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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 02-15-2015, 07:20 PM   #11 (permalink)
Cd
Ultimate Fail
 
Cd's Avatar
 
Join Date: Feb 2008
Location: Austin,Texas
Posts: 3,038
Thanks: 2,261
Thanked 764 Times in 442 Posts
This is from the article :

For comparison with our modified Camaro, A2 also tested Dave Matyjasiks closer-to-stock version. Without the grille plug and air dam and with no spoiler but with a lowered ride height and omitted rearview mirrors, the Cd was 0.497. Adding the grille plug and air dam dropped it to 0.337, then a rear spoiler that mimics the one from the HOT ROD Spl. dropped it to 0.292. Meanwhile, tricks on the HRM Spl. got the Cd as low as 0.201. Thats more than a 50 percent improvement from stock, which is enormous.

Read more: Car Aerodynamics - Hot Rod Magazine
Follow us: @HotRodMagazine on Twitter | HotRodMag on Facebook

Top 5 Easy Aero Mods That Almost Always Work
We pressed Eaker to give us clues about simple aero tricks for typical musclecars-stuff that will work nearly every time even without tunnel testing. The delta between Cd numbers is often referred to as "counts," or thousandths of a point, so the difference between a Cd of 0.250 and 0.200 is 50 counts. Eaker gave us some rough estimates on how many counts of Cd you might improve when these mods are applied to a typical older musclecar. Try these next time you're at the track.

Lower the ride height: "Dropping the car-front or rear-will always reduce drag." On our Camaro, raising the tail 1.5 inches changed the Cd from 0.201 to 0.227.Improvement: At least 20 counts per inch

Block the grille: Eaker's tip is "Always get air around the car rather than through it." Stopping air from entering the grille has shown dragstrip e.t. reductions of a tenth or two even on 120-mph cars. This will also reduce front-end lift, and when the front end raises due to lift, drag increases even more. (Bonus tip: Stiff front springs can also help prevent front-end lift). Grille blockage is more effective on older cars than on newer ones with sealed radiator areas, and obviously, it can only be used for short-duration events due to reduced engine cooling.
Improvement: 15 to 30 counts of reduction in Cd and 50 to 100 counts in reduction of Cl

Add a front air dam: "You can usually get 90 percent there just by adding a dam straight down from the front bumper, just like the one on your Camaro." Even Bonneville guys ask us why we have that big barn door on the front of the car, but keeping air out from under the car both reduces drag and neutralizes lift for solid aero gains.
Improvement: 20 counts less drag, 50 less lift. The taller the car sits, the more important the air dam is.

Seal the back of the hood to the cowl: This is another area that's less critical on newer cars that are already well sealed. Cowl-induction hoods have a high-pressure area at the base of the hood. Air does not travel out the back of the hood; it is forced down into the engine compartment. That air must escape through the car, causing flow disruptions and drag.
Improvement: 10-20 counts less drag, 50 to 75 in lift

Remove the outside rearview mirrors: Factory mirrors hanging off the doors are almost always obstacles to airflow. The '94-up Chevy Impalas and Caprices are notable exceptions; on those cars, the Cd actually gets worse when you remove the mirrors.
Improvement: 10 to 20 counts of drag



Read more: Car Aerodynamics - Hot Rod Magazine
Follow us: @HotRodMagazine on Twitter | HotRodMag on Facebook

__________________
"You don't fail until you give up. You learn, and move on." - Christ

" Hypermiling is not going slow, it's driving with more intelligence." - UFO
  Reply With Quote
The Following 4 Users Say Thank You to Cd For This Useful Post:
aerohead (02-18-2015), freebeard (02-15-2015), pgfpro (03-01-2015), Xist (02-15-2015)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 02-15-2015, 08:50 PM   #12 (permalink)
EcoModding Apprentice
 
Join Date: Jun 2011
Location: Earth
Posts: 181
Thanks: 11
Thanked 77 Times in 51 Posts
Quote:
Originally Posted by California98Civic View Post
I don't know, but some of what they are doing cannot be done on street cars, like radical lowering, a road scraping airdam ... The radical lowering also improves the fineness ratio. I guess the answers are in some of those things...
I'm thinking front air bags (adjustable ride height) and an air dam would work well together.
  Reply With Quote
Old 02-15-2015, 09:21 PM   #13 (permalink)
EcoModding Apprentice
 
Join Date: Jun 2011
Location: Earth
Posts: 181
Thanks: 11
Thanked 77 Times in 51 Posts
Now this seems like a "real" wind tunnel picture, as opposed to the single smoke stream going over the top.
Attached Thumbnails
Click image for larger version

Name:	real wind tunnel picture.jpg
Views:	49
Size:	48.2 KB
ID:	17022  
  Reply With Quote
Old 02-15-2015, 09:56 PM   #14 (permalink)
Cd
Ultimate Fail
 
