01 honda accord aero-advice

[chilimac02]

Hey guys, Love your forum, and ingenuity. I can get about 40% over EPA in my accord by using hypermiling techniques. I know Aero-mods would crank it up higher... I've read the intro article on this site, but...

Where should I start first? What 3 mods will make the biggest difference on my accord sedan?

thanks in advance,
-Justin

[MetroMPG]

Hi Justin - welcome to the forum.

Congrats on learning to adjust the nut behind the wheel. 40% over EPA is nothing to sneeze at!

As for aero mods, my own experience has shown that the fuel economy gains from each individual mod I've investigated are about 2-3% at around 55 mph:

• 2.3% - kardboard kammback
• 2.3% - pass. mirror delete & driver's side fold back
• 5.7% - grille block & rear wheel skirts
• 2.2% - full undertray

Of these, you might as well do the easier ones first.

1. partial grille block (it'll also help with faster engine/transaxle warm-up)
2. passenger mirror delete, with inside convex replacement
3. underbody paneling

Some might suggest wheel skirts before underbody paneling, but I think rear skirts are likely less effective on larger cars than on small cars where the wheels are at the extreme rear of the vehicle.

[chilimac02]

I'm a loser for not getting back sooner. I think I'm gonna get after my car's aero stuff pretty soon. I plan to start with the grill block/airdam project...

Here's what I want to do to my 6th Gen. 98-02 Accord...

Guys (girls too) let me know if this sounds right:

1. I want to block the "unnecessary" cut outs in my front air dam, including the unused fog light area...

2. I want to partially cover everything underneath the car from the air dam back to the front axles.

3. I plan to extend the underbody paneling back as much as possible to make it flush with the bumper, but still leave room for the exhaust components to vent their heat...

4. Rear wheel Fairings... Flat Wheel covers (like hubcaps)...

How's that sound?

[chilimac02]

I finally got motivated, and had some quality cardboard to play with, so I went for it tonight. My car already has a decent undertray, so I made a grill block, and rear wheel fairings. It took about an hour. I used heavy duty cardboard (close to 1/2 inch thick), two coat hangers, packing tape, a measuring tape, box cutter, + 2 buckets of sweat. Seriously, I soaked through a shirt in the heat tonight.

[chilimac02]

I have already managed one 45.6mpg morning commute, with no aero-mods. Tomorrow, I aim for 50mpg!!

PS, I flipped both mirrors back too, we'll see if all of it together can get me there.

[Hasbro]

#1. Pump up the tires. I'm at 54/50 psi and it improved mpg by 3-4%. Better handling on stock suspension and it's free. Next tires will be at about 60 psi.

[chilimac02]

Trial Commute #1
28.5mi one way
43.6 there (crosswind of 15mph)
39.7 back (headwind of 10-15mph)

Not bad, but I can't wait to see what it will do in favorable conditions.

[thebrad]

You may want to ditch the driver side mirror and cover it with a block plate, I'd imagine there is a lot of overlap between that mirror and the rearview. This is assuming you always look over your shoulder before entering a lane. Or would this be a safety inspection issue in the state of Texas?

Another aero tip I picked up from Honda is creating panel overlap. For example the fender and front door you want the the beginning of the door to tuck into the end of the fender. According to them it creates continuity in airflow across the car, but mainly serves to reduce wind noise.

[MetroMPG]

thebrad - that's a really interesting tidbit. Thanks for posting.

chilimac - nice to see you getting started on stuff.

You realize of course that it'll likely be difficult to identify an improvement of a few percent in day to day driving in the short term? Just saying.

[rjacob]

chilimac, I will interested to see what becomes of this. I have a 2000 Honda Civic, so any changes you make will be relevent to my car.

I have played with covering the fake fog light things. What I have been thinking of doing is just filling em in with expanding foam, and then carve the foam flush. I could smooth it out with bondo, sand it, and paint it to make them look like they were never there. I would want to find some spray paint to match the color of my car (paint code G95P).

I like the idea of rear wheel shirts, but most of the home-made ones I have seen are just frigging ugly! I would

[thebrad]

Originally Posted by rjacob

chilimac, I will interested to see what becomes of this. I have a 2000 Honda Civic, so any changes you make will be relevent to my car.

I have played with covering the fake fog light things. What I have been thinking of doing is just filling em in with expanding foam, and then carve the foam flush. I could smooth it out with bondo, sand it, and paint it to make them look like they were never there. I would want to find some spray paint to match the color of my car (paint code G95P).

I like the idea of rear wheel shirts, but most of the home-made ones I have seen are just frigging ugly! I would

Probably more hassle than it's worth but you could try and find someone with a 96-98 who wants the 99-00 bumper, but this would also involve swapping fenders and hoods if I remember right. Plus the color match would again be a huge issue.

[aerohead]

Originally Posted by thebrad

You may want to ditch the driver side mirror and cover it with a block plate, I'd imagine there is a lot of overlap between that mirror and the rearview. This is assuming you always look over your shoulder before entering a lane. Or would this be a safety inspection issue in the state of Texas?

Another aero tip I picked up from Honda is creating panel overlap. For example the fender and front door you want the the beginning of the door to tuck into the end of the fender. According to them it creates continuity in airflow across the car, but mainly serves to reduce wind noise.

I'm afraid that if local police or Dept. of Public Safety officers pick up on that,it will be a ticket for sure.Can't wait to see OEM sideview cameras on new cars,then the gendarmes won't be looking at that part of the car so much.-------------------------- Nice piece on "shingleing".Guess Honda looked at Hoerner's work.Thanks for sharing that!

[pawilkes]

i've been driving around w/ my drivers side mirror folded in for weeks now and haven't had any issues including when a cop was right behind me at a stop light. i've just rigged up an adjustable inside side mirror that has nearly the same view range as my outside one. using that plus a convex review mirror i can see more behind and to the side of me than the 3 stock mirrors could. in KY, the law says you have to have a side mirror but it doesn't say that it has to be outside the vehicle.

[chilimac02]

As far as panel overlap on the pseudo rear-wheel skirts... their crap.

I appreciate the advice on getting more data. I'll try and do that. I'm just a little insecure about driving around with cardboard taped to my car...

[lunarhighway]

my car has fish scaled panel all round... at first i thought it was a panel mismatch, i noticed it as the slightly different alignment made the pannels seem a slightly different color from some angles, which might indicate a repaired accident, but it turned out each leading panel ended a few mm higher than the next.

not easy to do yourself i think though... i'm looking for something like rubber window sealing strips i could clip on the edges of my hood so that the seams would be covered

[chilimac02]

Lunarhighway- not a bad idea!

i removed my cardboard wheel skirts. They did make an improvement, but i was too self conscious. I'm going to make some permanent ones out of some scrap plexiglass that my in-laws have. I'll feel a little better about that than my redneck looking job.

I should get the stuff in the next few weeks, I'll let you know how it goes then. If those skirts added 2%, then that would put me at a normal commute of 43mpg.

I've been folding in my mirrors lately, no cops have cared (like 20 have seen 'em).

After the wheel skirts, I'll do a rear bumper body pan kind of thing. If that gave 2% I'd be pushing 44mpg. I'd have to have a source of coroplast or plexiglass to do the bumper thing though.

[chilimac02]

Plexi-glass is now in the garage. This weekend, I'll be cutting it and figuring out how to mount the stuff...

Any suggestions?

[rjacob]

You can use a heat gun to soften and bend the plexiglass a little bit. Practice with some scrap pieces first. Also remove the plastic scratch protection stuff first, or it you will never get it off after using the heat gun as it sort of bakes it on.