Adaptation to Electronic Tuning?

[yky]

Hi,

Has anyone any idea whether the car's stock ECU would ultimately adapt to a piggyback ECU's ( OBit ) attempts to feed false ( altered ) data to it, cancelling any improvement in performance? That's what adaptation is all about isn't it?

From what I read in the writeup by WT, it seems that would be the case.

If that is so, does that mean that piggybacks or even AFC would not be useful methods of tuning for BMs?

Thanks for any advise.

 

[Whisky_Tango]

Re: Adaptation to Electronic Tuning?

Hi,

Has anyone any idea whether the car's stock ECU would ultimately adapt to a piggyback ECU's ( OBit ) attempts to feed false ( altered ) data to it, cancelling any improvement in performance?

Not necessary. So long as the close loop mode AFR is not remapped. Close loop mode is ON during idling and to some speed or loading which still is a question.
So just for simple analogy, we assume close loop mode is during idle and to 3000rpm.
At this range fuel mapping must not be touched. Reason is that the ECU will make sure that AFR of 14.7:1 is obtain. And if you have touch this range, the ECU Long Term Fuel Trim (LTFT) will be messed up.

Outside this range, 3000rpm(assumption) onwards to redline. You can do whatever you want. No issue.

That's what adaptation is all about isn't it?

Yes, its STFT and LTFT. When ur car loose power, reset the ECU and the LTFT will be erased and re-adapt each time u start, drive and shut off. But this is not a solution.

From what I read in the writeup by WT, it seems that would be the case.
If that is so, does that mean that piggybacks or even AFC would not be useful methods of tuning for BMs?

Yes it will be the case.

So long as close loop mode is untouch, piggybacks and AFC will work.

Cheers!

 

[yky]

Thanks for the info,

There had been many instances in the forum whereby members gave glowing reports after piggyback installation ( better then OBD flash programing even ), testifying to the potency of the mod.

Why do you think it is so if the STFT and LTFT will adapt back to its original settings anyway as the piggyback is tuned for maximum improvement 'across the range', ie. both closed and open loop phases?

Thanks

 

[piggyboyz]

Hi there...

I remembered that u were asking for the re-mapping for your car right ?

I think they r now able to do it on your E65 liao... Try checking back again

 

[yky]

Thanks piggy,
Can't tahan to wait so long for HIOP program to be ready.
After hearing so many good reports on OBit from our members, went to BVO and took the plunge. So far very good results.

As Bernard said that he tuned the Obit 'across the range', I took it that he did also tuned the close loop portion as well. So by right, the ECU should adapt back to its original settings sooner or later.....I just hope that it's later...or not at all , as I am enjoying the improved 'light' feeling of my drive now

If the car really adapts back to the original power settings, then may have no choice but to do flash programming liao....this will not adapt right?

By the way, any idea whether the Obit and flash programing ( HIOP ) can co-exist or must I remove the Obit B4 flashing?

Thanks again.

 

[Racebred]

obit being the piggyback will override the hiop reflash program.

i've been wondering very long how obit control ignition timing since our ECU constantly coorelates the the crankshaft sensors to the cam sensors, which are linked to our DVANOS unit, which is not touched at all by Obit. this is because unlike e-manage which controls the ignition coils directly, obit attempts to fool the ecu into thinking the "position marker" for the crankshaft sensor is somewhat behind, therefore advancing the timing.

I believe unsuccessful closed-loop checking of the relative positions of the crankshaft and camshaft sensors will cause the vehicle to shudder.

which brings about another qn, so does it mean that using this method, retardation is not possible?

i'm been thinking about this for very long, to decide if i should go obit or not. anybody with any insights? but then also all the cars that came out with obit installations are sui sui too.

 

[yky]

So far my car sui sui...but as I said, don't know if the clever factory ECU will adapt or not in the long term.

Bernard specifically told me that he tunes the Obit to alter the AFR only.
I asked him if he touches the ignition timing at all and he said no. He said that by doing, things would get 'messed up', whatever that means.

I tried looking into the Cartronics website for more explanation on Obit but I find it hard to understand.

 

[Shaun]

RB, it makes perfect sense since DVANOS needs to reference crank position to phase the cams. If DVANOS is active at all load and RPMs, then the loop is always closed and ign timing changes cannot be made. And now YKY reports that Bernard says he doesn't touch ign timing at all. So it all goes together.

So now the benefit of Obit has been narrowed down to open loop AFR only.

Closed loop AFR cannot, ignition timing under any circumstance cannot.

I did not remember about DVANOS in previous analysis. Now it is revealed to be even worse than I originally thought.

 

[Racebred]

okay thanks for the explanation yky. So that means it's like an SAFC but better coz it has 8 load points while SAFC has only 3. I wonder if cartronics themselves has any solution to the ignition conundrum. piggybacks are useful only if they can outsmart the ecu in which case bmw electronics are too high tech liao.

