2011 Kia Optima SX Turbo: Big Honkus, Little Ducting
June 06, 2011
After reading Jay Kav's engine walkaround, I was curious about the Optima's intake honkus which is precariously squeezed between the hood and the plastic trim surrounding the hood latch.
First, in this photo, notice the rubber seal running laterally about eight inches back from the leading edge of the hood. That seal pins itself to the top of the intake honkus just in front of the radiator (notice the witness mark in the top photo) ensuring that hot air which has passed through the cooling system isn't injested by the engine.
This is all good and fine until one closes the hood.
It's clear that Kia wanted a clean seal between the hood and bumper cover, which means there's no air sneaking in that gap to feed the engine. Near as I can tell, that leaves only one source for cool air: the small lateral slits on either side of the hood latch. They can potentially feed the engine cool air which passed through the grille but didn't pass through the radiator.
Now if I know anything about air it's this: air is lazy. And getting it through the grille, through those tiny slits and then laterally into the intake honkus is going to require energy. I'd guess that at speed there's some flow, but you don't need to be an aerodynamicist to know there's little cool air getting to the honkus at low speeds. Still, must be enough given this engine's impressive specific output on low-octane fuel.
But I bet some dyno work would prove this car is sensitive to heat soak. Maybe we'll give it a run.
Josh Jacquot, Senior editor