Go Back   EcoModder Forum > EcoModding > Aerodynamics
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 08-03-2009, 08:32 PM   #1 (permalink)
Master EcoModder
 
Join Date: Jan 2009
Location: Maui, Hawaii
Posts: 813
Thanks: 5
Thanked 34 Times in 26 Posts
New Dodge Ram's forward leaning grill



You'd think it would create more drag than a rearward sloping grill, but it apparently doesn't.

Quote:
Style and aesthetics started to give way to practical considerations, like aerodynamics. "We don’t concern ourselves with aero too much when we’re doing theme searching. The thing that concerned senior management most was the grille. I wanted the cant-forward grille but management looked at it and thought it wouldn't work. So we went and built a second version with the grille leaning back but it didn't make a difference (in aerodynamics).
By the time we were done we beat the aerodynamic stretch goal for (the new Ram),"
PickupTruck.com - Ram Tough Choices: Other Designs Chrysler Considered for the 2009 Dodge Ram


Why is this?? I can think of a few possibilities:

1) The crossbar and surround are so thick that even with a rearward-cant grill, they don't smoothly channel air up and over the hood

2) The angle could force more air through the grill. Forcing oncoming air into the engine compartment and out the bottom could create the same drag as throwing turbulent air up over the hood and windshield

3) The angle of the grill, combined with the bumper right below it, funnels air to the sides, past the curved headlights, and along the sides of the truck, with attached flow the whole way


Also, I'm surprised aerodynamics were even a consideration. I'd expect the senior management to care about looks first, and fuel economy second, because presumably a 1mpg difference isn't going to influence sales that much but looking macho vs girly would.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 08-03-2009, 08:36 PM   #2 (permalink)
Dartmouth 2010
 
SVOboy's Avatar
 
Join Date: Nov 2007
Location: Hanover, NH
Posts: 6,427

Vegan Powa! - '91 Honda CRX DX
Team Honda
90 day: 66.52 mpg (US)
Thanks: 92
Thanked 114 Times in 82 Posts
Send a message via AIM to SVOboy Send a message via MSN to SVOboy Send a message via Yahoo to SVOboy
I would assume the over the top aero is so bad it doesn't matter if it goes underneath instead. *shrug*
  Reply With Quote
Old 08-04-2009, 01:09 AM   #3 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,759

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,583
Thanked 3,543 Times in 2,213 Posts
Are we gonna do the blunt front end aero thing again???

A big "bubble" gets pushed in front of vehicles. As long as flow is attached at the front/sides/top transition, it's all good.

^P.S. That's a gross oversimplification that ignores underhood airflow, but otherwise I'll stand by it.
__________________



Last edited by Frank Lee; 08-04-2009 at 02:13 AM..
  Reply With Quote
Old 08-04-2009, 02:10 AM   #4 (permalink)
EcoModding Apprentice
 
QuickLTD's Avatar
 
Join Date: Apr 2009
Location: Tampa, Florida
Posts: 188

Flying Brick - '96 Pontiac Bonneville SE
90 day: 23.57 mpg (US)
Thanks: 1
Thanked 15 Times in 8 Posts
Send a message via AIM to QuickLTD Send a message via Yahoo to QuickLTD
The eye can be decieving.. Look at all the swoopy European sports cars from the early 60's and the streamliners from the 30's with th CD of a brick. That truck probably has better aero than most of those old cars.
__________________
1996 Pontiac Bonneville SE 3.8L V6
  Reply With Quote
Old 08-04-2009, 02:27 AM   #5 (permalink)
Master EcoModder
 
Join Date: Feb 2008
Location: belgium
Posts: 663

vectra a - '95 Opel Vectra GLS
90 day: 37.51 mpg (US)
Thanks: 14
Thanked 60 Times in 43 Posts
i think the important thing is the curvature above and beside the grill and how open the grill really is (some grills are partly blocked and some have better internal ducting than others) also the tip of the hood isn't the most forward part of the car, the bumper is. is you fill the void between the bumper and the hood with a high pressure bubble (easiest to spot in the concept sketch) you'll get an almost round shape.

once certain things like the size of a grill is determined by either function or fashion it's all about small details... tweaking certain angles and curves
  Reply With Quote
Old 08-04-2009, 05:49 PM   #6 (permalink)
Master EcoModder
 
Join Date: Jan 2009
Location: Maui, Hawaii
Posts: 813
Thanks: 5
Thanked 34 Times in 26 Posts
Quote:
Originally Posted by Frank Lee View Post
Are we gonna do the blunt front end aero thing again???

A big "bubble" gets pushed in front of vehicles. As long as flow is attached at the front/sides/top transition, it's all good.

^P.S. That's a gross oversimplification that ignores underhood airflow, but otherwise I'll stand by it.
This isn't a case of blunt vs pointy, but blunt and sloped back vs blunt and sloped forward... With the added factor of a bumper below the grill helping form a kind of concave parachute shape, at least when viewed from the side.

Seems like the high pressure bubble lunarhighway is talking about within the V profile is very different from the bubble in front of a blunt convex nose.
  Reply With Quote
Old 08-05-2009, 01:47 AM   #7 (permalink)
Master EcoModder
 
orange4boy's Avatar
 
Join Date: Aug 2008
Location: The Wet Coast, Kanuckistan.
Posts: 1,272

The Golden Egg - '93 Toyota Previa DX
90 day: 31.91 mpg (US)

Chewie - '03 Toyota Prius
90 day: 57 mpg (US)

The Spaceship - '00 Honda Insight
Thanks: 98
Thanked 297 Times in 174 Posts
Ooooh! forward leaning grill.... how.... forward of them.

