2021 Kia stinger gt1 overboost

[Mlan21]

Sup guys I’m new to the forum please be nice lol..... last summer sometime in July I bought a 2020 Kia stinger gt 3.3 tt after break in I installed injen intakes secondary cat deletes and a borla cat back. Everything worked flawlessly till I got side swiped and car was totaled.2 months ago I bought a 2021 Kia stinger gt1 and after breakin I installed the same parts cai secondary cat deletes and borla catback.... for some reason car is over boosting every time I full throttle and going into limp mode/check engine light for over boosting.I’m stumped because the car is suppose to adjust ecu on its own. :/ I reset the ecu with my friends fancy scanner and to no avail problem comes back. I have an app on this upcoming Monday at the dealership. Hoping they won’t be a**holes about the mods. Any inputs on what it can be and if I’m better off taking off the mods?

 

[Hojae84]

Sup guys I’m new to the forum please be nice lol..... last summer sometime in July I bought a 2020 Kia stinger gt 3.3 tt after break in I installed injen intakes secondary cat deletes and a borla cat back. Everything worked flawlessly till I got side swiped and car was totaled.2 months ago I bought a 2021 Kia stinger gt1 and after breakin I installed the same parts cai secondary cat deletes and borla catback.... for some reason car is over boosting every time I full throttle and going into limp mode/check engine light for over boosting.I’m stumped because the car is suppose to adjust ecu on its own. :/ I reset the ecu with my friends fancy scanner and to no avail problem comes back. I have an app on this upcoming Monday at the dealership. Hoping they won’t be a**holes about the mods. Any inputs on what it can be and if I’m better off taking off the mods?

At minimum put the stock secondary back on

 

[MerlintheMad]

I'll just welcome you to the forum, since, not being a car guy, I cannot weigh in with your issues. My car is fully stock in the drivetrain. I can offer the (more or less) consensus on here about mods like yours and warranty: it totally depends on your dealer. I know a local guy who installed his own air intakes; and when his car shut down while driving, they took it apart and even called in a Kia tech; and ended up (according to him) denying him warranty coverage because he had installed the intakes himself; they said that his car was unrepairable and "couldn't" even tell him what the issue was. Later (again, according to his story), he checked on his VIN and saw that the dealer had sold his car; by then he was into a new Stinger; clearly, he was pissed at his tale of woe. So, be warned, that many remove their mods when going into the dealer to submit a warranty check/claim.

 

[Mlan21]

I'll just welcome you to the forum, since, not being a car guy, I cannot weigh in with your issues. My car is fully stock in the drivetrain. I can offer the (more or less) consensus on here about mods like yours and warranty: it totally depends on your dealer. I know a local guy who installed his own air intakes; and when his car shut down while driving, they took it apart and even called in a Kia tech; and ended up (according to him) denying him warranty coverage because he had installed the intakes himself; they said that his car was unrepairable and "couldn't" even tell him what the issue was. Later (again, according to his story), he checked on his VIN and saw that the dealer had sold his car; by then he was into a new Stinger; clearly, he was pissed at his tale of woe. So, be warned, that many remove their mods when going into the dealer to submit a warranty check/claim.

Thanks for replying my brother and thanks for welcoming me. Today I full throttled a couple of times and the car didn’t overboost and it was a lot warmer out today 50 degrees F .... it seems to me it only over boost when it’s really cold outside . But anyways ima take the intakes of and the secondary cats off and put the stocks back on. I am leaving the borla catback I don’t see how that can cause problems. Better safe than sorry thanks for the input guys

 

[monusa]

My car is fully stock in the drivetrain.

By some of my posts, you are aware i am a 2.0 owner. New engine still impresses me. Since you are still stock 3.3, have you had the urge to install any mods?

Still up in the air about upgrading to 3.3 GT or going completely to the "dark side" and going for a Supra. Which ever choice, my choice to upgrade engines/powertrains is so that mods are not needed. Too much upkeep for the mostly 30 min drive to work and occasional weekend drive.

Thoughts???

