LNF in sandrail boost help

[mayhem]

Hey guys ive been building this long travel sandrail and finally got it up and running this summer and im trying to work the bugs out. This thing is a monster..1st gear would wheelie strait up in the air, 2nd would pull it back up and to the same, then 3rd with alittle bounce i could ride it out at like a 45%.. anyways it was down for a month or so while i made some changes and finished up somethings on it. The maf was unplug because i had relocated it and the BPV was capped off. We hooked up the BPV and i started working on calibrating the maf and i just couldnt get it right so i ended up putting the original tune i had back in and its just never had the same power i couldnt even get it to wheelie even after unhookin the maf and capping off the BPV like it was originally.

So ive spent the last week or so reading up on tuning these things figured i start at the begining and work my way up i got the maf almost dialed in and was working my way though it and my computer does and update and somehow i couldnt read the maf. i finally got that maf hist working but a few mins before it will read anything but 0s. still a work in progess il have everything pretty close to 0s and then next time i look at it there all over the place

Anyways it still seems down on power so i was thinking maybe i hurt it or have a boost leak as my boost histo still only shows like 16-17lbs. when from my understanding it should be 22-25 with DAL cranked up to 325 and WG at 95% soo for shits and giggles i drop the WG down to 65% and put the DALs back down where they were and to my shock the thing seems to be making more power and starts to wheelie again sooo im confused i do a handful of short logs playing with the wg in just the 100% load column from 65 to 80 to 85 and still only can get 18lbs.. what im i missing??

[cobaltssoverbooster]

the dal table is very problematic at values over 255. this is because the max cap of the table has been found to match the max cap for the hard coded intake map sensor which was stock 255 kpa.
try limiting your dal to 255 and using the boost controls as designed. at 255 you should be able to push any turbo well past 28psi using standard corrections between the wgdc% and the PID control system.
now these arent going to fix your boos tlimit issue but it will help you control boost more reliably knowing this information.

to fix your 18 psi boost limit you need to visit the "PRESSURE RPM FACTOR" table. under the OEM OS which is a 2.5 bar OS it was originally tuned for 14-15 psi stock and the pressure rpm factor table was set to limit boost to 18.6 psi for system protection.
To fix this issue raise it to 2.63 which will raise the max boost limit to 24 psi. anything higher than that on the OEM turbo and you will be overheating. Not to mention in your current ecu format you are only capable of boosting to 23.5 psi before you cap the sensor out anyways. You would need to install a set of GM 3 bar sensors from the gmp kit to go past that. A few vendors sell just the upgrade sensors and harness to convert them without any harness splicing like the original kit made us do.

[mayhem]

Thank you for the response that makes total sense now. you have obviously put in a few hours in on these motors. With respect to that i decided to scrap my tune and use your Generic starter file to knock the learning curve down. Needless to say the logs look just a touch better..lol im showing 22.88 psi with DALs at 2.53.. i will try bumping the 2.53 up to 2.63 and do another log.

Screenshot (8).png
Screenshot (9).png


log 9 22psi.hpl

[mayhem]

i did have alittle surging which i assumed is coming from the maf not being dialed in. I tried to copy and paste by % but it would barely run after i did that. I set the maf correction base to 1 then I setup a histogram to match the maf and used EQ ratio error for the parameter. Then did the same thing for the maf calibration i tried using the Eq ratio error and ltft vs stft math. but something isnt rightScreenshot (10).pngScreenshot (11).pngScreenshot (12).png

[TurboWood]

Such epic talk of wheelies and no pictures...wtf?

[cobaltssoverbooster]

i only use stft when tuning. ltft is a one cell trim.
i personally tune DI Ecotecs without using the maths function. Personal preference i guess.

you didnt just hit 22.8 psi....you capped out the sensor. You have exceeded its limit. i only know this since there isnt a change from one rpm to the next which happens to be just about impossible to reproduce.
true boost is read through the 'boost lo res' sensor and i read it in kpa-101kpa to get true boost.

thin your channels list out...you have way too much stuff in there and it will slow the scanner down.
for fueling and boost you really only need:
rpm
coolant
boost lo res
absolute load
advance
knock retard
wb lambda b1
stft bank 1
iat2
maf hz
maf flow lb/hr
ve flow lb/hr
commanded lambda
vehicle speed
etc throttle %
pedal %
thats about it. anything else can be considered not necessary at this point. since your in a rail application where exactly did you locate your maf in relation to the intake system? if you put it too close to the turbocharger the factory bpv will cause a back feed signal on the maf when it is opened. if your too close to the throttle body then you can experience some turbulence at lower etc % values.

