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Discussion Starter #1
It looks like I am missing the underbody panels on my 2002 CVT, from the radiator to the rear of the engine bay. Aerodynamically speaking, how important are these?
 

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Like everything else, maybe 1%. It's when you add them all up that it makes a big difference. Probably the tires are the most important thing. The panels may affect engine cooling a bit, but I doubt if it's very much.
 

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I can't talk about the underbody panel itself, but like the earlier poster said, everything counts.

I had lost the driver side "air dam" that sits in front of the tire, and also the inner fender. (I hit some road debris...)

I've been doing some long distance commuting (700 plus miles each way) on Interstate 80. With the damage, my mpg was hovering around the 50 mpg number. Once I replaced them I slid up to the 60 range. This all at "highway speeds"....

(I also pulled off a 70 mpg trip, but in that one I kept my eye on the display the whole time, drove in the Carter speed range, and despite teh weather, kept my a/c off. I ain't doing that again).

Oh, a picture of my mileage display on that last trip:
http://www.panix.com/~dannyb/images/mich-to-nyc.jpg

(2001 CVT)
 

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The panel may protect debris from getting caught in the accessory belts :shock:
 

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I tore mine off by driving through a deep puddle at too high a speed (right after a night of heavy rains). The front screws tore through the dam material itself, and then the leading edge came into contact with the road, and it basically dragged itself down back and under itself until it was more than halfway off. I pulled over and got wet and muddy pulling it the rest of the way off.

Amazingly, the Honda dealer near me replaced the thing for $102.25 -- basically the cost of the part alone. He didn't charge me for the labor (although it wouldn't have been much).

When it was off the car, I could see exposed wires running along the underbody; I was worried they might get snagged on something. I was glad to get it replaced so cheaply.

Good luck

MF
 

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i was doing 112mph yesterday (overtaking some guy in his new Merc) and one of mine came off - thought i had damaged the engine with all the noise. New one is about $70
 

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jack9994 said:
i was doing 112mph yesterday (overtaking some guy in his new Merc)
Whoa! Got any points on your licence yet?!
 

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And then... while you were passing that other
car, you heard a Nash Rambler going beep-beep.
 

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Christian

Yes, i got 3 points in the Insight last month - doing 84mph on the motorway by one of the Cumbria Road Safety vans parked on a bridge - wasnt paying attention - i'm sure the police would have ignored me at that speed. First points for 23 years!!!

Cheers
John
 

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By all means, replace the panels. It's easy to underestimate the importance of under-body airflow management. It's no killer to MPG at very low, urban speeds. But on the highway, it's major. At high speeds with NO panels, substantial turbulence is created. The panels will help to keep the airflow laminar.

My experience with this, comes from being a test-pilot back in the 80's and 90's. You see, airplanes with retractable gear have doors that fit up tightly to hide the wheels and smooth the airflow. For example, one of our single-engine planes (Glasair) had a top speed of 244 mph at sea level. Testing without the gear doors showed a top speed of only 230 mph.

Anytime you can smooth, hide, streamline, etc, both parasite and induced drag is reduced.
 

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Hi Bagwell; From my flying notes back in 1993, as quoted in "Air & Space Progress" magazine. "None of the 737 series have ever had full main gear doors. Instead, partial doors cover the legs, while the outer wall of the tires meet with aerodynamic seals to make a smooth surface on the underside of the aircraft."

afaik, both the Embraer 145 and 170 employ main and nose gear doors supplied by Gamesa, inc. or the Sonaca Group......
 

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Discussion Starter #14
Thanks to all.

Thanks everyone, I got underneath the car tonight and realized I was missing the Front Lower cover and both lower engine covers. I have new ones on order.

I think I am going to make templates of them before I install them. With the Chicago snow, I may make a set out of 1/4" aluminum to prevent them from ripping off. I'll have to see how sturdy the attachment points are first.
 

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Re: Thanks to all.

WindyCityInsight said:
I may make a set out of 1/4" aluminum to prevent them from ripping off.
Planning to bobsled with your Insight :?: :p

IMO you'd end up ripping up the floor pan before 1/4" AL panels would give way. And if one did come off you'd better pray that it dosen't slice open the fuel tank on its way :!: :shock:

Ummm. Looks good "on paper" 'til you consider all the other consequences. I'd strongly recommend don't do it.

Be careful out there guys :!:

HTH! :)
 

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Over the past 1200 miles I have averaged 70.6 mpg with no panels. I go from one small town to another (15 miles each way) daily at an average of 55mph.

If somebody has the bottom panels off of their Insight I sure would appreciate it if templates could be made. I will pay money for your trouble!

I believe some sort of rigid plastic sheeting will be a decent substitute.

My 2000 Insight was missing them when I purchased it. It has over 140,000 on it and I don't want to spend the money for new ones so I drive carefully and keep the car on the highway.
 

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Discussion Starter #18
Re: Thanks to all.

"bagwellhow much were you quoted for all the panels?

t.i.a.
I just ordered them from the Majestic website. The main lower panel and the two lower side panels were $140.

I am thinking sheet aluminum might be better than the 1/4". ;)
 

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I noticed about a month ago that the black plastic "dam" in the front (on the drivers side) was hanging loose from the bottom of the bumper. I took a quick look and saw that two screws were missing and just assumed that they needed to be replaced and it could wait.

Last weekend I finally got around to looking closer and found out that the reason the screws are missing is that the plastic they screw into (the bottom of the front bumper) is broken in one place and stripped in another.

There are scuffs on the bumper in this area so I'm guessing that the previous owner may have bumped a curb or something along those lines.

Is there any recommended way to repair this other than replacing the entire bumper? I have a few ideas but I wanted to see if anyone has come up with something that works.
 

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I don't know about those parts specifically, but I've repaired minor cracks on some panels (the rocker panel under the door, and trim piece behind the front wheel) with ABS pipe cement from the hardware store. (ABS is the black pipe, the white is PVC which uses a different cement.) I don't know how well the repairs would stand up to stress, though.
 
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