So.... I bought a sheet of 1/2 inch foam insulation yesterday. 4 feet wide x 8 feet long.

A project for my 1999 Ford Escort:

My plan is to take this and place it under the front of the body and at the rear of the body (away from the exhaust) for smoother air flow under the car.

This stuff is pretty firm. It looks like the sheets you would put behind your walls in the garage. (not foam rolls, a solid sheet enclosed with a thin aluminum tape/film)

Here is a link to a similar idea (from an Audi underbody) underbody aerodynamic panels

Thoughts? Ideas? Suggestions?

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Fitness Entrepreneur
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[This message has been edited by xquaid (edited 06-26-2013).]

P.S. The insulation panel only cost me $11.00.

If the car underbody idea doesn't work I will be able to build a few extra light mini-airplanes

quote Originally posted by xquaid: P.S. The insulation panel only cost me $11.00. If the car underbody idea doesn't work I will be able to build a few extra light mini-airplanes

build the airplanes, that doesn't sound like it will work, now one solid sheet of sheet metal might but I think what you want to do with a foam even a solid foam product won't work. it might help if you go into a lake and help you float, but as far as helping aerodynamics go I don't think it will work. just my opinion as I am no engineer, but I did stay a holiday inn once.

Steve

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Technology is great when it works,
and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

[This message has been edited by 84fiero123 (edited 06-26-2013).]

I've been looking for that to use as an under hood insulation replacement for my old Buick.
I had it in my old Mercury, and it looked and worked great.
The local Lowes doesn't have it.
Where did you get it?

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Drive safely!

The engine bay will get pretty hot. Much of the engine cooling is airflow from under the car. I don't think it would help much on an Escort, anyway. The Escort isn't a very aerodynamic car in stock form.

quote Originally posted by Monkeyman: The engine bay will get pretty hot. Much of the engine cooling is airflow from under the car. I don't think it would help much on an Escort, anyway. The Escort isn't a very aerodynamic car in stock form.

well all hoods, I have ever seen anyway do have insulation under the hood, not that kind but it is there to keep the heat under the hood as engines need to heat up and stay at the proper temp to run properly. why else would they put the insulation under the hood at the factory.

I also think that completely enclosing the underside of the body with an insulation will work for keeping heat in the car but I don't think it will help for aerodynamics. what was posted was metal, from the looks without any more info than the picture anyway. that was made for the car maker and took things like heat into account, what you want to do may damage things by keeping heat in places that shouldn't be kept hot. like exhaust heat, that needs to go away from the car, not stay there, proven by heat shields on mufflers and catalytic converters. I would think just the heat from those could cause the foam to melt and even catch on fire.

Steve

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Technology is great when it works,
and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

[This message has been edited by 84fiero123 (edited 06-26-2013).]

I hope you have good insurance. The Styrofoam board with whatever fasteners you use to afix it will still only be held on by the strength of the Styrofoam itself. When the wind catches it and breaks it free allowing it to fly out from under your car, you better hope no one is behind you and that it doesn't cause a accident.

quote Originally posted by 84fiero123: well all hoods, I have ever seen anyway do have insulation under the hood, not that kind but it is there to keep the heat under the hood as engines need to heat up and stay at the proper temp to run properly. why else would they put the insulation under the hood at the factory. Steve

Its for sound. The heat escapes where it was designed to escape.

quote Originally posted by Khw: I hope you have good insurance. The Styrofoam board with whatever fasteners you use to afix it will still only be held on by the strength of the Styrofoam itself. When the wind catches it and breaks it free allowing it to fly out from under your car, you better hope no one is behind you and that it doesn't cause a accident.

Thats the first thing that came to mind lol. Now a sheet of 1/8" aluminum would be more feasible. Regardless I don't think you'll notice any difference, you'd probably be better off lowering a solid amount.

foam inherently is not a smooth surface. A smooth painted surface has less friction. I expect the friction of the surface would offset any smoothing.

I agree that metal shields are better.

It sounds like allot of work for no return IMHO. But, that foam should be good for insulation on something.

Arn

It brings to mind racing boats that catch wind underneath and go flying and flipping. I'm not so sure you WANT a smooth surface under the car! I think your efforts might be better applied to devising ways to keep air from going under the car in the first place. I'd start with an air dam or a splitter.

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Jonathan

'68-69 GTO Nose - The Project has Begun!
My '85 L67 Build Thread

Looks like I'm the only one who thinks it may be worth anything. But first...

Find an empty stretch of deserted, level road. Preferably on a not very windy day. Use a stopwatch to measure the time it takes to coast down from 70 to 50 mph in neutral. Make an average of like, five runs in each direction.

Now attach your underbody panel. It would be good to have built it before so its ready to go. That way all your conditions are the same.

Make five more runs each way and average your new coast-down time. If the new times all fall outside the range of the old ones, you're acheived something.

