Hood Louvers Question

[GhostDakota]

I got mine installed.. I'll get photos posted on Monday at work. They loook sweet :-D

 

[Thumpersdriver]

Excuse me for breakin into the thread here. It occours to me that the I6 would be significantly hotter on the Intake/exhaust (Driver) Side of the engine compartment. Should this make a difference in placement/size of ones chosen scoops and/or louverplates?

 

[chrslefty]

^^^^ Um, what the hell is THAT? ^^^^

thats funny ! i tought the same thing when i saw it : )

 

[Gojeep]

Also here for more on placement but sounds like it may be too late already?
http://go.jeep-xj.info/HowtoBonnet260ZVents.htm

 

[nhrocker]

Also here for more on placement but sounds like it may be too late already?
http://go.jeep-xj.info/HowtoBonnet260ZVents.htm

It's not too late for others searching. Thanks for the link!

I need to get some more air moving under my hood, I managed to block quite a bit of airflow with a Donaldson air filter housing.

 

[GhostDakota]

Too late for me, yes... but the search feature is a great tool like NH said.

Long story short for anyone searching: If you want your engine to be cool while wheeling, put it in the rear 1/3 of your hood. If you want it to be cool while driving 40+ MPH, put it in the front 1/3 of your hood.

 

[GhostDakota]

Two quick photos I snapped of 'em after they were finished being installed:

 

[XJ4PLAY]

Too late for me, yes... but the search feature is a great tool like NH said.

Long story short for anyone searching: If you want your engine to be cool while wheeling, put it in the rear 1/3 of your hood. If you want it to be cool while driving 40+ MPH, put it in the front 1/3 of your hood.

So if you install both is it effective for both, or does the effect only work for either front or back by itself?

 

[Sniggs]

"Get this baby up to 88mph, you're going to see some SERIOUS SHIT!"
:laugh:

 

[MogifiedXJ]

"Get this baby up to 88mph, you're going to see some SERIOUS SHIT!"
:laugh:

Perhaps one of these would work better...

 

[53guy]

you'd get good ventelation with something like that. I don't know if they're rated for huricane force winds though!

 

[Boghog1]

So if you install both is it effective for both, or does the effect only work for either front or back by itself?

I don't know that I agree with the front vs rear. but to each his own, you don't get much slower than being parked in the driveway and by putting my vents up front, the radiator now runs cooler which in turn would make the engine run cooler, when you put them in the rear 1/3 you are putting them in an area that gets high pressure by the windshield. so now that high pressure will try to go to an area of low pressure e.g. the engine compartment through your vents. this would thereby cause a limited flow through your radiator at high speeds. ask those that have installed cowl induction hoods, you will find that some have developed overheating issues when at speed. I feel that the front third is best but have no scientific proof, and after reading go-jeeps site about this he does not appear to have it either. Maybe this is a job for mythbusters.

 

[GhostDakota]

I don't know that I agree with the front vs rear. but to each his own, you don't get much slower than being parked in the driveway and by putting my vents up front, the radiator now runs cooler which in turn would make the engine run cooler, when you put them in the rear 1/3 you are putting them in an area that gets high pressure by the windshield. so now that high pressure will try to go to an area of low pressure e.g. the engine compartment through your vents. this would thereby cause a limited flow through your radiator at high speeds. ask those that have installed cowl induction hoods, you will find that some have developed overheating issues when at speed. I feel that the front third is best but have no scientific proof, and after reading go-jeeps site about this he does not appear to have it either. Maybe this is a job for mythbusters.

I have no problems while driving on the highway. The times when I get closest to overheating are in traffic or while wheeling (speeds all below 10 MPH). This is the reason I put them in the rear of the hood.

 

[TiRod]

Well, I got a set of Lebarons, and it's an important issue to figure out before I go cutting a perfectly good hood. At least the paint on the vents and hood match - clear coat cracked black, more commonly know as trailer park camo.

In front, by Gojeep, lets out more heat at slow speeds. In the rear, at speed, allows cold air under the hood because of the high pressure buildup along the cowl. According to the link on heat flow CAD simulation, a high heat under the hood occurs just behind the radiator, and because of the intrusion of the block, to both sides. So it would seem best at low speeds to have them forward and to the sides. At high speeds, what happens? The airflow at the front of the hood, per Gojeeps photos, shows a lot of straightline movement over the front location. Would this act as an extractor, or block flow? Note it's not dead air, like the high pressure location at the cowl.
I see why some using a cowl induction hood see higher temps - cowl induction from the factories being sealed to the intake only seems pretty common - so rear louvers open to the engine bay may be counterproductive in some cases.
Still with me?:compwork: To sum: front louvers Ok at low speed, Ok at high speed. Rear louvers, ok at low speed, problematic at high speed. What do we see from the factory? HMMV, radiator vents vertically at 45 degress in the front, Lebarons and everybody else at the rear. Oh gee.
Maybe they were just trying to minimize the paint cracking over the turbo. At least one thing is sure - louvers can help.

As a positive contribution, the rain catchers necessary over the CPS, etc, as cautioned in other threads can be dealt with using lite aluminum turkey basting pans. Bend the edges down some, bolt or duct tape to the hood, and slam fit when you drop it. There's my contribution of ozark engineering.

Now I gotta decide where to put the louvers.

 

[GhostDakota]

What I have noticed so far with these installed:
-Highway speeds - no difference at all (this is going by my temp gauge which could be inaccurate for all I know)
-Surface streets - VERY SLIGHTLY lower temp
-Idling - TBD
-Off-road - TBD

 

[streetpirate]

cut the inner structure out of your hood, and remove the hinges. make it a full pin-on hood that you can just remove while wheeling.

 

[Michaelarchangelo]

Way back when I had a Sierra Cosworth, the hood vents were placed in the front to the sides.

 

[Boghog1]

I look at it this way, when Jeep put the vents on the 5.9 grand cherokee they probably did a lot of R&D in placement. they are on the front third, so thats where mine went.

 

[jjvande]

I look at it this way, when Jeep put the vents on the 5.9 grand cherokee they probably did a lot of R&D in placement. they are on the front third, so thats where mine went.

haha.... jeep?

 

[RichP]

With those size of vents, narrow and thin I would have considered putting them above the sport tape on the fenders. It would pull air out at hiway speeds vs the spot you put them on the hood. The closer you get to the windshield the higher the pressure forcing air into the engine compartment, nearer the front it has lower pressure. I did the washer trick and removed that rubber piece that goes across the back of the engine bay. Next day I noticed that my temps went up about 10 degrees when going to work and home at 75mph + speeds between lehigh valley and mahoning valley on the NE extension of the tpke. I've got a set of transam vents, about 2" wide and 6" long that I will get around to installing eventually.