Aerodynamic Afternoon

[wanderlost]

This afternoon I decided to try some aerodynamic (backyard) engineering.
1st I removed my roof rack and rear wiper. This not only removed a giant bug catcher from my roof but easily shed almost 30 pounds from my car.
I planned to drive through a tank like this to note any improvements but my friends duct tape and cardboard came out and with a shot of black paint my subaru has its lower grill blocked.
After a day of driving I noticed the bottom duct tape was being ripped off (air being diverted under the car?) So I recycled some bottle caps and left over screws to hold it in place.
If my mileage is noticeably higher I will remove the grill block and test my mileage without it to try and determine the impact the roof rack and wiper removal have on my mileage.
If the grill block is successful I will recreate it using sheet metal, sheet aluminum, or old chloroplast election signs depending on what is most available/ what I have on hand.

[spacemanspif]

Good start with the roof rack delete. Grill block is good but it’s usually best to block the upper grill. The idea is to take air in at the lowest point so that it can exit under the car and create as little engine bay turbulence as possible.

[Vman455]

Originally Posted by spacemanspif

Good start with the roof rack delete. Grill block is good but it’s usually best to block the upper grill. The idea is to take air in at the lowest point so that it can exit under the car and create as little engine bay turbulence as possible.

Also, generally you're going to have higher pressure further down, which will improve cooling efficiency with a partially blocked front end (so you can cover more of an upper grill opening relative to the total [stock] open area than you can cover of a lower grill opening and maintain the same cooling capacity).