tuning the Power FC: dedicated topic

J

Jobi Joba

Member
I've been tuning my PFC for about 4 weeks and I now begin to know the datalogit software pretty well.

To tune the PFC correctly,the first thing to know is that u need the datalogit.Otherwise you won't be able to modify important settings and more important,u won't be able to use particular loging functions which prove to help saving a lot of time.

If you want to fine tune your car, you'll also need a wideband O2 device which has a wideband signal output (better if the output signal is linear...like on the Techedge devices) and to avoid running dangerous EGT you'll need a type K thermocouple fitted in the exhaust manifold,just before the tubby.

the basics:
- max power afr: about 13:1
- max EGT to avoid destroying mani and tubby: 950°C
- max knock level: it SEEMS that 40 is a pretty safe limit (with std PFC settings,the knock alarm is set up at 60:too high and u need the datalogit to change this setting)

Of course,the EGT is important because if you run 13:1 afr,you'll see egt way above 1000°C at WOT...so to avoid running such high EGT,you have to add fuel...

You also have to put as much ignition advance as possible to have a faster tubby spool up.But you have to take care to avoid knock.Otherwise... :cry:

When running std or pretty std spec,the basic map of the RNN14 PFC is not that bad.

With a walbro fuel pump,you can run up std boost with no risk of damaging your engine:knock level and afr will be pretty good.

If you run 700cc injectors,a good setting would be 57% and +0.18ms
More than 59% will make your engine run way too rich and less than 55% can cause det.

After having proceeded to the self learning session (when engine turned on for the first time,10 min idling with no electrical load,10 min idling with A/C on if you have it,10 min idling with rear defroster on) you'll probably find out that your idle speed is too high.This is partly due to a high ignition advance setting on the ignition map for the idling zone: just use the map tracer mode to see where you are on the map while idling and back off the advance to 20°.

It helped my engine a lot.

If you start raising boost (let's say: 1bar + ) you'll see that when at wot in 4th or 5th gear,your knock level goes above 40 in the 4000-5500 rpm area.

At the mo' I'm running 1 bar and with my ignition timing back off on the proper N and P positions (as low as 14° for one particular point) I don't go above 40 anymore,even at WOT in 5th and climbing a hill.

For those using the datalogit,I particularly recommand the map watch mode which allows you to monitor the parameter you want (boost,afr,knock,etc...) on a grid with same N and P reference as used for the ign and inj maps.For example,thanks to that function you instantly know when you see det. :wink:

I'm about to add the EGT logging on my datalogit device,using an AD595CQ to amplify the type K thermocouple signal in order to have a voltage high enough to be logged by the datalogit.I will let you know how it works next week.

I also rescaled my rpm ref points cause I just don't care of a 400rpm setting (like on the std scale) but I'm interested in 8,400rpm (400rpm increments).

I also changed my accelerate injector setup as I saw that when suddenly flooring the gas pedal,my afr was going too rich for a few tenths of second.Same prob when flooring again after shifting gears.

Finaly I found out that another intersting setting on the datlogit was the tps vs inj setup:with my sheepdog recirc dump valve,I had problems when partly releasing the gas pedal after having run the engine at a stabilized speed.I had to change the fuelling for this particular condition (less fuel) and the engine is now reacting more smoothly.

I hope this helps,and I want this topic to be full of advise for the PFC setup.I guess Ross will tell u about his experience soon.

Last thing to know:when tuning an engine,start with a low boost level (0.7bar) and a low setting for the rev limiter (5,500rpm) and raise the rpm limit by 500rpm steps after having checked that everything was ok,and finaly,raise the boost by 0.2b steps max.


For those who want to know my engine specs,here u got:
- balanced and knife edged crank
- PAR forged rods
- Tomei 87mm forged pistons
- Tomei 1.5mm head gasket
- Jun head studs
- Tomei 260° 12mm lift camshafts
- Ferrea springs
- HKS rocker arms stopper
- gasflowed head
- HKS GTRS tubby with ceramic coating on the turbine housing
- std mani with little mods and a ceramic coating
- twin dump pipe with full 3" zorst
- Greddy R-SPL R33GTS FMIC with custom made stainless steel piping kit
- Z32 MAF with JWT filter
- sheepdog recirc dumpvalve
- Denso IK27 plugs
- Walbro 255lph fuelpump
- Sard 700cc injectors
- Power FC (of course!)
- AVCR
- OS Giken twin plate clutch
- PAR gearset
- Mocal oil cooler with thermostatic plate
- Nismo engine mounts

I think there's everything related to the engine and tranny! ;)
 
A

AJ4

Guest
So far I have tuned mine for part throttle and economy / emmisions. I have also done a few WOT throttle runs and made a few adjustments, but just for safety at the moment, not for performance.

The reason you should do the part throttle first is that fueling way down on the rpm range can have a noticeable effect on the higher rpm. If you are running too rich part throttle, when you go to WOT it can affect the rest of the range. I think its something to do with the excess fuel being leeched off the inlet walls as the rpm rises, but I know its a bad thing anyway.

