ratio (AFR) tells whether the engine is running rich or lean. When neither rich or lean the engine is at what is called stoichiometric (~14.7:1 for gas) which is the proper air to fuel ratio that all oxygen combines with all the fuel. This is good for emmissions and gas mileage but too lean for a turbocharged wankel at full throttle (should be about 11:1 AFR). Also notice the smaller the ratio the richer. The WBO2 is the number one tool used to tune the fuel maps in a PFC. The fuel maps tell how much fuel to inject at a particular RPM and pressure.

EGT: The exhaust gas temperature probe tells how hot the exhaust is. It is most commonly used to adjust the timing maps in the PFC. The timing maps tell when the spark plugs are sparked based on RPM and pressure. This tool is more for the advanced tuner but some old school tuners still prefer it as it was used long before cheap wide band O2 sensors were available.

I have the PFC+Commander (in one of my 3rd gen RX-7s) Datalogit and the new Innovative WBO2 setup but it's not installed yet. I don't have an EGT. I'm going to try and tune my RX-7 myself. I'm kind of a geek though as many people just take there cars to a tuner and dyno and have it tuned for them. There is a lot of advantages to tuning it on the road by oneself though.

Enough for now. We don't want a brain freeze. %) .

 

haha awesome Ill look it over. ya I want the datalogit so I can look at play with everything on a laptop.. but 1st I should learn EVERYTHING possible. It sucks because theres not really anyone here in the sticks that knows everything about the pfc. The rotary shop in town knows a lot, but im not sure how much. I want to have it dyno tuned but like they say "if its not broke dont fix it" so im fine with the way it is right now. I'll do some reading and any other links you think are helpful and I'll understand send my way