Just as an side to all the discussion about the Fan Shroud.

Here in the UK the general opinion is to cut the bottom off of the fan shroud. This means it can just be lifted out without having to feed it around the fan.

Mind you, it does tend to be a bit colder here

 

Now that's interesting! I would have never guessed these shrouds could have kept all of us from around the world so busy! It's been one heck of a post! So many variations and spins on a simple part. Too bad there wasn't a big database that could capture all this info!
Maybe that can be the next Google for Jeeps!

 

Duh now I get it my imagination was locked on fan shrouds thanks for the smack up side the head. That would improve things though if the vortex coming off the windshield wouldn't impede the air coming out. An interesting side note you would definitely know when you had an oil leak instead of waiting for the smell

 

Red91... Check it out here. This guy has lots of data on it.
http://www.go.jeep-xj.info/

 

I have seen them. One thing that has already been noted is that that is a high pressure area. That type of design was originally used to provide higher pressure air for carburetor intakes and get a little more horsepower. In theory, you will be forcing air back toward the front. The consensus is to use Chrysler LeBaron hood vents. The guys that have used them report better air flow and lower operating temps. The plain fact is that these jeeps just don't breath well

 

Sweet I noticed that he used bits of wool for his test instead of toilet paper I just wonder if he had a spotter so he could keep an eye on the road while noting the airflow directional change. I did forget that the windshield vortex doesn't come into play until above 35 mph by then it doesn't really matter because frontal air pressure would be enough to overcome it. It is kind of neat that he observed that it increases cool air volume under the hood.

 

That go-jeep guy did some simple tests on that hood. I thought he had some interesting points. Have you read that article lately on the site I posted above?
Do you remember any of the sites where I could look at more test data on the hood vents verses the cowl hood? That would be great if I could review them too before I pick a direction.
Thanks

 

I am not aware of any actual tests. All the testimonials are qualitative, not quantitative. A test you could do yourself is similar to what I did. Just remove your hood and see how you like it. My engine compartment and cab temp was significantly reduced. so when the hood goes back on, there will be some significant venting.

 

Yes, I like the fact that he collected data on his changes. "Data doesn't lie, people do"... Something a smart man said to me once! I'm going to do more research on this.

4.3L:
Did you read the article we are referring to here? The one on the link I posted?
I also see that in the "High-Performance Jeep Cherokee XJ builders Guide" that Eric Zappe put some Chrysler Lebaron vents on his Jeep hood. He said his temp gage runs lower and he can see the heat billowing out.

 

Interesting how a simple question about a fan shroud can turn into a discussion about heat flow and dispersion under the hood and different ideas from different parts of the globe. That comment about the guy who registered a 70 degree drop in under the hood temp amazed me, I never thought about how hot it actually got under there. It makes you wonder about those guys that show their cold air intake sitting exposed under the hood as to how much benefit they are actually getting from such a set up.

 

a note on the heat and venting

im running both 3/4" hood spacers in the rear and LeBaron hood vents and there was a noticeable drop on the gauge aswell as the heat that you can see pouring out of the vents and at slow speed you can click the fan on and the heat pours out the back its actually surprising how much heat pours out and how hot it actually is

and as for the cold air intake having a RENIX 4.0L i was left to my own creations as far as the intake tube setup went so with 3" exhaust pipe some fittings brazed on and a 6x9 K&N cone filter i had my setup that ive yet to build a shield for and while i relize it sucks in more warm air i also relize it pulls in alot more air then the factory box allowed and at driving speed i figure theres enough cold air blowing in through the hole between the rad and the headlight that im fine although a a shield would be a benfit ive just never got around to fabbin it up

again the increase air intake was a noticeable mod in the throttle response

 

Thanks I was really wondering if there was a benefit in a do it yourself outfit like that so the difference from stock is really noticeable sweet! On that hood spacer idea how do you do that just stack some washers and get a longer bolt or do you have to fab up something more solid? I was thinking about something like that on mine but wasn't sure how it would look.

 

just 3/4" box tube and longer bolts
http://www.myxj.net/tech/hoodspacers/

 

That is the usual testimony of those who vent their hoods. The LeBaron vents are the most popular.

 

I decided to create a new thread for this question...