[cobaltssoverbooster]

can you upload your scanner layout file so we can see what your looking at?
i can only open your file with my GMC Yukon or ProMod layouts active which gives me a completely different set of information.

[mayhem]

Ok i thinned out my layout to this
rail layout 2.Layout.xml

This is where i have the maf
IMG_4020.jpg

[Super Sky]

I noticed in the screen shot it shows the Intake manifold pressure at +6.7PSI and the graph shows a neg. -6.70. I'm confused enough with out seeing this.

This is for Cobalt...if I'm going to log only 1 boost reading is the boost low res the best one to use????

Thanks, Larry

[mayhem]

Such epic talk of wheelies and no pictures...wtf?

im tryin to upload a video but the file is to large.. any idea what the max size can be?

[mayhem]

quick log from this morning with a cold start..the surging was the worse when i first started driving.. seems to be making better power it power wheelied 2nd gear and i had to lift before i hit the rear wing lol i forgot i bumped the boost up from 2.52 to 2.62 i will have to see if i can get some new 3bar map sensors.. ZZperformance is only about an hour from me i think..ive never been there but sounds like if anyone is going to have it they would..atleast i hope.

[mayhem]

quick log from this morning with a cold start..the surging was the worse when i first started driving.. seems to be making better power it power wheelied 2nd gear and i had to lift before i hit the rear wing lol i forgot i bumped the boost up from 2.52 to 2.62 i will have to see if i can get some new 3bar map sensors.. ZZperformance is only about an hour from me i think..ive never been there but sounds like if anyone is going to have it they would..atleast i hope.RDR railtune1.hptlog 10.hpl

[cobaltssoverbooster]

First things is to address the dal table again. I am not 100% sure you understand it so i will try elaborating the explanation a little bit more. I shall remind you that the hard coded limit is 255. after which the system get very unruly. You are to run the dals down and use the WGDC% table to bring the boost up until its limit. There are videos and how-to's on controlling lnf boost. So here is how i do it... I start at dals of 245 and wgdc% of 78%. i creep the wgdc% up until it hits my desired boost level or it the wg% table gets to 95%. if i am at 95% and i still haven't hit my boost target i then lower that cell back to 80% and raise the dal up by 5 to 250. At 95% the wg solenoid is just about out of adjustable range and its at risk of overheating the internal coil (much like a fuel injector always running wot at the same 95%). Bottom line is you shouldn't need to exceed 255 if your commanding the wg% properly, particularly on a stock turbocharger.

As for boost pids. the only one you should be reading is Boost lo res. It is the only reliable sensor input for boost. According to your last log you hit a max of 248 kpa on the boost lo res which equates to roughly 21.3 psi. This is a great place for the factory turbocharger Particularly in a rail that sees tons of revs. i would use the mentioned method to continue to target this 21 psi zone.
Your maf doesn't seem that far off until i look at the stft by itself then its off by 10% on average. Are you still tuning with the evap solenoid in the intake manifold still plugged in? When leaving the evap plugged in you have to tune with the ltft+stft maths function because ltft is left as an active controller. If you disconnect the solenoid it will shut the ltft off which allows you to use stft only tuning strategy. When maf tuning we tune by "percent half" functions. the full "percent" function tends to overshoot the values.

i dont see a location error when it comes to the maf sensor installed position. You guys did good there. To back that up your logs represent afr errors that are equivalent to the ltft+stft maths function report in your histogram list. the motor seems to be running safely for now, with a few maf cells requiring a little more attention but overall not bad.

This is for Cobalt...if I'm going to log only 1 boost reading is the boost low res the best one to use????
Thanks, Larry
The reason we only use the Boost lo res sensor is due too the lack of other sensor inputs that aren't capped or track with behavior issues. Back in 2008-2009 there was some testing done with external psi gauges and it was found that the map sensor had issues when reading past a small amount of boost. The Boost lo res however was completely tracking with the external gauge. This sensor is more accurate since it solely focuses on boost as its located in a position where vacuum is never present. You can test this yourself. Record both Boost lo res and manifold pressure and watch what happens when the boost really starts to come in. The map should start deviating from the Boost lo res. The other reason we only read this sensor is because the map sensor is not referenced directly to any tables in these ecu's. It is used for internal calculation only which means we dont need to read it because it doesnt pertain to us. instead we mostly focus on load x rpm and maf freq. in Hz.

[Super Sky]

Mayhem, what boost sensor are you displaying that shows actual boost pressure ie 22psi. ???? Both of my sensors display the actual boost plus 14.8psi. My car is a 2007 Saturn Redline. I have heard the 2007 pcms are different. Maybe that is the issue. Maybe CobaltSS will chime in here.

