Saw another grill block :)

[Tony Raine]

Originally Posted by Mandilon

I read that grille blocks are ineffective. EPA blocked an 18 wheeler's grille oppening and there wasn't any effect in wind resistance. I have the PDF file somewhere hope I find it.

i read somewhere that elvis was still alive, doesn't make it true


but to be more serious....

on an 18 wheeler, i can see how a grill block would be a bad thing. an 18 wheeler grill is very wide, tall, and vertical. with an "open" grill, air will pass through it and while most of it just bounces around and creates turbulence, some of it has a fighting chance to make it out the bottom of the rig.

with a grill block, air just hits a massive wall at a 90 degrees to the road.

compare trying to run down the road holding a 4'x8' sheet of plywood straight up to doing the same with a 4'x8' window screen.

on a car/pickup/suv, the grill block diverts the air over/under the car at a more aerodynamically pleasing angle. think teardrop shape.

[Xringer]

Originally Posted by Tony Raine

7
compare trying to run down the road holding a 4'x8' sheet of plywood straight up to doing the same with a 4'x8' window screen.

If you are running above 40 mph, the surface of a mesh screen starts to act just like it was a solid.
That's why those old mesh satellite dishes blow around in a heavy wind storm.

[gascort]

Originally Posted by Tony Raine

compare trying to run down the road holding a 4'x8' sheet of plywood straight up to doing the same with a 4'x8' window screen.

But... to be less serious, could someone please try this and post video?

I bet the window screen has at least 50% of the resistance of a plywood sheet at high speeds though. Seems like a lot of turbulence would be generated.

The grill blocks on our cars also push air up, over, and around a vehicle that has good aerodynamics. The semi - it doesn't matter where the air goes around - it's not good.

[gascort]

Originally Posted by Mandilon

...I think the EPA tests are *smarter* than YOURS.

Please tell me you are kidding, and that you don't also believe Jamie and Adam on Mythbusters never have error in their experimentation...

[azraelswrd]

Originally Posted by Xringer

If you are running above 40 mph, the surface of a mesh screen starts to act just like it was a solid.
That's why those old mesh satellite dishes blow around in a heavy wind storm.

Wow, I didn't know that. Cool! (I was wondering why people were using mesh for belly pans) Does it involve Bernoulli's principle or am I making it that obvious I'm not a physicist?

[trikkonceptz]

OMG, I did this for nothing? Seriously, 2 mpg from grill and fog blocks are nothing to sneeze at ..

Plus, ghetto bug splatter wind tunnel testing shows bug only like the bottom 4 inches of the nose. everything else now stays clean .. whoo hoo ...

[Xringer]

Originally Posted by gascort

But... to be less serious, could someone please try this and post video?

I bet the window screen has at least 50% of the resistance of a plywood sheet at high speeds though. Seems like a lot of turbulence would be generated.

The grill blocks on our cars also push air up, over, and around a vehicle that has good aerodynamics. The semi - it doesn't matter where the air goes around - it's not good.

What kind of speeds are we talking about? Because, 50% is a big number..

Can't find much info about this on the web..

I think this "reduce by 40%" chart is most likely for a K-band dish
which has pretty large holes in it's mesh.
Whereas if we are talking about a window screen.. I would have to guess
it would say reduce by 20% at the most..

[EP3]

Originally Posted by Mandilon

....sorry. I didn't know 'aerodynamics' CARED. I thought that they affected EVERYTHING ***PROPORTIONATLY****

I think the EPA tests are *smarter* than YOURS.

LOL Wow this is a way to start off posting. Reguardless if you are right or not (which I strongly disagree with you). Real life trial and error is where you will see real results. Yea you go ahead and trust everything the governt throughs at you. And I have not been an Ecomodder here long, but I am offended when you insult someone on here.

If this was meant in any other way then I read this, please explain again.

[EP3]

Originally Posted by Xringer

What kind of speeds are we talking about? Because, 50% is a big number..

Can't find much info about this on the web..

I think this "reduce by 40%" chart is most likely for a K-band dish
which has pretty large holes in it's mesh.
Whereas if we are talking about a window screen.. I would have to guess
it would say reduce by 20% at the most..

ROTFLMAO

I am impressed that you found such a chart. Wow! that this chart even existed. Funny stuff never the less.

[EP3]

Originally Posted by Tony Raine

compare trying to run down the road holding a 4'x8' sheet of plywood straight up to doing the same with a 4'x8' window screen.

LOL I am so going to do this. I can see me now...Out of breath, my wife yelling "What the!! What are you doing" The neibors staring as if I am on some kind of drug induced rage. The Police showing up shortly after with the COPS camera crew. Me yelling at the Police saying "no its ok I am a firefighter doing a areodynamics test"... Me getting tazed as I run towards the Police because they take the screen as some kind of weapon... The last words before I wet myself from being tazed "Ecomodder Till I DIE!!"

Sorry I must be tired 2:42am EST coming off a 24hr shift.