[dzenno]

I'll tell you one thing, its definitely not about logging but its cool that we can

[Joshboody]

The last graph, timing event happened right when you stabbed the throttle... cool.

For the procede operation, if we have to use 1 cylinder for reference... how about giving us the option to choose the cylinder that we log and autotune. Of course we need the ability to log all cylinders at once to diagnose which is the weakest cylinder.

Shiv, would monitoring all cylinders be a processing issue?

Dzenno, do you see a trend with certain cylinder corrections more prevalent... or fairly even?

[dzenno]

Originally Posted by Joshboody

The last graph, timing event happened right when you stabbed the throttle... cool.

For the procede operation, if we have to use 1 cylinder for reference... how about giving us the option to choose the cylinder that we log and autotune. Of course we need the ability to log all cylinders at once to diagnose which is the weakest cylinder.

Shiv, would monitoring all cylinders be a processing issue?

Dzenno, do you see a trend with certain cylinder corrections more prevalent... or fairly even?

I haven't really had a chance to do any decent compares/correlations...might do that actually as I've got tons of logs at this point

[themyst]

Originally Posted by Joshboody

The last graph, timing event happened right when you stabbed the throttle... cool.

For the procede operation, if we have to use 1 cylinder for reference... how about giving us the option to choose the cylinder that we log and autotune. Of course we need the ability to log all cylinders at once to diagnose which is the weakest cylinder.

Shiv, would monitoring all cylinders be a processing issue?

Dzenno, do you see a trend with certain cylinder corrections more prevalent... or fairly even?

The problem is the piggy vendors need to find the CAN command to monitor the other cylinders. The good news is CPS does offset ignition globally so it is useful for suppressing those dropouts more so than not running CPS, even if we can't monitor it.

[dzenno]

Originally Posted by themyst

The problem is the piggy vendors need to find the CAN command to monitor the other cylinders. The good news is CPS does offset ignition globally so it is useful for suppressing those dropouts more so than not running CPS, even if we can't monitor it.

Applying ignition "retard" globally through CPS is fine and does work as designed/intended as we know and have seen with the Procede and on the JB4/CPS module...the issue is when you base other algorithms and allude to adding ignition advance using CPS offsetting based solely on cyl 1's timing that freaks me out...especially if a piggy takes into account only ignition timing dropouts and not the ideal timing curve for given CPS offset...AFAIK this isn't the case with the procede anymore with their autotuning but I haven't had a chance to see it/log it so no idea..

[Joshboody]

My understanding of autotuning looking at the opened maps and speaking with Shiv long time ago is that it targets a certain ignition advance at rpm/boost. So:
- There's an advance target that's related to aggression (actual I assume)
- IC is adjusted based on DME adv target and potentially knock events
Let's say you have X as the low side IC... maybe 30%
and Y as the high side... maybe 70%

When you reach X, then boost will start to increase... once you reach Y, then boost will decrease... and on you go.

Much of above is conjecture on my part.

This is without DIC... would love to know more about Shiv's DIC.

[vasillalov]

Originally Posted by dzenno

Sure it will, of course...DME is built with its own version of "autotune" in mind to save the engine and I'm not being sarcastic at all actually...these timing corrections show it pretty clearly...procede's ignition correction is sort of along the same lines only that its global across all 6 cylinders..

I *suspect* that Shiv will come in and say that by using CPS offsetting, he is shifting the overall ignition advance up and the DME is still capable of making per cylinder corrections. But this is just a guess at this point.

Individual ignition correction has been done for several reasons: fuel efficiency, power and primarily for safety. Engine manufacturers long ago have known that there could be a significant variation in the operating environment between cylinders, especially in longitudinally mounted engines where the front of the engine sees cooler temperatures than the rear of the engine...

[themyst]

Originally Posted by vasillalov

I *suspect* that Shiv will come in and say that by using CPS offsetting, he is shifting the overall ignition advance up and the DME is still capable of making per cylinder corrections. But this is just a guess at this point.