Thank you, Larry.

[cobaltssoverbooster]

there is a pid parameter for boost based on map sensor. its not that accurate because its using the wrong sensor

[mayhem]

Mayhem, what boost sensor are you displaying that shows actual boost pressure ie 22psi. ???? Both of my sensors display the actual boost plus 14.8psi. My car is a 2007 Saturn Redline. I have heard the 2007 pcms are different. Maybe that is the issue. Maybe CobaltSS will chime in here.

Thank you, Larry.

i cant find one that works either..the only way ive know of that makes any sense is to setup a histogram and use "boost math" .. so i ran up to zzperformance today and picked up the the 3bar map sensors as i was maxing the stock ones out this morning and now im only showing 19-20.. man as soon as i think im starting to get an understanding of this stuff i get confused again.

[cobaltssoverbooster]

you flashed the map sensor data in as they said yes?
Also lowering the dal and starting at a lower wg% causes lower boost. you will und up fixing it with adjustment but it takes a while to rope it in properly. These ecu's are known for being temperamental, patience is a must with these bad boys. Your gonna get it right dont fret.

[mayhem]

First things is to address the dal table again. I am not 100% sure you understand it so i will try elaborating the explanation a little bit more. I shall remind you that the hard coded limit is 255. after which the system get very unruly. You are to run the dals down and use the WGDC% table to bring the boost up until its limit. There are videos and how-to's on controlling lnf boost. So here is how i do it... I start at dals of 245 and wgdc% of 78%. i creep the wgdc% up until it hits my desired boost level or it the wg% table gets to 95%. if i am at 95% and i still haven't hit my boost target i then lower that cell back to 80% and raise the dal up by 5 to 250. At 95% the wg solenoid is just about out of adjustable range and its at risk of overheating the internal coil (much like a fuel injector always running wot at the same 95%). Bottom line is you shouldn't need to exceed 255 if your commanding the wg% properly, particularly on a stock turbocharger.

As for boost pids. the only one you should be reading is Boost lo res. It is the only reliable sensor input for boost. According to your last log you hit a max of 248 kpa on the boost lo res which equates to roughly 21.3 psi. This is a great place for the factory turbocharger Particularly in a rail that sees tons of revs. i would use the mentioned method to continue to target this 21 psi zone.
Your maf doesn't seem that far off until i look at the stft by itself then its off by 10% on average. Are you still tuning with the evap solenoid in the intake manifold still plugged in? When leaving the evap plugged in you have to tune with the ltft+stft maths function because ltft is left as an active controller. If you disconnect the solenoid it will shut the ltft off which allows you to use stft only tuning strategy. When maf tuning we tune by "percent half" functions. the full "percent" function tends to overshoot the values.

i dont see a location error when it comes to the maf sensor installed position. You guys did good there. To back that up your logs represent afr errors that are equivalent to the ltft+stft maths function report in your histogram list. the motor seems to be running safely for now, with a few maf cells requiring a little more attention but overall not bad.

ok that makes more sense now.. i see where i got where i confused myself you were talking about raising the " pressure rpm factor" to 2.62 earlier and i had the DAL table stuck in my mind... the "pressure rpm factor" is currently at 6.0 im assuming that beyond the limits and is fine or do i need to drop it down to 2.62 ?
Screenshot (14).png

No the evap is not connected my harness doesnt have a plug for it actually. Sense i dont have an evap ive now eliminated all the LTFT and LTFT+STFT for the scanner. Im assuming that might throw the EQ ratio error off.. so im assuming i should now use the STFT theres also a STFT bank 1 that seems to be close to the same but theres alittle different on the histogram

I have the BPV capped off on the turbo and the BPV solenoid is pluged do i need to loop the vac lines back to itself or just cap the ends off or unplug it? not sure if that would be causing any issues.

[mayhem]

you flashed the map sensor data in as they said yes?
Also lowering the dal and starting at a lower wg% causes lower boost. you will und up fixing it with adjustment but it takes a while to rope it in properly. These ecu's are known for being temperamental, patience is a must with these bad boys. Your gonna get it right dont fret.

They didnt give me any data with the sensors..igot there just a few mins before the closed and started asking about about how far i could push this setup and almost came home with the z54 turbo, stage 2 cams and opel injectors. anyways i had already changed the map to 65.89kpa and offset to -6.35kpa and the diagnostics to Screenshot (15).png

[cobaltssoverbooster]

did you change the one under sc/tc settings to that as well?