LNF Boost taper and missing timing!

[01 MidMet WS6]

Afternoon all, after spending more hours reading LNF tuning guides than I care to recall. I jumped into my first one. The car I am tuning is an 08 Sky Redline M5 with an intake tube and turbo back exhaust (no cat).

So after spending a couple of hours with the car I feel that I have come up with a tune that is pretty solid. Here is a breakdown of what issues I am currently having.

Please see the tune, log and config below. I am using the standard LNF config with a couple of changes. I did also install a LM1 in the rear O2 sensor bung (don't trust this newfangled technology

1st off: I am having boost taper issues above 5,000 rpm. You can see it in the data log I posted below (starting at from 2600). The car is running perfect at 260kpa at 82% DC, at 5,000 rpm the DC% (and boost) starts to taper. I am sure this is something that I have overlooked with TM or..... I have read a bunch of posts on how to eliminate this but have not found a definitive answer.

2nd Issue: I am seeing knock retard when adding just a couple of degrees of timing @ WOT (also see in the log posted). I have heard that many people are running 15-16* and I am know where near that. Does it seems unusual that I am limited with the timing that I am running?

3rd issue: NOT PRESENT in the data log. I am having a substantial timing dropout when the car comes into boost around or below 3000 rpm. I found a thread that goes over this but again did not find a solution.

Thanks to everyone that has put in so much time and effort making the information on tuning these engines available. There is an overwhelming amount of information on this forum. I will hopefully be able to add to it by the time I am done with this car.

As a side note I have not touched the cam timing tables and only dabbled with timing. I come from the LS world and these engines are completely different to me. I understand there is some privacy due to $$$ and not everyone wants to show their cards. If anyone would feel more comfortable sharing through PM please feel free.

Thanks in advance!

[cobaltssoverbooster]

you still have torque management engaged
try a .86 power enrich at wot you should cool the cylinder off and get that timing you want
you dals are so high with these mods im pretty sure you have maxed the factory 2.5 bars out so unless you have a external boost gauge you need to start low with the dals and bring them up until they hit 23 psi. your boost is so high its causing excessive cylinder temps and then additionally increasing kr

[01 MidMet WS6]

you still have torque management engaged
try a .86 power enrich at wot you should cool the cylinder off and get that timing you want
you dals are so high with these mods im pretty sure you have maxed the factory 2.5 bars out so unless you have a external boost gauge you need to start low with the dals and bring them up until they hit 23 psi. your boost is so high its causing excessive cylinder temps and then additionally increasing kr

Where is the torque management that need to be removed. Is this the reason that it is pulling boost away up top?

I will try a little additional fuel earlier to help cool things down. I currently have it running between .88-.86 off of what I have read from others.

The DALs are high but the MALT table is not maxed. Boost feels like it comes smooth that way. Am I incorrect in the thinking that I can monitor boost using the the LoRes PID. The most I am currently seeing is 260 KPA/23psi.

Thanks for the quick response!

[cobaltssoverbooster]

no if you boost over 24 psi the turbobecomes a choke point and looses boost around 5k.
if you get it turned down to true 23 psi then you can have a better hold uptop.

torque management tab- general sub tab- all the options on the left need to be 100
except the max air load torque whic should be like 99.99 @3k and the rest after to max rpm 100 iirc but fix the boost first if you want to keep your pistons

[01 MidMet WS6]

I understand your boost theory but don't think it applies here. I am using the MALT tab in torque management to control the initial boost spike. As seen in the log the MAX low res KPA is 262 (23.3 psi). This is right where you are saying it should be?

The choke point on my setup appears to be the boost DC dropping from around 82% down to under 70%. I understand that the turbo will not keep up all the way to the top but it should command more boost.

Can I use the low res kpa to measure boost, if not what should I be using and how what is it accurate to? I will stuff a pressure sensor in it and log it externally if I need to but I was under the impression that the factory hardware was good up over 25 psi?

[cobaltssoverbooster]

yes but did you work your way up to 23 psi. because setting the wg to 100% and having a dal of 300 will net 28psi on the factory turbo. and the factory sensors are only good to 23 psi and the max psi for the turbo without damaging side effects.
just try lowering the dals to 275-280 running the wg to 75% at wot and max out the malt table. and your optimum torque could use an increase up top. with everything set you then increase boost and control the spikes with the wg dc controller. its more stable and easy to control

[01 MidMet WS6]

yes but did you work your way up to 23 psi. because setting the wg to 100% and having a dal of 300 will net 28psi on the factory turbo. and the factory sensors are only good to 23 psi and the max psi for the turbo without damaging side effects.
just try lowering the dals to 275-280 running the wg to 75% at wot and max out the malt table. and your optimum torque could use an increase up top. with everything set you then increase boost and control the spikes with the wg dc controller. its more stable and easy to control

Yes I worked my way up and I think I am right where I need to be. I will try your settings and see if this eliminates my issues. When you state to run the wg at 75% max are you recommending using the prop max or duty cycle correction table?

When you state that my optimum torque could use work up top do you have a recommendation on what to adjust to and why? When does that table come into play?

I will post how things worked out when I get a chance later today.

[SloFive]

The stock MAP sensors will only display up to 255kpa. Since it's flat lining in the scanner, it's actually going above what the sensor can read. That's why you want to work your way up to that limit. Don't ask me what happens to your ringlands if you run more than that. Setup a custom PID for boost to see where it's actually at.

