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Retuning A Pfc For Running In New Motor


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i had my rb25 rebuilt (with stock parts) a few months back. We didnt change anything on the pfc during the run in stage.

Once i had done 1000km and it was way past the being run in stage my tuner slaped it on the dyno and made a few minor adjustments.

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well just get it tuned after you bed the rings :angry:

nice and easy really

Rings wont bed if you wash the bores. Just run it in on the dyno - get them to do a bottom end tune up to 3 or 4 psi of boost and 5000rpm.

Edited by rob82
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With the new motor I'm going to run 440cc injectors and z32 afm although these could be fitted after it's initial run in.

Shouldn't I do something to the tune before I even turn the key?

Would it even run with the rb20 tune?

How long does it take to run it in on the dyno?

It sounds expensive at $120+/hr

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With the new motor I'm going to run 440cc injectors and z32 afm although these could be fitted after it's initial run in.

Shouldn't I do something to the tune before I even turn the key?

Would it even run with the rb20 tune?

How long does it take to run it in on the dyno?

It sounds expensive at $120+/hr

can't help you with the power fc info, (still trying to sort mine out!!)

but we used to run in 400HP+ 11 sec V8's in less than an hour on the dyno, they can put the engine under high load at moderate rpm's, half a dozen run ups like this is more effective than you driving up a hundred hills in the next month.

after the dyno session the engine is basically run in, from memory, you just need avoid 75% & above RPM range for say 500k's, but this way, the rings are definately bedded & you can 75% flog it straight outa the box.

Prolly a mineral oil (or semi synthetic) for start up & initial dyno work, then full syn after 500k's

Talk to your local dyno guru, he will surely give you the right routine! It's a darn site better than having to do so many rpm for the first 500, then so much for the next 500 & so on.....................................

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If no access to dyno I would leave the injectors off and replace the power fc with a stock ecu for the first 500km or so, then install injectors and power fc and dyno tune at the same time... but I maybe overly cautious

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The problem is i live in a regional center and there is nobody with a dyno locally.

I would have to trailer my car to the goldcoast or brisbane but I don't know who to trust.

Booster, know how you feel brother...................aint even a dyno in the COUNTRY where i live.

i think your biggest problem is going to be loading the FC with RB25 stuff, good luck, i wish i could help.

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I doubt you could run the motor with a stock rb20 ecu as it has over 30% more capacity than an rb20.

Could you just factor in a 30% fuelling increase into the pfc and see if it starts and immediately check the afr and trim it accordingly?

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Could you just factor in a 30% fuelling increase into the pfc and see if it starts and immediately check the afr and trim it accordingly?

No. The PFC uses airflow to calculate fueling anyway, if you're running a larger engine it will inject more fuel. However it will probably run rich as shit because on an RB20 pulling that much air at those revs would be very high load, so you will wash your bores down. Adding 30% more fuel will make the problem worse.

You've just spent a few grand rebuilding an engine, spend a few hundred bucks getting it put on the dyno, they can start it and get a base tune going and do a few ramps up to 75% redline at a few pounds of boost like rob82 said.

You should always run an engine in a proper state of tune. Anything else is just brainless.

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Like I said the rings wont bed if its too rich as it will wash the bores - so run it in on the dyno and make sure your mixtures are right.

I was hoping he would be using a builder/workshop to run it in etc so they "should" know whats needed

:D

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Here’s what I would do;

Use the PFC

Drain the tank and put some Shell Optimix Extreme 100 ron in it.

Stick the 444 cc injectors in it

Reduce the injector duration by 30% (close enough for 444 cc’s / 270 cc’s)

Start it and check the exhaust pipe smoke

If it’s thick and black, then take another 5% out of the duration

Let it warm up at a fast idle, say 1200 to 1500 rpm till it gets to ~80 degrees

Drop the idle to normal (~750 rpm)

Then check the exhaust pipe smoke, smell it

If you can smell heavy unburnt fuel, then lean it off 2% at a time.

The PFC will go into closed loop running once the unburnt fuel smell is gone.

Keep the boost low, take it for a drive and watch the knock readings on the Commander.

If you are getting ANY knock, retard the ignition until it disappears

After 15 minutes or so, go home, open the bonnet, pull up a chair and have a beer

Once the engine is cooled down, pull the plugs out and have a look at them

They should be dark brown, but not black.

If they are not black, then set off early in the morning to the dyno.

Try and make sure you run closed loop cruising as much as possible

By the time you get there it will be run in enough for a mild tune.

:) cheers :)

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