grill blocking, does it work from the back?

[2000mc]

i was thinking of doing some grill blocking. i was wondering if anyone had tried blocking air with panels held up to the back sides of grill openings? would this be just as good in some cases, or would smoothing the front side make much more of a difference?

[SVOboy]

Smoothing out the front would make more difference, but from the back is good if you're going for a radiator block without any sexy exterior mods.

[thisisntjared]

the difference would not be as great because of a parachuting effect. i wonder if recessed blocks would actually be worse...

[trebuchet03]

It should help -- you're going to create a high pressure zone inside the cavity, and if you could see it's shape, it should be "cone-like."

It would be better to be completely flush, but it's surely better than letting air impact a vertical "wall" of a radiator

Here's what an apple does -while it's no car, it does have a cavity that's blocked...

[MnFocus]

Originally Posted by thisisntjared

the difference would not be as great because of a parachuting effect. i wonder if recessed blocks would actually be worse...

It may not be quite as good ...I don't think I'll notice the difference.

[thisisntjared]

thanks for the pic! now i definitely think it will be better than no block at all. i was recently thinking about doing the same thing today because i want anyone that sees my car to think it is completely unmodified(theft deterrent) but i still want to block the grill for the winter months. i do not want to sit for more than a minute to let my car warm up.

i think i want to go for a degree in aerodynamics.

[MnFocus]

my temporary test block :

It was still in very good shape after a couple months ! Its now made of 1/8" lexan and painted satin black Krylon Fusion-I deleted the 1"x6" cut out as well as 90% of the lower grille .

[91CavGT]

I blocked off the back of my grill on my truck, but every time an 18 wheeler passed me the wind blew the duct tape off.

[GasSavers_Ryland]

well, the stock grill block that came on the civic VX sat behind the grill, it also helps by preventing air from entering that less then airodynamic engine compartment and going under the car.

[trebuchet03]

Originally Posted by thisisntjared

i think i want to go for a degree in aerodynamics.

The funny thing is... I'm not an aerospace major - I'm mechanical But I still got to play with a water tunnel, and now I'm developing a fairing for another human powered vehicle

I wanted to compare apples to oranges in the aerodynamic sense... I couldn't find an orange though :/

Just for fun.. I here's a few more pictures from my collection

I did the calculations awhile back, and IIRC the equivalent wind speed was something like 6mph for those car models... This tunnel is just for flow visualization

Check out the pressure wave formed behind the shield - that's actually very significant (think sound pressure wave in some cars when only one window is open)

Very Slippery Shuttle

Toy Car (I brought a box of die cast Porsche cars)


Here's the water tunnel


Sorry to thread jack there