supercharged GPEC2 SRT8 hidden fuel cut/torque limiter table?

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04-12-2022
Hydra Performance

supercharged GPEC2 SRT8 hidden fuel cut/torque limiter table?

Howdy all,

I hope you don't mind me reaching out for a helping hand, as I'm at my wit's end here. I'm in the process of tuning a cammed Procharged 6.4L SRT8 Challenger with with built motor, 3-bar MAP sensor and I like to think that the tune is close to completion with no issues except the following. At 3000ft elevation, it hits ~195-200kpa @ redline without issue, however down at sea level, where I see the same boost @ approximately 5800rpm it hits some sort of limiter and refuses to rev any higher. Now I have all the torque limiters and torque management nannies maxed out and have absolutely no idea what could be causing this. NN and VVT are disabled/locked-out and I'm using the VE tables to tune. Any ideas what's going on here?

I have attached the tune in question, along with logs @ elevation without issue and on the dyno (where the problem manifests itself)
Please advise, thank you!
04-12-2022
N2speed

I will take a look. Do you have the stock read as well?
04-12-2022
Hydra Performance

1 Attachment(s)

Quote:

Originally Posted by N2speed

I will take a look. Do you have the stock read as well?

Thanks a million! Yes, I do

Attachment 119224
04-13-2022
SultanHassanMasTuning

1 Attachment(s)

Attachment 119241

you need to log better channels

fuel source spark source

all limits

also spark control under fuel cutt seems disabled
04-13-2022
Hydra Performance

Quote:

Originally Posted by SultanHassanMasTuning

Attachment 119241

you need to log better channels

fuel source spark source

all limits

also spark control under fuel cutt seems disabled

Yeah FWIW I logged throttle torque source in a later datalog (which unfortunately I did not save) and it remained @ "Pedal" throughout, despite the early cutoff (where you can obviously see the throttle closing)

I will try again and get back to you ASAP, thank you very much for your assistance
04-13-2022
white1

Quote:

Originally Posted by Hydra Performance

Howdy all,

I hope you don't mind me reaching out for a helping hand, as I'm at my wit's end here. I'm in the process of tuning a cammed Procharged 6.4L SRT8 Challenger with with built motor, 3-bar MAP sensor and I like to think that the tune is close to completion with no issues except the following. At 3000ft elevation, it hits ~195-200kpa @ redline without issue, however down at sea level, where I see the same boost @ approximately 5800rpm it hits some sort of limiter and refuses to rev any higher. Now I have all the torque limiters and torque management nannies maxed out and have absolutely no idea what could be causing this. NN and VVT are disabled/locked-out and I'm using the VE tables to tune. Any ideas what's going on here?

I have attached the tune in question, along with logs @ elevation without issue and on the dyno (where the problem manifests itself)
Please advise, thank you!

Attachment 119221
Attachment 119222
Attachment 119223

One thing that jumped out at me in the "arabi7" log is the ECT. Looks like the sensor failed and is reading -78*F I had a GC give me some fits a week ago, and it seemed the culprit was the ECT sensor. The jeep ran great until it got to operating temp. When it did, the sensor failed, and the gauge on the dash went to the bottom. The log would start reading correct again but the display on the dash would not. Once I swapped that sensor everything cleared up
04-13-2022
Hydra Performance

Quote:

Originally Posted by white1

One thing that jumped out at me in the "arabi7" log is the ECT. Looks like the sensor failed and is reading -78*F I had a GC give me some fits a week ago, and it seemed the culprit was the ECT sensor. The jeep ran great until it got to operating temp. When it did, the sensor failed, and the gauge on the dash went to the bottom. The log would start reading correct again but the display on the dash would not. Once I swapped that sensor everything cleared up

What I found very unusual was that the indicated (graphical) ECT and IAT readings on the dash you see are not the same as the textual ECT & IAT values you see on the left half of the VCM Scanner. Didn't really bother figuring out the reason for the discrepancy as the text values appear normal.
04-20-2022
Hydra Performance

4 Attachment(s)

Quick update for you guys. I performed all the suggested modifications to the tune and tried again. Still the same no change... It would appear as though its cuts out @ exactly 200kPA which leads me to believe that this may be something hardcoded in the OS? I have attached a copy of the latest tune & a few sea-level logs, both with and without the air filter attached. When the air filter is removed it cuts out approx 250rpm sooner but also very close to the 200kPa boost ceiling. Please advise :/

Attachment 119451
Attachment 119452
Attachment 119453
Attachment 119454
04-21-2022
DakBuilder

So I'm not 100% on this, but I've been told and have heard that for the 09-14 gpec2a ecu's they do not handle boost levels above 200 kpa ~ 15 psi of boost. If this is the case the hack for this is to any tuning above 200 kpa as if it were 200 kpa. I have a 13 Challenger R/t with GPEC2a ecu, and I'm getting tuned tomorrow. I'll report back if I run into this issue on the dyno as well. I also have a 3 bar map, so many of the mods are the similar.
04-21-2022
Hydra Performance

Quote:

Originally Posted by DakBuilder

So I'm not 100% on this, but I've been told and have heard that for the 09-14 gpec2a ecu's they do not handle boost levels above 200 kpa ~ 15 psi of boost. If this is the case the hack for this is to any tuning above 200 kpa as if it were 200 kpa. I have a 13 Challenger R/t with GPEC2a ecu, and I'm getting tuned tomorrow. I'll report back if I run into this issue on the dyno as well. I also have a 3 bar map, so many of the mods are the similar.

What's happening here is that its simply cutting out/hitting an early rev-limit, making further tuning impossibru. What I might do, if there is no other choice, is to rescale the MAP sensor and all the affected load tables so that it reads 200kPa say @ an actual 250kPa instead...
04-27-2022
Team_hellcat

bored on my lunch break , did not review file but i would say put max map for 195 kpa
have a good day
04-27-2022
DakBuilder

Just wanted to report back, my tune was cleaned up by a tuner. I had some bad data put into the injector scaling. That cleaned up a lot of my issues. I'll get into the boost limit issues here soon
04-28-2022
Hydra Performance

Just wanted to report back myself, putting max map @ 197kPa solved the issue and all is good now!
04-29-2022
f.creek-ranch

did you measure the real kpa externally? Would be interesting.
05-04-2022
Hydra Performance

Quote:

Originally Posted by f.creek-ranch

did you measure the real kpa externally? Would be interesting.

Not yet, delivered the car to the customer. Will definitely be doing this next time around @ the next round of mods :)
05-05-2022
DakBuilder

Quote:

Originally Posted by Team_hellcat

bored on my lunch break , did not review file but i would say put max map for 195 kpa
have a good day

Why is setting the max KPA to 195 the solution? I'm good with inputting those values, but I like to understand what is actually happening.
05-24-2022
coanan

Quote:

Originally Posted by DakBuilder

Why is setting the max KPA to 195 the solution? I'm good with inputting those values, but I like to understand what is actually happening.

Did you ever figure this out? Going thru the same thing with my Whipple build.