 

[piggyboyz]

As Bernard said that he tuned the Obit 'across the range', I took it that he did also tuned the close loop portion as well. So by right, the ECU should adapt back to its original settings sooner or later.....I just hope that it's later...or not at all , as I am enjoying the improved 'light' feeling of my drive now

If the car really adapts back to the original power settings, then may have no choice but to do flash programming liao....this will not adapt right?

By the way, any idea whether the Obit and flash programing ( HIOP ) can co-exist or must I remove the Obit B4 flashing?

Thanks again.

Re-programming will overide whatever the existing program, but only to the portion on the engine management. This will means that the new program will be the base line for the engine parameters to run. Piggyback, by definition, will still make use of the existing factory programme and make adjustment to it. For a car w/o adaptation, like the E30 and E36, it will make more sense to have a piggyback than a re-programme since now the fine tuning can be done everytime u do a mod on a piggyback, wheras in Singapore, u can't fine a tuner who runs a dyno tune, then store into a chip and fix it..

The engine management will definitely re adapt if the parameter is outside what the factory setting are.

We have talked about it a couple of time and there is no reason why we should tune the close loop section unless u have done some serious mod to the car. The reason being that the close loop thingee is when the car is cruising and in such mode, u don need power, so the engine management gives the maximum economy. Tuning it just makes it less economical

The engine takes between 2 days to 2 weeks for re-adaptation from short term to long term trimming. The factory management have got like 6 setting that can store driving behavior, from super economy to very aggresive driving mode. That is the reason why there are ppl who will complain that the car takes a while to response when they suddenly do a kick down after they have been driving gently for a while.

Try putting in a CAI into the car and the car straightaway hunt for a while. This is the adaptation taking place, short term one. When moving, the car keeps on storing data and make adjustment based on the new toy u fitted. That is long term.

If u were to decide on re-programme the car later, the piggyback must be retuned again sicne now the factory setting is different.

Anyone who is interested to read up more on this can let me know, i have got the pdf files of how the engine management works for our car. But the file is 2.4MB though..

 

[Shaun]

Alan, PMed you my email address. THanks

 

[yky]

Aiyah! Does that mean that in normal layman language, flash programing would still be more desirable ( reap benefits across the range ) then piggybacks for the clever BMW ECUs? :ehhh:

 

[piggyboyz]

Aiyah! Does that mean that in normal layman language, flash programing would still be more desirable ( reap benefits across the range ) then piggybacks for the clever BMW ECUs? :ehhh:

Very Simply, yes cos the programmer can tune the car in 3 dimensional by taking care of engine load, ignition timing and AFR by simple programming taking care of details..

 

[Racebred]

but flash programming is more like a shirt you buy off the store. S, M, L, XL only. If they get it right the first time, subsequent customers will all get good products.

piggyback is like a tailor made shirt. if properly done, it should be superior to one size fits all.

since the cost is about the same, ultimately you as the consumer should choose what you think is more suitable for you.

however, piggybacks that cannot control the ignition timings will lose one dimension of power improvements.

 

[Whisky_Tango]

Why do you think it is so if the STFT and LTFT will adapt back to its original settings anyway as the piggyback is tuned for maximum improvement 'across the range', ie. both closed and open loop phases?

Thanks

In close loop mode, the ecu MUST have Oxygen Sensor readings and this reading MUST be 14.7 AFR(+/- 0.5). This value is the most ideal for complete Petrol combustion which has less exhaust emission.
So if lets say the close loop AFR is remap for performance, tune to 13 AFR (means running richer), the ecu will detect this "out of bound" value and re-adjust back to 14.7 AFR.

How the ecu adjust back to 14.7 AFR is by leaning out the petrol. Meaning ecu will slow down the fuel pump and/or reduce the fuel injectors open duration (duty cycle) until the oxygen sensor reads 14.7 AFR (+/- 0.5).

While ecu is running the above process, STFT values are changed instantly and overtime (30mins of running or a day or two) the LTFT adaptation comes in. Please read "5) What is Short Term Fuel Trim (STFT) and Long Term Fuel Trim (LTFT) from the "Summary of Aftermarket ECU" thread. It tells you how STFT & LTFT adjustments can be disastrous!! for this case.

In open loop mode, ecu DOES NOT REQUIRE oxygen sensor reading and thus 14.7 AFR WILL NOT BE MET. So you can lean out or richen the petrol to get your desired power.

The rest both Piggy and Shaun have explained too.

 

[k3nny]

piggyboyz: Do u mind emailing me the file?

And then i wouldnt mind hosting it and putting a link here for ppl to download it.

If u dont mind, lemme know and ill pm u my email address.

Thanks