Sealing the Mitsubishi Mirage hood gap

[Daox]

I have already blocked my lower grill and upper grill on the Mirage. The only remaining area that is open on the car is the fairly large gap between the hood and the front bumper cover and headlights. I am looking to close that gap.







I measured the gap the other day and its roughly 3/8" wide. So, while it is a thin area, it extends all the way from one side of the car to the other. The width of the car is 66.5 inches. So, lets be conservative and say its 55" of hood gap. That still gives us about 20.6 square inches of opening. That is the same as just over a 5" hole in the front of the car.

There is no rubber gasket under the hood at all, nor on the bumper cover or headlights.





My question to you aero guys is, is it worth trying to fill the gap so its relatively flat? Or, should I just put in some weather stripping wherever I can to block it off? This would likely be about 2 inches back from the opening.

[Daschicken]

I vote weatherstripping. As long as the air doesn't have anywhere to go, that cavity shouldn't be too detrimental to aero.

[Stubby79]

I agree...the D-shaped stuff.

[Daox]

Yeah, the D shaped stuff is what I was thinking too. However, I can't seem to find any that is thick enough.

I measured my gaps the other day with a piece of dough. Yes, dough. I made up a piece (flour and water), and put it in the hood opening to get smashed like a home made piece of plastigauge. Then I let it freeze. This is what resulted. The narrowest area is 3/4" thick. The thickest D profile I can find is .59". Sheesh eh?









The bulge in the middle top is from a piece of weather stripping I already stuffed in there. You can just barely see it in the picture above. So, I'm going to take it out as its doing nothing. But, I think the step up on the bottom is where I'll stick the new weather stripping. I just have to find some stuff that is 3/4" thick at least.

[Vman455]

I'm really surprised the Mirage doesn't have a gap filler there from the factory; most cars do these days. That said, you might be able to scavenge one from a production car that might work?

[Daox]

I'm thinking I'm going to have to double up on the weather stripping to get the required height. I don't feel like scavenging. However, some of these weather strippings are pretty darn pricey when you look online. I don't think this mod is worth $20.

[BamZipPow]

Have you looked at a garage door bottom seal strip? You might be able to make something of that.

[Daox]

Haha, if that wouldn't do it, nothing would!

[oldtamiyaphile]

You could VHB some flexible plastic to the top of the grille, in layers if need be, then close the remaining gap with a regular sealing strip.

[oldtamiyaphile]

Originally Posted by Vman455

I'm really surprised the Mirage doesn't have a gap filler there from the factory; most cars do these days.

Sealing the hood gap was a thing in the 80s-90s, in my experience new cars generally don't have these seals anymore. Some have suggested it's to allow airflow to cool the various underhood components. Could also be that the airflow is aerodynamically stalled at speed and therefore seals are simply not required.