2000 Honda Insight aero tail extension: made from spare bumper, 5% MPG gain
 

Second project I'm posting on behalf of a longstanding 'lurker' member, with permission (see also his aeromodded/mechanically modded 65 mpg Austin Healey Sprite.)

It's another Insight tail, made by adding on an additional Insight bumper cover, cut and tapered:

http://ecomodder.com/forum/attachmen...1&d=1391028133

http://ecomodder.com/forum/attachmen...7&d=1391028133

http://ecomodder.com/forum/attachmen...p;d=1393184019

"Crude" says the builder, but effective:

• I took a second bumper and decreased the tail to .55 of standard (original) area.
• 16" extension using a shortened and narrowed g1 bumper and sheet lexan, plus sheet metal screws.
• In 7 trips of my 18 mile test course it gained from 71 to 74.8 mpg (about 5%) at 55 MPH on cruise control and 40 degree F temp.

Another Insight tail joins the fleet!

Love to see his long term results on mileage.
I would like to say it looks good but :D

I wonder how Honda decided where to cut the rear end of the car off at.

Fascinating project.

I've certainly seen worse grafting projects.

http://forums.pelicanparts.com/off-t...ures-1262.html
http://forums.pelicanparts.com/uploa...1391094495.jpg

Hi Ron22-l thought of that also, but when I read about them adding a short (16") tail on the GM-EV1 to gain speed, and they were successful, I decided to try it. I do not have to face the real world because of being retired 21 years, and buying groceries or a beer run is the only required driving. When the weather gets warmer, longer excursions are in order, and I will report.

xpedro01 is that you car?
Like you I gave up a long time ago what other people thing.
Keep up the work and keep up informed.

Yes Ron22, this mod was made in the last month. Windydrew is preparing an IMAC&C mod to install and while waiting l made this 16" extension. So far, it is meeting expectations.

I think I know the short tail of which you speak...

http://ecomodder.com/forum/member-ae...-duct-tape.jpg

74.8 mpg = Cd 0.223
 

I took xpedro01's MPG numbers and did a quick napkin calc.,yielding Cd 0.223 for the boat tail modification,using Honda's published Cd 0.25 for the 'naked' car.
Fun! Beer and groceries just got cheaper.:thumbup:

GM Impact/EV1 LSR
 

Goro Tamai had some numbers for GM's land speed record car in an endnote on page 19.
In 1999 GM reported Cd 0.197 for Impact/EV1.
For the speed record they:
*deleted wipers
*covered over the cowl area
*deleted the side-view mirrors
*created fairings at the lower front tire leading edge
*installed flat aluminum wheel disks
*added the 16-inch "Yellow Ferret" boat tail
*taped over body gaps
*lowered the car 40 mm (1.57")
*installed Michelin speed-rated tires
*the nose fascia was devoid of any openings
--------------------------------------------------------------------------
Goro Tamai reported that GM's team got the Cd to 0.14 (if frontal area was considered a constant).That could mean Cd 0.149 if considering 'points.'
Since the frontal area was impacted by the mirror delete and lowering,the Cd was probably a bit higher.
By itself,the tail pushed top speed from 178 mph,to 183.From Hucho's drag/speed relationship this would roughly equate to a 8.4% drag reduction.:)

Aerohead--great minds must run in the same gutter. Using ecomodders very good calculater l took standard numbers for the insight + ones l could change, till they matched my before conditions. Then after the installation and testing 4- 18 mile runs, l changed only cd in the info till it matched my mileage for 55MPH with cruise control and 40 degrees(same as before), and it just about agreed with your number. Thanks for verifying.

verifying
 

xpedro01,you're very welcome.This sort of thing is fun for me,and it's a joy to have access to the fruits of others which remind me of all the good work going on out in the world.
I hope one day,that Wolf Hucho will stumble onto EcoModder and get an eyeful of your work,going back to before he got into aero.You've been doing since the 70s,everything he's advocated since the mid-1980s.I think it would be a big kick for him as it is for me.Thanks big-time!:thumbup:

This could be done cleaner on cars with a sedan counterpart. A civic or metro where the sedan bumper has more rear overhang than the hatchback. Hmmm, another item for the pick a part list....

Subscribed!

I'm being inspired again. Thank you!
Subscribed.

MetroMPG--You got it! It was the racing impact.

Benphyr-I am unhappy with the spray can color match. I tried another company and they asked for the 11th digit of the vin number, which tells them about a batch number of the original paint. instead of NH-630M they will be sending NH-630M-T which l hope matches my 2000 silverstone silver lnsight. xpedro01.

Nice! I think bumper extension could be fruitful on a lot of sports cars such as mine where the bumper barely pokes past the rear wheels. Adding a couple inches and pushing the edges out I think would create noticable gains. The 911 has a 0.29 drag coefficient vs. the Cayman/Boxster's 0.30 despite a more open bumper, more cooling, and a wider rear track/tires, and I would think that the extra couple of inches has something to do with it. Porsche cars would be hard to modify though, since the body slants downward well past the bottom of the rear hatch.

Ron22-I finally got some longer trip numbers. On a trip from Manhattan Kansas to Glen Elder, which is 100 miles on US24, cruise control at 55MPH, (the same as test track) temperature 40 degrees, resulted in a reading of 80.8 MPG. Returning 2 days later-roughly same temperature, when I drove in the yard, l shot the dash at exactly the same number; 80.8 MPG. Now I NEED to run tests at speeds real cars run at.

Nice going, Tom! You make me pine for my Insight.

PS: I see some new modifications:

- plexi-bubble around the side mirror?
- front wheel arch bubble, similar to on your Sprite?

http://ecomodder.com/forum/member-xp...847-trlr07.jpg

June 20, 2015.
My brother in law died and I went to the funeral. The distance is 270 miles, and the altitude in Garden City is 3000 ft; we are 1100+ here in Manhattan. There was no wind & temperature was in the 80's. Cruise control at 55 (Nixon speed) meant all cars passed me. Mpg was 80.6 for 270miles.

On the return trip, I elected to drive at posted speed limits.
US-156 from Garden City to I-70 north of Elsworth is 171 miles.The temp was in the mid 90's and there was a semi favorable breeze. MPG was 78.2 for 171miles at cruise set at 65. This was higher than I expected.

I-70 goes straight east. 65.5 miles at 75 MPH yielded 66.0 MPG. All in all I was very pleased with the Insight. It appears the mod improved mileage. These were ideal conditions, I must admit.

phenomenal!
am wanting to speed up too on the highway to keep more tailgaters and "change lanes at the last second" people from coming too close.
want to belly pan it using a drop in bed liner. goal is get same mileage at a higher speed.