Kia Stinger 2.0T G4KL - G25-550 Full Setup Introduction

[Bugra demir]

Hello everyone,

My car is a 2018 Kia Stinger 2.0T (G4KL engine), and I’ve been working on a detailed performance build for a while now. My goal was to create a setup that is both daily drivable and performance-oriented, while maintaining durability and safety. Here’s my current mod list:

Engine & Performance Modifications:

• Garrett G25-550 Twin Scroll turbo
• 44mm GFB external wastegate
• GFB G-Force III electronic boost controller
• 11-liter custom intercooler
• Full straight 70mm chrome exhaust system (including downpipe)
• K&N 5060 open air intake filter
• Snow Performance 2.5 methanol injection kit
• 1-liter oil catch can
• HKS high-performance spark plugs
• SCORCHER High-Performance ignition coils
• ARP CA625+ cylinder head studs
• Cometic reinforced cylinder head gasket
• N75 upgraded high-flow injectors
• N75 upgraded high-pressure fuel pump (HPFP)
• N75 Tuning custom ECU software

Target Figures:

• 20 PSI boost pressure
• Safe AFR and methanol ratios aiming for 350-400hp

While building this setup, I’ve carefully considered the limits of the stock internals, as well as cooling, fueling, and overall engine safety.


Now I’d like to ask you guys:


What are the generally accepted safe power and torque limits for the Kia Stinger 2.0T (G4KL) engine with stock internals?

I’m especially interested in hearing your experiences and opinions regarding long-term reliability in the 350-400hp range.





Thanks in advance!

 

[Snicklefritz]

Very few 2.0L modified powertrains on the forum. Your list is the most extensive that I have seen. I have a 2.0L as well, bone stock. But the subject interests me. You are questing for well over 50% increased HP. That would be the equivalent of boosting the 365 HP V6 to 500-572 HP, which is a lot, but I think it is fairly common. And we don't get blown engine reports very much. So, your probably "safe". Ah hah.

 

[Bugra demir]

Thank you, you’re absolutely right. My actual goal is not to exceed 50% over stock power. My ideal target is more like a 35-40% increase. So, I’m aiming for around 360 HP. I believe this level can be achieved while keeping it suitable for daily use and maintaining thermal and mechanical loads under control without risking engine longevity.





To support this, I’m planning to stay within safe limits with a more efficient turbo choice (such as the G25-550), a high-capacity intercooler, methanol injection to cool intake air and reduce knock risk, and by reinforcing the fuel system. My main goal is not exaggerated “dyno records,” but rather a sustainable and reliable power increase.

 

[Death]

Excited to follow this as a fellow 2.0 enjoyer.

 

[Snicklefritz]

Garrett G25-550 Twin Scroll turbo

Ima curious if you can tell a significant difference in reduced turbo lag and increased torque with this upgrade over OE twin scroll?

 

[Thomby]

I think ~400 horsepower from a modern 2.0, with aftermarket cooling & turbo, is very reasonable. Mercedes has been selling the A45/CLA45 with those numbers stock for years, and tons of Evo, WRX, and DSM guys have done it over the past couple decades.

 

[Bugra demir]

I think ~400 horsepower from a modern 2.0, with aftermarket cooling & turbo, is very reasonable. Mercedes has been selling the A45/CLA45 with those numbers stock for years, and tons of Evo, WRX, and DSM guys have done it over the past couple decades.

Even though methanol injection helps, I don’t think the stock internal engine components can reliably handle 400 horsepower for a long period. In collaboration with N75, we’ll be testing to find out the maximum and safest power we can achieve. I’ll be sharing all the data with you as we progress.”

 

[Bugra demir]

Hello everyone,

We’re slowly approaching the end of the project. Currently, the injectors, methanol kit, and electronic boost controller have not yet been installed. I’ve completed the break-in process with the car in this condition. Next week, the missing components will be installed, and I’ll upload the final tune.

For now, I’m using a base map provided by N75, designed for the 15 PSI spring in the wastegate, and I’m quite satisfied with it. Since the engine is freshly built, I’ve only done one pull so far, which I’m sharing with you here. Once everything is fully set up, I’ll do another pull and share the results again.

 

[Snicklefritz]

Nice update. Looking forward to the rest.

Meanwhile, in the interim, I have had my stock high pressure fuel pump and valve cover gasket replaced. Fuel pump was a TSB from December 2023, which I responded to, and KIA did the software update and declared my high pressure fuel pump good to go. A year and a half later, that was no longer the case.

Both were replaced under warranty.

Have you checked your high pressure fuel pump as KIA recommended?

 

[Bugra demir]

Nice update. Looking forward to the rest.

