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RB20DET AP Engineering Power FC Tune

SimonR32

By SimonR32,
in Engines & Forced Induction

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SimonR32 Grand Master

SimonR32

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When my car came over from Japan I got it dynoed @ 1 bar as soon as it came over and it made 274rwhp. Then we backed the timing off (to prevent pinging) and turned the boost up to just under 1.2 bar and it made 297rwhp. It did this with the Japanese chipped standard computer that the car came with. The AFR's were off the chart rich as soon as it came on boost and the overall tune was not very tidy at all.

I decided to purchase a AP Engineering Power FC to get the tune spot on and went to get it tuned. On the dyno the fuel and ignition were being played with but the car did not seem to be making decent power. Timing was around 14 and the AFR's around 11.8 with the boost set around 1.2bar. The motor was struggling as soon as it came on boost. At around 4.5k it stopped making power at around 240rwhp and then fluctuated between about 230-250rwhp all the way throught to redline.

It did not seem to be missing but we changed the plugs, changed the AFM with a brand new one and everything seemed to be working fine but the car was just not making power. To check it wasnt anything mechanical I plugged the Japanese remap in and the car once again made decent power so it has to be something to do with the Power FC.

Mods done to the car so far are.

GTR front mount

GTR injectors with resistor pack

Z32 AFM

GTR Fuel Pump

Decent sized Apexi BB Turbo

Auto to Manual Conversion

I have talked to many ppl about the problem and noone seems to be able to shed too much light onto what could be wrong with the tune. Can anyone offer any suggestions on what the problem could be? The only things I can think of is the Auto loom causing some kind of problem as the computer is only meant to be used with a Manual car only.

PLEASE PLEASE HELP. This is total :bs!: and is pissing me off and stressing me out

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Sydneykid Grand Master

Sydneykid

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As the guys have already suggested, ignition timing would be where I would start. Check it with a timing light at 5,000 rpm with the chipped ecu and compare that to the Power FC at the same RPM.

SimonR32 Grand Master

SimonR32

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user posted image

Went and got some runs printed out from the dyno today. The blue shows the power fc tune while the green is half a run with the jap retune, it would have made around about 290rwhp+ with a full run.

The power fc is tuned with afr's about 11.8:1 while the jap tune is a LOT richer than that.

Will test the timing with the light toinght and get back those results tommorrow.

Once again thanks for the help

Sydneykid Grand Master

Sydneykid

Posted
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Looking at the power graph, my first guess would be that the ignition timing is all over the place. Since the boost and A/F ratios are stable, that's the only logical alternative. It's up and down more than 20 rwhp in some places. Very interested in seeing the A/F ratios graph and what happens when you run the timing light over it.:cheers:

  • 2 weeks later...
dangerous_daveo Grand Master

dangerous_daveo

Posted
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']try some new knock sensors

i suspect yours have failed, and are retarding the timing coming onto boost

other options : test the power fc in another car to see if thats the cause.

Id doubt it would be them, as chaning ECUs shouldnt change those problems.

It pretty much has to be narrowed down to the ECUs tune and or wiring.

Id also just double check to see if their AFR metre gauge thingy it working correctly, as if that is out, then it would be throwing out their tuning something chronic. (had it kinda happen before, AFR line was fine, just down about 2 on what it should have been ie should have been at 12, but was reading about 10)

jnr32r Proficient

jnr32r

Posted
Posted
As the guys have already suggested, ignition timing would be where I would start.  Check it with a timing light at 5,000 rpm with the chipped ecu and compare that to the Power FC at the same RPM.

Why do you say to try comparing the timming at 5000rpm not say idle?

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