Grille Blocking Front or Rear
 

I have read many post regarding grill blocks and I myself have done it to the Vibe. I want to do it to my 4-runner also, however will I get the same benefits from blocking the grille from inside the hood as I would just blocking the front side of the grille? In this case the first motivation is aesthetics.

I hope you guys understand my question ...

You'll likely get the same benefit blocking the rear of the grille vs. the front. The difference between the two approaches would be very small (though presenting a smooth face to the wind is always best).

blocking the rear would create a "pocket" of spinning air similar to what you would find in a truck bed. not quite as efficient as a smooth surface, but it would promote laminar flow.

The only advantage to blocking the rear side is you don't get that tacky cheap look.

Hey, cheap gets a bad rap!!! I consider it "theft deterrence". :D

You could always look around the forums and find some of the "professional" looking grill blocks and model yours after that. That way you get the advantage of one being on the front while still having your car look good, but then again you do lose that "theft deterrence" quality, lol.

it would be better in front, if you know someone that can mold plastic you could mold clear plastic and it wouldn't stick out, unless they went close and would be solid.

I made mine a behind-the-grill block so as not to attract the cops' attention. I suspect it works almost as well as in front of the grill; that's what an aerodynamicist at the university told me, too.
The newer BMW's have automatic behind-the-grill block blinds that are at least 3 inches behind the grill, i.e. huge air pocket. It must work, though, or they wouldn't go to all the trouble.

Not everything in a final product is for functionality but a balance between that and aesthetic styling. For example did I really need 2 giant dimples in my fender for non-existant fog lights? I think not. Probably doesn't make a mjor difference in Cd but I don't know how smart it was for divots in the first place though I suspect cost was a factor vs a plastic covering over the divots.

Tooling up to mold a front end without those pockets probably killed that idea, it's not that much more plastic, but the R&D on it, tooling and the production line space to make a separate bumper.

on my car (wich has the lightest engine available for the model) part of the top grill is backed of from the factory with a flimsy plastic insert that blocks of two rows of grill as well as the back of the opel logo wich would also allow quite some air in.

also the bottom grill wich consists of 2 openings has the bottom one blocked, although i can't see if it's part of the bumper molding or a separate piece.

anyway, for the top grill it's is almost a 50% block with a cheap looking plastic bit that snaps in place behind the grill.

although this might very well be the cheapest bit on the car, the fact opel cared enough to put it there should mean it would deliver a measurable improvement wich could be marketed as better economy and emission figures (the later became more strict around the time the car came out).

personally i think the difference, between grillblock vs no grillblock is far greater than between internet and external.

a smooth external block would be best, but in the real world i think an internal block might be easier to make without altering the looks of the car, and still be just as effective.

I feel the same way, I blocked the one on my wifes car from the rear.
SWMBO doesn't want any "Ugly" alterations to her vehicle.
So far everything I've done has the "appearance" of being stock.
http://ecomodder.com/forum/showthrea...over-1707.html
Some stuff helped noticeably and some didn't.
But it is all still there (so far).

Schultz