OK, While I really don't need vents for my XJ as the thing stays cool pretty well, I've been toying with an idea for vents. Here's my concept. Keep in mind this is a work in progress.





They're shaped to fit in the opening on the underside of the hood as shown.



And, being as open as they are I'm looking to put drip trays on them something like below, but leave a 1/2 gap or so so they aren't too restrictive.



What do you guys think? Any tips for improvement? Would there be any interest in purchasing something like this? I've been working with what primitive tools I have, but I was thinking if I could sell some of these I might be able to invest in a small break and such to form and cut the pieces more professionally. Once to be sold would be higher quality (made with proper tools) than my "prototypes" in the pictures.

 

What happens to the water after it fills the drip pan?

 

Why are you putting drip trays under the vents? The vents are supposed to be open so the air can circulate through them.

 

This. I like the vents themselves, but they're pointless if you're going to just let water sit in a tray under them. It's going fill up and boil over and instead of rain hitting stuff it's going to be boiling water.

 

I'm guessing cause I'm on my phone that the bottom right corner let's the water drip to a safe place.

 

I've always been iffy on the whole hood vent thing because of water getting in. I'd rather do a nice set of scoops on the hood that don't make it look dumb. I've seen some pretty tasteful ones that I've been tempted to replicate.

 

ya, nobody else looked close enough...drip pans are there to redirect the water...not hold it and boil it...sheesh.

 

I like it. Not sure about the placement though. I normally see vents towards the back of the engine, the back of head is generally the hottest part of the engine.

 

Yeah, I'll admit I missed it completely. Doesn't change the fact that it's blocking air flow which defeats the point of the vent.

 

This. The idea is to have the air flow travel thru the entire engine bay before exiting at the back, allowing for a more efficient airflow. Set it up to be near the rear of the hood and you'll be on to somethin. Also, water does not seem to be an issue, even without a drip pan. Dialectic grease stuff if your worried.

 

And this.

 

I don't knock anything and am up for all ideas but I give you my thought. Air pushes thru the grill in the front. If vents go in the front you won't be getting a chance to let the hot air out like you would if they were in the back. As soon as I start my jeep I can feel it forcing air out my vents at the back. Second, vents in the back should have a drip pan because were they are located could interfere with certain things. Vents in the vent where you have them doesn't have much need for the pan. There's not much there that should hurt. I don't have any drip pans on mine and I took it to the car wash today. Like I say, not meaning anything negative by it because I like it when people have original ideas but I just wanted to try to help may looking a little closer at the design.

 

I think they look sweet. Vents to the front are suppose to help more at higher speeds I guess. How much do you think you have into the vents?

 

Sorry for the late response, I've been out of town on a camping trip for the weekend.

The drip pans would be optional. My thoughts are to place them so that there's at least about a half inch or so gap between them and the vent to allow air flow. They way they are they have to be tilted inboard so that the water will drain between the battery and the A/C compressor on the passenger side, and between the air box and power steering pump on the driver side. This angle will open the gap up quite a bit on the inboard side since the hood is sloped outward. With the vents located where they are I want the drip pans to keep rain and snow from getting directly on the battery and air box and either sucking into the intake or freezing up on the battery.

The location is intentional. At any speed there is a high pressure zone at the base of the windshield that would want to push air into the hood instead of creating a vacuum to pull the hot air out. The front of the hood has a vacuum that will help draw air out of the hood. At low speed my thought with this is that the coolant system takes the head from the engine and dissipates it through the radiator. If the vents are in the front of the hood directly behind the radiator as I've placed them here the heat can easily escape. The idea is to make the cooling system run more efficiently. While vents in the rear are to let the trapped hot air out, I think it's less efficient. Think of it this way. The engine creates heat. It's a water cooled engine so probably 95% of the heat is dissipated through the radiator. The other 5% would be transferred to the air from the block directly. Now when the hood vents are in the back, the heat starts in the engine, transfers to the air, gets blown back past the engine heating it again, before being allowed to escape out the vents.

I run the rubber mat thing under the radiator to keep slashing of the alternator to a minimum and that also reduces the heat transfer efficiency because the hot air can't get blown down the bottom of the engine bay as easily. The placement of the vents in the front is to allow the air that passes through the radiator an easy and direct route out of the engine bay with out having to pass by the engine first.

 

I think they also can work better at low speeds also by allowing the radiator to do it's job more efficiently. I've spent about $40 on materials so far, but that's also including most of the SS hardware I need to mount them, and also including my dinking around making templates, screwing up parts etc. lol.