 

[monusa]

for some reason car is over boosting every time I full throttle and going into limp mode/check engine light for over boosting.I’m stumped because the car is suppose to adjust ecu on its own.

Not an expert but with the mods, lack of "backpressure" could do this.....without it, nothing stopping full exhaust pressure from spinning turbo(more to it than that but i can only provide "layman's terms")

 

[Mlan21]

I understand but my last stinger had the same parts till I got sideswiped at 10,000miles no issues what so ever the only difference was my 2020 stinger never saw cold weather just my new 2021 stinger gt1

 

[monusa]

With the mods on the first Stinger, were any changes made electronically(progamming ecu, etc.) to accomadate the increase in exhaust flow/lack of backpressure? My understanding of this process (again, not expert) is that basically, overboost occurs when the boost pressure is higher than the engine can effectively use it. If the pressure is not relieved in a given period of time, an overboost code will be thrown by the engine.......exhaust flow plays a role as does other things like wastegate control, etc.

If the engine can't use it fast enough or there is no way to relieve the additional pressure, you get overboost. In other words, what is different in the setup on the second stinger vs. the first one? Maybe something you did the first time but forgot the second time???

 

[Mlan21]

With the mods on the first Stinger, were any changes made electronically(progamming ecu, etc.) to accomadate the increase in exhaust flow/lack of backpressure? My understanding of this process (again, not expert) is that basically, overboost occurs when the boost pressure is higher than the engine can effectively use it. If the pressure is not relieved in a given period of time, an overboost code will be thrown by the engine.......exhaust flow plays a role as does other things like wastegate control, etc.

If the engine can't use it fast enough or there is no way to relieve the additional pressure, you get overboost. In other words, what is different in the setup on the second stinger vs. the first one? Maybe something you did the first time but forgot the second time???

I gotcha 100% I looked everything over a million times only thing that is different now is that my stinger is a 2021 rather than a 2020 and its being driven during the winter rather than in the summer. Maybe it’s the cold weather. Maybe Kia changed something on the 2021 Kia stinger. Or maybe something is defective mechanically

 

[Mlan21]

I gotcha 100% I looked everything over a million times only thing that is different now is that my stinger is a 2021 rather than a 2020 and its being driven during the winter rather than in the summer. Maybe it’s the cold weather. Maybe Kia changed something on the 2021 Kia stinger. Or maybe something is defective mechanically

Both stingers were never tuned just threw on the 3 bolt on parts

 

[The Madhouse]

Any chance you were stepping on it before she was fully warmed up. Because that will throw limp mode.

 

[Oryan]

Cold air. I ran into the same issues. The car is building boost faster than the ECU is used to seeing with it's default tables, so boost just spikes and when the ECU sees that, it'll protect itself by going into limp mode and/or throwing codes. I also took mine to the dealer and they found nothing wrong with the car. I also brought it in as it was, meaning it had everything on it in my signature minus the JB4 which I didn't have at the time.

IMO you're probably going to either have take something off until it warms up, or get it tuned so the car can better deal with the boost. For me, a JB4 with EWG wires and dialing back wastegate duty cycle helped a lot.

 

[MerlintheMad]

By some of my posts, you are aware i am a 2.0 owner. New engine still impresses me. Since you are still stock 3.3, have you had the urge to install any mods?

Still up in the air about upgrading to 3.3 GT or going completely to the "dark side" and going for a Supra. Which ever choice, my choice to upgrade engines/powertrains is so that mods are not needed. Too much upkeep for the mostly 30 min drive to work and occasional weekend drive.

Thoughts???

I've never considered doing drivetrain mods: simply because when I hit the kickdown switch I can still make myself short of breath with how fast the 3.3L accelerates. Even though I've grown accustomed to the performance limits of the stock setup, it is more than enough for me. I seldom use or need acceleration at full potential. When I do, it's just for fun.

 

[Mlan21]

Any chance you were stepping on it before she was fully warmed up. Because that will throw limp mode.