Most of all, BE SAFE! Air resistance can build up a lot of force on things, much more than you expected. And obviously, as you're aware, heat may will be an issue.

quote Originally posted by NEPTUNE: Its for sound. The heat escapes where it was designed to escape.

I always thought it was to protect the paint on the hood.

It sounds if you are trying to bleed a stone. While it may work for a little while the foam will get worn and break down...espscially in the winters with snow and such. When it breaks down it will go flying out.
It may provide slighlty, every so slighly better fuel economy, but probably marginally measurable.

Given the time, cost of materials, and life of the modificaiton to me it seems like a loosing propoistion.

What's the difference between these two Tahoes?


Look at the front air dam.

[This message has been edited by Gokart Mozart (edited 06-26-2013).]

Do you want to offer a explanation about what the difference in air dams has to do with a belly pan?

quote Originally posted by Khw: Do you want to offer a explanation about what the difference in air dams has to do with a belly pan?

Instead of trying to find a way to better manage the air that goes under the car, it makes more sense to try to stop it from going there in the first place.

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Jonathan

'68-69 GTO Nose - The Project has Begun!
My '85 L67 Build Thread

quote Originally posted by NEPTUNE: I've been looking for that to use as an under hood insulation replacement for my old Buick. I had it in my old Mercury, and it looked and worked great. The local Lowes doesn't have it. Where did you get it?

I purchased mine at Lowes (Dublin, Ohio).
I am sure Menards and Home Depot sell it.

The specific brand is "R-Matte +3"
It was very similar to this.... FOAM INSULATION w/ Aluminum Tape Lining

quote Originally posted by xquaid: How about an air dam that is constantly in contact with the ground? NO air under the car.... hmmm..... lol

Kinda like having a broom/ squeegee attached to your bumper. Have stiff bristles/ rubber that won't deflect from wind but will on impact with speed bumps and whatnot. Do it lol.

quote Originally posted by xquaid: How about an air dam that is constantly in contact with the ground? NO air under the car.... hmmm..... lol

Study the concepts of "frontal Area" and "Coefficient of Drag". It will tell you an airdam that reaches the ground will increase the apparent "size" of the car, while not necessarily making it any slipperyer. A good underbody will make the original size car have less drag.

Will yours be good? Build it, test it, and let me know. My Senior Project in engineering school was exactly like this. Except in 1979. I doubt you were even born then. Air still acts the same.

quote Originally posted by Zeb: Study the concepts of "frontal Area" and "Coefficient of Drag". It will tell you an airdam that reaches the ground will increase the apparent "size" of the car, while not necessarily making it any slipperyer. A good underbody will make the original size car have less drag. Will yours be good? Build it, test it, and let me know. My Senior Project in engineering school was exactly like this. Except in 1979. I doubt you were even born then. Air still acts the same.

I will give it a shot in the next week
Air act the same as much as people act the same: People sit around and complain about the cost of gas and do nothing about it. I take ACTION instead of using empty words to complain. Complaining accomplishes nothing. Actions accomplishes much.

Trial and error beats complain and maintain.
Thomas Edison identified 10,000 ways NOT to make a light bulb...

quote Originally posted by xquaid: How about an air dam that is constantly in contact with the ground? NO air under the car.... hmmm..... lol

Nascar agrees with you!

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Jonathan

'68-69 GTO Nose - The Project has Begun!
My '85 L67 Build Thread

Unless you have a 200 mph Escort, anything you do aerodynamicly to it isnt worth the effort. A box slicing thru the air is still a box.

I actually think hood a insulation pad is mostly to keep the engine from blistering or cracking the paint on the hood or to help insulate noise myself. Ive taken ratty ones off and thrown them away. I threw all the firewall insulation away on every Fiero I ever had with no ill effect.

quote Originally posted by xquaid: So.... I bought a sheet of 1/2 inch foam insulation yesterday. 4 feet wide x 8 feet long. A project for my 1999 Ford Escort: My plan is to take this and place it under the front of the body and at the rear of the body (away from the exhaust) for smoother air flow under the car. This stuff is pretty firm. It looks like the sheets you would put behind your walls in the garage. (not foam rolls, a solid sheet enclosed with a thin aluminum tape/film) Here is a link to a similar idea (from an Audi underbody) underbody aerodynamic panels Thoughts? Ideas? Suggestions?

I'm also on the Crown Victoria list because I also have a Crown Vic. There are a bunch of people who (like me) have the civilian Crown Victoria and pull parts off the Police Interceptors to get either slightly better performance, or things that weren't otherwise available. One of these things (sold through aftermarket) is a belly pan and a trailing body pan. A lot of rear-bumpers on cars tend to "catch wind" sort of like trying to run with an umbrella open. There's no where for the air to go, so it kind of creates a pocket.

