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Cowl Hood vs Hood Vents

JNickel101

NAXJA Forum User
Location
Alamogordo, NM
Let the debate begin....

My main question - which one would better reduce the under-hood temperature? I've read GoJeep's writeups on both - but I wanted to get a forum opinion (maybe someone who's run both) and see what everyone thinks...

New Mexico is super hot in the summer, and I want something to help reduce the under hood temps to as close to ambient temp as possible. Thank you!

MrF
 
Some one on here needs to come up with a way the rear of the hood can be tilted up for wheelin or heavy traffic and then pushed back into place for the trip home and highway driving. This couldn't be hard to do.

I know the old VW's had something like a cantelevered hinge to pop the top of the hood open and help cool the little lawn mower engine in there.

I might try to work on something this winter.

I know that didn't answer your question but it got me thinking this am.
 
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Well, I'm running hood spacers right now, and they help a tiny bit, but the hood still gets hot enough in the summer to cook steaks on....too hot to even touch. I know the hood is gonna be hot, the engine runs hot enough to boil water...but I just want the heat buildup to dissipate faster - so vents or cowl? :)
 
I don't know anything about cowl hoods but I have heard many great things about hood vents and i have seen them on a lot of xj's. plus they are a lot cheaper. have you tried an aftermarket electric fan? that helped me keep a lot cooler. I am sure you know that you can get vents from an old LeBaron at a junk yard, anyway hope that helps a bit. If you do get vents here is a good write up that may help you install:

http://www.ericsxj.com/vents.htm
 
Stumpalump, if you're out there...do you have pics of how you made your own "cowl hood"?
 
I believe GoGeeps writeup on his site indicated that a cowl hood at speeds actually increases heat and at low speeds does allow heat to escape. I also know a guy on another forum that raised his hood and exprienced higher temps at speed.

I based my vent design on his information and they work extremely well at all speeds. My method allow little to no outside elements into the engine bay. http://www.soxja.org/forum/viewtopic.php?t=314
 
I dont see where it says the heat INCREASES at speed...it just draws more cool air in at speed, where as, low speed, it lets more heat escape....

Either way, the cowl works...
 
Maybe i'll do cowl and vents....
 
Got a pic of that? LOL...
 
JNickel101 said:
Stumpalump, if you're out there...do you have pics of how you made your own "cowl hood"?
I didn't make a hood but the way I opened mine up for cowl induction type air flow is this. I removed the rear hood sealing gasket and beat down the metal flange that held it. Then I added 1/2" hood spacers. To let even more air thru I adjusted the hood forward and put a 2x6 on the cowl and closed the hood slowly to bow the hood up in the middle. Cowl is fiberglass so go real easy or find a better way. Next I stood on the rocker guards and leaned hard on the rear hood corners so the hood dosn't looked jacked up from the side. You can see my engine from the rear of the hood now and it lets a lot of air thru. Rig your electric fan to run when you want and it helps alot. I since added hood vents for basically looks because more air exits the cowl than thru the Labaron vents by far. The vents look cool especially since my junk is plain white with black bumpers. The black vents add style and isn't style what it's all about?
 
Do you have any pics of how your hood looks now?

I'm still a little confused what you mean by sliding the hood forward and using the 2x6 to bow the hood up? did you put the 2x6 up the middle of your engine bay and close on it like that?
 
I had a vent in my jeep. Look and work great. But since the swap I need to go with a cowl scoop instead. I got the scoop haven't gotton around to putting it on yet.
2523955_46_full.jpg
 
You could buy a universal cowl from Jegs or Summit and graft/rivet it onto your hood after cutting the proper size hole. My brother did that to his scout and it worked great as well as looked awesome!
 
JNickel101 said:
Do you have any pics of how your hood looks now?

I'm still a little confused what you mean by sliding the hood forward and using the 2x6 to bow the hood up? did you put the 2x6 up the middle of your engine bay and close on it like that?
The hood is bolted on so loosen the bolts and slide the hood up or forward. You need sombody to hold it up and out while you tigten down the bolts. The 2x6 layed on the cowl and over the engine. When you slowly close the hood the 2x6 pushes up on the rear center of the hood cousing it to bow up. I just bowed it enough to open up the air slot probably under an inch.
If you go here to post 30, last picture you can see that my hood still looks stock from the sides but you can stick your hand in the slot it created.
http://www.colorado4x4.org/vbb/attachment.php?attachmentid=7459&d=1194822595
 
JNickel101 said:
I dont see where it says the heat INCREASES at speed...it just draws more cool air in at speed, where as, low speed, it lets more heat escape....

Either way, the cowl works...

If I am not mistaken, a cowl hood draws air from just in front of the windshield due to a low pressure area that occurs at speeds. It does not draw air through the radiator.

However, hood vents don't draw air at all. I believe they give the air (at low speeds) another place to go besides through the radiator and then down.

At low speeds I think a cowl hood pretty much have the same effect.

I have vents. They seem to work well at low speeds
 
Stumpalump said:
The hood is bolted on so loosen the bolts and slide the hood up or forward. You need sombody to hold it up and out while you tigten down the bolts. The 2x6 layed on the cowl and over the engine. When you slowly close the hood the 2x6 pushes up on the rear center of the hood cousing it to bow up. I just bowed it enough to open up the air slot probably under an inch.
If you go here to post 30, last picture you can see that my hood still looks stock from the sides but you can stick your hand in the slot it created.
http://www.colorado4x4.org/vbb/attachment.php?attachmentid=7459&d=1194822595

Not getting anything from that link...

thanks, gotcha now on the explanation :) still would like to see how it looks :)
 
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