[COBB Tuning]

Originally Posted by biz77

Thank you Cobb. I think this will help answer and quell many questions about the factory ECU and its ability to "autotune." Hopefully after the basic tables, you can maybe post some compensation tables to show how the ECU compensates for variations in atmospheric changes?

Would you be willing to share how the ECU calculates "Load?"

Rob will likely have to chime in with a more detailed answer but essentially the ECU takes an estimated airflow and throws it into an equation referenced against RPM. Many modern ECUs use "Load" as an effective torque estimate...bigger numbers represent more airflow through the engine at a given RPM.

Originally Posted by biz77

I believe this is the most important point to take away from your post:

Constantly probing for more power by inducing knock and then backing off once it is found is not good for your bearings or ring lands. I will always chose a system that is tuned for MBT (minimum timing for best torque) given the parts installed on the car versus trying to "autotune" a parameter such as timing to squeeze out a bit more power.

So far, this looks pretty similar to the Subaru ECU architecture. Adding parts will increase VE and therefore load and eventually put you off the right side of the scale into no-man's land, correct?

Indeed! We do our absolute best to entirely eliminate detonation -- or at least to a lower level than was tolerated by the factory. When doing "power" tuning, an absolute premium should always be placed on det-free operation.

The data is presented in a similar fashion but the underlying logic is much different than a Subaru. Adding parts will increase pumping efficiency but should not increase the actual load values being targeted or reached; taking advantage of the extra breathing capacity will mean rescaling to stay out of no-man's land though

Best regards,
Lance

[COBB Tuning]

Originally Posted by Clap135

Well if the ecu, over time, reduces load due to repeated knock events, why would the lower loads have higher timing then the timing it was just knocking on.

In theory this makes no sesnse, one would think this the ecu would pull back load and drop timing, not pull back load and raise timing only to possibly knock again.

Timing is only one part of the "knock" equation -- boost level, incoming charge temps, EGT, fuel grade, etc. all play an integral part. Additionally, they don't employee an active "high octane" or "low octane" timing map like some mfg's, so the timing values targeted are somewhat static whereas load requested can be varied as necessary.

Regards,
Lance

[Clap135]

Originally Posted by COBB Tuning

Timing is only one part of the "knock" equation -- boost level, incoming charge temps, EGT, fuel grade, etc. all play an integral part. Additionally, they don't employee an active "high octane" or "low octane" timing map like some mfg's, so the timing values targeted are somewhat static whereas load requested can be varied as necessary.

Regards,
Lance

This timing variance actually makes sense. I have seen countless piggy back cars running high boost/race gas/meth and timing on some were in the 13-14 range, and on other it was in the 11-12 range.

Safe to assume the 11-12 guys, despite lower timing, are actually running higher load with less knock.

Reason I state this, some piggy back manufactures are bent out of shape about claiming to run stock timing (read, higher is better) as proof the car is running knock free and safe...

[Clap135]

Originally Posted by maxnix

Pretty transparent post. I wonder how many other tuners are taking notes?

Only thing I am comparing here, is results I have logged and seen from multiple piggy back cars. Weather it be the jb/procede/standback whatever.

[BmwFanFL]

Great stuff. This is one of the most transparent and helpful posts on tuning internals I've seen here. IMO, the product and participation here set a new standard for n54... I'm finally ready for a tune.

[roninsoldier83]

Originally Posted by COBB Tuning

Rob Irish - BMW ECU Guru in Austin, TX.
Lance Lucas - Lead BMW R&D Calibrator in Austin, TX.
Danny Heng - Marketing and Sales at the SoCal store.
Travis Geny - Online Relations and Marketing at the Surgeline store in Portland, OR.
Kevin Heist(myself) - I'm in Plano, TX and handle Marketing and Sales for the Plano store.
Gary Sheehan - Marketing Director.

Thanks!

Kevin

Thanks for clearing that up! Just curious though, is Christian mostly just a tuner then?

I haven't kept up much with your company for the past year or so, but is Trey still involved with things, or has he stepped away/taken more of a managerial/ownership role? Sorry, I know it's pretty off topic, I was just curious haha.

