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hi guys,

i have been on this forum for a while now, and have been reading a lot, but havent been posting a lot...

now its about time, because recently i purchased a PowerFc Pro for my modded RB25DET ... here are some specs:

*RB25det with modded pistons (reduced comp.)

*Metal head gasket

*Big Turbo

*Oil Cooler

*10W60 OMW Racing

*VERY big aftermarket watercooler (more available if u want)

*FMIC

*Ogura Racing Twin plate clutch

*550cc

*Denso iridium sparks

*Power FC

*Blitz dual boost controller

*entire rear end of the R33 skyline (fitted in directly ?!)

*Upgraded full front and rear brakes inc. goodridge break lines and brake cylinder

*Full 3" turbo-back exhaust

once i had received and mounted the PFC, i set the injector duty to 67% & 0.02m/s and also turned OFF the Boost Control Kit option (cause i dont have it )... the engine fired up straight away and ran very smooth...

now the problem... since i am from Austria (Europe), no skylines where ever imported to this country (and all neighbouring countries) and therefore NOBODY has any experience with these great engines...

i would like to get some advice from you guys on how to tune the PFC... i have the Handcontroller, Wideband lambda & a dyno at my disposal... (NO boost control kit)

could you maybe give me some (easy understandable :angry: ) guidelines on how to tune the engine with the PFC... using these 20x20 gridlines for ign. , inj, etc...

turbo & engine should push close to 500hp ...

so go ahead and shoot the info :)

thanks guys...

nico

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Hay man

i have asked this question in many forums and it just happens that no body wants to share their skills in tuning.

the best place for u to hunt for this type of stuff is RX7forum

thoes guys actualy tune their cars and share their maps with each other.

they might give u the basic knowledge and u can tune it ur self.

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;) ... i have worked on a Haltech E6X before, but it cannot be compared to this 20x20 grid on the hand controller from the PFC...

anyway, i just wanted to have some guidlines because i anyway have a dyno and wideband lambda to do the measuring... its just getting the inital hang of it that would be a great help... the rest i will have to figure out myself somehow, but i dont want my engine to suffer from it...

thx anyway guys,

nico

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basically you want to do some runs looking at the map tracer and keeping and eye on the afr, then switch to the setting mode and adjust the relevant cells. I would do the fuelling first, then adjust the ign timing, but i'm not an expert. fuel basically you want to adjust to a target you set yourself. on my car i wanted 11.8:1 up to 7000rpm then richening up to about 11:1 all the way to 8000rpm for a little insurance up top. timing generally you want as much as you can get before it starts to knock.

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Tuning a Power FC is no different to any other ECU, from one of my previous posts this is how I do it;

Tuning with a PFC pretty easy, the base maps are not too far from the right shape. All up the R32GTST took about 40 minutes to tune. My method for A/F ratio tuning;

1. Do a power run with zero correction, took about 8 seconds.

2. Closely look at the A/F ratios from that power run. Took about 3 minutes

3. Pick a range where the A/F ratios were fairly constant but very crappy, which in my case was 4,000 to 4,500 rpm where they were just under 10 to 1.

4. Do another run and used the dyno load to hold it in that rpm range and apply correction until the A/F ratios were between 11.8 and 12.0 to 1. Make sure there is no pre-ignition with those corrections. Took about 15 seconds.

5. Make careful note of that correction, about 5 points made 1.5 A/F ratio diff. Then make guesses for the other load points following the A/F ratios from the first power run. Took about 10 minutes.

6. Do a power run, and tidy up the A/F ratios as required. Took about 40 seconds.

7. Finished.

The real trick is #5, noting how much correction does what to the A/F ratios and where the various load points are on the map. That reduces the time under load on the dyno and it is very fast loading up corrections off line. Doing it in during a power run is tricky and much slower, plus it heats up the engine rather quickly and is not good for the transmission (no 160 kph airflow to cool it down).

