Full under body panel for 10% fuel efficiency gain. (about 20% aero drag reduction)

[mikeyjd]

Front

Front underside

Drivers side under door

Rear


Materials used.
1 1/2 pieces of coroplast ($17)
1" tornilo screws (1box $4)
1" diameter washer (on hand)
20' of flooring metal ( had it on hand)
10' of L shaped aluminum track (had it on hand)
Card board used to pattern the form (leftover from a recent tub install)
Utility knife (I use this for work so now cost to me here)
Time spent= 8 hours
Total money invested= $21.00

[wflaw45]

Where did you find the large sheets of Coroplast?

[200KGPGTP]

Awesome! I've always wanted to do this

[Bert]

I hope you can figure out a way to keep good records so as to compare before and after. Great idea.
You might chuckle about this but dimples on golf balls create a boundary air layer that allows for more efficient travel. I wonder if thoroughly working a Festy over with a ball peen hammer would make it more fuel efficient.

[zoom zoom]

How close is that to touching your exhaust? Your not worried about it melting through are you?

[F3BZ]

i've thought about this also. not the full belly pan but judiciously placed small foils/covers over or in front of suspension components in the airstream. potential problems i'd think about with the full pan treatment: engine cooling. where does the air entering the radiator now exit? becoming airborn. the right speed, the low weight, the gust of wind. you've surely seen a news clip of a hydroplane boat flipping?

[sketchman]

Nice. Yes, before and after numbers anxiously awaiting.

[Spike]

My biggest concern (because I have so much rus- err - weight reduction) is that it would hold in excess moisture, thus leading to extra weight reduction.

I suppose if you triple-sprayed it before putting this belly on, it might not matter as much.

-Joe

[TominMO]

There's no way this will work. The increased drag of the attached jackstands on the ground will more than compensate for the lower drag of the belly pan.

[Spike]

Hey hey! Don't 'jack (stand)' this thread!

-Joe

[FestYboy]

There's no way this will work. The increased drag of the attached jackstands on the ground will more than compensate for the lower drag of the belly pan.

Tom, you so FUNNY!!!

[jawbraeka]

this is exactly what i was talking about..might be better if it were shaped from the one piece of material, but excellent prototype none the less. just need a aerodynamic bodykit and you're set.

i had a few ideas about this in regards to the heating and airflow

wrap the exhaust in heat shield like what is done for exhaust header to reduce heat escaping, then have a "boxed channel" around the exhaust to allow for airflow down to the rear of the car where an "exit" is available to allow the airflow to suck the hot air out..

at the front of the car, have a narrow gap between the car and the undercar plate of maybe 2" and funnel the air into the formentioned channel to allow the airflow down the channel. also have an opening for the engine bay to allow air to be pulled through to the back of the car also, and two vents on the bonnet to allow air to be "sucked" into the bay and i think you guys can see where i'm going.

here is a picture to help you "plan and refine your design"


i'd also do a bit of research into the ferrari's and lamborghini's that use this design as a standard feature..

it'd be cool to see this implemented into the festiva.

[mikeyjd]

Where did you find the large sheets of Coroplast?

http://www.piedmontplastics.com/

Awesome! I've always wanted to do this

you should.

I hope you can figure out a way to keep good records so as to compare before and after. Great idea.
You might chuckle about this but dimples on golf balls create a boundary air layer that allows for more efficient travel. I wonder if thoroughly working a Festy over with a ball peen hammer would make it more fuel efficient.

I've kept records. It's impossible to to calculate with 100% certainty as I have done other mods in conjunction. This belly is a month old and has worked quite well thus far. My estimates for affectives (in the post title) are based on anecdotal observations and projections as well as other under belly pans on ecomodder.com.

How close is that to touching your exhaust? Your not worried about it melting through are you?

4 inches of white (not pink) fiberglass insulation has held up thus far. It is ever so slightly warped where the catalytic converter is, so I'm contemplating integrating a steel mesh insert 18''x12'' or so.

i've thought about this also. not the full belly pan but judiciously placed small foils/covers over or in front of suspension components in the airstream. potential problems i'd think about with the full pan treatment: engine cooling. where does the air entering the radiator now exit? becoming airborn. the right speed, the low weight, the gust of wind. you've surely seen a news clip of a hydroplane boat flipping?

engine cooling hasn't been an issue even during long trips in 85+ weather thus far. the air entering the radiator still has plenty of places to exit (hood cowl, wheel wells, it's rigid but it's not tight to the oil pan either)

Nice. Yes, before and after numbers anxiously awaiting.

before all mods baseline mpg = 48.8mpg
since mods = 62.65 (including better driving although the baseline tank did include some hypermiling)

My biggest concern (because I have so much rus- err - weight reduction) is that it would hold in excess moisture, thus leading to extra weight reduction.

I suppose if you triple-sprayed it before putting this belly on, it might not matter as much.

-Joe

I've taken this off a couple times after rain to check for moisture issues. So far so good.

There's no way this will work. The increased drag of the attached jackstands on the ground will more than compensate for the lower drag of the belly pan.

Sometimes style is more important ^

[mikeyjd]

this is exactly what i was talking about..might be better if it were shaped from the one piece of material, but excellent prototype none the less. just need a aerodynamic bodykit and you're set.

I like it in more than one piece for the sake of maintenance, but 2 pieces would be better than the 3 mine is. Fiberglass or carbon fiber or some sort of oem abs pan would be awesome. Unfortunately no one makes em, and I probably couldn't afford them if they did . And I would love a custom aero festy lol. Who wants to build me one?

[mikeyjd]

this is exactly what i was talking about..might be better if it were shaped from the one piece of material, but excellent prototype none the less. just need a aerodynamic bodykit and you're set.

i had a few ideas about this in regards to the heating and airflow

wrap the exhaust in heat shield like what is done for exhaust header to reduce heat escaping, then have a "boxed channel" around the exhaust to allow for airflow down to the rear of the car where an "exit" is available to allow the airflow to suck the hot air out..

at the front of the car, have a narrow gap between the car and the undercar plate of maybe 2" and funnel the air into the formentioned channel to allow the airflow down the channel. also have an opening for the engine bay to allow air to be pulled through to the back of the car also, and two vents on the bonnet to allow air to be "sucked" into the bay and i think you guys can see where i'm going.

here is a picture to help you "plan and refine your design"


i'd also do a bit of research into the ferrari's and lamborghini's that use this design as a standard feature..

it'd be cool to see this implemented into the festiva.

i'll look into it. It seems to be working well so far as is, but I will revisit this if I run into any problems this summer. Thanks for the pics, they could also aid in my boat tail design.