Full boat tail on a Matrix

[Weather Spotter]

Here is a collection of under car pics.

Front part:


Middle:


Back:




Looking from the back:






What are you thoughts on the axle height, will the back belly pan act as a sail?

[JasonG]

Looks like it may act as a parachute.
The open area between the axle and the gas tank/ rear floor/ not sure what it is will act as an inlet for air and snow/mud.
Looks like you need to add a piece from the axle forward.

you are really getting it done on this car :thumbs:

[Weather Spotter]

From what I can see it looks like there is not much of a gap on top of the gas tank, so most (if not all) air is flowing under the tank. If so it is lower then the axle already.

Also there is no exit for the air (some my tires but not much) so where would it go? would it not just build up a static layer or am I missing something?

I think I found a second driver so I might just get a video done today

[NeilBlanchard]

My experience with a similar belly panel, was that it does parachute.

You'll want to block the gap that is shown best in the fourth photo (in your above post).

[Weather Spotter]

Well I took it for a test run a few min ago. Nothing fell off

I was testing two things in this run:

1. How my new belly pan worked

2. Air flow over boat tail

Comments on #1

It is still on! It moves up and down over bumps a bit (I hear the screws holding the metal parts on bump up on the exhaust).

After my test run I looked at where the snow was building up on the belly pan. I saw none on the inside that did not appear to come from the tires. The whole underside of the belly pan (ground side) was wet from the snow. The metal areas had melted and were dripping.





Side piece right behind the tires: (camera was not level)



Comments on #2
Video to come once it is up loaded.

As I started I had about 1" of snow on the top of the car. I watched this snow as it went off the back window. It was running parallel to the window and was almost touching it (might have been .5-1" off). I do end up with a very thin layer of snow attaching to the window (I think it is sticking to the window).

Snow did stick to the tail, mostly in areas that only have one layer of fiberglass (surface is a bit rough).


Side: note, other side has 3 layers of fiberglass and has no snow sticking to it.


Back:


Does the back snow build up something I can fix or will it be there unless I taper it to a point?

From trailing the car I think the underside air flow has improved. I saw less roiled air in the middle. I think that most of the roiled air was from the tires.

[Weather Spotter]

Here is the video:

I had a cross wind (from left to right)

http://www.youtube.com/watch?v=Sq9G6lep688

Here is the first for compare:

http://www.youtube.com/watch?v=0apq9kCL4Vs

Fire away on the comments

[richtate]

What would be interesting would be to see the video from a stationary location with the Matrix and the chaser car passing a block or so away from each other for comparison.

[alohaspirit]

great stuff

this is more entertaining than Tron

[Weather Spotter]

Originally Posted by richtate

What would be interesting would be to see the video from a stationary location with the Matrix and the chaser car passing a block or so away from each other for comparison.

That is not a bad idea, I would need a similar car to make a fair comparison. I can tell that the wake is smaller then pre tail. On most cars I see the wake of spinning and vortex snow is the same or taller then the car. It is wider then the car as well. On mine it is as tall as the tail (ending height) and only slightly wider then the tail is (ending width).

From trailing I can also see that it keeps this shape for a time then dissipates in about 1/3- 1/2 the normal length.

If I were to fix things more I would try to do a mini boat tail behind each tire. This would get in the way of snow and road debris so I am not planning on doing it.

I might work on the front wheel wells to reduce the gap.

One issue I have with the tail is that the foam pieces somewhere (I think in the front) are rubbing and making the nasty foam noise. What can I do to fix it? The noise is just when I go over bumps but small ones do it to so it is doing it about 90% of the time. It is not very loud but it is grating. I can live with it but others can not.

I was thinking:
Fiberglass it (not a fan but I could do, I would have to buy more stuff and the smell)
paint (might not get the surfaces that are rubbing, it could be edge on edge)
noise reduction insulation (cost $$$$)

Other ideas?

[redneck]

Silicone spray.

Just don't get it where you'll be modifying or painting later.

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