Cold air. I ran into the same issues. The car is building boost faster than the ECU is used to seeing with it's default tables, so boost just spikes and when the ECU sees that, it'll protect itself by going into limp mode and/or throwing codes. I also took mine to the dealer and they found nothing wrong with the car. I also brought it in as it was, meaning it had everything on it in my signature minus the JB4 which I didn't have at the time.

IMO you're probably going to either have take something off until it warms up, or get it tuned so the car can better deal with the boost. For me, a JB4 with EWG wires and dialing back wastegate duty cycle helped a lot.

Funny thing brother I just ordered my jb4 and was looking at those wastegate wires myself as a remedy and a tune as well. Don’t feel like taking my parts off again . Thanks for the input .

 

[Mlan21]

Any chance you were stepping on it before she was fully warmed up. Because that will throw limp mode.

I always make sure my oil temp is close to 180-200 degrees Fahrenheit before I step on it I’m coming from a 2016 wrx before the stinger the motor lasted me 100k pushing 350whp surprisingly

 

[Mlan21]

Cold air. I ran into the same issues. The car is building boost faster than the ECU is used to seeing with it's default tables, so boost just spikes and when the ECU sees that, it'll protect itself by going into limp mode and/or throwing codes. I also took mine to the dealer and they found nothing wrong with the car. I also brought it in as it was, meaning it had everything on it in my signature minus the JB4 which I didn't have at the time.

IMO you're probably going to either have take something off until it warms up, or get it tuned so the car can better deal with the boost. For me, a JB4 with EWG wires and dialing back wastegate duty cycle helped a lot.

So let me get this straight you only dial back the waste gate duty cycle when it’s cold out ?

 

[Oryan]

So let me get this straight you only dial back the waste gate duty cycle when it’s cold out ?

Can't say for sure yet seeing that I only got the JB4 in October/November, so it's only been on for cold weather. It will be interesting to see how it behaves when it warms up.

 

[monusa]

Cold air. I ran into the same issues. The car is building boost faster than the ECU is used to seeing with it's default tables, so boost just spikes and when the ECU sees that, it'll protect itself by going into limp mode and/or throwing codes.

Again, not an expert but this is my understanding as well. Right now, our high temps are in the low 30's and my IAT temps are hovering around 60deg. and below.....for a turbo car, that is similar to having an additional intercooler and i can really tell when the boost comes up....my vehicle is also stock (2.0) so the ecu knows exactly what to do but maybe with the extra flow of the exhaust, the ecu can't compensate enough....some exhausts have a valve that can be partially closed during this condition which forces the wastegate to stay open a little longer thus, allowing some of that boost to be relieved before the ecu has a chance to trip the CEL.......jb4 will probably "trip" shortly before the ecu does seeing that it gets the overboost signal first.

 

[Oryan]

Again, not an expert but this is my understanding as well. Right now, our high temps are in the low 30's and my IAT temps are hovering around 60deg. and below.....for a turbo car, that is similar to having an additional intercooler and i can really tell when the boost comes up....my vehicle is also stock (2.0) so the ecu knows exactly what to do but maybe with the extra flow of the exhaust, the ecu can't compensate enough....some exhausts have a valve that can be partially closed during this condition which forces the wastegate to stay open a little longer thus, allowing some of that boost to be relieved before the ecu has a chance to trip the CEL.......jb4 will probably "trip" shortly before the ecu does seeing that it gets the overboost signal first.

The JB4's boost safety trip is default 24psi. I haven't tripped that. The JB4 has also never thrown a code for me. The ECU can still put the car into limp mode if the boost it is seeing, is still higher than normal. The JB4 is hitting the boost target it's aiming for so it doesn't necessarily see a problem. My issue was the car was just sailing into 16-17 psi ranges stock, with spikes on throttle going even higher. The JB4, ironically, has lowered my stock boost levels the ECU is seeing since I lowered FF so my target boost is in the 17-18 range peak on map 1...which feels stronger and more responsive than map 2 but that's another topic I'm going to explore a bit on my own.

Also, I just don't even bother going WOT below 40F. Low 40s I spun a bit from 60.

 

[Mlan21]

So your saying the jb4 alone can fix my problem and that I don’t need waste gate wires?.