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-   -   Hood louvers... Do they really work? (http://www.jeepforum.com/forum/f9/hood-louvers-do-they-really-work-1064062/)

TeeJay00 07-06-2010 06:06 AM

Hood louvers... Do they really work?
 
I have searched this forum for hood louvers and all I got was threads of how to install them and debates on which kind to use and so on from guys who plan on installing them...

Now my question is for the people who are using these hood louvers or vents.
Do they actually work on reducing engine tempreture? If so, how much cooling is expected off of them?

stogie25 07-06-2010 06:24 AM

I did home made vents. Using my Scangauge II to monitor the intake temperature the vents lowered the temperature approximately 30 degrees. I had my hood off last week while it was getting repainted, and the temperature went down another 30 degrees on average.

http://i299.photobucket.com/albums/m...p/43c3508f.jpg

Sundowner 07-06-2010 06:52 AM

What sort of intake temperatures were you seeing, incidentally?

PhulesAu 07-06-2010 08:28 AM

Yes they work very well. Especially at slow speeds and when towing.

stogie25 07-06-2010 09:10 AM

Quote:

Originally Posted by Sundowner (Post 9741131)
What sort of intake temperatures were you seeing, incidentally?

My readings are through the ECU from the air intake sensor as opposed to actual underhood temperatures. It is screwed into the intake manifold, above the header. The Jeep gets hottest when it has ran a while, then sat for a few minutes, then ran again. This is the condition at which I was taking my readings. With the hood complete, I was getting high temperatures in the 180's. With the vents, I am getting temperatures in the 150's. With the hood off the temperatures were in the 120's.

One can feel the hot air billowing out of the vents when I park the Jeep.

Sundowner 07-06-2010 09:40 AM

180's? Yowza. That's quite the oven-like environment. I might have to look into fabbing something up. Any clear pictures of the vents in question?

rastadog 07-06-2010 10:36 AM

According to the owner of Off Road Trail Tools Hood Louvers, Black, Jeep, wrangler, TJ, YJ, JK, LJ, CJ, RubiconDoes your Jeep run hot? Most do. We run these on our personal Jeeps. Hood louvers have been around forever. Why? Because they work. We see decreases in the area of 10-20 degrees cooler d they work very well when placed as shown.
http://www.offroadtrailtools.com/images/DSC01414.JPG

It's hotter than Satan's b@llsack in DC with HIGH humidity so I'm considering installing these vents. I just replaced my fan clutch and installed a high-flow housing and a high flow thermostat. I also removed my metalcrafters grille insert. I lowered my temp almost 20 degrees.

jim

Sundowner 07-06-2010 11:37 AM

Is there a compelling reason that they're mounting the louvers in the locations shown? The only thing I can come up with would be that, as located, they provide an air outlet directly over the open areas adjacent to the engine, thus allowing cold air from underneath the Jeep to flow up through the engine bay and out...can anyone verify/contradict this?

rastadog 07-06-2010 11:44 AM

Quote:

Originally Posted by Sundowner (Post 9742250)
Is there a compelling reason that they're mounting the louvers in the locations shown? The only thing I can come up with would be that, as located, they provide an air outlet directly over the open areas adjacent to the engine, thus allowing cold air from underneath the Jeep to flow up through the engine bay and out...can anyone verify/contradict this?

According the the owner of OffRoadTrailTools, the placement is key for the proper cooling. He made that very clear when I spoke with him on the phone.

The way I understand it, the whole point is giving hot air a place to escape, it's not about getting cold air in. Having vents right above the radiator and each side of the engine bay make sense to me.

2005X 07-06-2010 11:44 AM

5 Attachment(s)
i have no scan guage to show differences, my main reason was to help heat escape the engine compartment to help witht he overheating of my PSC steering pump. unfortunately my jeep is broke so i have to test it on the trails which is where the real test is, so basically i have nothing to add to this thread except pics of where i did my vents.

Sundowner 07-06-2010 11:50 AM

That's awesome. Hood vents via hole saw. :D

2005X 07-06-2010 11:52 AM

Quote:

Originally Posted by Sundowner (Post 9742335)
That's awesome. Hood vents via hole saw. :D

total cost for my vents was $15. hole saw was free, bought some gutter guards from lowes for $2, then bought some RTV sealant, and a C clamp.

Zen 07-06-2010 01:05 PM

There were a couple of home brew aero studies done on TJ's, but I'd have to do a search for links. One of the studies I read was very detailed. The author tested underhood temps in various places and found the highest temperatures to be in front of a directly over the engine. Then he taped 3" pieces of yarn all over the hood and did an old school wind streamline road test. He found that there was a low pressure area directly behind the radiator and one on either side of the engine. Overlaping diagrams of the heat pattern and the low pressure zones showed that the best placement of hood vents would be the locations shown in Rastadog's photo.

AEV's heat reduction hood takes advantage of the low pressure zone behind the radiator to suck out hot air and increase airflow through the radiator. It would appear that they came to a similar conclusion.

LINKY, LINKY: Oman 4X4 Hood Vent Theory

dbbd1 07-06-2010 01:32 PM

Here is what I did...

Almost as cheap as the hole saw idea

Budget Hood Vents - JeepsUnlimited.com Forums

TeeJay00 07-06-2010 03:08 PM

So the hood louvers idea should actually work in reducing engine heat as long as you place them in those specific locations. And that kit from off-road tools does look good and simple.


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