Go Back   Honda-Tech > Honda and Acura Model-Specific Technical Forums > Honda Civic/Del Sol (1992 - 2000)
Sign in using an external account
Register Forgot Password?
Search


Welcome to Honda-Tech!
Welcome to Honda-Tech.com.

You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the Honda-Tech community today!


Reply
 
 
 
submit to reddit
 
Thread Tools Search this Thread
Old 06-26-2009, 12:35 PM   #101
rkcarguy
Honda-Tech Member
Garage is empty, add now
 
Join Date: Feb 2009
Location: Failingham
Posts: 296
iTrader Rating: (0)
Default Re: better gas mileage out of an eg

Quote:
Originally Posted by tw1tch View Post
I dunno about that. The hatchbacks weigh less than the coupes and sedans, so I still believe a hatch with the same setup as a coupe will get higher mpg.
I dissagree. Possibly with more stop and go the hatch will see better mpg's due to weight loss, but I have owned several EG's and noticed slightly better freeway MPG than the hatchbacks. One thing that helps though is every EG I've owned always gets dropped and a front lip, which helps.
IIRC the Si and Vx had slightly lower CD(.01) than the rest of the models probably due to the lip.
rkcarguy is offline   Reply With Quote
Old 06-26-2009, 12:58 PM   #102
ESmooth
Junior Member
Garage is empty, add now
 
Join Date: Dec 2007
Location: SoCal
Posts: 19
iTrader Rating: (0)
Default Re: better gas mileage out of an eg

Agreed, lowering the height of the car and controlling the airflow beneath it will make a differnece. Going with a flat bottom is actually better than a lip since you arent increasing frontal area but either way can help, assuming there are no canards or excessive scoopery going on with the lip.
ESmooth is offline   Reply With Quote
Old 06-26-2009, 03:30 PM   #103
brucepick
Honda-Tech Member
Garage is empty, add now
 
brucepick's Avatar
 
Join Date: Nov 2007
Location: Mystic, CT, USA
Posts: 151
iTrader Rating: (0)
Default Re: better gas mileage out of an eg

Hatchbacks and aero...

It's possible for a coupe or a hatch to have a lower .cd than it's sister sedan but not necessarily.
Look up Kamm Back in wikipedia.
And/or go to http://ecomodder.com/forum/aerodynamics.html and start reading the stickies at the top of the Aerodynamics forum.

Here's some of the how and why.

One goal is to make the air flow follow the car's contour. Or more accurately, design the contour so that the air can follow it. A curved or angled surface that the air can follow at 40 mph might no longer work at faster speeds.

Another goal is to create the smallest possible wake. Someone posted re. fish, birds, and may have also mentioned teardrops. Those are basically the ideal shape, with the tapered end of the teardrop at the rear. The air/water can follow the gentle curve/slope as it tapers, and the airflow over top, bottom and sides joins back together where the tail tapers together.

The opposite of a small tapered back would be a full-size square back, like an 18-wheeler trailer. It sucks a huge vacuum behind it. The vehicle's engine is working to produce the energy to create that vacuum. Wasted effort. It shows up as a higher .cd and reduced mpg.

You can chop off that teardrop tail at any point and that works very well. Not as well as continuing to a fine tip but better than a full width, full height, back end.

The benefit that a coupe has, is that the rear seats don't usually have the same headroom as the fronts. The roof can start sloping down a bit earlier so the angle is more gentle. That way the air flow can follow the body at a higher speed, or follow it better assuming the same speed. The Civic couple does this, in comparison to the 4-door. I visually compared the '96-00 body styles and it's true, sedan vs. coupe.

A hatchback can have a gently sloping rear that can also do this job. However, many hatches keep a lot of height, and the Civic hatch is an example. Not that good for aero, compared to a back that tapers to a smaller cross section, but handy for carrying stuff. And probably better aero than compared vs. SUVs and wagons, pickups, etc.
__________________
Driving a '97 Civic HX 5-spd: VTEC-E Lean Burn coupe.
Wifemobile: '96 Accord 5-spd, 4-dr, F22B2

Last edited by brucepick; 06-26-2009 at 03:37 PM.
brucepick is offline   Reply With Quote
Old 06-26-2009, 04:33 PM   #104
kulo
Honda-Tech Member
Garage is empty, add now
 
kulo's Avatar
 
Join Date: Mar 2007
Location: suffolk
Posts: 1,675
iTrader Rating: (0)
Default Re: better gas mileage out of an eg

will having the sunroof open affect mpg?

or get a moon roof visor

like wind deflectors
__________________
Jdm ap1 bb sold
ek b18cr motor parted out
jdm itr dc2 rhd 98 my dd/track car
kulo is offline   Reply With Quote
Old 06-26-2009, 05:28 PM   #105
brucepick
Honda-Tech Member
Garage is empty, add now
 
brucepick's Avatar
 
Join Date: Nov 2007
Location: Mystic, CT, USA
Posts: 151
iTrader Rating: (0)
Default Re: better gas mileage out of an eg

Quote:
Originally Posted by kulo View Post
will having the sunroof open affect mpg?

or get a moon roof visor

like wind deflectors
Generally yes - for any of those. The smooth path over the roof is interrupted when the air moves in or out of the open sunroof. Of course if you don't run the a/c because the roof is open, you probably come out ahead due to the high load the a/c would create.

Visors and wind deflectors - same idea. What would be a smooth air flow path is now a path with bumps and detours. Your engine is spending energy moving air around.
__________________
Driving a '97 Civic HX 5-spd: VTEC-E Lean Burn coupe.
Wifemobile: '96 Accord 5-spd, 4-dr, F22B2
brucepick is offline   Reply With Quote
 
 
 
submit to reddit
Reply

Tags
2000, bad, civic, del, gas, honda, improve, mileage, mini, odysseys, responsibility, rxd, rxf, sol, txd, waste

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -8. The time now is 01:27 PM.



2008 Copyright, InternetBrands Inc.
Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.

Honda and the Honda marquee are registered trademarks of the American Honda Motor Company, Inc. Neither American Honda Motor Company nor its subsidiaries or affiliates shall bear any responsibility for Honda-Tech.com content, comments, or advertising. Honda-Tech.com is not affiliated with American Honda Motor Company in any way. American Honda Motor Company does not sponsor, support, or endorse Honda-Tech.com in any way. Copyright/trademark/sales mark infringements are not intended or implied.
Emails & Contact Details