Chevy Bolt's aero is a 'disaster,'

[Vman455]

Originally Posted by tsimitpo

A Drag Coefficient of .32 seems a bit high to me as well, especially when considering that the new Audi A4 has a Cd of .23.

Not in the U.S., it doesn't--scroll down to page 8 in Audi's press release: Cd .31 for the American version. This is another case of Europe getting the low-drag variant while on this side of the pond, where we tend to do more highway traveling but gas is significantly cheaper, it's apparently not worth it to the manufacturer to go to the trouble or expense of adding low-drag features, just like Mercedes-Benz with the CLA.

[JSH]

Originally Posted by danwat1234

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

The aero could have been better but the utility of the vehicle would have been less. I put large items in my car and expect a wagon or hatchback to have a large opening and take bulky cargo. I HATE the trend of ever more rounded hatches (whether they are on wagons, SUVs, or hatchbacks) My 2003 Jetta Wagon TDI had a great cargo area. (My 05 and 09 Prius not so much)

238 miles is way more battery than I need. I have a 2016 Chevy Spark EV rated at 82 miles. It actually goes about 95 miles in my mixed driving. That is enough to take me to work and back twice or take me anywhere in my metro area and home on a single charge. I don't need 200, 250, 300 miles of range. To me that is just extra cost and extra weight to drag around. 150 miles would be more than enough and the car would cost significantly less and be more efficient. Hopefully but the time my lease is up in 3 years the Bolt will be offered with multiple sized battery packs or some other manufacturers will have decided not to play the "who can go the farthest" game.

[paconassa]

Large back opening is a BS excuse from GM and here's why: Mercedes Bionic - 0.19 Cd



https://en.wikipedia.org/wiki/Mercedes-Benz_Bionic

And 0.19 is BAD, because the box fish, in which it was based, has a 0.04 Cd (!!!)

[freebeard]

When you cut wheel wells in the Boxfish, it's Cd goes up.

[JSH]

Originally Posted by paconassa

Large back opening is a BS excuse from GM and here's why: Mercedes Bionic - 0.19 Cd

There is a HUGE difference between the two that you are overlooking.

• The Bionic was a show car, a styling exercise never meant for production.
• The Bolt is a production car that needs to sell tens of thousands of units per year.

GM very specifically decided to make the Bolt a conventional looking car so that it would appeal to the largest segment of the population. They basically took the benchmark leader of the segment (Honda Fit) and made it 350% more fuel efficient by making it a electric car. Could they have made it 10-20% more efficient by using a polarizing aero design like the Bionic? Yes, but they are in the business to sell cars.

[NHB]

Originally Posted by Vman455

Not in the U.S., it doesn't--scroll down to page 8 in Audi's press release: Cd .31 for the American version. This is another case of Europe getting the low-drag variant while on this side of the pond, where we tend to do more highway traveling but gas is significantly cheaper, it's apparently not worth it to the manufacturer to go to the trouble or expense of adding low-drag features, just like Mercedes-Benz with the CLA.

tsimitpo was talking about the new 2017 model, which is totally new model. You have chosen the old 2016 model.


European manufacturers don't sell low power variants in the States. These models usually have the lowest drag.

EDIT: Here is the new model: https://www.audiusa.com/content/dam/...-media-kit.pdf
The U.S. model is 252 hp 2.0 TSI. Cw = 0.27.
Here in Europe we have 150 hp 1.4 TSI and 190 hp 2.0 TSI Miller cycle engine.

[NeilBlanchard]

Originally Posted by paconassa

Large back opening is a BS excuse from GM and here's why: Mercedes Bionic - 0.19 Cd



https://en.wikipedia.org/wiki/Mercedes-Benz_Bionic

And 0.19 is BAD, because the box fish, in which it was based, has a 0.04 Cd (!!!)

Your first statement is correct - except that 0.19 probably doesn't include the side view mirrors.

But a Cd of 0.19 is excellent. The Boxfish is what I modeled my CarBEN design on, so I am very familiar with the design. The blue model:



has a Cd of 0.095 (as far as I can find). And the earliest model of the boxfish had a Cd of 0.06 - seen at the back:


By Ryan Somma - originally posted to Flickr as Mercedes-Benz bionic car, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4498798

The hardest part of car aerodynamics - is dealing with the wheels on the ground. So, you need to realize what an achievement anything around 0.20 or less is.

[NHB]

Originally Posted by JSH

There is a HUGE difference between the two that you are overlooking.

• The Bionic was a show car, a styling exercise never meant for production.
• The Bolt is a production car that needs to sell tens of thousands of units per year.

GM very specifically decided to make the Bolt a conventional looking car so that it would appeal to the largest segment of the population. They basically took the benchmark leader of the segment (Honda Fit) and made it 350% more fuel efficient by making it a electric car. Could they have made it 10-20% more efficient by using a polarizing aero design like the Bionic? Yes, but they are in the business to sell cars.

Bionic has a plenty of features, which make it not production ready.

• Rear seat only for two with no space for standard height men
• no mirrors
• no rear door
• no real door handles
• no brake cooling
• no ground clearance
• missing window wipers

There a long way from a design study to a production ready design.

[rmay635703]

Originally Posted by NHB

Bionic has a plenty of features, which make it not production ready.

• Rear seat only for two with no space for standard height men
• no mirrors
• no rear door
• no real door handles
• no brake cooling
• no ground clearance
• missing window wipers

There a long way from a design study to a production ready design.

Most of those issues can be easily addressed (and some are becoming no longer important), for it to be production ready you would need a BOM and real pilots, on those terms the bionic is not production ready.

[freebeard]

Could they have made it 10-20% more efficient by using a polarizing aero design like the Bionic? Yes, but they are in the business to sell cars.

While I'm not a Prius fan (just the Lexus/Highlander HSG rear axle), I like that they disrupted the public's perception to introduce that box-fish-like profile.