Aerocivic - how to drop your Cd from 0.31 to 0.17

[euromodder]

Originally Posted by richtate

Maybe they copied him! Yes?

No, they (as in both) used long known aerodynamic principles that regular car manufacturers seem to have forgotten about - or at least aren't using in their products anymore.

Rear-wheel skirts were once very common features.
These days they are oddities.
Boattails were once the norm for sportscars.


Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - euromodder's Album: The Lost Art of Car Design

[2003protege]

Originally Posted by richtate

Maybe they copied him! Yes?

And to answer the question, I think Mike himself has said he modeled it after some german car used to test tires at 100+ mph

[richtate]

Agreed guys, I was joking of course. I've been reading the posts over the last couple of weeks and just giving props to basjoos and looking forward to an Aptera type production vehicle. I don't have the time in reality to mod a car, I'll have to purchase. I'm getting some ideas from other discussions that I'll try on my truck (no where near the extent here) but I'd like to have an everyday driver that does much better than anything in production. Until Aptera or some other vendor...comes along.

[3-Wheeler]

Originally Posted by richtate

... I'm getting some ideas from other discussions that I'll try on my truck (no where near the extent here) but I'd like to have an everyday driver that does much better than anything in production. Until Aptera or some other vendor...comes along....

The interesting thing about this is that Mike has made a car that rivals or at least gets very close to the mileage that the Aptera will get in real-life situations at only a fraction of the cost.

You have to really give Mike a pat-on-the-back for his efforts.

Jim.

[euromodder]

Originally Posted by 3-Wheeler

The interesting thing about this is that Mike has made a car that rivals or at least gets very close to the mileage that the Aptera will get in real-life situations at only a fraction of the cost.

And that he has done so starting with late '80s technology, rather than expensive high tech.

Done properly (i.e. industrially with today's tech) we could all be driving 60+ mpg vehicles already.

[basjoos]

And more importantly, get 60+mpg while still driving at normal interstate/autobahn speeds instead of having to creep along at 50-60mph as you have to do to get 60mpg out of an aerodynamically challenged mass produced car.

[richtate]

Originally Posted by 3-Wheeler

You have to really give Mike a pat-on-the-back for his efforts.

Cheers!

[rkcarguy]

Originally Posted by Sigurd

The '77 Rabbit 1.5 N/A diesels got 55-60mpg out of the box, but don't ask about particulates.

You don't have to ask, the visual evidence is usually all over the rear end of those.

[Cd]

Hello Mike. I was just looking over your album once again and noticing things I had not seen before.

( I like a lot of what i am seeing ) Details. details. Very sleek machine ! 'thumbs up'

One thing that has been bugging me for some time is that you say that the car got 95 MPG at 65MPH with the previous non lean burn engine.
Since a 20 % reduction in drag is roughly equal to a 10 % increase in fuel economy, how can this be ?
Stock, you car got 47 MPG* highway and you reduced its drag from .31 to .17.
If my math is right ( it's most likely wrong ) .17 is around 45 % of .31, so you reduced your drag by 45 % ?
Wouldn't that equal out to around 58.75 MPG ?

Where are the other 36 MPG coming from ? The AeroCivic.com site states that you get 95 MPG on a level road at 65 MPH. This makes it sound as if no engine off coasting and other tricks are used, so I'm confused.

* Old rating at 55 MPH and now rated at 41 MPG highway according to the new measuring system at fuelecomony.gov

[basjoos]

That 95 mpg at 65mph is the mileage measured on the SuperMID in on a hot summer day constant speed on a flat road. The 47mpg is the average calculated mileage I would get when gassing up, in the winter it would be 44 mpg, in the summer it was 51 mpg just driving it normally with minimal hypermiling used. I didn't get a SuperMID until I was well into the aeromodding process so I have no way of knowing what the steady state at 65 mph mileage of my stock vehicle was. A more direct comparison would be the 47 mpg average I got before aero modding when I was just hypermiling to the 68 mpg average I got on the old engine with aeromods and hypermiling to the 73 mpg average I get on the lean burn engine with aeromods and hypermiling. Other factors that affected my mileage through this time period were the changes in tires over the years as I reduced the RR of my tires. Also the amount of hypermiling I did and the speeds I travelled varied. Before I started aeromodding, I increased the amount of hypermiling techniques used and tried to keep the speed below 50mph. As I added aeromods, I gradually increased my speeds to normal interstate speeds and slightly reduced the intensity of hypermiling techniques used.