Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Increasing downforce while reducing drag?

NeilBlanchard · 08-09-2009, 07:02 AM

Hi,

Thanks for posting the pictures -- I would call them deflectors.

With a fully ducted cooling system, you can cool the engine with a LOT less air. NASCAR has found that 16 sq. in. of intake for each 100HP is adequate. That is an opening 4" x 4" to cool 100HP engine. Small opening = less drag.

Not all of a large grill is necessarily taking IN air! If the lower part of the grill is more efficient at taking in air (as it is), then on some cars at least, the upper part of the grill has air flowing OUT. That air does not flow through the radiator, and will not cool the engine -- it only adds drag.

Have you read the Hucho book "Aerodynamics of Road Vehicles: From Fluid Mechanics to Vehicle Engineering"? I have started to read it, and you should check out the chapter on the internal engine bay air flow.

Also, see my xA build thread, dude: http://ecomodder.com/forum/showthrea...mods-2969.html

08-09-2009, 07:02 AM	#30 (permalink)
NeilBlanchard Master EcoModder Join Date: May 2008 Location: Maynard, MA Eaarth Posts: 7,907 Mica Blue - '05 Scion xA RS 2.0 Team Toyota 90 day: 42.48 mpg (US) Forest - '15 Nissan Leaf S Team Nissan 90 day: 156.46 mpg (US) Number 7 - '15 VW e-Golf SEL TEAM VW AUDI Group 90 day: 155.81 mpg (US) Thanks: 3,475 Thanked 2,950 Times in 1,844 Posts	Hi, Thanks for posting the pictures -- I would call them deflectors. With a fully ducted cooling system, you can cool the engine with a LOT less air. NASCAR has found that 16 sq. in. of intake for each 100HP is adequate. That is an opening 4" x 4" to cool 100HP engine. Small opening = less drag. Not all of a large grill is necessarily taking IN air! If the lower part of the grill is more efficient at taking in air (as it is), then on some cars at least, the upper part of the grill has air flowing OUT. That air does not flow through the radiator, and will not cool the engine -- it only adds drag. Have you read the Hucho book "Aerodynamics of Road Vehicles: From Fluid Mechanics to Vehicle Engineering"? I have started to read it, and you should check out the chapter on the internal engine bay air flow. Also, see my xA build thread, dude: http://ecomodder.com/forum/showthrea...mods-2969.html __________________ Sincerely, Neil http://neilblanchard.blogspot.com/