effect of underbelly panels on mpg

[Jivko57]

Hi, my silver 2000 mt was missing all the under body panels (in the front ) when I bought it 6 months ago. I bought the parts (all ~ 500.00 from majestic) and finally got to fix them couple of weeks ago.

At some point i regretted spending so much money for almost nothing as I knew the mpg impact could not be significant anyway.

So i am driving the car now for 2 weeks as it is closer to original configuration (still missing one of the long panels that has been covering the brake lines initially).

I can definitely attest that I feel more engine power even at low speeds which is curious as the drag increase from the missing panels at 30mph or less should be very minimal if present at all.

However I feel more engine power at all speed , bigger lean burn window, less assist used and overall increased MPG. if i should quantify the mpg effect i would say it is somewhere between 4-8 mpg.

I cannot set a more precise number as now I find my car feels better at higher speeds so where I was driving with 48-50 mph before now I keep 53-55 mph and at the end I still get somewhat more mpg than before (even with the "higher" speeds).

It was a pleasant surprise.

[RobertSmalls]

I find that aerodynamic attention to detail can have a pretty big impact. When I straightened out my front bulkhead and reduced my gaping panel gaps somewhat, the fuel economy improved noticeably.

By the way, what kind of fuel economy are you getting at 55mph?

[JoeIsbell]

anyone have pictures of what the underbody should be? should the bottom be totally covered?

[Jivko57]

Originally Posted by RobertSmalls

I find that aerodynamic attention to detail can have a pretty big impact. When I straightened out my front bulkhead and reduced my gaping panel gaps somewhat, the fuel economy improved noticeably.

By the way, what kind of fuel economy are you getting at 55mph?

Yes I saw your post in another thread couple of days ago and i tried different scenarios to find out , my usual speed now is ~ 52-53 mph so a couple of times I deliberately went to 55 and kept it there but there was no easy answer for me .It is hard to say what I am getting at 55mph on a level road as the roads i drive almost everywhere have some sort of incline or decline . even when there is some so so level part, then the wind plays a big role.

so I would say when there is a very small incline or a little unfavorable wind i am getting ~ 105 at 55mph when there is some decline or tail wind I see ~125 mpg.

[Jivko57]

Originally Posted by JoeIsbell

anyone have pictures of what the underbody should be? should the bottom be totally covered?

somebody posted their underbody pictures a couple of days ago , it was a blue insight for sale ~ 11000 dollars , 2002 with either 30k or 60k miles

I do not remember the thread name but I cannot create links anyway...

[02insight]

I found some pictures here, but not really an overall view:
underneath

but you can always check out Honda parts for the diagrams.
www.hondaautomotiveparts.com

[RyanA]

Originally Posted by 02insight

I found some pictures here, but not really an overall view:
underneath

but you can always check out Honda parts for the diagrams.
www.hondaautomotiveparts.com

Where exactly are you finding the parts explosion view of the underbody panels? I've looked a couple times with no success...

[Delta Flyer]

Completely covering up the underside is a good way to streamline a car - and nobody has to look at the craftmanship.

This guy is not too concerned about the aesthetics of his 1992 Civic, but for $400, he reduced the Cd from 0.34 to 0.17

Aerocivic - Honda Civic modifications for maximum gas mileage - aerocivic.com

[RobertSmalls]

Speaking of the AeroCivic, I intend to complete a similar tail extension. Concern for aesthetics had stalled the project, but my need for good fuel economy at >70mph has me working on a removable tail extension.

[Jivko57]

Most of the engine underbody panels are listed under "FRONT FENDER"