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2015 SX-T SWP, 2012 EX, Spicy Red
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73 Posts
Discussion Starter #1
See, I never wanted the intake. My buddy said it would make mad power and the stainless heat shield with carbon infused black paint and my original snorkel is near the short ram intake filter, but not sealed.

See, I think it makes a lot of noise, but I am down on power and refinement. Kia and Hyundai spent millions making sure the stock intake would concentrate oxygen right as the spark plug fires. Also, I have been getting a pathetic 11.9 mpg, and the carbon buildup in the exhaust tells me one thing: UNBURNED FUEL. Fuel just rolling out my Magnaflows, which I drove before the intake..big improvement there. After the intake installed? Less usable power. Everything is made at high RPM.
So, I am having my guy put the stock intake back in.
I am still going to try the Lap3 chip, but not until MY BABY runs correctly. The oil is clear and full, I have done everything I have been told....but adding a bunch of airflow with 93 octane fuel that only burns 馃敟 with hotter plug temps at high RPM'S IS NOT WORKING.
So, back to stock. Back to 89 octane, and then I will see if I get my turbo thrust back. It just doesn't run quite right like this. There is no warning lights...just idles like a NASCAR and accelerates like a Civic. Sucks.

WHAT IS YOU GUYS OPINION?
 

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2012 Kia Optima SX
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19 Posts
My buddy said it would make mad power
Your buddy is mad full of it. You see minor torque and horsepower gains due to increased airflow, caused by decreased filtration quality (which is pretty bad news for GDI's). As you point out, the stock intake was designed the way it was for a reason.

I have been getting a pathetic 11.9 mpg
That has a lot more to do with your right foot than it does the intake.

the carbon buildup in the exhaust tells me one thing: UNBURNED FUEL.
Turbo GDI's do that no matter what.

After the intake installed? Less usable power. Everything is made at high RPM.
That's what the stock powerband looks like...? You're not even making 150+ WHP until you're at 4k RPM.

The oil is clear and full,
Won't be after 500 miles with the turbo, no matter what you do.

back to stock. Back to 89 octane
Stock is 87.




I have a sneaking suspicion that something else is going on.
 

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2018 KIA Optima
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22 Posts
Possible.. yes, it is the 2.0t. City driving in eco mode and trying to maintain good mileage I can do 18~ if I drive spiritedly... yea it can drop hard.

1/2 hwy 1/2 city 25mile drive to work nets me an average of 25mpg cruise control set at 83. In 93 octane pump fuel fully stock myself.
 

Premium Member
2015 SX-T SWP, 2012 EX, Spicy Red
Joined
73 Posts
Discussion Starter #5
Your buddy is mad full of it. You see minor torque and horsepower gains due to increased airflow, caused by decreased filtration quality (which is pretty bad news for GDI's). As you point out, the stock intake was designed the way it was for a reason.



That has a lot more to do with your right foot than it does the intake.



Turbo GDI's do that no matter what.



That's what the stock powerband looks like...? You're not even making 150+ WHP until you're at 4k RPM.



Won't be after 500 miles with the turbo, no matter what you do.



Stock is 87.




I have a sneaking suspicion that something else is going on.
No....nothing wrong
I appreciate you breaking down what I was talking about.....and it took just 1 STEP to figure it out. I ran it out of premium. Added a full tank of 87 octane, and all tge power was back where it belonged, and my FE rose to almost 20, vs 11.7. There is NO reason to go back to stock right now. I just hope the HPS intake filter is very high quality, as you said. These GDI Engines do not like dirty intakes.
Thanks to my buddy Joe for testing just about everything on my ride, and his co workers down at the shop; and your feedback here. Perfect!!!!!馃樂馃憤
 

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2011 KIA Optima
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41 Posts
This has always been true of I/E modifications on all cars and trucks. The stock I/E system is usually already pretty optimized. The way I tell people to think about it is to think of your engine as a fan and your peak performance is based on air velocity - not air volume. I/E mods increase the air volume and proportionately decrease the air velocity. This is because the bigger your make your openings on both the I/E sides, the more volume of air you need to push to achieve the same velocity. This means that your peak power is moved to higher RPMs which generally is to your detriment. On a visualized power curve, you are shifting the peak to the right - you lose power at "normal" RPMs and only see gains higher up.
 

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2018 Kia Optima
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973 Posts
Many folks seem to focus on only two values when it comes to stuff like HP--max/peak HP and max absolute gain/increase when what they really should be focusing on is the increase in HP at a given RPM and/or within the RPM band where the engine spends much of its time in. Personally I never really understood the fascination regarding higher peak HP values that are realized only at higher RPMs where most folks don't spend much of their driving time at those engine speeds...which like you said, peak power at higher RPMs is generally a detriment, at least when it comes to typical driving manners.
 

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No....nothing wrong
I appreciate you breaking down what I was talking about.....and it took just 1 STEP to figure it out. I ran it out of premium. Added a full tank of 87 octane, and all tge power was back where it belonged, and my FE rose to almost 20, vs 11.7. There is NO reason to go back to stock right now. I just hope the HPS intake filter is very high quality, as you said. These GDI Engines do not like dirty intakes.
Thanks to my buddy Joe for testing just about everything on my ride, and his co workers down at the shop; and your feedback here. Perfect!!!!!馃樂馃憤
So wait, going to 87 octane was all it was???o_O
 

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2012 Black SX Prem. & Tech.
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1,693 Posts
Careful, you might be drawing the wrong conclusion that the octane was the issue.

If you replaced the gas and the problem went away, perhaps the problem was simply bad gas.

Gas can be bad for various reasons, unrelated to the octane. You can get unlucky when you fill up at a gas station.

You might be right about the octane being the issue, but I wouldn't be so sure unless you can try premium again, and see if the problem comes back.
 

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2013 Kia Optima
Joined
443 Posts
Another thing to watch out for is crud on your intake valves. If they gum up, the engine won't be able to draw in air as easily, and the combustion chamber will not seal properly, leading to a loss of power. Apply some CRC GDI Intake Cleaner, and run a bottle of Redline through to get things back to spec.
 
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