Another ....somewhat Noob question

[vladr]

Can someone explain what all of these metrics mean on that the COBB AP measures? And what normal levels of each should be for our cars?

Any additional info would be great too like:

What mods impact which metrics, what is physically going on in the engine with respect to each metric, etc...


Here is the list (some are obvious):


Battery Volt - (obvious)

Vehicle Speed - (obvious)

RPM - (obvious)

Air Fuel Ratio - (obvious meaning, but what is the implication for our car/mods/whats normal?)

MAF - ?

Load Act. - ??

TPS Act. - ??

TPS Req. - ??

Baro Pressure - (obvious..i think?)

MAP - ??

Req. Boost Abs. - ??

Boost Abs. - ??

WGDC - ??

Timing CA -?? (whats normal?)

ECT - ??

Oil Temp. - (obvious)

Amb. Temp - (obvious)

Intake Mani. Temp. (obvious) I think without meth or FMIC normal is like 110 +/- 3-5 deg

Boost - (obvious)



TIA...

~V

[Kamal]

I'd love for the more well-versed to chime in here as I'm also curious about a number of these things. I'll share what I know for now...

MAF - mass air flow (usually in grams/second)
Load actual - a measure of MAF over engine speed
TPS - throttle position sensor, actual and requested
MAP - mass air pressure, similar to MAF
WGDC - waste gate duty cycle
Timing CA - timing correction advance? One of the important parameters for determining engine preignition and detonation (knock)
ECT - engine coolant temp.

[Frampton]

I'll try to add my two cents on top of Kamals, please correct me if I'm blatantly wrong, I'm still learning every day...

Originally Posted by vladr

Can someone explain what all of these metrics mean on that the COBB AP measures? And what normal levels of each should be for our cars?

Any additional info would be great too like:

What mods impact which metrics, what is physically going on in the engine with respect to each metric, etc...


Here is the list (some are obvious):


Battery Volt - (obvious)

Vehicle Speed - (obvious)

RPM - (obvious)

Air Fuel Ratio - (obvious meaning, but what is the implication for our car/mods/whats normal?)
This should be between 12 and 14.7. The afr curve by rpm is different between stock and COBB stage 1, COBB will sit around 12 or so starting at about 3000 rpms and hold longer where stock it stays around 14 or so thorugh most of the rpm range tapering to 12. Here is a one of my dyno charts with AFR on COBB stage 1 vs stock.




MAF - mass air flow (usually in grams/second)
This is used to measure the volume of air entering an engine so it can calculate the amount of fuel required to hit a specific AFR

Load Act. - a measure of MAF over engine speed
This is used to cross reference a table to determine a lot of what the engine does mainly around boost requested and i'm going to guess fuel needs. This is the heart of our ECU and is the main reason why you will see your boost levels fluctuate with ambient conditions and you wont see power fluctuate as much with those ambient condition changes. A boost targeted ecu works opposite of that where it targets a boost level and puts as much power down as possible with given ambient conditions.

TPS Act. - throttle position sensor, actual and requested
Actual is where your foot is on the accelerator pedal

TPS Req. - throttle position sensor, actual and requested
Requested is a calculated from a table in the ecu that takes your input from tps actual and sends a different value to determine load requested.

Baro Pressure - (obvious..i think?)
Should be around 1 atmosphere or 14.7. I usually see around 14.5 or 14.6.

MAP - mass air pressure, similar to MAF
I believe this is some calculation value between the boost and MAF sensors???

Req. Boost Abs. - Requested Boost Absolute
This is what the boost level the ecu is asking the turbos to produce via WGDC. The absolute part means that it measures atmoshperic pressure plus the requested boost value. On COBB stage 1 you should see, 13-16psi + 14.7, so it should read about 27.7-30.7. There may be spikes when you look at the min and max values since the closing of the throttle body creates a pressure surge at the sensor and not in the cylinders.[/

Boost Abs. - Boost Absolute
Similar to above but this is the measured value of boost entering the engine. It should be very close to requested boost absolute or there is something interfering with the engine and ecu's ability to hit that requested boost level. Again sohuld be around 27.7-30.7 on COBB Stage 1

WGDC - waste gate duty cycle
Controlling the waste gate actuator to hit a certain level of boost at a specific rpm.

