Go Back   EcoModder Forum > EcoModding > The Unicorn Corral
Register Now
 Register Now

Now available from EcoModder: ScanGauge II fuel economy gauge.  Click for details.  


Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 09-06-2011, 04:55 PM   #21 (permalink)
The PRC.
 
Arragonis's Avatar
 
Join Date: Oct 2009
Location: Wanting to be in a Mini again.
Posts: 4,891

Hermann - '06 Audi A6 Avant S-Line Quattro
90 day: 31.21 mpg (US)
Thanks: 242
Thanked 413 Times in 300 Posts
Quote:
Originally Posted by euromodder View Post
Nobody on here has been able to proof they do improve FE, and it wasn't for lack of trying

I still think they could work, but not in the usual massively/truck-sized variety on a regular car.

Something more subtle might do the trick. Renault / Dacia had them on the rear roof line of their eco-Logan.
OK, but Dacia probably had some wind-tunnel time via Renault to try things out ?

We know there is a return with some people from a grill block (although both you and I have tried these and not seen a significant difference - but that might be the difference in Euro vs US driving conditions - long cruises and journeys in the US vs. our more busy and choked roads).

We have seen coast downs with boat tails which seems to suggest an improvement and with wheel covers (front and rear), new noses, wheel spats, mud flaps removal or reversal. Even some differences with mirrors folded and removed vs not.

The coast downs with tabs suggest minimal effect and threads testing them on cars longer term show no difference at all as far as I can tell, or whatever difference is recorded could well be inside an error range.

So at the moment we have to say at best "maybe" or it has "potential", but on a firm this-makes-a-firm-difference basis we have to say "no".

@Neil - I would love to see those instructions and for someone to do some proper testing having followed them.

__________________
  Reply With Quote
Old 09-08-2011, 08:31 AM   #22 (permalink)
dcb
needs more cowbell
 
dcb's Avatar
 
Join Date: Feb 2008
Location:
Posts: 5,032

pimp mobile - '81 suzuki gs 250 t
90 day: 96.29 mpg (US)

schnitzel - '01 Volkswagen Golf TDI
90 day: 53.56 mpg (US)
Thanks: 156
Thanked 263 Times in 206 Posts
Quote:
Originally Posted by Arragonis View Post
We know there is a return with some people from a grill block
The difference is that the barriers to implementing a grill block are about non-existant. I think the first one was wet newspaper or something, any sort of material can be bodged into a grill block (of varying durability), you can prototype one with coloured duck tape, or even cram neglected beanie babies into your grill.


Quote:
Originally Posted by Arragonis View Post
So at the moment we have to say at best "maybe" or it has "potential", but on a firm this-makes-a-firm-difference basis we have to say "no".
VG's for fuel efficiency are surrounded by mystery, or bullocks if you prefer. There is no end to the number of things you could be told you are doing wrong after trying them, it isn't well defined how it is supposed to be helping car efficiency. There simply is no defined theory as it relates to efficiency or it's application. The potential here seems not worth mentioning in the "I think someone else should try this" sense, what you do with your own time is a different matter.

Quote:
Originally Posted by Arragonis View Post
@Neil - I would love to see those instructions and for someone to do some proper testing having followed them.
I'm confused, you don't think these other people did proper testing? On what basis?
Google Custom Search

Can you properly define proper testing of vortex generators? Can you also define proper testing for non-existence of invisible pink unicorns?
__________________
WINDMILLS DO NOT WORK THAT WAY!!!
  Reply With Quote
Old 09-08-2011, 09:44 AM   #23 (permalink)
The PRC.
 
Arragonis's Avatar
 
Join Date: Oct 2009
Location: Wanting to be in a Mini again.
Posts: 4,891

Hermann - '06 Audi A6 Avant S-Line Quattro
90 day: 31.21 mpg (US)
Thanks: 242
Thanked 413 Times in 300 Posts
Quote:
Originally Posted by dcb View Post
Can you properly define proper testing of vortex generators?
A-B-A, of which your search picks up quite a few I thought maybe Neil had something new. Maybe not.

Picking through the first page of results at random, nobody seems to show a measurable effect on FE, certainly not the "riches and world peace" claimed by the makers. The MIRA test linked in one of the posts seems to show about 2.8% improvement on a truck.

Quote:
Originally Posted by dcb View Post
Can you also define proper testing for non-existence of invisible pink unicorns?
Heretic...

