rotorbrain

whats up everybody? im new to the forum. ive been checking out all the threads to try and find a reasonable way to tune this thing. i love it to death, but i cant understand the tuning. i bought the car with the pfc on it. so i dont have any idea what it was set at. all i know is that my car ran like crap (its a 94 rx-7 BTW) when i got it. so i did the dreaded vaccum hose replacement. that was fun. after i did that the car ran alright, but i could tell there was something missing. im getting almost 15 psi and it just doesnt feel right. at WOT the the boost guage flutters around 14-15 psi. the car surges too. almost like its missing. i went to the dyno and spent a lot of money to try to tune it. i gained like 30 hp, but the a/f curve was bunpy like a country road. i wanted to smooth it out. everyone i talked to was running at like 11.5:1 A/F and i was trying to achieve 12.5:1. i gained more horsepower when i leaned it out. why do i have to make it so rich? i know rotaries run a little richer, but it didnt seem like it hurt the car. i saw chuck westbrook use a formula that is supposed to get you around the A/F ratio that you want. so i went and started punching that in. well when i got to around the 15-16 fuel cell i noticed that the formula at hand would lean out the cells past cell#15. . . well, they were leaner than the cells before that. is it supposed to be like that? i richened them up for safer use until i get more knowledge on that.

now we go to the ignition tables. i have no EGT sensor so i cant tune those at all. could somebody help me with that. im dying to get that done. i dont have a datalogit. . . yet. so i have to punch everything one at a time.

mods on my car:
efini y-pipe
3 inch d-pipe
gutted stock cat
3 in. hks carbon-ti hyper cat. back
and the beloved power fc

thats all for now. somebody please help me!!!!!!!!!!

cruser

I would also love to know how to tune with the Power FC. Is there a write-up on this somewhere??

rotorbrain

well, there's a lot on the forum, but i seem to be missing something. there are maps posted if thats what you're looking for. other than that i dont know. thats why im all freaking out about mine.

the_glass_man

iTrader: (2)

First Get a Datalogit, that would help you out a lot. Then find someone who can tune it right.

cewrx7r1

iTrader: (2)

First of all running AFRs around 12.5 under heavy boost will eventually blow your engine. The UEGO linear O2 sensor instructions list 12.5 as the leanest to run with turbos. But since rotary engines run hotter than piston engines, that is too lean. If you checked the SINGLE TURBO forum, about 12.1 is the leanest to be safe if your fuel and ignition system is running great. A slight misfire will cause your AFR to be richer than they really are. You also have to check the EGTs to prevent melting the turbine blades when under max boost for long periods like road racing. Thus high 11s is better.

Your mods are barely above stock so you can safely use stock maps. Look at my most recent posted maps under my tuning posts and look at my mods. You can start with those but take out the extra fuel added on the PIM maps.

You start you tuning at low boost, get that correct than move up slowing with the tuning. You don't just jump in at 15psi! 15 is too high to run anyway with stock turbos. That is pushing them too hard.

AS USUALL, I CLAIM NO RESPONSIBILITY FOR WHAT YOU DO AND WHAT HAPPENS TO YOUR ENGINE!

rotorbrain

hey, chuck. you're the man ive been wanting to talk to. i initialized my pfc and went back through with your formula (AFR desired/actual AFR)(reading in cell). ill probably go back through and do it again because i set it too lean. i know what cells are being used by using the ghost map tracer. . . does that mean that i only need to change the ones being used. about the PIM maps. i just got in and i looked at the "ETC" section. the PIM was at around 1.60 at idle. i dont know what it is supposed to be, so . . . whatever.

i would send it off and have it tuned but i cant fathom a person tuning my ecu while its off my car. there is no one out here to go to. i talk to bryan smith at rotorsportsracing.com (thanks a lot bryan if you see this. . . i think i call him way too much). so you think that the best thing is to initialize the settings? i know its safe, but my fuel mileage is absolutely horrible and it burns extremely rich at start-up. . . a lot of smoke when i start it.

oh yeah, when i went to the dyno i noticed that im losing coolant. it seems to be purging out of the overflow tank. the ast has been removed. i checked out a lot of the how to's on this mod. and it seems to be consistent with the instructions. the coolant just fills up in the o-tank. im not sure if its the dreaded coolant seal leak, because its not bubblling out of the top of the o-tank. im almost tired of messing with it and im thinking about starting all over again with a new motor and turbos. probably from rotorsportsracing.com

okay, thanks

cewrx7r1

iTrader: (2)

My formular for adjusting the fuel cells works only if you have used a linear O2 sensor to log you AFRs from low to high revs as a reference for the area you are tuning.

If you do a ghost trace and records what cells were lit up, they are not definite. Usually the PFC lights up the lower of the pressure rows it was using.

If you calculate the pressure for row P17, it is 10.9 PSI.
Row P18 is 13.8. The PFC extrapolates for values between. You adjust two rows at a time. Same along a row. Each column is for only 400 rpms. In between the PFC also extrapolates. I notice that our club 's linear O2 sensor displays about 400rpms late because the engine revs so fast compared to the O2 sampling rate, calculation, and then display of the value.

rotorbrain

okay, ive decided to just leave it alone until i get my new engine built. i think my major problem is that 3 people have owned this power fc. i dont know what the maps are set for. all i know is that there is a definate miss. i cant tell what it is. ive replaced spark plugs twice. i just replaced the first set that i bought. they were caked with all kinds of crud. ive noticed the car runs way better at about 3/4 throttle as opposed to full throttle. at full throttle i get 15psi, which needs to be turned down, and its slow as hell and seems to miss the whole time its at full throttle. first of all how do i turn down the boost with the pfc? i really want to keep my car from missing. i would go in and change the ignition timing, but im not very educated in that area yet. im thinking about comparing the base stock map on the map comparison page with mine after i initialize it. i wonder if its different. whats the deal with the ignition split map? ive never seen that before on the power fc. how in the world to you set it and what in the world is its meaning. thanks guys for your help.


oh and also im wondering if my 944 intercooler will work okay on my fd. if anyone can give me feedback on that it would be greaty appreciated. ive had it for a while and i would like to see if its a worthwhile upgrade before i sell it and get another one.

the_glass_man

iTrader: (2)

Time to hit the reset button!

