H3 aerodynamics in action

[alrock]

Someone left a flyer on my windshield. Instead of laying flat against my windshield with passing air, apparently the air is being forced downwards and forwards when I drive.

[video=youtube_share;9tSZ8zDgImI]http://youtu.be/9tSZ8zDgImI[/video]

 

[Hunner]

Just like a brick!
That makes the grill area at the base of the windshield a high pressure area forcing air into the engine compartment.
It also sucks rocks into the glass instead of making a windscreen.
I guess it holds the front of the truck down too, with all the awesome acceleration available.
My Dodge truck does that too and I cut a 4 inch hole in the fire wall beneath that for more air intake.

 

[Hans3T]

So that's why we get stellar gas mileage! :wink:

 

[alrock]

Don't remind me. I'm barely cracking 13 now I think in part to the sagging rear springs. I measured vs. a stock H3 today and I'm almost 2" low at the rear bumper now.

 

[benlaud87]

I averaged about 13 mpg on my last tank. I was pretty impressed, I was expecting 10

 

[Paladine71]

Ironically, this will probably help with my engine cooling after I vent my hood. :giggle:

Just looking for the silver lining...

 

[alrock]

Hope it does help. I think someone posted up here before about a Jeep guy that did a lot of homework before venting his hood in looking both for the hot spots and the air pressure at different points on the hood. Our "vent" spot is pretty much predetermined but I'm still curious as to the airflow over the hood. Someday I'll put telltales on the hood and video it as I go down the road to see which way the air circulates over our hoods.

 

[elripster]

What's pushing that flyer down is a vortex caused by air building up in front of the windshield and then spinning as the air passes over it and onto the roof. Creating vortices is never a good thing. If venting the hood can counter that and stop the spinning it might help MPG a little.

Frank

 

[58Bisc]

The Jeep XJ guys lift the back of the hood to create a cowl scoop. The 4.0's get hot when sitting. It lets warm air out while crawling and cold air in at highway speeds. I just did this to my future son in laws XJ for him. Cut two lines down the hood, builds a frame out of 3/8 steel bar, fill in the sides with sheet metal and Bondo as needed.