PI : DI Ratio Discussion

[freerunner]

Originally Posted by KoolBRZ

PP.S. Do I make timing advances to Base timing A, B, or some other table?

Base B.

edit: base timing A is for emergency mode, I believe

PS: thread has been turned to awesome overnight (at least in my timezone )

[ztan]

Originally Posted by freerunner

Base B.

edit: base timing A is for emergency mode, I believe

PS: thread has been turned to awesome overnight (at least in my timezone )

Base timing A is only active for a short time after ECU reset. EcuTek define it as AVCS inactive. There is a float value in the code (at FFF8ADB8 in A01G) which equals 0.0 when inactive and moves to 1.0 within a few minutes of ECU reset which interpolates between the tables.

The vast majority of the time is spent on Base timing B.

[steve99]

Originally Posted by KoolBRZ

I want drive-ability and power, and I want it smooth with no flat spots. I want smooth economy up to .7 load, and acceleration from .7 to 1.0 load, then sheer power from 1.0 to ~3.0 load. Yes, I am slightly super-charged with the Phantom ESC, and that's how I can get to 3.0 load. That change thambu19 made to the PI to DI ratio table has made more of a difference to open-loop acceleration than any other improvement I have made so far. Closed loop is pretty good too. Since I am super-charged I can't boost my timing by too much, since I am already using Shiv's Phantom ESC tune's timing tables. If I'm having a hard time improving on his table, that's my way of showing respect for his work. I'll always keep trying though.
P.S. @thambu19 can you please get an OFT? There are always a few for sale in the member classifieds. OFT users need your input. I can also send you a tune with my revised AVCS tables, and you can show me where I went wrong.
PP.S. Do I make timing advances to Base timing A, B, or some other table?

Use Base Timing B

Their is rearly no difference between using oft or tactrix other than ease of use if were just talking flashing rom is same.

Oft has far easier to use logging and real time display, tuning alerts ect. which tqctrix does not.

[thambu19]

Originally Posted by steve99

Use Base Timing B

Their is rearly no difference between using oft or tactrix other than ease of use if were just talking flashing rom is same.

Oft has far easier to use logging and real time display, tuning alerts ect. which tqctrix does not.

@KoolBRZ My car is still STOCK. Yes that sucks to hear I know. It wont stay stock for long. Fact of the matter is I did not even know that there was a way to get into the ECU until I stumbled upon this forum a month ago or so ago so I am new to this forum. I got the Tactrix because I blew my yearly budget on my M3. I think the OFT is GREAT. Simply great. I gotta wait though. The work the OFT guys have done is mindblowing but take this: OEMs spend two years calibrating something and they still cant get everything right. The OFT folks got two - three weeks to do the same. So we continue where they left off.

I forgot you were on the Phanton ESC. If you are boosted even slightly the gains you will see from 100% DI will be far more than those with NA will see because earlier with 50% PFI you were probably just short circuiting fuel into the exhaust for no reason. Short circuiting fuel is also bad for exh and CAT because the fuel dumped will burn up there causing heat and stress. But by going DI you may now see some lean-ness in the exhaust being picked up by the O2 sensor but that is okay.

Regarding AVCS or timing it is an altogether different topic and we should start a timing discussion like this PFI/DI. In short though with even a slight boost your timing should be slightly (2-5 deg) more advanced (open and close earlier) than stock timing depending on how much boost you are running. With a lot of boost it will be more advanced. I can explain why in another timing thread.

[thambu19]

Originally Posted by steve99

@thambu19 how much PI is needed and where load rpm wise to maintain intake valve cleaning properties ?

another question, if you have a look at the intake cam tables at low load rpm they do a weird dance go from zero then negitive then back to zero then increase above zero. I have assumed the negitive dance was emmissions related ?

@steve99
Are the negative values real? I mean does the the cam actually go there? I thought the rage of authority was only from 0-40deg for intake.
In that case the negative values could be a strategy to force the cams to go to their end-stop or lock-pin positions where Duty cycle = 0. Next time you log data in that area can you check if the DC goes to 0 at this region? This will be a strategy to learn end-stop location so that the ECU can learn the shift in position if any due to tolerance limitations part to part or even chain stretch when it happens on a newer engine. I see that exhaust does not use it. Not sure why not.

[Kodename47]

Originally Posted by thambu19

@steve99
Are the negative values real? I mean does the the cam actually go there? I thought the rage of authority was only from 0-40deg for intake.
In that case the negative values could be a strategy to force the cams to go to their end-stop or lock-pin positions where Duty cycle = 0. Next time you log data in that area can you check if the DC goes to 0 at this region? This will be a strategy to learn end-stop location so that the ECU can learn the shift in position if any due to tolerance limitations part to part or even chain stretch when it happens on a newer engine. I see that exhaust does not use it. Not sure why not.

IIRC the Intake cam 0 position is 10 degrees from minimum, ie it can go to -10. Cam calibration is done within the 1st minute or so after reflash at idle.

Regarding AVCS tuning, go for this thread: http://www.ft86club.com/forums/showt...highlight=AVCS

[KoolBRZ]

Originally Posted by thambu19

@KoolBRZ My car is still STOCK. Yes that sucks to hear I know. It wont stay stock for long. Fact of the matter is I did not even know that there was a way to get into the ECU until I stumbled upon this forum a month ago or so ago so I am new to this forum. I got the Tactrix because I blew my yearly budget on my M3. I think the OFT is GREAT. Simply great. I gotta wait though. The work the OFT guys have done is mindblowing but take this: OEMs spend two years calibrating something and they still cant get everything right. The OFT folks got two - three weeks to do the same. So we continue where they left off.

