Good or bad grill block?

[RedDevil]

Originally Posted by taco

I don't know about the sides being open if that created bad turbulence. I was wondering if it would be better to block it all the way across or if it gets too hot, to block off the outer parts and leave a hole for the center.

I'd say block all except the sides vents...!
They are there by design, deliberately blocking the air flow.
Same principle as the protruding A pillars, between which the front window seems sunken as if set back too far. That too lowers drag, counterintuitively.

As I see it, if you cover them more air will flow along the sides instead of over the car, but the angle around the bumper is too sharp; it will cause extra drag.
The 'scoops' at the sides of the bumper create a high pressure area which pushes the air around the bumper more smoothly.
You want as much air flow over the car as possible. That's where the energy that was put in moving the air away can be gained back by the gentle curve of the roof. The sides don't do that.

[Vakarian]

Block as much as you can, probably entire lower section plus the vents and simply see how it goes. If you're cautious about blocking too much do it piece by piece and test results.

[taco]

Originally Posted by Frank Lee

Can't hurt. Block the brake vents too unless you're crazy hard on 'em.

i dont understand what you mean by brake vents.
the black pieces under the headlights are blocked and so are the pieces under them.
the center has the slit above the black bar and the center section of the mouth open then a little bit of the piece under the bumper is open. then it has a shield the covers all the underneath to the rear tires.

i got to find some more coroplast and i will completely block it off( center part.)

Originally Posted by serialk11r

Off topic, but I'm surprised you're idling at 0.19gph with that Skyactiv engine. My 1ZZ-FE (designed in 1999) is 0.18-0.19gph idle. I would've hoped that with direct injection, high compression ratio, better VVT, and such that they would've been able to cut idle consumption more than 10% (since the displacement is bigger on the Skyactiv).

ill check it when i get to work the eve.
this car is also the pzev if that matters. drops hp from 155 to 154 dont know what else it does.

no heated seats in the i touring, did have fan on 1 out of 4 and the temp set to the middle.

[spacemanspif]

With the slit above the black bar you should be able to completely block the lower grill and still get adequate cooling in the winter.

[Frank Lee]

Oh. Since they're already nothing but styling elements, don't mind me.

I blocked the actual vents on my car tho'.

[kafer65]

Thanks for posting Taco. I've got all of my CX-5 blocked except for a 1 inch slit 6 inches wide. My only means of monitoring temp is if the cooling fans come on or not. So far I can't detect any cooling fan activity and I've been running my AC for defogging alot too. We've been in the high twenties low thirties here and my mileage is way down from normal. Right off the highway I'm up to 36.7 from 32 mpg pure city at the beginning of my tank. So far I think I'm bleeding enough heat toward the passenger compartment to have it work but I'll probably need to open it up more to be able to modulate it more.

[Sven7]

As a general rule, if you're going to only block part of the grille, leave the center open. The reason for this is that if you have the sides open as you have now, you are spoiling clean airflow coming from the very front of the car. It is instead best to pull from the stagnation point and let anything outside of that flow around cleanly.

One notable exception is the Civic EG, whose radiator occupies only the passenger side of the grille opening.

[kafer65]

Here is what mine looks like. Not sure I like it being tilted on the bottom and the sides flare a little on the top and bottom. Not sure this is a very good design for catching air in the stagnation area without disturbing the sides. I'm considering smoothing the brake fill-its too. Taco, do you have any details you would share about getting the mgpguino hooked up in your Skyactive rig?

[redpoint5]

I'll also add that I can do 100% grill blocking on the TSX in city driving without overheating. I'm able to do this by running the climate control. Whenever the HVAC is turned on, it runs 1 cooling fan. This is enough to keep the coolant temps in check.

[redpoint5]

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