[themyst]

Originally Posted by Clap135

This timing variance actually makes sense. I have seen countless piggy back cars running high boost/race gas/meth and timing on some were in the 13-14 range, and on other it was in the 11-12 range.

Safe to assume the 11-12 guys, despite lower timing, are actually running higher load with less knock.

Reason I state this, some piggy back manufactures are bent out of shape about claiming to run stock timing (read, higher is better) as proof the car is running knock free and safe...

Can't this be alleviated by resetting the corresponding adaptations? If the ECU is reducing load due to multiple knock events, wouldn't resetting adaptations provide the end user a "clean slate" so to speak? (Speaking from the piggyback point of view)

[Clap135]

Originally Posted by themyst

Can't this be alleviated by resetting the corresponding adaptations? If the ECU is reducing load due to multiple knock events, wouldn't resetting adaptations provide the end user a "clean slate" so to speak? (Speaking from the piggyback point of view)

Clean slate, yes. However the ecu dropped load for a reason, and will drop it again for that same reason, knock. so what you are doing, is basically making your knock again untill it levels off to whatever load it chooses?

[themyst]

Originally Posted by Clap135

Clean slate, yes. However the ecu dropped load for a reason, and will drop it again for that same reason, knock. so what you are doing, is basically making your knock again untill it levels off to whatever load it chooses?

I was only pointing this out as a possible solution for piggyback users who were fiddling with overaggressive boost levels / CPS offset (if applicable) to reset any learning the ECU may have recorded. e.g. run 16psi on pump gas, car has massive KR, reset adaptations, run lower boost level and more ignition retard.

It might even help, at least in theory based on the information provided, to reset the adaptations after autotune (on the Procede side) has stabilized.

[blisstik]

I got a question. As far as the "stock" map is concerned, does it follow the same timing table as OEM map? Or does it have any efficiencies or enhancements from stage 1 OTS?

[COBB Tuning]

Originally Posted by blisstik

I got a question. As far as the "stock" map is concerned, does it follow the same timing table as OEM map? Or does it have any efficiencies or enhancements from stage 1 OTS?

The stock map (Stage 0) is the exact OEM mapping. No changes or enhancements of any kind We provide that to allow people to test their vehicles in "stock" form without having to uninstall then reinstall the AccessPORT.

Regards,
Lance

[COBB Tuning]

So, what other topics would you like to hear about? I know that Tim is preparing a post about our software's logging capabilities and show some of the information we have to work with from the tuning side of things, so keep an eye out for that. Tuning cars is definitely 1 part art and 1 part science, so please don't hesitate to ask if you'd like to know more about a certain aspect of what goes in to the tuning process around here

[Smitty1]

What if you decide to take your car with the cobb and take to a local tuner?

Any advice or warnings?

[themyst]

Originally Posted by COBB Tuning

So, what other topics would you like to hear about? I know that Tim is preparing a post about our software's logging capabilities and show some of the information we have to work with from the tuning side of things, so keep an eye out for that. Tuning cars is definitely 1 part art and 1 part science, so please don't hesitate to ask if you'd like to know more about a certain aspect of what goes in to the tuning process around here

Right now, I think we want to see accelerated development on OTS stg2/3 maps and ATP/ATR. The curve and numbers are very impressive for the initial stg1 map, but you are missing out on a huge chunk of the market for us heavily modified.

I want to see the ECU load limit defeated and how that would benefit those of us looking to convert from piggybacks.

[COBB Tuning]

Originally Posted by Clap135

Also based on the results of many cars on here, it apears that most of these cars don't actually run in the 130 load range as you stated. It seems to bounch between 105 and 120. I am basing this off the timing values your provided.

I think I now see what's at hand here...I wasn't really elaborate enough and I think we're actually seeing the same thing. Stock, 135 is the peak target, though the target does waver into the 120's depending on RPM and is below 120 above 6k. So your description seems pretty accurate. I should probably hold off on posting a screen shot of that for now...it will be available for all to see when the AccessTUNER Race software is released

Best regards,
Lance

[boom]

I'd like some insight on the afr targets chosen. BMW saw fit to run near stoich under boost for the midrange. You dramatically richening in that area while also pulling timing makes me wonder if the rich afr is actually necessary. Would appreciate the facts about how the fueling targets were selected. Thanks.

