Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Honda Insight Under-body Smoothing Panels (custom belly pan / undertray)

3-Wheeler · 11-08-2009, 11:45 PM

On some ways, the rear panels by the gas tank were harder to make than the front engine panel. This picture shows a shot from the rear of the car looking forward at several mounting points that were added.

Several more mounting points are shown here. The extreme left of the picture shows the area where foam blocks were added to flare in front of the rear tire, and where Great Stuff Foam was used to fill in the small gaps.

You can also see how much the thickness of the driver side panel varies. The panel wants to be as thick as possible for high bending strength, but not protrude down into the air stream under the car.

Here's another picture of the wood blocks used to stabilize the panel under the car.

This mount was added after the panel was almost complete in shape. The author just wanted to have slightly better mounting support in this area.

This pictures shows both panels in various states of completion.

Here weights are used to hold the layers of foam tightly together until the glue dries.

Now you can see the extra thickness from gluing large foam pieces to increase the thickness in various areas.

Various instruments are used to trim the foam thickness where needed.

About two weeks later, and after adding several coats of light-weight spackling, you get a glimpse of just how much sanding dust one can make when smoothing things out.

Whoops!! The sanding went a little too far towards the left and right most areas of this picture!! On the right side, more spackling is added, and on the left, another piece of foam.

It's hard to tell in this photo, but the entire back side of the panel has been painted with Latex based paint. The panel has already seen life on the car, and through several very rainy days.

Here is the reverse side after fiber-glassing.

Both rear panels side by side. You can barely make out the layer of wood in the thinnest area of the panel, which is about 1/4 inch thick. The wood is heavier than foam, but gives needed support in this area.

You can clearly see a portion of the accumulated road dirt in this shot. So far the panel has seen several weeks of rainy fall weather.

Here is a shot of the panels mounted on the car.

Another shot of the gas tank panels. You can see the cutouts for the exhaust pipe and rear brake cables. There is about a 1.0 inch gap on either side of the tail pipe in this area. There have been no signs of foam overheating is this area. Foam starts to degrade at about 250F or so, and it looks great in this area, so the tail pipe runs cooler than that here.

Of course my driving may have something to do with this, as my typical speed on the way to work is usually 45mph or so.

Jim.

11-08-2009, 11:45 PM	#23 (permalink)
3-Wheeler Master EcoModder Join Date: Dec 2008 Location: Southern WI Posts: 829 AlienMobile - '00 Honda Insight Team Honda 90 day: 80.05 mpg (US) Thanks: 101 Thanked 563 Times in 191 Posts	On some ways, the rear panels by the gas tank were harder to make than the front engine panel. This picture shows a shot from the rear of the car looking forward at several mounting points that were added. Several more mounting points are shown here. The extreme left of the picture shows the area where foam blocks were added to flare in front of the rear tire, and where Great Stuff Foam was used to fill in the small gaps. You can also see how much the thickness of the driver side panel varies. The panel wants to be as thick as possible for high bending strength, but not protrude down into the air stream under the car. Here's another picture of the wood blocks used to stabilize the panel under the car. This mount was added after the panel was almost complete in shape. The author just wanted to have slightly better mounting support in this area. This pictures shows both panels in various states of completion. Here weights are used to hold the layers of foam tightly together until the glue dries. Now you can see the extra thickness from gluing large foam pieces to increase the thickness in various areas. Various instruments are used to trim the foam thickness where needed. About two weeks later, and after adding several coats of light-weight spackling, you get a glimpse of just how much sanding dust one can make when smoothing things out. Whoops!! The sanding went a little too far towards the left and right most areas of this picture!! On the right side, more spackling is added, and on the left, another piece of foam. It's hard to tell in this photo, but the entire back side of the panel has been painted with Latex based paint. The panel has already seen life on the car, and through several very rainy days. Here is the reverse side after fiber-glassing. Both rear panels side by side. You can barely make out the layer of wood in the thinnest area of the panel, which is about 1/4 inch thick. The wood is heavier than foam, but gives needed support in this area. You can clearly see a portion of the accumulated road dirt in this shot. So far the panel has seen several weeks of rainy fall weather. Here is a shot of the panels mounted on the car. Another shot of the gas tank panels. You can see the cutouts for the exhaust pipe and rear brake cables. There is about a 1.0 inch gap on either side of the tail pipe in this area. There have been no signs of foam overheating is this area. Foam starts to degrade at about 250F or so, and it looks great in this area, so the tail pipe runs cooler than that here. Of course my driving may have something to do with this, as my typical speed on the way to work is usually 45mph or so. Jim. Attached Thumbnails Last edited by 3-Wheeler; 11-08-2009 at 11:59 PM..