I'm starting to think the Cerato/Forte's intake isn't hampered anywhere near as much as the Velosters.
1; We don't have that maze of intake resonators.
2; None of those magnetic flappy doors inside the box.
3; AEM's dyno seems to show a significant difference between the two. 4hp peak gain for the Kia @ 3800rpm or something like that.
4; Very slightly larger filter.
No doubt that those 3.5 inch CAI's work, just maybe not as much as the Hyundai's'?
I know they said the ES filter was about 12% bigger than that on the veloster. When I had the forte and ES filter side by side I calculated only a difference of about 4 sq in in surface area which was about a 10% difference.
On the snorkel side mine just in from the car spot and directly down to the filter box.
In pics the longer filter is the one from my F5, the other is the ES. It did not fit
I have a 15 forte5. A friend has the es sand that's where I got that airbox to try. But it would not fit sadly. My next step however is to redo the rest of the pipe with a larger 3.5 pipe. I've already removed the restrictor by the turbo. You can see it in the picture here on the car and then how restrictive the stock resonator I replaced is.