Ignition timing is even easier, stick the ears on and advance it up until you hear it ping then back it off. Do that at around 5 or 6 load points, then (off line) extrapolate that over the map. It's always a bit tricky at boost building time, so we have to spend a few minutes in that area getting the timing just right.

One power run to log everything and then maybe a little tidy up here or there. That's the real advantage of a PFC, the base stuff is already there, so you don't have to approach it like EVERYTHING needs changing.

Most of the tuning on the race team cars is done by our dyno guy, he has a "feel" for it. What takes me 10 minutes to get 99% right, he does in 2 and gets it 100% right. :fart:

Hope that helps

:) cheers :D

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Hay man

i have asked this question in many forums and it just happens that no body wants to share their skills in tuning.

the best place for u to hunt for this type of stuff is RX7forum

thoes guys actualy tune their cars and share their maps with each other.

they might give u the basic knowledge and u can tune it ur self.

Sharing maps for RB's is not aways a good idea, let's face it rotaries are pretty much all 13B's. We have RB20/23/24/25/26/27/28/30/31 and you can't just whack an RB31 map into an RB20 and expect it to run. Add in single tubos, twin turbos, 20 or so different camshaft profiles, 15 or more common injector sizes and you can understand why most maps don't transfer from one engine to another.

There is plenty of tuning info on this forum as well as DIY guides, you just have to be prepared to do a search and then spend the time reading.

:) cheers :D

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Hi SK,

Can you please elaborate on this process for me.

"Ignition timing is even easier, stick the ears on and advance it up until you hear it ping then back it off. Do that at around 5 or 6 load points, then (off line) extrapolate that over the map. It's always a bit tricky at boost building time, so we have to spend a few minutes in that area getting the timing just right."

Im guessing that you rev the engine to say, 5000rpm and load point xx, then advance the timing as you described, then go back and at the same rpm go for a bit more load until you have all the 5000rpm points done? I guess you then go back and do all the 6000rpm points and then intrapolate all the inbetween bits?

Have I got this right?

Thanks,

Matt

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SydneyKid,

Great run down. Im sure a lot of people appreciate it.

One question if I may. I have just built a "knock box" with ears. Where is the best pick up point on the RB26 to mount the mic to detect any knock.

Some say mid block near head base others say intake plenum?

Cheers

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  • 4 weeks later...
Hi SK,

Can you please elaborate on this process for me.

"Ignition timing is even easier, stick the ears on and advance it up until you hear it ping then back it off. Do that at around 5 or 6 load points, then (off line) extrapolate that over the map. It's always a bit tricky at boost building time, so we have to spend a few minutes in that area getting the timing just right."

Im guessing that you rev the engine to say, 5000rpm and load point xx, then advance the timing as you described, then go back and at the same rpm go for a bit more load until you have all the 5000rpm points done?  I guess you then go back and do all the 6000rpm points and then intrapolate all the inbetween bits?

Have I got this right?

Thanks,

Matt

You got it Matt.

:P cheers :(

just one more quick question: whats the limit that the knock sensor limit should not exceed ??

From a recent post..............

Firstly, knock sensors are simply microphones, they are calibrated to hear upper cylinder pre-ignition frequencies and pretty much ignore all other noises. Unfortunately there are quite few noises in cars that have similar frequencies to pre-ignition and the knock sensor can't tell the difference. Being a microphone, they simply transfer the noise into electrical signals that the ECU receives and interprets. The displayed knock is simply a number, it's not knocks per minute/second/hour.....it's just a number. In the case of a Power FC (my terminology) 100 is really bad (stop right now and fix it), 80 is bad (stop soon and fix it), 60 is almost OK (get the tune checked as soon as you can), 40 is OK (maybe get the tune checked if you are worried), 20 is perfectly safe (press on) and 10 is too low (the engine is not tuned close enough).

These are consistent numbers under load, not random flashes on overrun.

:) cheers :)

Edited by Sydneykid
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