Cd's Avatar
 
Join Date: Feb 2008
Location: Austin,Texas
Posts: 3,038
Thanks: 2,261
Thanked 764 Times in 442 Posts
That's a different tunnel. Also, the smoke stream is adjustable.
The AeroDyn windtunnel is comprised of two tunnels, with the main ( high dollar ) one being quite advanced.
__________________
"You don't fail until you give up. You learn, and move on." - Christ

" Hypermiling is not going slow, it's driving with more intelligence." - UFO
  Reply With Quote
Old 02-16-2015, 03:19 PM   #15 (permalink)
EcoModding Apprentice
 
Join Date: Jun 2011
Location: Earth
Posts: 181
Thanks: 11
Thanked 77 Times in 51 Posts
I was surprised at how well the Camaro lines up with the AST. Thanks to seifrob and orangustang for the online AST tool- I've used it a lot.
Attached Thumbnails
Click image for larger version

Name:	Camaro LSR AST.JPG
Views:	49
Size:	34.1 KB
ID:	17039  
  Reply With Quote
Old 02-16-2015, 05:02 PM   #16 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 11,102
Thanks: 17,547
Thanked 5,919 Times in 3,588 Posts
Ast

Quote:
Originally Posted by sgtlethargic View Post
I was surprised at how well the Camaro lines up with the AST. Thanks to seifrob and orangustang for the online AST tool- I've used it a lot.
Here is the Firebird of the same vintage

*With the Camaro's actual nose on the ground,the frontal area isn't aggravated that much.
*The minimized airdam gap lowers drag (Feisal Ahmed's Masters Thesis)
*With the sealed nose,we lose the entire cooling system drag.
*Cooling fan delete (1-hp @ 70-mph/ 8-hp @ 140-mph/ 64-hp @ 280-mph)
*With the nose down,the max camber point of the roof is moved aft,and the separation line with it.
*The nose drop also alters the apparent contour of the windshield header.
*The dropped nose kills the second stagnation point at the cowl.
*The Pro-Comp scoop alters the windshield area pressure spike due the favorable change in sectional density.
*The Pro-Comp scoop saves 150-hp due to reduced drag,compared to the exposed blower,scoop,and drive.
*Wiper delete.
*Mirror delete.
*The rake also affects the apparent backlight to boot geometry.
*The spoiler extension improves the fineness ratio.
*The 'flat' spoiler also kills any upwards deflected 'jet' of the original up-swept spoiler.
*The drag chute 'stuffs' some of the near wake.
*This car was tested with a full aluminum belly pan.
*The big GOODYEARs close some of the wheel/body gap,cleaning up the side flow a bit.
*MOONs are good for delta Cd 0.024.(GM's measurement at Lockheed Marietta)
*All these big and little things add up.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
The Following 2 Users Say Thank You to aerohead For This Useful Post:
California98Civic (02-17-2015), Cd (04-07-2015)
Old 02-16-2015, 05:27 PM   #17 (permalink)
...beats walking...
 
Join Date: Jul 2009
Location: .
Posts: 6,191
Thanks: 179
Thanked 1,521 Times in 1,122 Posts
BIG numbers are typically comprised on many, many LITTLE numbers.
  Reply With Quote
The Following User Says Thank You to gone-ot For This Useful Post:
aerohead (02-16-2015)
Old 02-17-2015, 04:03 PM   #18 (permalink)
EcoModding Apprentice
 
Join Date: Jun 2011
Location: Earth
Posts: 181
Thanks: 11
Thanked 77 Times in 51 Posts
Thanks for the replies

So it looks like this era of Camaro/Firebird are a good candidate for MPG. Reduce weight, transplant a smaller engine, air dam, lower/air bags, rear spoiler.
  Reply With Quote
Old 02-17-2015, 05:30 PM   #19 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 15,861
Thanks: 4,141
Thanked 5,306 Times in 4,226 Posts
Plus it can be had with a T-top. And a screaming chicken on the hood.
  Reply With Quote
Old 02-17-2015, 05:46 PM   #20 (permalink)
Spaced out...
 
spacemanspif's Avatar
 
Join Date: Jul 2013
Location: Dirty Jersey
Posts: 748

The New Focus - '07 Ford Focus ZX5
90 day: 32.44 mpg (US)
Thanks: 142
Thanked 204 Times in 148 Posts
Quote:
Originally Posted by freebeard View Post
Plus it can be had with a T-top. And a screaming chicken on the hood.
I think the chicken is easily worth 5-10 more MPG making the Firebird the better candidate over the Camaro lol

__________________
-Mike

2007 Ford Focus ZX5 - 91k - SGII, pending upper and lower grill bocks - auto trans
1987 Monte Carlo SS - 5.3/4L80E swap - 13.67 @ 106
2007 Ford Focus Estate - 230k - 33mpg - Retired 4/2018
1995 Saturn SL2 - 256K miles - 44mpg - Retired 9/2014

Cost to Operate Spreadsheet for "The New Focus"

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com