EDIT - The MIRA test appears on the Airtabs website too. But from memory I haven't seen any ParcelFarce trucks with tabs on that I can remember. Going to track one down and photo it.
__________________
  Reply With Quote
Old 09-27-2014, 04:40 PM   #24 (permalink)
EcoModding Lurker
 
Join Date: Sep 2014
Location: Germany
Posts: 21
Thanks: 7
Thanked 38 Times in 11 Posts
Hi,
at the wheelhouse, I test a special version of vortex generators.
The goal was to improve the airflow at the wheelhouse.
In the windtunnel measured, the drag was not reduced by vortex generators, but the balance (lift/downforce) between the front and rear axis changed.

Ulrich

  Reply With Quote
Old 09-27-2014, 10:17 PM   #25 (permalink)
Master EcoModder
 
oldtamiyaphile's Avatar
 
Join Date: May 2009
Location: Western Australia
Posts: 258

UFI - '12 Fiat 500 Twinair
90 day: 37.34 mpg (US)

Jeep - '05 Jeep Wrangler Renegade
90 day: 17.84 mpg (US)

R32 - '89 Nissan Skyline

T5 - '07 VW Transporter
90 day: 29.75 mpg (US)

Suzuki - '94 Suzuki Swift Cino 5 Door
90 day: 53.92 mpg (US)
Thanks: 27
Thanked 45 Times in 38 Posts
Quote:
Originally Posted by u.steinlechner View Post
Hi,
at the wheelhouse, I test a special version of vortex generators.
The goal was to improve the airflow at the wheelhouse.
In the windtunnel measured, the drag was not reduced by vortex generators, but the balance (lift/downforce) between the front and rear axis changed.
So did they give you positive or negative lift?
__________________




  Reply With Quote
Old Yesterday, 07:02 AM   #26 (permalink)
EcoModding Alien Observer
 
suspectnumber961's Avatar
 
Join Date: Mar 2008
Location: I flitter here and there
Posts: 543

highcountryexplorer - '86 Nissan 720 KC 4x4 ST with fiberglass cap
90 day: 26.68 mpg (US)

Elroy - '03 Ford Focus ZX3 w/Zetec DOHC engine
90 day: 34.72 mpg (US)
Thanks: 6
Thanked 75 Times in 63 Posts
I asked a guy who has some on a light plane about any mpg gain...said there was none...but they did result in a lower stall speed...which is why they use them on planes. They allow better control at lower speeds.
__________________
Carry on humans...we are extremely proud of you. ..................

Forty-six percent of Americans believe in the creationist view that God created humans in their present form at one time within the last 10,000 years. GALLUP POLL
  Reply With Quote
Old Yesterday, 04:02 PM   #27 (permalink)
EcoModding Lurker
 
Join Date: Sep 2014
Location: Germany
Posts: 21
Thanks: 7
Thanked 38 Times in 11 Posts
Results from the windtunel, vortex generators in front of the wheelhouse

Quote:
Originally Posted by oldtamiyaphile View Post
So did they give you positive or negative lift?
Hi,

here is the answer:

the aritabs were not used at the rear edge of the car, but in front of the wheelhouse.

So this values are not to evaluate Airtabs as the intended use case.

CW Widerstand drag
CA Auftrieb gesamt lift
Cav Auftrieb vorne lift front
Cah Auftrieb hinten lift rear


Serial state, Serienzustand
speed 140 km/h
CW 0,323
CA 0,0402
CAv -0,0223
CAh 0,0626


Xanon aerodynamic bumper with vortex generators
speed 140 km/h
CW 0,2971
CA 0,0256
CAv -0,1053
CAh 0,1309



Xanon aerodynamic bumper without vortex generators
speed 140 km/h
CW 0,2961
CA 0,0213
CAv -0,097
CAh 0,1184

Ulrich

  Reply With Quote
Reply  Post New Thread

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Honda IACV explained TomO Off-Topic Tech 15 05-23-2013 02:47 AM
Conversion idea, 2L inline 4 -> piston boosted 1.0L 2 banger? Warning....Long thread JoJotheTireMan EcoModding Central 56 06-12-2011 03:09 AM
The Mechanism Behind Flow Separation LostCause Aerodynamics 46 07-15-2010 07:38 AM
Comparing Warm Air Intakes (WAI) & Cold Air Intakes (CAI) toomuch EcoModding Central 22 04-07-2009 09:30 PM
OEM Air Injection, Yay or nay? Dane-ger EcoModding Central 11 01-14-2008 10:05 AM




Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com