Help understanding the Cobb ATR load control / request logic diagram

[syclone2032]

that is a very clean log indeed, especially the relation between req. and act. load is very constant and smooth.
i have the post shifting timing drop too, not sure if it is something to worry about.

[syclone2032]

Any more input on these logs
http://datazap.me/u/nugs/ptf-vtt2-st...11-162&mark=48
Same problem, misfiring like symptoms then limp mode if I don't get off the throttle quick enough.
Looks like the throttle starts closing when load goes over requested. Is it not possible to raise the load limit?
Also if I make it to the change to 4th it 'misfires' and limps even worse.

that is the classic misfire when the load limit is set too high. you are right that raising the load limit will help you get rid of TCs , but then you will run into the misfires again. so you will have to dial in your load limit so you don't get misfires any more, the remaining TCs you can cure by reducing WGDC.
and yes, act. load exceeding req. load will get you a TC, in your case a quite rude one down to 19% TPS.

[tke344]

Any more input on these logs
http://datazap.me/u/nugs/ptf-vtt2-st...11-162&mark=48
Same problem, misfiring like symptoms then limp mode if I don't get off the throttle quick enough.
Looks like the throttle starts closing when load goes over requested. Is it not possible to raise the load limit?
Also if I make it to the change to 4th it 'misfires' and limps even worse.

Looking at that log again, I think there's more going on than just actual load exceeding requested, requested simply doesn't drop like that under normal conditions. I just noticed your timing is 8.8 deg at ~4500 RPM and 20PSI .. that seems very aggressive for an N55. I'd scale that back to half that ending around 8 deg. at redline. Also, what plugs are you running?

[Nugs]

Running NGK plugs.
I'm FBO with a Vargas Stage 2 turbo. I have a milder pump gas map so this is meant to be my aggressive one.
Where requested drops off a cliff is where I actually got off and back on the throttle, to avoid limp mode from the 'misifres'.

Tuning is being done by PTF so I can't actually look at or edit the map. Was just interested in your input as there is not much info out there about people tuning their N55s themselves with ATR and you two seems fairly switched on.

[tke344]

Not sure if linking other forums is allowed but check out this thread by Terry regarding the N55

http://www.n54tech.com/forums/showthread.php?t=22563

"Unfortunately for better or worse it appears the ~7 degree OEM timing curve is pretty close to MBT. I tried various timing curves from 5 to 13 degrees peak with no significant change in output. I also tried various air/fuel ratios with no significant change in output. Attached is a log of the OEM flash and one of various back end flash setups tested. Along with the corresponding dyno chart for comparison."

The motor is just different than the N54, basically it doesn't require as much timing to make the same power with everything else equal. You'd need to get on a dyno to be sure but almost 9 deg of timing at 4500RPM is probably causing a lot of stress (and the misfires) for little to no gain. It's like they pasted in the wrong timing table, those numbers would be appropriate on an aggressively tuned N54.

[Nugs]

Interestingly he also said this when tuning his N55 with a Vargas Stage 2

2) Tuning is done using JB4 ISO v5.2. We also reworked the back end flash for the E50 + meth fuel and found MBT around 9 degrees peak. The flash is loaded using a Cobb AP. Currently, they only support 2011-early 2012 models. Hopefully more models are added soon. The turbo can be used with the OEM flash but only with E85, or E85 + meth. We'll write pump gas maps for the turbo in the coming weeks for those who are using the back end flash and want to run 91 or 93.

http://www.n54tech.com/forums/showth...ghlight=VARGAS

[tke344]

Seems like I misunderstood his post, based on that graph it looks like he rides 8-9deg of timing most of the RPM range. I read it as - timing should ramp up to 8 deg. at redline. Your timing table may be fine after all. I wish I could actually see the map.

[tke344]

And with that said, I think I need to revisit my timing table, probably leaving power on the table where boost starts to taper.

[tke344]

I decided to re-scale the Y-axis on the torque limit table 1,2 - I was getting annoyed that I couldn't fine tune the area in between 2500 and 5000RPM - Setting the cells in the 5kRPM row too high would result in misfires from 3500-4000 but never from 4k-5k. I figured I was sacrificing some power in that higher range so I evenly scaled the column, from 500RPM to redline. There were probably other ways to accomplish the same thing but it seemed like a good solution. I also upped timing a bit from 4500RPM to redline, I know I won't be able to ride 8 deg. the whole way but we'll see how close I get.

Next mod on my list is meth, supposedly it helps with pre-ignition more than the ethanol can, cheaper than a FMIC and it cleans the valves. Pretty good bang for the buck IMO. That won't be until the spring however.

[tke344]

Logged again this morning, I thought I was misfiring at the time but it may have just been wheel hop now that I'm looking at the graph - Right around 3800-4100. I realized afterwards I forgot to turn off DTC so that could be part of it. I think I'd see more timing being pulled if it was a misfire, all there really was is a little noise on cyl 2, and in a misfire condition I do believe requested load will drop like what Nugs is experiencing. I pulled a little WGDC in that area anyway because 21PSI probably isn't healthy.

http://www.datazap.me/u/tke344/1017?...12-13-14-15-16

[syclone2032]

IIRC, before i got rid of my misfires, they were not obvious in the log; the only hint was a kink in the rpm graph. i´d have to look at my older logs, but i am pretty sure requested load will not drop, if not rise. the misfires get in the way of the engine accomplishing its goal, so it tries to request for more.
if the misfires are serious enough and you try to "drive through it", the DME will switch off the affected cylinders.

[syclone2032]

today i tried upping the WGDC spool table by 10% but didn't like the result, car became very jerky after stepping on it, just didn't feel right.
the car also showed some misfires in 2nd gear although them showing after increasing the spool table doesn't make any sense to me?!

the "boost ceiling" table was set to 2000 hPa in the Cobb Stage 2+ Sport OTS map; i tried to lower it to 1950 to see what happens (if you could limit boost that way). nothing, actually. boost did not drop, in fact it was minimally higher afterwards but i left it for the time being. maybe reducing it by just 50 is not enough. to see some effect.