[COBB Tuning]

Originally Posted by Smitty1

What if you decide to take your car with the cobb and take to a local tuner?

Any advice or warnings?

That's actually a really good question! If anything, my best suggestion is to look for a company that is presents themselves professionally and provides great customer service. Ask them some basic questions and make sure you're comfortable with them before you make a decision. Getting a tune should not be a singular transaction in history, it should be the beginning of a relationship with someone you trust to take care of your needs and your car!

Originally Posted by themyst

Right now, I think we want to see accelerated development on OTS stg2/3 maps and ATP/ATR. The curve and numbers are very impressive for the initial stg1 map, but you are missing out on a huge chunk of the market for us heavily modified.

I want to see the ECU load limit defeated and how that would benefit those of us looking to convert from piggybacks.

I have some more dates with the dyno and a certain pretty lil 335 coming up very soon I will keep you guys updated along the way!

Regards,
Lance

[COBB Tuning]

Originally Posted by boom

I'd like some insight on the afr targets chosen. BMW saw fit to run near stoich under boost for the midrange. You dramatically richening in that area while also pulling timing makes me wonder if the rich afr is actually necessary. Would appreciate the facts about how the fueling targets were selected. Thanks.

Excellent question. First, a few assumptions about BMW's fueling choice -- thanks to the numerous benefits that direct injection provides to a turbo engine, they are afforded the ability to run the engine that lean to achieve great fuel economy and probably just as importantly, tailpipe emissions. It's important to note that they run the car @ stoich until just after 4k RPM. Not too coincidentally, Suburu uses an extremely lean AFR through this same RPM range. In both cases, this is likely because this is one of the RPM thresholds used during federal emissions testing for vehicle certification.

Yes, I did find that richening AFRs was beneficial to reducing/eliminating detonation. It did not have a significant affect on power output though AFR's in the 11's and below did seem to begin measurably reducing power. The OTS maps are richer than was necessary to quiet the knock control system as a measure of safety.

AFR will always be up for debate and I am completely upfront -- there is more than one way to get the job done and I happily allow for the fact that someone else may prefer a different AFR curve. Thanks to our forthcoming AccessTUNER software, tuners will be able to achieve just that

Thanks again for the good question!

Regards,
Lance

[Rob@Cobb]

Originally Posted by themyst

I want to see the ECU load limit defeated and how that would benefit those of us looking to convert from piggybacks.

I have removed all the limits we have hit so far. If we hit more, I will remove them as well. Is there specific load limit you are concerned with?

Cheers,
Rob

[themyst]

Originally Posted by Rob@Cobb

I have removed all the limits we have hit so far. If we hit more, I will remove them as well. Is there specific load limit you are concerned with?

Cheers,
Rob

Not concerned with a specific load limit, just the theory that the piggybacks are limited by the stock load target. Some more clarification would be appreciated!

[Rob@Cobb]

Originally Posted by themyst

Not concerned with a specific load limit, just the theory that the piggybacks are limited by the stock load target. Some more clarification would be appreciated!

Quite honestly I have not tuned a piggieback or attempted to trick the ECU. It's a feat they can push the motors as hard as they do while telling the ECU life is peachy. They have my respect for the number of hours spend modeling what the ECU needs to hear.

I'm am not 100% sure what their limitations are. The bulk of my time is spend looking for ways to properly tune a motor using the factory ECU. We hit limitations electronic or mechanical and look for proper solutions that retain a very OEM level of quality and smoothness.

Cheers,
Rob

[Joshboody]

I had some questions before, but not sure if they were answered in the many pages on the other threads.

Do the flashes have to follow the same torque/load targeting logic in increasing boost in hotter weather and reducing in cold? i've seen about a 2.5psi swing from summer to winter when stock. The piggies of course target the boost you want.

Also I would love to see some of the changes in timing tables due to weather. When stock in the summer I'm bouncing off the knock threshold, but in the winter... smooth. the dme doesn't really seem to learn in the summer when i can't get much beyond 5-7deg advance.

The tunable version will have tables for different weather conditions, or you adjust general timing and a correction for weather is added automatically?

sorry if this has been answered or i haven't read everything thoroughly enough to understand.