Timing CA -timing correction advance? One of the important parameters for determining engine preignition and detonation (knock)
I think its more of deterrent to pre-ignition or detonation and not a knock sensor value. This will be the something to do with how much the timing is changing dependent on rpm, boost levels, intake air temperatures, load, etc. to prevent knock and create the most power. Advancing the timing usually makes more power to a certain extent but will eventually create knock and therefore have to be scaled back in tuning. At the end of the day you do not want any knock, that's how motors blow up, not really sure determining was the word Kamal was looking for. A knock sensor usually retards timing when predetonation occurs, you would then see a more negative timing advance value than normal at a given rpm. I'm sure this could take up an entire thread. Hope I explained it well...

ECT - engine coolant temp.
obvious once the acronym is explained

Oil Temp. - (obvious)

Amb. Temp - (obvious)

Intake Mani. Temp. (obvious) I think without meth or FMIC normal is like 110 +/- 3-5 deg
I want to live where you live!!! That is all dependent on street driving vs the track, ambient air temperatures, boost levels, and mods. I see around 135-145 on a daily basis street driving in 95-105 degree ambient temperatures. I see 150-160 at auto x events in similar air temps. I see 165-175 at hpde track events where i turn a 25 minute session on the stock intercooler. I have seen people run 125's all day long with aftermarket intercoolers.

Boost - (obvious)
This is your measured boost value after subtracting ambient barometric pressure. This fluctuates based on a lot of different things on this ecu since its a load targeted ecu and not a boost targeted ecu.



TIA...

~V

[vladr]

Originally Posted by Frampton

I'll try to add my two cents on top of Kamals, please correct me if I'm blatantly wrong, I'm still learning every day...

Arent we all... lol...

PS: DAAYYUM Thats gonna take me a while to read over. Thanks for putting in the time and energy to answer this man..

~V

[Frampton]

Hahaha, im trying to put in the time to understand everything ahead of ATR coming out!

Hope this helps!

[Kamal]

Originally Posted by Frampton

Timing CA -timing correction advance? One of the important parameters for determining engine preignition and detonation (knock)
I think its more of deterrent to pre-ignition or detonation and not a knock sensor value. This will be the something to do with how much the timing is changing dependent on rpm, boost levels, intake air temperatures, load, etc. to prevent knock and create the most power. Advancing the timing usually makes more power to a certain extent but will eventually create knock and therefore have to be scaled back in tuning. At the end of the day you do not want any knock, that's how motors blow up, not really sure determining was the word Kamal was looking for. A knock sensor usually retards timing when predetonation occurs, you would then see a more negative timing advance value than normal at a given rpm. I'm sure this could take up an entire thread. Hope I explained it well...

I wrote the response quickly and quite late at night! My wording was poor, but I meant to say something quite similar to what you've just posted. This is one of the parameters that I'd love to learn more about, but can't seem to find a single resource that does an excellent job of covering this topic. Assuming that Timing CA is "correction advance," then positive values would indicate timing advance to yield more power before knock occurs, and negative values would be timing retardation to prevent preignition. I probably just misworded something again.. but that's ok, I'm trying to learn as well!

Originally Posted by Frampton

Hahaha, im trying to put in the time to understand everything ahead of ATR coming out!

Same here... I've posted on the Cobb tuning forums multiple times to get them to provide us with some insight into what we should be looking for when looking at data logs to no avail. I'm guessing they'll release a technical article when the ATR software comes out... also, is the ATR program free?

[Frampton]

I'm sure ATR will be free if you look at the other platforms like mazda and subaru as comparisons. I've seen it connected to my car, it will allow us to do way more than any one of us is capable of doing without a dyno, a bit of spare time, and a lot of knowledge.

I'll try to dig a bit on the Timing CA stuff, I know there is a lot of power to be had with this car playing around with the timing. This motor and ecu allows you to tune cylinder by cylinder as well which is pretty slick!

[escobar929]

I'm not sure if the N54 is diff than other boosted platforms but 12-14.7 AFR is not where is supposed to be

the magic number is 11.4, anything around that is safe. anything under 11 is considered rich and anything approaching 13s is considered dangerous, at full load that is

those stock AFR number from cobb look high but also depends where they put the sniffer

[Kamal]

Originally Posted by escobar929

I'm not sure if the N54 is diff than other boosted platforms but 12-14.7 AFR is not where is supposed to be

the magic number is 11.4, anything around that is safe. anything under 11 is considered rich and anything approaching 13s is considered dangerous, at full load that is

those stock AFR number from cobb look high but also depends where they put the sniffer

I've always seen 12-14 AFRs and from other data logs I've seen with other tunes, that's normal for this platform. Not sure where the AFR data is coming from and if the difference is from direct injection vs. port injection.

