Purpose of the air dam

rlanda · **Posted:** Thu Nov 06, 2008 11:09 am

What is the purpose of the air dam??

It seems to affect dramatically the approach angle in the KK. I read somewhere that without it, this measurement increases from 29.1° to 39° !!!

So, why it is important to have it installed?

jeepkj02 · **Posted:** Thu Nov 06, 2008 11:18 am

It does serve a purpose, but a lot of people have cut it off for the reason you stated. If you do decide to cut it off it would be wise to find another source for air to enter your engine such as hood louvers.

ATXKJ · **Posted:** Thu Nov 06, 2008 11:53 am

2 purposes

1) increased highway mileage

2) low pressure helps pull air through the radiators

neither is a huge impact and so depending on your driving it may or may not be an issue.

jerbacher · **Posted:** Thu Nov 06, 2008 1:01 pm

also keep in mind that it is somewhat flexible plastic and would probably just flex out of the way of a rock, so approach angle might not be that be that big of a concern

sleeve84028 · **Posted:** Fri Nov 07, 2008 9:09 am

Since this topic is here: Does anyone think that removing the air dam causes any less air to be forced into the A/C condensor & radiator from a lack of the air pressure pocket?

I mean, the front grill has some pretty big slots in it to allow a lot of airflow... So would removing the air dam cause any problems? [Personally I don't think so] But what does the group think?

itsajeepthing · **Posted:** Fri Nov 07, 2008 10:36 am

I took the air dam off mine at the beginning of the summer because it was damaged du to a rock hit. I just drilled out the rivets holding it in place. I went through the whole summer without noticing any difference in cooling/ac performance, or mileage for that matter.

Guest · **Posted:** Fri Nov 07, 2008 1:31 pm

sleeve84028 wrote:

Since this topic is here: Does anyone think that removing the air dam causes any less air to be forced into the A/C condensor & radiator from a lack of the air pressure pocket?

I mean, the front grill has some pretty big slots in it to allow a lot of airflow... So would removing the air dam cause any problems? [Personally I don't think so] But what does the group think?

Just for the record...
The theory behind this part is to block air from coming up between the cradle/engine and radiator, and creating a high pressure condition there. It helps direct airflow THROUGH the radiator. Slots in the grille or not, you can take the grille off and that wouldn't affect anything.

Your Jeep. take it off if you like. I'm not gonna cry when mine finally falls off, but I'm also not gonna go out of my way to take it off.

Fulltimer · **Posted:** Fri Nov 07, 2008 1:36 pm

Here is mine. Even with temps in the upper 90's I haven't had any problems. Hood vents to take the heat out are a great idea, and they really do it too.

Terry

ATXKJ · **Posted:** Fri Nov 07, 2008 1:48 pm

I think one of the guys in Arizona noticed a temp difference pre/post air dam removal

but he was looking at 100F+ days - so for most people it's just theoritical.

ATXKJ · **Posted:** Fri Nov 07, 2008 2:01 pm

I'm fairly certain Fulltimer posted his response after mine - even though his shows first - so the time/post thing still isn't fixed - however

The thread I saw the reference on was air deflector thingy
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?p=386561#386561

and Pablo measured a 20 degree transmission temp swing in AZ

jerbacher · **Posted:** Fri Nov 07, 2008 2:04 pm

ha! i started that one! woo!

Guest · **Posted:** Sun Nov 09, 2008 3:17 am

ThunderbirdJunkie wrote:

sleeve84028 wrote:

Since this topic is here: Does anyone think that removing the air dam causes any less air to be forced into the A/C condensor & radiator from a lack of the air pressure pocket?

I mean, the front grill has some pretty big slots in it to allow a lot of airflow... So would removing the air dam cause any problems? [Personally I don't think so] But what does the group think?

Just for the record...
The theory behind this part is to block air from coming up between the cradle/engine and radiator, and creating a high pressure condition there. It helps direct airflow THROUGH the radiator. Slots in the grille or not, you can take the grille off and that wouldn't affect anything.

Your Jeep. take it off if you like. I'm not gonna cry when mine finally falls off, but I'm also not gonna go out of my way to take it off.

This is what i was thinking. What the air dam does is help create a wind tunnel through your radiator by blocking off other air entrances that would reduce pressure through the front opening. For example a computer case tries to create a wind tunnel by having an opening in the front and the rear of this case and fans to suck air through the length of the case. If you open the side case door this actually reduce the air travelling through the computer because it provides an alternative air input/output that reduces pressure.

So the question then is how can you remove the air dam and yet still keep this wind tunnel effect? You simply have to block air flow going up from the bottom to the back of the radiator (ie.block air from coming up between the cradle/engine and radiator). How do you do this? One possible way is with a front skid plate that covers that area or blocks the area from the front bumper to the engine skid.

501 · **Posted:** Sun Nov 09, 2008 3:22 am

Like this?

Guest · **Posted:** Sun Nov 09, 2008 4:50 am

yes, something like that. Although it would need to be wider to be more effective, at least wider than the width of the radiator. Because that one still has large air entrances on either side of the skid. Perhaps something shaped wide at the bumper and then narrows down to meet the engine skid plate mounts.

VTNomad · **Posted:** Sun Nov 09, 2008 12:13 pm

I ripped the air dam off my 2008 F-250 Diesel work truck (caught it on a branch or stump on a job site) and notced my mileage dropped by 1.5 mpg. I went to Ford, ordered another one and my mileage went back up.

It forces more air into the engine compartment, adding oxygen, and cooling engine temperatures, both increase efficiency.

sleeve84028 · **Posted:** Mon Nov 10, 2008 9:26 am

Thanks everyone.. It appears, that (in the KJ) the only negative on the removal of the air-dam is when traveling through hotter climates like Arizona. I don't plan on removing mine, but I always wonder about silly stuff like this.

Oh and on the flip side... What about in really cold weather?

Guest · **Posted:** Mon Nov 17, 2008 3:44 am

In cold weather it should have the opposite effect. It used to be that in colder climates like where i live some people stick cardboard in front of the radiator so that the engine warms up faster. Otherwise it never gets hot enough or takes too long to warm up the inside. It depends on the vehicle of course.

Purpose of the air dam

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