Here's an example:



It mounts to the lower portion of the rear bumper, and tucks up under to the bottom of the car's floor pan. It diverts air to go under the bumper, rather than get caught around it.

They have one for the front too... but it's 1/4" thick steel plate and it's meant to be more of a protective guard than to deflect air. Problem with this of course is that it weighs 200+ pounds and hurts fuel economy.

if done right - yes - great
but - I cant see the stuff holding together for one thing. the bottom of a car get ALOT of debris kicked about. and once there is a hole - it will catch air, and rip itself apart.

and, then there is the design. you dont want to create a "skipping stone" out of your car. it must be concave. and getting sloping away from the ground the further back you go.

the better bang for the buck with front air damn & side skirting. just reduce the actual "under car air".

quote Originally posted by Pyrthian: if done right - yes - great but - I cant see the stuff holding together for one thing. the bottom of a car get ALOT of debris kicked about. and once there is a hole - it will catch air, and rip itself apart. and, then there is the design. you dont want to create a "skipping stone" out of your car. it must be concave. and getting sloping away from the ground the further back you go. the better bang for the buck with front air damn & side skirting. just reduce the actual "under car air".

What about duct tape reinforcement? :P :P :P

Go to Home Depot. Buy a 4 x 8 sheet of back splash. The thin white plastic like you find on cheap gas station bathroom walls. Cut and fit to size. Perhaps using several pieces to be able to fit easier or add and remove for testing.

Once the pattern is made, go to a bed liner dealer and have them spray the pieces. It holds up incredibly well. I have seen this method used to make wheel liners, and still is in one piece and no white showing.

Use short self tappers to fasten the material to the undercarriage. PREDRILL YOUR HOLES FIRST. It will crack before the bed liner seals it.

If you stop by the EcoModder forums, there are several people who have made belly pans for their cars and observed measurable fuel economy improvements.

That said, I don't think foam is going to be a good material. It's too fragile. However, people have reported good results using corrugated plastic sheets (aka coroplast). But the plastic sheets will need some reinforcement to keep them from sagging (and possibly being torn off the car).

Best of luck!

quote Originally posted by Tony Kania: Go to Home Depot. Buy a 4 x 8 sheet of back splash. The thin white plastic like you find on cheap gas station bathroom walls. Cut and fit to size. Perhaps using several pieces to be able to fit easier or add and remove for testing. Once the pattern is made, go to a bed liner dealer and have them spray the pieces. It holds up incredibly well. I have seen this method used to make wheel liners, and still is in one piece and no white showing. Use short self tappers to fasten the material to the undercarriage. PREDRILL YOUR HOLES FIRST. It will crack before the bed liner seals it.

Thank you for the idea

Don't get me wrong with my first post. I don't discount the idea, it's more the choice of material to execute it. Styrofoam is not very strong, I know considering I work with it being in construction and all. It will flex from the air traveling over it and as others have said, one crack or small hole punched in it and say bye bye. Add in that it will be mounted below your engine... There are plenty of caustic fluids that could leak out on to it and you'd have the perfect catalyst for a fire. What is it they call Styrofoam and gas again? Oh yeah, bathtub napalm.

If you follow thru with any material, just be aware that your responsible for any damage or accident caused if any of it comes loose on the road.

I thought I read on a hyper-miler site about smoothing the bottom out. My first thought was HEAT. I mean you said it is insulation, I don't think it will help, except to maybe get you in closed loop faster. The other guys were using another material I thought and I don't think they were covering the underside, but just trying to deflect it downward. Think the opposite of the semi truck toppers. I personally wouldn't do it. Liquids splashing, heat build-up, material breaking off and hitting others or getting in your belts/pulleys. I believe changing your driving habits would be a MUCH better way to get mileage out of your car. Stripping the interior or removing all extra accessories I bet would get more of a gain than this idea. Do both? Monitor how much throttle you are using to accelerate and when you are driving, like rush hour. Don't run the A/C. Don't idle the car. Never park where you have to back-up. Try to time all lights to be able to coast through and not come to a full stop. Keep up on your maintenance. Cruise isn't the most efficient way to travel. When going down hills, use neutral.

Wish I could remember that MPG forum I used to frequent.

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$50 a month unlimited cell

I get excellent gas mileage from everything I own. I up my tire pressures for one thing. I do drive ahead of cars in front of me to anticipate things like traffic and stop lights and signs. I try to gradually slow for stops from a farther distance. Saves gas and brakes. I dont accelerate faster than the car can do it...I only give it the gas it needs to speed up. Flooring it to beat a light or pass someone uses more gas in a few seconds than it takes to go a mile or 2. Your car can only accelerate at its own rate, giving it more gas wont make it go any quicker. I plan ahead...trying to figure in advance what lane or what exit I need to be in. Its like flight planning in my plane to me. I generally dont like AC, so turning it off is not a problem. Im usually alone or with 1 passenger. I typically beat the manufacturers expected mileage.