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Discussion Starter #1
Anyone know if the active grille shutters effect the main grille, or is it just for the lowers?
 

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Does the ST have active grill shutters? I know there has been some debate about which Focus come with them. I've never checked out my Titanium to see if they are there.
 

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I just read this:
Active Shutters like on the Focus SFE, which is suppose to help the intercooler
 

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Yes, article states ST has them.
 

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To answer OP, yes it has shudders but i believe it only affects below crash bar/license plate bracket. This is where shudders are on my titanium.
 

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Discussion Starter #7
Excellent. I was wondering how they'd work on the big grille mouth of the ST. They don't, 'cause they ain't there.
 

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The active grill shutters are on the Focus ST.

I imagine they're located at the bottom of the front end, much like how the Ferrari 458 has them down low (that's where they're most effective).
 

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They are a motorized grill (looks like shudders on a window) that open or close depending on variables. Open for more cooling in needed or closed for better aerodynamics. Youtube has some videos about them. Pretty cool technology. My Titanium warms up really quick during cold weather because the shudders stay closed to allow engine to warm up. The ST's are there for same reasons, but i also heard they are programmed to allow more air into intocooler as well.
 

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Aahh, yes one of the first things I will be taking off my ST. I don't see any gain from blocking airflow to the intercooler.
Because when you're driving at speed on the highway, you're really not using much turbo power (relatively), so they shut to increase your aerodynamic efficiency.

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The shutters do next to nothing for aero dynamics, in fact they hinder more than help when shut.

They help control engine efficiency by having more active temperature control.

By being able to keep the temp in a closer variable range they can make the engine more efficient and return better fuel mileage.

Oh and the shutters dont cover the intercooler. They are behind it.

- Drew
 

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Uh, yes, they help aerodynamic efficiency. They decrease turbulence by shutting off part of the opening. Didn't you pay attention in fluid dynamics?

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Never been to college.

I just work with the engineers who designed them everyday.

Oddly enough, speaking of turbulence, do you know where that trapped air goes after it hits the shutters?

Around and under the radiator and into the engine bay, where it would have ended up had it just passed through the rad anyway.

If these shutters were on the front fascia, improving aero, you'd be right. They simply control engine temp and keep it at optimum operating efficiency more of the time. Before these they had to rely solely on a thermostat to open and create a huge discrepancy in operating range. The closer they keep it, in all climates, the more successful they are at fine tuning the driving/load calibration.

- Drew
 

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Discussion Starter #19
Not having seen the wind tunnel testing myself, I'm dubious of any claims that the shutters are not functional in aero. Isolating the discussion to and focusing on the us of the shutters (which I know the engineers surely didn't do), it's difficult to necessarily know how they effect aero. The assertion that they actually cause worse aero by forcing air under the car sounds very dubious to me as they've got a "skid plate" type deal between the front of the bumper and the radiator core support, and then there is a deep airdam at the face of the radiator core support to force air around to the sides (assuming path of least resistance), not so much under. Typical wisdom for this is that using a deep airdam before the engine compartment creates a low pressure zone below the engine compartment, thus allowing hot engine air and excess underhood air pressureto be evacuated very efficiently. Given that the ST is intended as a performance vehicle and rated to a computer regulated 155mph, I think they'd take significant steps to avoid front end lift at speed. I intend to actually see how this works out in real life by doing a standing mile event or similar, like maybe the long straight at Sebring, and we'll see.

One last thing, speaking of blocking air... at every top speed event I know of, it is common practice to tape up and block as much airflow across the front of the car, especially on the blockiest of front ends, to the point of often causing engine overheating. The result is usually at least a few more mph on the top end. I believe that has more to do with the aero benefits of blocking all that air than with any contributions to engine heat control, and that's what I've been told by the racers that do it.

Just my .02.
 

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Discussion Starter #20
Well, I had a second and was curious and did a quick youtube search. There's nothing on the ST, but there is stuff on the 2012 Focus... here's what I've found:


From Ford:








From Ford of Europe:




Clearly grille shutters can be aerodynamically beneficial, but whether that is true on the ST is yet unknown definitively.
 
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