Two question on my active grill block?
 

So my Ioniq had active grill shutters for the main section. You can clear see them closed automatically since it’s winter time

But the lower section I circled in blue doesn’t have an active shutter system. It goes towards the radiator at the bottom. There are also little ramps of holes in the front under tray

My two segmented questions are-


Would I be helping or hurting aerodynamics but blocking off those lower holes? Everyone says grill blocks help aero, but what if Hyundai wanted some air to fly in and then go down thru the front under tray to help with something secret they discovered in the wind tunnel? What about stagnation points or adding higher pressure to that front grill lip area? Could that add drag? Or does it just seem like I’m over thinking and it’s making no difference?


The main reason I’m curious to blocking off that section is to limit air flow from going into the engine bay and radiator since it’s so cold now. My cars heat inside only works when the engine is fully warmed up. That or I’m freezing. The hybrid issue is every time I come to a stop light, the engine cuts off and switches to battery and I lose my heat pretty fast. Also hybrids take longer to warm up than most cars. Do I run any chance of overheating by blocking that area off and being a full 100 percent grill block? Should I leave it as is? I really want my engine to warm up faster and stay warm longer. If the engine gets too hot, the active shutters should open up right? I just feel like even with the active shutters closed, allowing cold winter air into the bay and lower radiator, even if it’s a small amount, is still hurting the warm up period. It also rains a lot here too so more water goes into the engine bay too with that lower opening.

Every car I've seen has an upper and lower grill opening. I fully blocked both the top and bottom grill on my Prius in the winter. In the summer I'd open half the upper grill, but leave everything else blocked.

I had Torque monitoring coolant temperature to make sure I didn't run so hot that the fans came on. Only once had the fans turn on while climbing a mountain.

Ok I’ll probably block off the little lower opening. If it gets too hot the upper grill will open anyways ( that happened this summer driving thru Arizona mountains in black car)

I’m assuming no aero benefit though since it’s such a small area?

I posted on this in another thread:

so block the lower opening that doesnt have active shutters or not? its getting cold in oregon as you know lol

Does it lead to the radiator or under the car?

A-B-A testing. Maybe 0.01-2 delta.

It goes straight ti the bottom part of the radiator. I guess to allow some slight airflow in the summer. The main shutters barely ever open. Even in summer in road trips they won’t open. They only
Open when it’s over 100 degrees and aggressive driving.

I put duct tape over the smaller opening And didn’t notice anything bad. I’m sure some air flow from the that vent into the lower skid plate area but I don’t think it affects anything

https://ecomodder.com/forum/attachme...p;d=1565844879
That's my old Civic Wagon. I had multiple holes for the license plate screws and would manually move the plate as required. It was usually as pictured most of the year just poking around at moderate speeds. If I took it on a higher speed trip, it needed more air. About half of a license plate (6" x 6") was usually enough. The splitter probably increased pressure at the opening, sending more air into it. It was fully blocked in winter. There really wasn't any useful upper grill opening. I don't think any air that made it through that upper slot would hit the radiator, but it's been a while since I looked at that poor car.

Hyundai might've left some grill always open in case the shutters fail to open. Just a guess.

One of my favorites. Mainly the tire deflectors. Are those conveyor belt material?

Baler belting from Tractor Supply. They used to sell it in bulk by the foot.

Bought some coroplast. Will be painting it black and I’ll be attaching it over the little grill opening using heavy duty velcro so I can remove it and put it back on easily Incase I’m going to be going somewhere warmer during a trip

Bought some coroplast? This is the season of free coroplast, lol.

It was 7 bucks at Home Depot. Blank slate is easier to paint. I’ll use some left over coroplast for other experiments too

benefit..........small area
 

That lower opening may constitute the actual forward stagnation point, and highest static pressure on the car.
If so, the actual air volume through there may be disproportionately high, considering its 'size.'
The upper grille may be exposed to accelerating ( pressure-reducing ) flow, as the Lanchester/Prandtl surface if discontinuity forms around the nose.
Just watch your temperature gauge.
Engine warmup has as much to do with the thermostat operation and internal plumbing, as it does with cooling air flow.

so there should be some type of aero benefit for blocking off the lower splitter grill even though it's so small?

and ill only be doing this grill block in winter weather here and will take it off in late spring. worst case scenario, is that the upper shutters should actively open if things get too hot, even in winter, right? as long as everything is functioning properly, i should be set?

Just watch your Lanchester/Prandtl surface discontinuities. :)

I think there could be aerodynamic detriment to blocking it off. A high static pressure being relieved can reduce drag if done right.

Also a 100% block is asking for trouble at some point. Engine coolant temps are used for controlling the cooling fans but other systems like electronics are stressed by higher under hood temps.

Except, active shutter would open if temps increase.

Not if they aren't monitored. As I stated engine coolant temps are often the only thing monitored. Reduced airflow increases under hood temperatures for other systems that are not monitored because they don't need to be as the car was designed.

Other components aren't monitored because excessive temps would first manifest in coolant temperature increase, most likely.

Are you recommending against grill blocking?

I'm am saying don't do a 100% grill block.

Did 300 mile trip to grants pass with full grill block. No overheat issues. Also popped hood and engine didn’t even radiate as much warmth as it does in the summer. Also still loses heat fast. May have to add hood insulation lol

Did you add hood insulation?
You wouldn't need it now! :)