Individual ignition correction has been done for several reasons: fuel efficiency, power and primarily for safety. Engine manufacturers long ago have known that there could be a significant variation in the operating environment between cylinders, especially in longitudinally mounted engines where the front of the engine sees cooler temperatures than the rear of the engine...

That's precisely what he said in the first page of this thread. Our motors wouldn't last too long if it didn't make those per-cylinder corrections.

[vasillalov]

I was just reading up on Controller Area Networks (CAN) on wikipedia and I wanted to throw this into the mix:

CAN is a multi-master broadcast serial bus standard for connecting electronic control units (ECUs).
Each node is able to send and receive messages, but not simultaneously.

The devices that are connected by a CAN network are typically sensors, actuators, and other control devices. These devices are not connected directly to the bus, but through a host processor and a CAN controller.

If the bus is free, any node may begin to transmit.

Bit rates up to 1 Mbit/s are possible at network lengths below 40 m

Alright, so it LOOKS like the CAN bus is just a communication pathway between various controllers, and not sensors. Controllers could be dumping data onto the CAN bus at different rates. Also, messages can be lost on the CAN bus if there is a transmission collision.

So, using the CAN bus to obtain information of how the engine is running is not optimal simply because you are limited by the amount of data the CAN bus is capable of supporting AND the speed at which controllers are dumping data into it. All sensors (correct me if I am wrong) are analog. So they provide a constant signal feed to their host controller on the CAN bus. However, the controller itself has to digitize that signal and there is inevitably going to be loss of data. Theoretically speaking...

Futhermore, a controller may not have the ability to broadcast constantly on the CAN bus all the time for various reasons: reduction of traffic collision on the bus and simply lack of processing power.

That being said, I certainly hope that the DME dumps enough data, at high enough frequency on the CAN bus for anyone to actually run a real-time tuning solution. It LOOKS like CAN bus data is good for logging, troubleshooting and generally learning how things are working.

I won't be surprised if the DME actually talks to sensors and makes adjustments much faster than it actually communicates on the CAN bus.

...just food for thought...

[335iSSA]

This may be a stupid question....but what feedback is the DME using to alter the timing of one of the cylinders over the other. There isn't an individual knock sensor for each cylinder, correct? So if there is one knock sensor each cylinder would have to knock at a different and distinguishable frequency.

[vasillalov]

Originally Posted by 335iSSA

... There isn't an individual knock sensor for each cylinder, correct? So if there is one knock sensor each cylinder would have to knock at a different and distinguishable frequency.

No, there is not a dedicated knock sensor for each cylinder. Even if there was, there is still no need for different distinguishable frequency for each. The DME will *see* knock events occurring on different pins on its harness. After that it will know where it is occurring.

[335iSSA]

Originally Posted by vasillalov

No, there is not a dedicated knock sensor for each cylinder. Even if there was, there is still no need for different distinguishable frequency for each. The DME will *see* knock events occurring on different pins on its harness. After that it will know where it is occurring.

Yeah just realized that it will know based on temporal firing sequence. See told you it was a stupid question.

[Bash]

Dzenno, so does that mean you have actual timing drops on Cy 2,3 and 5?
but CY 1,4 6 are ok?

[dzenno]

Originally Posted by Bash

Dzenno, so does that mean you have actual timing drops on Cy 2,3 and 5?
but CY 1,4 6 are ok?

On that particular run that's what the story was

[Bash]

That is really interesting, as we all try to fine tune basing our parameters on Cyl 1 while in fact there might be even worse numbers on the other cylinders.
What i dont get is, ur FBO+RBs which means you would need much less boost to reach max load whilst in your log you are holding an average of 14 psi tapering off at redline + the car is pulling timing. By the looks of it timing pulls or retard is a normal thing with these cars so might as well run the piggybacks and knock it to death..lol

Cobb lowers timing but i dont think lowering even more is wise, too much boost and no advance = not much power and pointless if you ask me.
Anyway will keep reading and learning..

Thanks