[RealityDesign]

Originally Posted by escobar929

I'm not sure if the N54 is diff than other boosted platforms but 12-14.7 AFR is not where is supposed to be

It is quite different. The N54 is direct injected, which is exactly why it can run those AFR's and get away with it. The entire point of direct injection is MUCH better control of the explosion in the cylinder, allowing for what was once "dangerously" lean AFR's without major risk of knock/detonation.

[Kamal]

copying this from the Cobb AP discussion thread so it's all in one easy to access thread...

Originally Posted by Freon

AFR- I don't know what they're targeting in the tune, but it is useful to track. If it is too high under full boost you could have issues. Cruising it should be right at 14.7. I think the tune targets around 12:1 under full boost, probably richer (lower number) at higher RPM for cooling purposes. If you see leaner (higher) than 13 at full boost and mid to high RPM you probably have an issue.

MAF - Stands for mass air flow. Unit of measure would be mass over time. Not sure since our cars do not have a MAF. May be calculated MAF based on speed density algorithm. Usually in something like grams per second, or pounds per hour. I haven't bothered logging this, but I would guess grams per second.

Load act. - Actual load level on car. This is most likely MAP times voluentric efficiency, which is a table or set of tables in the ECU, and possibly also accounts for fuel learning. It's how much air is actually in the combustion chamber per combustion event. It's generally highest at peak torque and would be shaped over RPM like your torque curve. This would be MAF divided by RPM.

TPS act. - Actual throttle plate opening percentage. 0 would be fully closed, 100 is probably straight horizontal, 90 degrees.

TPS req. - Request throttle plate (related to accelerator pedal). Since this is a drive-by-wire car, your foot is not directly attached to the throttle plate.

MAP - Manifold absolute pressure. Pressure in your intake manifold. Anything over your barometric pressure would be "boost." Probably in psiA (pounds per square in absolute). Same thing as boost, different unit of measure.

Req. boost abs - Requested boost in absolute pressure. How much boost the car is trying to target. This is controlled by WGDC, and sometimes TPS Act. by the ECU used a closed loop controller.

WGDC - Wastegate duty cycle. The wastegate which controls boost is controlled by two solenoids and they are clicked on and off (pulse width modulated) to control air pressure. By clicking on and off, part of the boost pressure the turbos make is allowed to leak back to the turbos and open the wastegates to keep you from overboosting. The duty cycle regulates the air pressure. Higher WGDC means the car is trying to increase boost. You will see it higher on spool up at lower RPM.

ECT - Engine Coolant Temp, I assume.

[escobar929]

Originally Posted by RealityDesign

It is quite different. The N54 is direct injected, which is exactly why it can run those AFR's and get away with it. The entire point of direct injection is MUCH better control of the explosion in the cylinder, allowing for what was once "dangerously" lean AFR's without major risk of knock/detonation.

good to know, thanks!

[Yuchi]

So reading the two boost level for stage 1, 28-32 is normal....?

[OneThreeFive]

Originally Posted by Yuchi

So reading the two boost level for stage 1, 28-32 is normal....?

This range seems normal for the Req. Boost Abs and Boost Abs parameters on the 93 octane Stage 1 maps. There is actually a separate Boost (PSI) parameter you can enable in the data logs (if you haven't already) which will show you the actual Boost read at the TMAP, pre throttle body. Generally this in the range of 12 - 16 with the Stage I OTS maps and depend on the octane level of the map and conditions. This is most likely the parameter you are looking for.

[BrokenVert]

Don't mean to thread jack.

But I'm trying buy gauges and I can't find these numbers.

Nominal N54 oil Pressure?

Nominal EGT?

Nominal Fuel pressure?

Crankcase Pressure?

Etc.

[Yuchi]

Originally Posted by OneThreeFive

This range seems normal for the Req. Boost Abs and Boost Abs parameters on the 93 octane Stage 1 maps. There is actually a separate Boost (PSI) parameter you can enable in the data logs (if you haven't already) which will show you the actual Boost read at the TMAP, pre throttle body. Generally this in the range of 12 - 16 with the Stage I OTS maps and depend on the octane level of the map and conditions. This is most likely the parameter you are looking for.

Oh jeez, so much to do on the AccessPort...You really have to show me this, please lol You missed the meet tonight!

[Kamal]

http://www.e90post.com/forums/showthread.php?t=571718