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I'll probably start some aerodynamic mods after my current tank. The stock Cd is 0.34 and frontal area is ~22ft^2. I calculated the air drag at my ambient conditions to be 56lbs at 55mph, 67lbs at 60mph, and 91lbs at 70mph. To flow better with traffic I'd like to be able to travel at 100% the speed limit on the highways (60mph in my area) instead of at 90% (54mph).

If I reduce my Cd to 0.285 or less, this goal would be accomplished. With a Cd of 0.285 the air drag would be 47lbs at 55mph, 56lbs at 60mph, and 76lbs at 70mph. An article posted elsewhere, "Contribution of different devices to the total drag," estimates that sealing your wheels can reduce drag from 0.012 to 0.08. I have a fairly open spoke patern on my 9-2x and am hoping their contribution is closer to the upper end than the lower end of the reduction estimate.

I don't yet have a scan gauge so the only way to quantify the effect will be to drive at 60mph on the highway for a tank after sealing the wheels and observe the effect on the FE. Maybe I should wait to purchase a scan gauge? :confused:

Hi Antrey:

___You and I must be the only ones reading and replying tonight ;)

___A SG-II will certainly help you quantify the change but what I would hope you find out what your actual average speed going back and forth to work, to the store, or anywhere where most of us drive 90% of the time. I travel 55 and 65 mph Interstates for up to 90% of my commute when I am not pushing for FE and holding at or just above the limits, the highest average I have seen since was 53 mph. There is simply to much slow down, stop, traveling through subdivisions and side streets, arterials, guard shacks, and parking lots, etc. to say a given Aero mod will give you so much FE improvement. Not that aero improvements do not work because they do but the Accord you see in the sig is bone stock with an ~ .30 Cd and more then 7/8 of its miles are out on the Interstate crossing almost as many states as I am old and in temps for at least 1/3 of the year most would rather simply forget about including myself :(

___I would work on my techniques as that is where the big numbers come from including out on the highway as that is where the Accord lives and she does takes care of the FE all on her own pretty darn well if I do say so myself!

___Good Luck

___Wayne

Mild hijack -- does this chart (http://techno-fandom.org/~hobbit/cars/hp.gif) look right for HP
vs speed to overcome air resistance? [the low end will be somewhat
unrealistic because I'm not accounting for rolling resistance..]
I started with an assumed 20 hp at 60 mph and extrapolated from there.
.
_H*

antrey

Get the SGII. Set back and watch the numbers. You will learn alot about yourself and the car. This will help you get your basic driving tatics down.

Take me for example. I know Papa's Express and myself are turning into a pretty good 50 mpg team. Best we could do before the SG was mid 40's. With the SG Ive seen some 60 mpg and 70 mpg 20 mile segments on my test loop. Now theres no way I can post up numbers like that in my daily grind. The speeds are just to low for pratical use.

Ive done one mod to my car. I fabed up a engine belly pan. I did this more for keeping my engine bay clean than a areo mod. And from what I see its not been a good aero mod. Maybe with more work under the car ir will be. But now no. It does help to keep the engine cleaner. :)

The pan will also help me explore a warm air intake this fall and winter. The SG has a air intake temp read out along with water temp read out. The engine pan cuts down air movement in the engine comparment.Results look promising. with some morning temps in the high 50's already Ive managed to keep intake air temps in the 80's. I will get more aggresive as temps drop and move to a three dollar alum flex hose and pull heat in from the cat. My goal is to not take a huge drop in mpg over the winter months.

This would not be possible if I didnt have a SG to guide the way.

Sorry for the ramble.
psy

I've installed a number of aero mods (grill block, full underbody panels, rear wheel skirts, smooth hubcaps, gap filling) on my 92 Civic CX hatch (aerocivic) and raised the MPG at interstate speeds (70 to 80mph) from the mid to low 40's to the upper 50's to low 60's. Fringe benefits of the aero mods are reduced wind noise inside, a slight performance boost at higher speeds due to the reduced drag, and less dirt on the back window after driving on dirt roads (and less of a dust plume behind the car).

I've installed a number of aero mods (grill block, full underbody panels, rear wheel skirts, smooth hubcaps, gap filling) on my 92 Civic CX hatch (aerocivic) and raised the MPG at interstate speeds (70 to 80mph) from the mid to low 40's to the upper 50's to low 60's. Fringe benefits of the aero mods are reduced wind noise inside, a slight performance boost at higher speeds due to the reduced drag, and less dirt on the back window after driving on dirt roads (and less of a dust plume behind the car).

Basjoos, my plan was largely inspired by the positive results you were able to achieve with your mods. How did fill the gaps along your doors and hood? I've started adding weather stripping to the inside of the door and hood edges and this seems to work well, but I'm wondering what your approach was.

My car is the same color as white caulk, so I ran a bead of caulk down the seams. After a day or two for the caulk to dry, I used a razor blade to slit the dried caulk so I could open the doors, hood, gas cover, etc.

My car is the same color as white caulk, so I ran a bead of caulk down the seams. After a day or two for the caulk to dry, I used a razor blade to slit the dried caulk so I could open the doors, hood, gas cover, etc.

That sounds like a good approach and much cheaper than weather stripping. In my case I could try black silicone sealant/gasket maker instead of caulk. I might try coating one of the edges with vaseline or something similar to keep the silicone from sticking.