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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 08-22-2016, 04:44 PM   #31 (permalink)
home of the odd vehicles
 
rmay635703's Avatar
 
Join Date: Jun 2008
Location: Somewhere in WI
Posts: 3,891

Silver - '10 Chevy Cobalt XFE
Thanks: 506
Thanked 867 Times in 654 Posts
Quote:
Originally Posted by paconassa View Post
0.32 is, indeed, a disaster.

#1 problem with EVs is highway range, so that Cd does not help at all.

With a proper, 21st century, drag coefficient of ~0.20, the Bolt would have a ~30% longer range on highway.
Actually with the intense advances in rr (which seems to be where most focus is by big auto)

The improvement might be more like 50% at the speeds people seem to drive.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 08-22-2016, 06:15 PM   #32 (permalink)
EcoModding Lurker
 
Join Date: Nov 2009
Location: Portugal
Posts: 17
Thanks: 8
Thanked 7 Times in 5 Posts
Quote:
Originally Posted by rmay635703 View Post
Actually with the intense advances in rr (which seems to be where most focus is by big auto)

The improvement might be more like 50% at the speeds people seem to drive.
For those speeds you refer to, we need zero EV development, any EV suffices. Who cares about 300km range @ city speeds...?
For long trips at highway speeds, aero is the top range killer
  Reply With Quote
Old 09-14-2016, 05:11 PM   #33 (permalink)
EcoModding Lurker
 
Join Date: Nov 2010
Location: washington state
Posts: 29
Thanks: 2
Thanked 3 Times in 2 Posts
Quote:
Originally Posted by paconassa View Post
0.32 is, indeed, a disaster.

#1 problem with EVs is highway range, so that Cd does not help at all.

With a proper, 21st century, drag coefficient of ~0.20, the Bolt would have a ~30% longer range on highway.
Yet is rated for 110MPGe highway. I don't know if that is estimated manufacture or final EPA.
Doesn't sound too bad but could have been better.

Concerned about almost no buffer in battery in order to get the 238 miles range
  Reply With Quote
Old 09-14-2016, 05:29 PM   #34 (permalink)
EcoModding Apprentice
 
Join Date: Apr 2014
Location: Oakland, CA
Posts: 110

True Blue - '89 Honda Civic Hatchback, 1.5ltr, 70hp, 4 spd, Base model
Team Honda
90 day: 47.19 mpg (US)

Shorty - '01 Mazda Miata SE
Sports Cars
90 day: 33.66 mpg (US)
Thanks: 101
Thanked 37 Times in 25 Posts
Can someone give a real world example of what a 0.32 vs 0.21 means?

I know that a lower number is better. But how much lower is how much better in practical, day-to-day terms?

And, what's the theoretical smallest drag number we can expect?
  Reply With Quote
Old 09-14-2016, 05:45 PM   #35 (permalink)
EcoModding Apprentice
 
kurzer's Avatar
 
Join Date: Dec 2011
Location: Germany
Posts: 104

Knut - '07 Toyota Prius
90 day: 50.9 mpg (US)

Santa - '00 Hyundai Santamo
90 day: 29.07 mpg (US)
Thanks: 62
Thanked 44 Times in 31 Posts
from 0,32 to 0,26 is like going 90km/h instead of 100 km/h.
__________________
kurzer Gruß

Prius II
Hyundai Santamo
  Reply With Quote
The Following 2 Users Say Thank You to kurzer For This Useful Post:
Cd (04-18-2021), ChewChewTrain (09-14-2016)
Old 09-14-2016, 05:54 PM   #36 (permalink)
EcoModding Apprentice
 
Join Date: Apr 2014
Location: Oakland, CA
Posts: 110

True Blue - '89 Honda Civic Hatchback, 1.5ltr, 70hp, 4 spd, Base model
Team Honda
90 day: 47.19 mpg (US)

Shorty - '01 Mazda Miata SE
Sports Cars
90 day: 33.66 mpg (US)
Thanks: 101
Thanked 37 Times in 25 Posts
Ah. Thanks. So the benefits of a slippery car don't shine until you do freeway speeds.

According to the Cummins' MPG research, speeds below 55mph is mostly a rolling resistance game. Speed above 55mph turns into an aerodynamic game.

For those that might have missed my posting, you can read it here:
https://cumminsengines.com/uploads/d...whitepaper.pdf
  Reply With Quote
The Following User Says Thank You to ChewChewTrain For This Useful Post:
BamZipPow (09-14-2016)
Old 09-14-2016, 06:02 PM   #37 (permalink)
EcoModding Lurker
 
Join Date: Nov 2009
Location: Portugal
Posts: 17
Thanks: 8
Thanked 7 Times in 5 Posts
For a Nissan Leaf, 0.20 would mean 46% higher range at 120 km/h
  Reply With Quote
The Following 2 Users Say Thank You to paconassa For This Useful Post:
Cd (04-18-2021), Fat Charlie (09-15-2016)
Old 09-14-2016, 07:01 PM   #38 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 28,557
Thanks: 8,092
Thanked 8,882 Times in 7,329 Posts
Quote:
And, what's the theoretical smallest drag number we can expect?
Paging aerohead.
  Reply With Quote
Old 09-14-2016, 07:50 PM   #39 (permalink)
EcoModding Lurker
 
Join Date: Jun 2009
Location: SE Michigan
Posts: 66

Moostange - '07 Ford Mustang GT
Last 3: 21.8 mpg (US)
Thanks: 1
Thanked 6 Times in 6 Posts
Quote:
Originally Posted by NeilBlanchard View Post
I wonder if GM has looked at video side mirrors? That could lower the Cd significantly and reduce the frontal area, too. They are using a optional rear view video mirror, so they have the chops.
Video side mirrors are not (yet) legal.
  Reply With Quote
Old 09-14-2016, 11:20 PM   #40 (permalink)
Model X Owner
 
Join Date: Jan 2009
Location: Stroudsburg, PA
Posts: 4
Thanks: 1
Thanked 2 Times in 1 Post
Quote:
Originally Posted by Vman455 View Post
That sounds too good to be true, so I went searching. While some magazines, like Auto Express and Automobile Magazine, reported Cd .24,
Bentley's own press release specifies Cd .34 for the Bentayga.[/url] Doh!
Maybe they confuse the Bentley with the Tesla Model X which does have a CD of 0.24.

  Reply With Quote
Reply  Post New Thread






Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com