To start with you want to disable any boost you have as it makes it much easier to tune, and then add boost progressively as you go up the load map.

Ideally you want an AFR ratio of 14.7:1 across the whole RPM range, over half the map ! I know this sounds a bit weird, but that is where you will spend 90% of your time, off boost cruising. At the higher rpm and lower load cells, you can go a little bit richer, but there is not much point. You can be cruising at 6000rpm, with very little throttle, and only need a small amount of fuel. Only when the load increases ( you put your foot down :D ) do you need to add more fuel to make more power.

First things first, you need to tune your lambda sensor. This is supposed to keep your airfuel ratio at 14.7:1 for all light cruising / idling. Unfortunately they age and tend to drift about a bit, but you can tune it out with the PFC.

Unfortunately because it is constantly switching on and off, the lambda reading will be all over the place and you won't be able to read it directly. You have to 'calibrate' it against your wideband lambda sensor first. To do that, untick the lambda control in the PFC so you are just running directly off the map. Find a map / load / idle position where you wideband measures an AFR of 14.7:1. ( or adjust one of the cells until it does ) Now measure the voltage output of the narrowband ( using datalogit ) to see what it reads at 14.7:1. It will still be pretty jumpy as it is really sensitive around the 14.7:1 mark, but you can get a good idea and estimate what voltage it is.

Say the voltage is 0.5 volts at 14.7:1, remember that voltage. Now switch back to lambda control on, and watch the lambda sensor voltage on one of the charts. Should you see it switching on and off regularly, with a maximum of around 1.1 volts and a minimum of 0.2 volts ( this is different for different lambda sensors, some people have lambda sensors that go up to 1.5 volts ). Now draw an imaginary line through the chart ( with your eye :? ) at the voltage you measure above, ie in my case 0.5 volts. Now you have to decide visually... does the signal spend more time above 0.5 volts or more time below it ? Ideally it should switch evenly around the middle, ie it should spend the same time at maximum as it does at minimum. Its a bit hard to explain...:D What you can see from the chart though is if you are biased one way or the other, ie, it is more to the high voltage than low voltage or vice versa. Now all you have to do is change the afr lambda fiddler in the PFC until it switches even around 0.5 volts. Easy ! :D

By doing this you should make your car idle a lot smoother. If your car is biased too far one way, say it is running too rich, then it spends a long time hunting around to find the 14.7:1 point ( and you waste a lot of fuel ) and it makes the idle uneven as the revs keep rising and dropping as it switches in and out. Ideally you want the Lambda sensor to do the minimum amount of switching, and switch evenly around the 14.7:1 point.

Now that the lambda sensor is tuned properly, you are going to switch it all off and tune the map as though you didn't have one :D Will explain in another post...
 
A

AJ4

Guest
Emmisions part 2 :D

Now that the lambda sensor is tuned, you need to tune the base map for the same, as if the lambda sensor wasn't connected. This is because when the system switches from closed loop ( lambda control ) to open loop ( map control ) the switchover has to be smooth or you get hesistation / stumbling.

Basically all your want to do is tune the base map to give a lambda of 14.7:1 all the way up the rev range over the first half of the map ( up to load cell 10 ). Then it doesn't matter if you are in closed loop or open loop, your lambda will be the same and you can switch between the two systems without noticing any difference. It also has the advantage that if your lambda sensor goes pop, you can run the car without it, you don't really need it.

Now make sure your lambda sensor is switched off before you start the next bit, and boost is turned down as low as possible.

Start off with the lower load cells, you probably wont be able to use load 1 & 2 because your idle speed will never be low enough to get into them. Also, when you decelerate, the injectors switch off and cause extreme lean conditions to be recorded in them.

Start off in third gear, at the lowest rpm and speed you can cruise at. I chose third gear so you don't end up doing ridiculous speeds, you don't want to be doing 120mph in fourth at 6500rpm while trying to program a laptop :D Gently press the gas and try and work your way up the rev range, but staying in the same load cell range. It takes a bit of practise, but after a while you kinda get a feel for it, apllying a constant 'load' on the engine.

Have a look at the first row, and make sure everything looks ok, your not going stupidly lean or anything. If everythings ok, procede onto the next row, then the next one. You don't have to go all the way up to your rev limit, after about 5500 rpm you can just interpolate and fill in the values by hand, they don't change much.

Now have a look at the first three rows and decide where you are rich / lean and make the adjustments to row 2 only ! Now do a rerun of the first three rows to make sure your changes worked, if not, go back and keep changing till it works. Only change the values in one row at a time, and only by small amounts. When the data is logged, sometimes it is on the 'edge' of a cell, so making changes can effect the cell above / below. When your happy with row 2, go on and measure rows 2,3 and 4 and adjust row 3. then measure 3,4 and 5, and adjust row 4 etc etc. For rows 1&2 that you skipped in the beginning, its pretty hard to do because of the injector overun / cutoff, so just have a look at the map and fill in the values by hand to give a smooth curve. Overall the map should be quite smooth, with no spikes etc. If you get any spikes in lambda when your measuring, just ignore them and fill in the value by hand to give a smooth curve.

