How To: Under-Body Air Smoothing Panels

[3-Wheeler]

It started out innocent enough...

When I bought the Insight this past spring, two items came to the top of the list.

1) Make oil changes easier
2) Replace the missing smoothing panel under the drivers side of the car

The first time I changed oil, it was 20°F outside in Wisconsin, and snow was falling in the driveway. I lay on my back with the car jacked up, *attempting* to get the panels off, to change the oil. Cold fingers on hard metal fasteners was not my idea of a good time.

Getting the panels back on took even longer, as the panels were 'tweaked' and jimmied back on by the previous owner. Needless to say, when warmer weather arrived, 'something' would be done to improve the situation.

Well, warmer weather did arrive in the form of 'summer' and I spent most of it, again on my back under car. But this time, with more purposeful disposition, that included fixing points 1 and 2.

Two air smoothing panels are now complete and on the car for the first weeks evaluation. You can see them here:

Picasa Web Albums - jsmosher - Air-Smoothing...

The panel under the engine vastly changes how the radiator block works. This spring I was running a 70% radiator block and could easily leave it at 50% blocked when the outside air temperature was 80°F or so.

Now I have completely removed the block after running the car on the Interstate highway as a safety check. With a 50% radiator block I saw temps as high as 204°F using a ScanGauge, just below the fan turn-on point. I typically do not run the car on the Interstate, but was curious what would happen.

The hot air intake mod is disabled for the time being. It was purposely only partially coupled to the intake snorkel to keep temperatures below 130°F, but now the under hood temperatures are so insulated that the hot air mod was generating temps above that temperature. Disabling it completely seemed easier than fine tuning it with outside temperatures close to 80°F right now.

With the radiator unblocked and running at 45mph on the back roads to work, I typically see radiator temps around 197°F or so, which makes me more comfortable, as I don't have to keep such a close eye on the ScanGauge while driving.

No Cd numbers yet, but that will eventually be done, when I finish smoothing out the rear of the car.

P.S. Highwater was an early inspiration to me. He posted some pictures of his 'engine blanket', and after numerous search attempts, I have been unable to find those early pictures he posted. Anyway thanks for getting things started.

Jim.

[Kevin Dougherty]

This what you are looking for?



Randall's Insight - MIMA Honda Insight Modified Integrated Motor Assist

[3-Wheeler]

Kevin,

Thanks Kevin, that's exactly what I spent many moons looking for!!

When I started the wheel well supports for the under-body panels, I looked in vain for those pictures, to remind myself how he did it. Very nice!!

I could have sworn however, that HighWater was the first to post about that design. Any relation to you?

Jim.

[Kevin Dougherty]

Originally Posted by 3-Wheeler

Thanks Kevin, that's exactly what I spent many moons looking for!!
Jim.

Your welcome

Originally Posted by 3-Wheeler

I could have sworn however, that HighWater was the first to post about that design. Any relation to you?Jim.

Nope

[jonnyvtec]

Why did he block the holes where the steering arms pass through.

Does the shaped front wing (fender?) to promote air flow out of the arch region not give a clue as to what they are for?

[3-Wheeler]

Hi johnnyvtec,

Why did he block the holes where the steering arms pass through.

Does the shaped front wing (fender?) to promote air flow out of the arch region not give a clue as to what they are for?

The blocked holes are there for several reasons:

1) When it rains out, and water is flooding the wheel wells, I am attempting to keep excess water from running on the *inside* of the panel by access through this area. Packed snow is another issue when it gets colder outside. I would have liked to close this area completely if possible, but some compromise had to be made to allow the suspension link and anti-sway bar to extend out.

2) The structure adds mechanical strength to support the panel in this area. Packed snow in this spot could easily break the panel if not supported here.

3) The area where the steering link passes through is *not* blocked, in hopes that flow through the radiator will pass through the engine bay and out this opening, to keep it from passing underneath the car. There is less drag by this method, and already allot of turbulence in this area.

The wing shape was added to maintain good air flow when the suspension is fully extended. I was trying to avoid a large hole in the flow coverage in this area. And the suspension hung down below the major flow path in this area. Thus the inverter wing shape to help maintain good flow and cover the dangling suspension link.

Hope this helps, Jim.

[3-Wheeler]

The under-hood temperatures are more reasonable now. After finally getting in touch with a catalytic converter salesman through an acquaintance, I was assured that the converter could be insulated with fiberglass batting.

My concern was that the converter might overheat if this was done. The salesman mentioned that insulating it would actually improve how quickly it warms up and reduce pollution slightly, since it would be above the minimum operating temperature more quickly.

The goal of insulating the converter was to reduce the under-hood air temperature by shielding the main heat source. After adding the engine compartment smoothing panel, I did notice a more rapid heat build-up with the original 70% radiator block, with the fan close to the activation point (205°F).

Now the radiator block is back to 50% with the air temperature close to 60°F, and the radiator temperature is still at 197°F or so.

Jim.

[mtgeekman]

Been keeping an eye on your picasa album, great work. I would love to have time/place to make a set for my insight.


noticed any improvements for mpg or handling at highway speeds?

[Kevin Dougherty]

If any one goes into the business I'd definately consider buying a set.

[nayrhyno]

This is fantastic work. I continue to be very impressed. Perhaps I have found my project for next summer if I can find the time and work space.