98' functional stock hood vent?

[amf201091]

Has anyone ever cut out the hood vents on their stock hood? I was contemplating on doing this since I've never seen it.

 

[white95]

If you want to, go for it. However, you won’t benefit much, if any, from doing so. If you’re looking to lessen engine compartment temps, I’d suggest something along the lines of a heat extraction hood.

 

[TrickVert]

Whoops.

 

[TrickVert]

I drilled a 1" or so hole under each one, but know it has little to no effect. Even opened up all the way, those vents would provide tiny holes with respect to the amount of air that needs to escape from under the hood. White95 is correct. A heat-extractor hood (or installing Terminator vents) is the only real option for reducing under-hood temps.

PS: Don't bother removing the rear weatherstripping on the firewall. That also does little/nothing.

 

[Monsterbishi]

The first problem is that they're located in a high pressure area, the amount of force means little to no air can escape from the engine bay which is considerably lower pressure.

The second problem is that they're located in front of the windshield, if your engine lunches itself, all and any smoke/oil/etc will then have a way to end up blocking your visibility.

If you want to bring underhood temps down significantly, wrap/coat the exhaust, block, heads & intake manifold, relocate your oil coolers to outside the engine bay, and reduce your underbody pressure as much as possible.

 

[ttocs]

I know I read somewhere at some time that they were designed to work by a physics property called the venturi effect. It creates suction by air passing over a hole which then sucks the hot air out of the bay. Its used more often in airplanes to cool engine bays because it doesn't create drag like a big scoop does. If you look at the bottom of the hood under the fire blanket you will see a series of holes along the back of the hood to allow the air to get sucked up into the void. I can't prove this but it always made sense to me.

 

[evilcw311]

If ya wanna cool you need something like this...................

That’s with the vents taken out. I’ve got pics somewhere that I can possibly find with them in. I noticed a lot better temps once I got my hood.


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[waynenorcross]

If you want to, go for it. However, you won’t benefit much, if any, from doing so. If you’re looking to lessen engine compartment temps, I’d suggest something along the lines of a heat extraction hood.

 

[waynenorcross]

Just remove the rubber gasket at the back of the hood where it meets the cowl when closed. That will give you an opening one inch by the width of the hood. Somebody took a before and after underhood measurement while open tracking and this free upgrade lowered the temp by ten degrees

 

[TrickVert]

Just remove the rubber gasket at the back of the hood where it meets the cowl when closed. That will give you an opening one inch by the width of the hood. Somebody took a before and after underhood measurement while open tracking and this free upgrade lowered the temp by ten degrees

I'd like to hear from this "somebody," and see their measurements. I removed the weatherstrip (thinking the same thing), placed a thermocouple above this point, and the air remained at ambient temperature. The area in front of the windshield is a high-pressure zone, so air isn't escaping from under the hood.

 

[waynenorcross]

I know I read somewhere at some time that they were designed to work by a physics property called the venturi effect. It creates suction by air passing over a hole which then sucks the hot air out of the bay. Its used more often in airplanes to cool engine bays because it doesn't create drag like a big scoop does. If you look at the bottom of the hood under the fire blanket you will see a series of holes along the back of the hood to allow the air to get sucked up into the void. I can't prove this but it always made sense to me.

You are talking about NACA vents.

 

[ttocs]

You are talking about NACA vents.

exactly. To make them really functional they need to be deeper but the stock hood is a similar design. Realistically just blowing air across the opening will create a vacuum just like is shown in this vid.

 

[waynenorcross]

I'd like to hear from this "somebody," and see their measurements. I removed the weatherstrip (thinking the same thing), placed a thermocouple above this point, and the air remained at ambient temperature. The area in front of the windshield is a high-pressure zone, so air isn't escaping from under the hood.

 

[waynenorcross]

I'd like to hear from this "somebody," and see their measurements. I removed the weatherstrip (thinking the same thing), placed a thermocouple above this point, and the air remained at ambient temperature. The area in front of the windshield is a high-pressure zone, so air isn't escaping from under the hood.

I wish I could remember his name. He was a local autocrosser and mechanical mechanical engineer who worked with me at GE. He was friends with Bruce Griggs and would use his Terminator Cobra as a test mule for new Griggs parts and helped me sort out my suspension.

 

[waynenorcross]

I wish I could remember his name. He was a local autocrosser and mechanical mechanical engineer who worked with me at GE. He was friends with Bruce Griggs and would use his Terminator Cobra as a test mule for new Griggs parts and helped me sort out my suspension.

I am not sure where you placed your thermocouple.

 

[TrickVert]

I am not sure where you placed your thermocouple.

Just behind the trailing edge of the hood.