Getting ready to put a new set of grill in my xB. In looking at the upper grille, it is solid. No air flow thru this piece of plastic. My thinking is that the more airflow the better. Does it affect airflow adversely by opening this area or will more air be better?

I suppose this was by design by Scion engineers. Could the airflow somehow be altered by opening this space thereby changing the proper flow and negatively affecting cooling? thoughts?

 

The radiators are cooled with air passing through the two lower grills. The top grill is DAMMED or closed. There are many threads discussing the change in air flow with a open top grill. I would perfer to NOT have rain, snow and slop enter my engine compartment. I like a clean machine. There is also evidence that when the top grill is opened, air is forced under the car.
The more air the better? Maybe not! If it changes the areo-dynamics that all those dedicated Japenes engineer's designed.

Anyway, read all the GRILL threads and decide for yourself. If you choose an open grill, take pictures of how clean your engine compartment is now.

 

Out of curiosity...

What "evidence" was ever presented to show that if you install an open grill that air is forced under the car?

That statement seems very misleading. To the point that someone that didn't know any better might think that by installing an open grill their car would be unstable due to lack of downforce.

 

if you're thinking about swapping out the grill and are worried about air flowing through the "grill", you can have a piece of aliminum fabbed up to prevent this. If you are getting a billet grill I'd paint the back piece black so not to distract from the grill. Have any of you turbo guys used this area behind the "grill to place a front mount intercooler? They might have a better idea on the airflow through an opened grill.

 

i have noticed that with my billet grille installed, my fan dont kick on as much anymore......seems to benefit me..less fan on = cooler engine due to air flow?? i guess if you like it get it.

 

If I remember right someone here with an aftermarket watertemp gauge posted that the water was hotter with an open grill on top. Only 10 or 15 degrees. Not sure if they ever figured out the science to it. But that post must be 2 or 3 year old by now.

 

really?? thats weird..............i cant for the life of me figure that one out

 

If you have an open top grille made of billet you're going to get a whistle at speed. Also, as was mentioned, your engine bay will be FILTHY!

I generally run overlays on the two bottom grilles in addition to the solid top grille and have never had cooling problems.

-Alex

 

how true you are........the week after i installed my upper grill i was on the highway at like 11pm, all of a sudden i hear this whistel....i was like what the heck?? then i realized it had to be the grill cause it was the first mod i did and thats when i noticed it....anyway i dont mind the whistle you only hear it when the windows are rolled up and the raido isint on

 

mine doesn't whistle. I have the grillcraft billet grills.

I wish they had a backing plate for it though.

 

^^indeed, you want the top "grille" to be solid and prevent airflow..

as mentioned, the air flow to cool the radiator and stuff is below that.

having the top open will adversely affect that flow.

 

I have fabricated a plate to keep this area damed. New grill will be in on Weds. I'll keep you posted. Thanks for the insights.

 

I still see nothing more than hearsay. I want proof. I don't buy the cooling problem. And I keep seeing conflicting information.

One person claims having an open upper grill forces more air under the car. The next person says it prevents more air from going to the lower grills. That same air being pushed down by the first statement would have to pass the lower grill locations from the second statement.

I want video, pictures, empirical data. Sorry, if you don't like the cynic in me coming out to play. But I am just not one to buy into the hype. And this isn't a personal attack on anyone who is relaying information from other people. I just want to see proof before I swallow these claims hook line and sinker. Until then, a full set of B-Cool Billet grills will be the next exterior modification for the wife's xB. (We can live with/deal with any whistle that might show up.)

 

I don't really think it's a big deal. However, if more air is going IN to the engine compartment where is it going to EXIT? ...For the most part under the car. Some of it will vent from under the back of the hood but most is going under the car. Path of least resistance and all.
I'm glad to hear that you wont "...buy into the hype." But, I dont think anyone is going to give you Video proof.

The real question is ... Is it Grill or Grille?

 

I have the jdm style open grill bought from Scionsport about 6+ months ago, I have no problems with cooling---and I see no difference in the engine bay being any dirtier...

 

What about the RS's?

Dont they have an open mesh top grill? If so. seems doubtful the additional airflow would be bad.

 

I think that people's panties are in a bunch and need to chill out.

BUT... I do think that we need to invest a few thousand dollars and experiment on this with a wind tunnel and various types of grilles!

..but seriously, if it does affect it, it's obviously negligable. so... QUIT CHER _____IN!

 

The RS2.0 grille has a plate in the back of it. The RS3.0 grille has a plate in front of it.