Meanwhile, in the interim, I have had my stock high pressure fuel pump and valve cover gasket replaced. Fuel pump was a TSB from December 2023, which I responded to, and KIA did the software update and declared my high pressure fuel pump good to go. A year and a half later, that was no longer the case.

Both were replaced under warranty.

Have you checked your high pressure fuel pump as KIA recommended?

Yes, I replaced the stock high pressure fuel pump with a high-flow upgraded one from N75. It’s been working great so far.

 

[Jelapeno]

very interested to hear in the result of this. im hoping to lightly mod mine to around 320bhp.

im thinking:
upgraded intercooler,
catch can,
takeda enclosed or open CAI (havent decided if enclosed is a hinderence),
upgraded spark plugs,
JB4 (i have warmed up to the idea of a piggyback tuner) map 1 - 2 (probs map 2 for spirited driving, map 1 for daily driving so not beating on map 2 every day)

note: im in the UK, i cant upgrade exhaust for performance as i will get basically 0 gains due to having a GPF fitted on the downpipe. and stock the car is rated for 244bhp here (think its detuned from the factory for emissions reasons)

Thoughts on whether 320bhp is safely achievable with this setup or would i need something else to get reliable 320bhp??

also has anyone ever actually found out what composition our rods and pistons are and what method is used to create them. is it powder cast, sintered etc?

 

[Bugra demir]

very interested to hear in the result of this. im hoping to lightly mod mine to around 320bhp.

im thinking:
upgraded intercooler,
catch can,
takeda enclosed or open CAI (havent decided if enclosed is a hinderence),
upgraded spark plugs,
JB4 (i have warmed up to the idea of a piggyback tuner) map 1 - 2 (probs map 2 for spirited driving, map 1 for daily driving so not beating on map 2 every day)

note: im in the UK, i cant upgrade exhaust for performance as i will get basically 0 gains due to having a GPF fitted on the downpipe. and stock the car is rated for 244bhp here (think its detuned from the factory for emissions reasons)

Thoughts on whether 320bhp is safely achievable with this setup or would i need something else to get reliable 320bhp??

also has anyone ever actually found out what composition our rods and pistons are and what method is used to create them. is it powder cast, sintered etc?

I’m currently making around 400 hp and have driven about 20,000 km with no issues at all.


Whether you can reach 320 hp with the stock turbo, I’m not entirely sure — you’ll probably need a hybrid turbo, which could get you around 340 hp.


The stock internals can handle up to roughly 400 hp safely, so at the power levels you mentioned, you shouldn’t have any problems.

 

[Jelapeno]

awesome thanks for letting me know. what mods have you got? and are you using JB4 or custom tune? 20,000 on 400bhp stock pistons and rods i would have thought to be quite risky. is that 400 at the crank or wheel? apologies for so many questions

 

[Bugra demir]

awesome thanks for letting me know. what mods have you got? and are you using JB4 or custom tune? 20,000 on 400bhp stock pistons and rods i would have thought to be quite risky. is that 400 at the crank or wheel? apologies for so many questions

Mate, you can ask as many questions as you want — I’ll always answer as best I can.


It’s making around 400 hp at the crank, and my 100–200 km/h times are roughly 10–11 seconds.


I’m not using a JB4 — I tune the car through an EK1 Mini2 device, with the software from NKSpeed.


At first, I worked with N75, but I wasn’t satisfied at all.





For daily driving, I keep it around 1 bar (≈320 hp), and I only switch to the high boost file (1.5 bar) for track or rolling runs.


You can see all the upgraded parts in my first message.


Without the methanol injection kit, reaching this power level might have been risky — but right now, all my parameters are in great condition.

 

[Jelapeno]

Ah awesome. Well I think cooling is my biggest drawback at the moment. Stock it's not great and I don't really want to add WMI. So thinking just a big intercooler. Not sure if Maintec one for the 2.0 is any good or not. And a closed cold air intake from takeda. Hoping that will keep the temps down enough for me to push 320.

Thing is I'm only looking to top out around 320 because it is my daily driving and 320 will be more than enough for UK roads.

But to be honest if I can get to 300 with my planned mod list I'd be happy with that.

Do you know if there is a PID for querying oil temps?

