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Quick R+R Question


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Just did some sensor logging and some full throttle runs to see how my setups is running: Stock ecu, but hypergear high flow @ 9-10psi and a 3 inch turbo back exhaust.

From second gear pulling to about 100kmh, I notice there is 30 degrees of timing around 4k rpm which drops to 12 degrees by 4.7k rpm. Interestingly it climbs back to 20 degrees by 5.5krpm and holds that until ~6.2k rpm.

Max AFM signal reaches 4.94, FWIW.

Normal, abnormal? Or anything else I should look out for in the logs?

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Just buy a nistune/aftermarket ECU. You will be amazed how much better it runs

The ECU will be confused with the extra airflow it's getting and I would put money on what your seeing being a case of R&R

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How are you logging timing?

By the way, I agree that it's normal for RB25s to do as you have described. It is not "correct" for them to do it, because there is no real reason for timing to go all the way back to 12deg apart from deliberate R&R and possibly the ECU detecting enough knock to pull even more timing.

I don't know what the normal RB25 maps look like in detail (because of the lack of Nistune for them), but the Neo maps don't go as low as 12deg anywhere.

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TP Load is just TP load, doesn't really mean anything..

No - not true. AFM voltage -> VQ curve -> divide by rpm -> multiply by "k" and one or two other little tweaks gives the answer = TP.

RB25 and RB25Neo have the same AFM and therefore VQ, the same rpm and basically the same flow characteristics vs rpm (sure, a bit in the favour of the Neo). For any given actual load on the two engines, I would have expected the two different ECUs to actually come up with about the same TP.

Given that you say the image you grabbed is from a VG30 ECU, that probably explains it. If the VG30 ECU was connected to an RB25 AFM, then you'd have to rescale k and that may well bring the TP index down to lower values.

As a counter example, stock RB20 maps top out at 80 TP or thereabouts, and when I wound the boost up on mine I had to rescale the maps to 104. Or maybe they stock out at 104 and I wound them up to 128. No...that's right....I reckon they start at 128 and I had to wind them up to 160. Doesn't matter anyway, and I can't check anything Nistune right now because I'm in the US and my laptop's motherboard has just shat itself. Blue screens from memory faults (on two good sticks of RAM!!!) every 4 minutes.

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I've datalogged my R34 GTT as well and it has a massive ignition hole in the midrange. Same deal, ~25 degrees drops to ~14 degrees and then once it's past peak torque the timing shoots back up into the 20's. Car is 100% stock.. need to pull my finger out and fit the Adaptronic I've already got :P

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