GoodfellaFD3S

iTrader: (213)

Hi Rotorbrain,

I may have the answer to your troubles. Get in touch with Spyfish007 on the forum. He lives in TN and knows quite a bit about the power fc. Also, he is friends with a shop owner (who also has an FD w/a power fc) in TN who has a dyno. Between the two of them, I'm willing to bet they'll be able to help you sort out your problems.

Hope this helps--

rotorbrain

hey goodfellafd3s, thanks man. this is what i have been needing. he lives in oak ridge doesnt he. hmmmmm. thats pretty cool. i appreciate it man. hey, what do you think about that that 944 fmic? do you think its a good idea? ive seen a lot of 944's go really fast with that intercooler. i just dont know how it will react to an rx-7. thanks again.

paul

ech

Rotorbrain,

also, it sounds like you might have some other problem with the car, like a bad coil or fuel filter or something. No amount of tuning will make other problems go away (to state the obvious).

SPOautos

please tell me your not running 14-15psi of boost with these mods..........

mods on my car:
efini y-pipe
3 inch d-pipe
gutted stock cat
3 in. hks carbon-ti hyper cat. back
and the beloved power fc


if so you are fixing to be hurting!!!! if you want to run over 13psi you need an IC upgrade, larger injectors, and a fuel pump!!! What injector duty cycle are you getting in the "monitor" display when under full boost? Whats the max that it hits. Use the "hold" feature to show you cause it moves to much to try and watch.

Also what plugs are you running at 15psi? Are you running the stock ignition with stock plugs? You need some colder plugs, if you want 14-15psi you need to at least run trailing plugs all the way around or get some colder racing plugs.

I think before you buy a new motor you should just do a compression test. Personally I think if you turn the boost down to about 13psi and run the base PFC map your problems will go away.

Later,
STEPHEN

rotorbrain

hey steven, i am running colder (trailing) plugs. i have read the manual over-and-over and i cant seem to figure out the "correct" way to set it down to 13 psi. im not very good with the conversion. i would go out and check the duty cycle, but when i got home today from work i found fuel all over the firewall. sounds great, huh. i was staying off the 15 psi, though. i havent been going full throttle for a while. ive been told to check my pulsation dampner (about the misplaced fuel on the firewall problem). what do you think? could the 15 psi have caused this. ive already done all the vaccum hoses. . . and i have checked and re-checked the hoses to make sure they are not kinked or blown off.

ech

Don't drive that car!! figure out your fuel problem - tow if needed. (!!!)

then get your boost reduced. - go to the settings - boost and set the target boost numbers at .75 or .8 and the duty cycle at what it reads in the manual, but maybe less by 6% or 8% or so.

then debug any other problems...

rotorbrain

alright. i dont really understand why there are two settings on the power fc: 1. pri. . . .
sec. . .

2. pri. . .
sec. . .


whats the deal with that? do i set both of those to the same thing or what?

Lost Time

You can program two seperate boost settings. Instead of 1 and 2, we'll call them A and B. You can preset A to run at say, 8lbs, for around town driving. And you can set B at say 12lbs for hard runs. Within each preset A and B you can adjust primary and secondary boost seperately, hence pri and sec.

SPOautos

Ok, go to the boost setting and turn the pri and sec boot down to .80 - .85 then adjust the duty cycle % down to about 50% or so for both boost settings. That should lower your boost to a safe level, if its too low you can raise the duty cycle % up a little at a time untill your boost gets where you want it.

I'f your getting fuel on the firewall I would suspect the fuel lines. The fuel lines that run under the car are hard lines, then when they get to the motor they go under the manifold, at that point they turn into rubber hose lines. That connection is made with the rubber line slipping over the hard line and held in place with a clamp. Its under the backside of the manifold and that is what I would suspect, its right there at the firewall. You might want to check those lines and connections, i know on mine it has 2 clamps.

Where is the fuel hitting the fire wall at? Is it on the passenger/drivers side or what?

I hope this helps some

BTW - those fuel lines are a bitch to get at, you'll need to pull the manifold to take a good look and them.

Later,
STEPHEN

rotorbrain

well, i changed the one fuel line on the back that runs to the pri. fuel rail when i changed out the vaccum hoses. it was brittle and freaking KINKED!!!! the guy that tried to change the hoses out the first time only changed out about five and left several disconnected. what a jerk. the fuel line that runs from the pri. f.r. to the sec. f.r. looked like it was in good condition so i left it alone. im gonna punch myself in the face if that one blew out. i dunno. im gonna take it all off this weekend.

thanks for the info on the boost controller. . . oh yeah, im getting datalogit sometime soon . . . i cant wait!!!!

DRAG0NEER

that wouldn't work...you're basically running a full exhaust system without actually controlling boost creeps from the wastegate. Do the home depot boost controller mod, it'll fix your problem. It fixed mine.