Really, this just smells of aerowashing. The sketch looks all dynamic but the lines are lost lost once you get to the actual vehicle. Looks like any other truck to me.

What's the comparison? Since we don't have a Cd before and after, there is no way to tell if it's better or not. All they seem to say is it's no worse than before.

What is the new Cd?
__________________
Vortex generators are old tech. My new and improved vortex alternators are unstoppable.

"Itís easy to explain how rockets work but explaining how a wing works takes a rocket scientist."
-Philippe Spalart


  Reply With Quote
Old 08-05-2009, 01:58 AM   #8 (permalink)
Moderate your Moderation.
 
Join Date: Nov 2008
Location: Troy, Pa.
Posts: 8,919

Pasta - '96 Volkswagen Passat TDi
90 day: 45.22 mpg (US)
Thanks: 1,369
Thanked 430 Times in 353 Posts
Considering the size of the grille opening, I don't think the slightly forward-leaning grille actually would make a difference, other than slightly raising the stagnation point.

Opinion, obviously, but those trucks tend to have enough room under the hood for a small child to stand in there and wrench on it... there is probably more air going through the grille opening than under it, which means that the forward leaning grille is probably a drop in the bucket compared to the grille.
__________________
"Ņʞɐǝɹɟ ɐ ǝɹ,noʎ uǝɥʍ 'ʇı ʇ,usı 'ʎlǝuol s,ʇı"

  Reply With Quote
Old 08-05-2009, 03:52 AM   #9 (permalink)
Master EcoModder
 
orange4boy's Avatar
 
Join Date: Aug 2008
Location: The Wet Coast, Kanuckistan.
Posts: 1,272

The Golden Egg - '93 Toyota Previa DX
90 day: 31.91 mpg (US)

Chewie - '03 Toyota Prius
90 day: 57 mpg (US)

The Spaceship - '00 Honda Insight
Thanks: 98
Thanked 297 Times in 174 Posts
In car aerodynamics the rear end is where it's at. Any time you see a car company bragging about the front and ignoring the rear they are BS-ing you.

Quote:
"We donít concern ourselves with aero too much when weíre doing theme searching.
That says it all, really.

Is this a post bail-out quote?
__________________
Vortex generators are old tech. My new and improved vortex alternators are unstoppable.

"Itís easy to explain how rockets work but explaining how a wing works takes a rocket scientist."
-Philippe Spalart


  Reply With Quote
Old 08-05-2009, 04:12 AM   #10 (permalink)
Master EcoModder
 
orange4boy's Avatar
 
Join Date: Aug 2008
Location: The Wet Coast, Kanuckistan.
Posts: 1,272

The Golden Egg - '93 Toyota Previa DX
90 day: 31.91 mpg (US)

Chewie - '03 Toyota Prius
90 day: 57 mpg (US)

The Spaceship - '00 Honda Insight
Thanks: 98
Thanked 297 Times in 174 Posts
After all my snarking, I found this: It may be an improvement over the 2008 model but the fact that one of the new models does the 1/4 mile in 14.4 seconds speaks to the main priorities: more power, lip service to efficiency. The new "improved" Ram has worse aero than the original 1994 version!

Quote:
The cooperative application of aerodynamic science and innovative styling led to aerodynamic improvements on the new Ram that resulted in an estimated coefficient of drag (Cd) of .422 for a crew cab 4x4 model – compared with a Cd of .463 for a 2008 Ram Quad Cabģ 4x4 (and .42 for the original 1994 Dodge Ram!). Extensive wind-tunnel testing was conducted to hone the 2009 Dodge Ram’s exterior shape.

The shape of the front grille, hood, and exterior mirrors cuts wind resistance
A subtle circumferential notch near the rear edge of each outside mirror housing causes airflow (and dust or water, when present) to separate from the housing. This also helps keep the door glass clean
An air dam directs air flow around the vehicle to reduce drag, and cool the engine and air conditioning condenser
Full cut-line doors reduce wind noise and drag
A carefully developed curve at the leading edge of the windshield frame reduces drag
A raised lip on the cowl screen directs air flow and water toward the sides of the windshield
The cowl screen smoothes the airflow transition from hood to windshield, reducing turbulence and wind noise
Troughs created by windshield side moldings channel water over the roof rather than around to the side windows
Side windows offset from door frames were minimized to help reduce turbulence and wind noise
Side sills are lowered, extending the attached air flow and eliminating some underbody turbulence
The new front-end module has smaller gaps around head lamps to help aero performance
A large tailgate spoiler integrated into the sheet metal improves aerodynamic flow
Lowered windshield-wiper location improves visibility, as well as reduces wind noise and drag
Flush-fit fog-lamp pockets eliminate drag of fog lamps
Reduced wheel openings help decrease drag
Optimized ride heights provide aerodynamic efficiencies
All that supposed wind tunnel testing and they ESTIMATED the Cd? It went from terrible to meh

__________________
Vortex generators are old tech. My new and improved vortex alternators are unstoppable.

"Itís easy to explain how rockets work but explaining how a wing works takes a rocket scientist."
-Philippe Spalart



Last edited by orange4boy; 08-05-2009 at 04:27 AM..
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Permanent Aluminum Grill Block and Belly Pan Markmysite EcoModding Central 41 02-27-2014 09:22 PM
grill "shield" rather than block? lunarhighway Aerodynamics 70 12-17-2010 03:50 AM
Spring mounted Grill Block cfg83 EcoModding Central 32 04-19-2009 06:00 PM
Airdam and grill block on the Mirage BrianAbington Aerodynamics 5 10-15-2008 06:54 PM
96-00 Civic Upper Grill Block Impulse Aerodynamics 2 07-12-2008 03:09 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com