I forgot you were on the Phanton ESC. If you are boosted even slightly the gains you will see from 100% DI will be far more than those with NA will see because earlier with 50% PFI you were probably just short circuiting fuel into the exhaust for no reason. Short circuiting fuel is also bad for exh and CAT because the fuel dumped will burn up there causing heat and stress. But by going DI you may now see some lean-ness in the exhaust being picked up by the O2 sensor but that is okay.

Regarding AVCS or timing it is an altogether different topic and we should start a timing discussion like this PFI/DI. In short though with even a slight boost your timing should be slightly (2-5 deg) more advanced (open and close earlier) than stock timing depending on how much boost you are running. With a lot of boost it will be more advanced. I can explain why in another timing thread.

I've done quite a lot of work in AVCS timing. I'm no expert though, just trial and error to find what drives better. The AT's are a whole other driving experience. The trans controller hasn't been cracked yet, so we AT owners have to tune to whatever trans controller wishes. It shifts when it wants to. A common issue is bogging after each shift, since they are geared much higher and have no way to slip the clutch to gain more power. Another common issue is rubber-band shifts in manual mode. I believe this is caused by the ecu's delayed reaction to the change in rpm's. It is completely solved by using the correct ratio of port injection to direct injection. @thambu19, your table has gotten rid of most of the rubber-band shifts in manual mode, and there is no bogging after shifts in automatic mode.
How would you like to contribute to a new thread, "PI to DI ratios and AVCS timing", since they do interact and affect each other? I think you should start the thread, based on the knowledge and experience you have.

[ztan]

Originally Posted by thambu19

Regarding AVCS or timing it is an altogether different topic and we should start a timing discussion like this PFI/DI. In short though with even a slight boost your timing should be slightly (2-5 deg) more advanced (open and close earlier) than stock timing depending on how much boost you are running. With a lot of boost it will be more advanced. I can explain why in another timing thread.

As well as Kodename47's thread, I also started one a while ago for boosted settings: http://www.ft86club.com/forums/showthread.php?t=85773

Would value your input on the differences between supercharger and turbo theory for AVCS.

[KoolBRZ]

It occurred to me that @thambu19 made his table before he had the means to edit the thresholds, so I created a table with the cells below .35 zero'd out, because the thresholds would have forced them to be treated as 0%. I'll be trying that one and several others tomorrow. So far only the tables very close to being identical with @thambu19's table have even come close. The tune with his table seems somehow unfinished, to drive just a bit off. So I've been trying to add or change it a little bit at a time to polish it and make it better. With an AT it's easy to know when a tune is right. The transmission shifts smoothly, with no hesitation, it accelerates easily, and just seems to coast when I let off the throttle.

[ztan]

Originally Posted by KoolBRZ

It occurred to me that @thambu19 made his table before he had the means to edit the thresholds, so I created a table with the cells below .35 zero'd out, because the thresholds would have forced them to be treated as 0%.

Almost...

The table values get interpolated and the thresholds are applied to the interpolated values, not the table values. So: a transition from 40% to 30% will be slightly more gentle till it hits 35% and gets cut than a transition from 40% to 0% will be.

[thambu19]

@KoolBRZ
Keep in mind that the shifting of an AT has many more parameters that affect it one of those being the torque model accuracy. The transmissions controller gets the torque (modeled) from the engine controller and uses the number to determine the clutch/band engagement and disengagement time to make sure there is not drag on the off going element etc which can cause hesitation. Imagine this like a DCT transmissions where both clutches are engaged at the same time wearing out both clutches and bogging down the engine during the shift. In normal case the modeled torque goes up as the estimated airflow goes up (via supercharging).

So with the AT it could be a zillion things that are making the perceived shift feel better.

I am going to be away for a week (vacation in Puerto Rico) so hope you guys would have perfected the DI/PFI by then.

Reg AVCS lets not start a new one. Let us use either @Kodename47 or @ztan thread and have those discussion going there. Yes the AVCS for turbo will be different from SC. The WOT timing for NA would be perfect on the OTS maps no doubt about that. There is probably more on the table at part throttle to improve drive feel but that will come at the cost of FE so not many will want to do that.

[thambu19]

We have been discussing here a lot and still dont know anyone personally. Need a thread to get to know each other better. A personal touch or connection can go a long way

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[KoolBRZ]

Originally Posted by thambu19

@KoolBRZ
Keep in mind that the shifting of an AT has many more parameters that affect it one of those being the torque model accuracy. The transmissions controller gets the torque (modeled) from the engine controller and uses the number to determine the clutch/band engagement and disengagement time to make sure there is not drag on the off going element etc which can cause hesitation. Imagine this like a DCT transmissions where both clutches are engaged at the same time wearing out both clutches and bogging down the engine during the shift. In normal case the modeled torque goes up as the estimated airflow goes up (via supercharging).

So with the AT it could be a zillion things that are making the perceived shift feel better.

I am going to be away for a week (vacation in Puerto Rico) so hope you guys would have perfected the DI/PFI by then.

Reg AVCS lets not start a new one. Let us use either @Kodename47 or @ztan thread and have those discussion going there. Yes the AVCS for turbo will be different from SC. The WOT timing for NA would be perfect on the OTS maps no doubt about that. There is probably more on the table at part throttle to improve drive feel but that will come at the cost of FE so not many will want to do that.

Because it can't be that warm where you live. I've visited Michigan, in the summer. Of course PFI/DI will be perfected by the time you get back. Then you'll show me where I went wrong and I'll have to start all over again. You should see my AVCS tables. Works of art but probably wrong in any number of places. I'll post them in the other AVCS threads. I have to swallow my pride if I want to learn how to tune better. I think it's safe to say that you are a master and I'm not.

[sato]

Humble people... I love this thread!

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