When you are finished, you should have a half filled map that starts off flat, and then starts to richen up slightly at peak torque ( but still reads 14.7:1 ). I think this is because at higher rpm, there is not enough time for the fuel to burn completely and some of it is wasted so you need to add more fuel to get 14.7:1 ( or something, I'm sure someone else can explain it better )

You'll notice that as you go up in load cells, you'll get to a point where there are parts of the map that you can't go into because the rpm is too high. For instance, it pretty impossible to get into load 10 at rpm 1, because to get that load you need to have high airflow, which mean higher rpm etc etc. Just interpolate and keep the curves smooth. Under some really weird conditions you might end up in one of those cells, so don't just ignore them but fill in a value that looks about right.

You can do all this for load cells 1 - 10, but I went a bit more aggressive and tuned mine for load 1 - 8, so I can use 9 - 20 for power. Its pretty much down to how you drive your car, whether you like to idle along at high rpm in gears, or shift a gear and labour a bit.

Throughout the whole thing, keep an eye on the knock sensor. For this type of tuning it is very unlikely to see high EGT or maxed out MAFs / injectors etc, but its really susceptible to knock, especially when applying moderate load from low rpms and the engine is labouring. If you start to see some knock, go to the Advance map and reduce it all around that point. Don't add more fuel as a way of countering knock - all you'll end up doing is wasting fuel and screwing up your fuel map. You can change the advance so you might as well do that :D Changes to the advance will cause changes to the fuelling, but should only be very minor and you should be able to compensate it easily.

When your finished, you know that forever and a day you can drive round with good fuel economy, no knock and have a very smooth engine. I know it sucks a$$ because you want to jump right into the WOT runs, but doing this first makes it much easier....
 
C

cmng

New Member
Jobi Joba said:
After having proceeded to the self learning session (when engine turned on for the first time,10 min idling with no electrical load,10 min idling with A/C on if you have it,10 min idling with rear defroster on) you'll probably find out that your idle speed is too high.This is partly due to a high ignition advance setting on the ignition map for the idling zone: just use the map tracer mode to see where you are on the map while idling and back off the advance to 20°.
Click to expand...
interesting on this fact
10 min idling.

do i need to off and on the engine for the second 10 min idling ?

or just straight away on AC after 10 min ?

Thank
 
C

cmng

New Member
ok..
to auto learn

start engine
off everything.. no AC, no radio,
nothing electrical on.
Then wait in 10 min.

after 10 min.. switch on AC

After 10 min switch Rear Defroster

that all

but do power FC hand set can set auto learn ?
i just need to reset the data and it will auto learn itself ?

Thank..
 
T

Thor

Member
Hi,

anybody know´s if is near germany who can adjust my power fc?? i have fit into my car:

HKS GT3037S
Tial 38mm External Wastegate
Race manifold
HKS 87mm Piston
ARP Rod bolts
HKS Iridum sparks
Sard 660cc Injectors
HKS 2.0mm Headgasket
HKS 264° Camshafts
Z32 Maf
Head ported and polished with bigger valves
OS Giken Twin plate Clutch

so, or can anyone here help me??? and what can i do that i become 20° degrees ign timing?? i still have 40° degrees ad that´s to high..

Thx
Sascha

Germany
______________
 
Roy Archer

Roy Archer

Member
ok i have read that any chance of it in english? :lol: i think i will wait and maybe take it to Abbey Motorsport to sort out!
 
boucherie

boucherie

New Member
fitted my power fc and couldnt believe just how easy it was to install, must be a level 1 job :!:

is there any way i can set the knock alarm down to 40, and what other basic settings can i set without taking it to a tuner as my cars not ready for that stage yet!

im only running 0.85Bar on setting B and 1.1Bar on setting A on my avcr, also how do i get rid of the engine check light, do i need to 'short it out' with the paper clip method :?:
 
N

Ninja_tune_factory

Guest
This is a realy good post guy top job ,

just a coulp of Q`s whats the soft where like for mapping the FC is it hard to use ? also im gessing you doing most of this on a lap top right ?, if so could you get some screen shots of fuel graths etc and post them up ?

on road mapping i like it 8)
 
Last edited by a moderator:
R

radiobar

New Member
hi !

just a quick question about EGT

----------
max EGT to avoid destroying mani and tubby: 950°C
----------

do you mean after the turbo or before ?

i got 2 EGT probes installed. one in the manifold
and one around 25cm after the turbo in the dump time.
before the turbo i got 1050°C,in other car we got 1100°C.

after the turbo its fine.

thanks for any info.
bye.
 
A

AJ4

Guest
I personally wouldn't go above 950'C before the turbo, as that means your piston temps are over 1000'C and the ring lands are very likely to melt or become very weak.
 
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