Can't see anywhere online that suggests the 2.0 has an oil temp sensor exposed to the canbus

 

[jack_blck101]

Hello everyone,

My car is a 2018 Kia Stinger 2.0T (G4KL engine), and I’ve been working on a detailed performance build for a while now. My goal was to create a setup that is both daily drivable and performance-oriented, while maintaining durability and safety. Here’s my current mod list:

Engine & Performance Modifications:

• Garrett G25-550 Twin Scroll turbo
• 44mm GFB external wastegate
• GFB G-Force III electronic boost controller
• 11-liter custom intercooler
• Full straight 70mm chrome exhaust system (including downpipe)
• K&N 5060 open air intake filter
• Snow Performance 2.5 methanol injection kit
• 1-liter oil catch can
• HKS high-performance spark plugs
• SCORCHER High-Performance ignition coils
• ARP CA625+ cylinder head studs
• Cometic reinforced cylinder head gasket
• N75 upgraded high-flow injectors
• N75 upgraded high-pressure fuel pump (HPFP)
• N75 Tuning custom ECU software

Target Figures:

• 20 PSI boost pressure
• Safe AFR and methanol ratios aiming for 350-400hp

While building this setup, I’ve carefully considered the limits of the stock internals, as well as cooling, fueling, and overall engine safety.


Now I’d like to ask you guys:


What are the generally accepted safe power and torque limits for the Kia Stinger 2.0T (G4KL) engine with stock internals?

I’m especially interested in hearing your experiences and opinions regarding long-term reliability in the 350-400hp range.





Thanks in advance!

LOVE THIS BUILD! i have a genesis 2.0 21 and ive been researching about it and if anyone has done anything and I've found someone! i was wondering if you have Insta or any other account si could see or follow this project?

 

[Bugra demir]

Ah awesome. Well I think cooling is my biggest drawback at the moment. Stock it's not great and I don't really want to add WMI. So thinking just a big intercooler. Not sure if Maintec one for the 2.0 is any good or not. And a closed cold air intake from takeda. Hoping that will keep the temps down enough for me to push 320.

Thing is I'm only looking to top out around 320 because it is my daily driving and 320 will be more than enough for UK roads.

But to be honest if I can get to 300 with my planned mod list I'd be happy with that.

Do you know if there is a PID for querying oil temps?

Can't see anywhere online that suggests the 2.0 has an oil temp sensor exposed to the canbus

For ~300 hp you don’t actually need to change anything hardware-wise.


With the stock setup, a proper and conservative tune is enough to reach that power level safely and reliably. Cooling and supporting mods only become more important once you start pushing beyond that range.

 

[Bugra demir]

LOVE THIS BUILD! i have a genesis 2.0 21 and ive been researching about it and if anyone has done anything and I've found someone! i was wondering if you have Insta or any other account si could see or follow this project?

Unfortunately I don’t have a page or public account, as these kinds of modifications are restricted in my country.


However, if you reach out to me directly, I’ll be more than happy to help you with anything you need.

 

[Jelapeno]

For ~300 hp you don’t actually need to change anything hardware-wise.


With the stock setup, a proper and conservative tune is enough to reach that power level safely and reliably. Cooling and supporting mods only become more important once you start pushing beyond that range.

to be honest im hoping for a little bit more than 300. 320 i think will be my sweet spot as i can probably take that to 150K miles with good maintenance, I will be getting an intercooler and Takeda sealed CAI and stuff to help with the tune temps and induction.

but that will be at the end of the year or next year. Il be taking mine in soon for potentially a new torque converter and maybe gearbox or just rebuilt gearbox as mine and anothers car have this issue with the torque converter not disengaging properly (or slipping enough is probably the term) when its cold and sometimes whilst warm too. means that if i stop and im in D the engine feels like its struggling to idle a bit. if i start my car, wait 30s and then put it into R the revs will drop by like 250rpm which is not normal. the other person had their warranty claim accepted so il hopefully get accepted too. and then it will be all set for modding when thats out the way


Whats the turbo lag like with your hybrid turbo or whatever you went for?

 

[Bugra demir]

to be honest im hoping for a little bit more than 300. 320 i think will be my sweet spot as i can probably take that to 150K miles with good maintenance, I will be getting an intercooler and Takeda sealed CAI and stuff to help with the tune temps and induction.

but that will be at the end of the year or next year. Il be taking mine in soon for potentially a new torque converter and maybe gearbox or just rebuilt gearbox as mine and anothers car have this issue with the torque converter not disengaging properly (or slipping enough is probably the term) when its cold and sometimes whilst warm too. means that if i stop and im in D the engine feels like its struggling to idle a bit. if i start my car, wait 30s and then put it into R the revs will drop by like 250rpm which is not normal. the other person had their warranty claim accepted so il hopefully get accepted too. and then it will be all set for modding when thats out the way


Whats the turbo lag like with your hybrid turbo or whatever you went for?

Got it, hope your transmission issue gets sorted out as soon as possible.


I’m running a big turbo, G25-550. There’s definitely some turbo lag — boost starts to come in after around 2,500 rpm — but the way it pulls after that is on another level