Auto rescaling not just scalers but also maps

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Re: Auto rescaling not just scalers but also maps

Postby Matt » Mon Jun 18, 2018 11:58 am

One thing which is missed from the above, especially regarding the 1000CC injectors is that the fuel values need adjusting by the same amount that TIM is adjusted for. For example:

370CC to 1000CC is about 2.7x the amount that TIM needs to be reduced by, but we also find that we have to flatten the fuel map by the same amount for it to keep the same AFRs (so values around 60 in the fuel map would now be about 22 in the top end)

NeWT
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Re: Auto rescaling not just scalers but also maps

Postby NeWT » Mon Jun 18, 2018 11:27 pm

If you agree that you need to adjust TP for boost, you not only need to rescale TP for fuel and timing, but then also find that your VCT, O2 feedback, Knock feedback, throttle enrichment etc are all operating from the previously configured TP scales, then you need to adjust TP for all of those too.


Are you sure that I need to readjust all TP related parameters if I replaced MAF and K? And if I rescale scalers? I thought "no", because:
Lets talk about real physical airflow in kg/min. And let this airflow be X kg/min at original R34 config at max 160TP, for example. Then I'm changing MAF to Z32 and K for (example) +50%. Then my max TP will be 160 + 50%= 240TP. But as I done this, the airflow of X [160TP pink MAF] will be equal to X [160TP Z32 MAF]. Am I right?
And if we will ajust scalers. I thought that TP scalers are only for fuel/ign/purge/VE maps, and not for other TP related parameters?
Then I think that if I look, for example, to VTC TP enable (=56 at stock ER34), then it will be right to leave it as is cause real airflow at TP56 [pink MAF] = TP56 [Z32 MAF].
Or no?

NeWT
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Re: Auto rescaling not just scalers but also maps

Postby NeWT » Mon Jun 18, 2018 11:42 pm

And after this, when I will want to reduce K and reduce TID to fit my "very strong in HP" car to max TP of ~250 (or smaller, just not to allow TP limited by 255), the K and TP will sail away, and only now I need to look at other TP related parameters? And I think, for example about VTC, it must be:
(56 (stock)) / ((K after MAF replaced) / (K after K reduced with TID reduced)).
So TP in VTC will be smaller then stock now.
It's my opinion. What do you think, colleagues?

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Re: Auto rescaling not just scalers but also maps

Postby Matt » Tue Jun 19, 2018 12:21 am

Lets talk about real physical airflow in kg/min. And let this airflow be X kg/min at original R34 config at max 160TP, for example. Then I'm changing MAF to Z32 and K for (example) +50%. Then my max TP will be 160 + 50%= 240TP. But as I done this, the airflow of X [160TP pink MAF] will be equal to X [160TP Z32 MAF]. Am I right?


Resize R34 MAF to Z32 MAF would be from K=348 to K=600 so that is a 1.72x multiplier. Our maximum TP (at max Z32 load) would be from TP=160 (say with R34 at 12psi of boost) to TP=275 (more than the map can physically index, so that is limited to 255)

The maximum HP capacity of the MAF figures changes from ~290HP to ~500HP

Current scales:
24 32 40 48 56 64 72 80 88 96 104 112 120 128 144 [160]

New scales
41 55 68 82 96 110 124 137 [151] 165 179 193 206 220 248 255

At 12psi where our MAF reads previously at 160 at full boost, looking at the above table we should now be maybe half way here. However VQ map is exponential, so actual position may be less with the Z32 MAF

And if we will ajust scalers. I thought that TP scalers are only for fuel/ign/purge/VE maps, and not for other TP related parameters?

VE is not TP based. Purge is not either. Other TP related parameters (for warmup, O2, feedback, accel enrichment) are available on per ECU basis (based on that I or others have discovered so far from diassembly)

Some background (based on actual tuning, not theoretical), we found massive issues with using a HPX MAF (3" 640rwhp) calibrated on my R34 prior to FP, whilst we could get K constant set correctly during warm dyno runs, the K constant resulted in higher TP and therefore high vlaue TP scales, that all ended up affecting O2 feedback and warmup.

My R34 with such a high TP ran so crap, that I have up using HPX back before working on feature pack. I did not code TIM for the injectors (no one was really running 1000CC five years ago) but for the HPX MAF support. Once I could pull K constant (and TP) lower, then the ECU started 'behaving'

Then I think that if I look, for example, to VTC TP enable (=56 at stock ER34), then it will be right to leave it as is cause real airflow at TP56 [pink MAF] = TP56 [Z32 MAF].

Off boost the TP will kick in around the same area perhaps on both cars. Would need to compare side by side against boost measurement vs TP map refernece to show if it is still activating VCT, and sticking in closed loop in the same areas than prior to tuning


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