[01 MidMet WS6]

The stock MAP sensors will only display up to 255kpa. Since it's flat lining in the scanner, it's actually going above what the sensor can read. That's why you want to work your way up to that limit. Don't ask me what happens to your ringlands if you run more than that. Setup a custom PID for boost to see where it's actually at.

I understand that now, I read somewhere that the low res read to over 300 kpa but that was not the case.

[01 MidMet WS6]

Alright update on the car.
Dropped the DAL's to a more manageable number, maxed out my MALT table and dropped the DC correction and prop max tables to around 75% at lower load areas. Boost is coming on much more tame now. However my boost drop is still present, I attached another log and you can see that the boost DC% follows commanded until just over 5300 when it takes a dive to 73%.

All knock is now gone using the same timing tables. Cobaltoverboost you were 100% right, I was well up and over the 255kpa limit causing excessive cylinder pressure and heat.

I am still also experiencing my timing drop out at around 2700 rpm in the data log. Not sure how to get that straightened out just yet.

[cobaltssoverbooster]

this is the optimum engine torque table something like this will help with engine torque calcuations and makes nice increases. any changes should be smooth.

for the wastegate controlls if you look at my 5k rpm limit and above the only thing we can do is garuntee that the wg is shut by maxing the wg cycle out.
give it a try and see if it holds better.
since you have the oem sensors and are running 23psi-255kpa this should hold slightly better.

edit: under engine diagnostics make your p0106 and p0236 range high values extend to the farthest unit of precision and copy and past the p0236 high into the p0106 high....this helps remove some turbo safety nanny if for some reason you hit over the 255kpa limit.

[01 MidMet WS6]

this is the optimum engine torque table something like this will help with engine torque calcuations and makes nice increases. any changes should be smooth.

for the wastegate controlls if you look at my 5k rpm limit and above the only thing we can do is garuntee that the wg is shut by maxing the wg cycle out.
give it a try and see if it holds better.
since you have the oem sensors and are running 23psi-255kpa this should hold slightly better.

edit: under engine diagnostics make your p0106 and p0236 range high values extend to the farthest unit of precision and copy and past the p0236 high into the p0106 high....this helps remove some turbo safety nanny if for some reason you hit over the 255kpa limit.

I already had my opt eng torque table at 99 but will raise it to reflect 100% as your table shows.

I moved my wg dc table to 105-120 as yours showed and will log it this afternoon if the weather clears a little (it is raining like crazy).

You stated the extend values to the farthest unit of percision, what do you mean by this. I would assume you are saying 262 kpa as that is the highest that it will read? But the stock tune has 512 in the p0236 tab.

Thanks a million for the help on this, I am impressed with how far this thing has come already and I haven't even started in on ign/cam timing.

[stromboli86]

You have some tip in limiting still in the tune under Spark/Retard/Tip-in Retard, that causes a small dip in the ignition timing plus added to a small amount of knock.

Then you can try adjusting the Pressure RPM Factor which is under torque management/turbocharger/pressure rpm factor.... raise the numbers for 5k and 6k rpm up some.

Also i would bump the pressure limit above 255kpa... like 265kpa... because you want to control boost using the wastegate dc table, not by bumping the pressure limit

This is what works really well for my tune, might help yours

[01 MidMet WS6]

You have some tip in limiting still in the tune under Spark/Retard/Tip-in Retard, that causes a small dip in the ignition timing plus added to a small amount of knock.

Then you can try adjusting the Pressure RPM Factor which is under torque management/turbocharger/pressure rpm factor.... raise the numbers for 5k and 6k rpm up some.

Also i would bump the pressure limit above 255kpa... like 265kpa... because you want to control boost using the wastegate dc table, not by bumping the pressure limit

This is what works really well for my tune, might help yours

Thanks for the info, it is now holding 95% from 5000 rpm on up. I will post a data log and tune file soon.

[cobaltssoverbooster]

glad you solved it

[01 MidMet WS6]

glad you solved it

Boost is coming on and holding very nice. Unfortunately I cannot get rid of the timing dip. I am stumped on that, furthermore after reading as much as I could about cam timing I am still not comfortable jumping in. Now that boost is taken care of I will finish up my MAF tuning and lean on the spark timing a little more. Thanks for the help.

Any recommended reads for optimal cam timing?

[cobaltssoverbooster]

All the motors come close but still different. All the good cam reads are listed in the thread I have listed in my sig.

[stromboli86]

Tune looks better, that timing dip is weird but im thinking it might have something to do with either flooring it at a very low rpm to start or because the engine was not fully warmed up when you did this pull. The timing jumped back up to where it should be when it ticked over 160 degrees coolant temp

[cobaltssoverbooster]

try using factory values on the malt table until 3k
at 3k use 99.99 and every cell after that 100
see if that had an affect on the timing. the car doesnt make 100% load before 3250rpm so there for the factory numbers before 3k dont need changing.

other than that its not physically pulling the timing out its straight commanding it to that level.
also may try just a little knock retard tip in timing reduction see if it likes it.

[01 MidMet WS6]

I dropped the tip in knock and it is still present. I will make changes to the MALT table to see if that helps.

As for the coolant temp having affect it does it even when the car is fully warmed up.