Cooling efficiency of different hoods?

[domingjm]

I put a Rubicon hood on the Sport S that I previously owned. It needed the vents and rather than put on the plastic ones, I used the Poison Spyder functional vents for the Rubicon hood. They worked well and you could see heat come out from under the hood. Only issue I could see is that rain and snow could get under the hood as they are open. I live in AZ where we don't get much rain and less snow!

https://shop.poisonspyder.com/JT-JL-Rubicon-Hood-Louver-Black-PC-p/19-53-012p1.htm

Were you able to make any quantitative comparisons before and after?

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[kickingaz]

Were you able to make any quantitative comparisons before and after?

I did not as it was not as much of a cooling issue on my 3.6, but it is an option I am considering for my 3.0 with AZ temps on the 115 range lately.

 

[kickingaz]

the main question is if your engine is overheating in the first place? i drive my sport s in 114 degrees and the engine stays rock solid on temps.

if not why change the air flow which could actually affect the cooling oddly enough. the 392 is different because the engine is different. when you put vents in you will alter the intended and designed cooling air pattern over the engine and it may or may not be good. second you can open your engine to rain, snow etc going right into the vents. engineers do a lot of work with design.

My 2021 Gladiator is a diesel 3.0. If you look at the forums for these there are multiple posts about heat issues and Jeep not providing any solutions.

 

[Snake Eyes]

My 2021 Gladiator is a diesel 3.0. If you look at the forums for these there are multiple posts about heat issues and Jeep not providing any solutions.

true. i was not thinking about the diesel. hood vents might still not be the best idea. it boils down to where the heat comes from. there are exhaust wraps, coatings, thermal barriers, etc to truly help keep things cooler… a lot of things outside of vents. ina.. honesty, many people get vented hoods just cause they look cool. they pay absolutely no attention to even vent placement which is important.

 

[kickingaz]

true. i was not thinking about the diesel. hood vents might still not be the best idea. it boils down to where the heat comes from. there are exhaust wraps, coatings, etc to help keep things cooler… a lot of things outside of vents.

I have only had this diesel Gladiator for less than a month, but I am aware of the issue and AZ is probably one of the worst places for a vehicle with heat issues. Jeep puts a few "pads" on the engine to deaden the sound and make it a quiet diesel. These will be removed as they hold a lot of heat in the engine and engine compartment. I will also do a fender chop and replace the inner fenders with aftermarket, likely DV8 as they seem to have a perforated inner fender. That and the Poison Spyder hood vents should allow a lot of heat to escape that is currently trapped under the hood. My choice of a front bumper was also driven by this issue as I wanted to select one that has a recessed winch mount in an effort to keep the entire grill area open.

 

[Kevlarr]

Why not just cut the inside of the Rubi vents to allow airflow?? Thats what I did

K

 

[NachoRuby]

Why not just cut the inside of the Rubi vents to allow airflow?? Thats what I did

K

What I find interesting about the hood vents is that on my wife's JKU, the vents are somewhat functional. They have an opening on the bottom. On my gladiator, they are completely sealed underneath, from what I can tell, and the under hood insulation thing covers them. On the JKU, The underhood insulation has a cutout in that area. Not sure why they made the change, but I feel like there had to be an engineering reason.

 

[kickingaz]

Why not just cut the inside of the Rubi vents to allow airflow?? Thats what I did

K

That is an option, but I am not sure they are designed to be functional. the Poison Spyder ones I used in the past are metal, have no bottom, and I could see the air coming up in cold weather at an idea. As you may recall from my first post, I needed vents for a prior hood and I did not have the plastic OEM ones in the hood. There was not much cost difference between the Poison Spyder metal functional vents vs. the OEM fake vents.

 

[Kevlarr]

" I am not sure they are designed to be functional." They weren't but they are now. In my humble opinion people tend to over think these things. It's not RamAir for racing... It's a hole in the hood that will let heat out. Hot air rises... If It doesn't work for some reason I'll order two new ones from the factory and replace these...

 

[CerOf]

So, Jeep engineers were tasked with making the diesel possible with the highest tow retina possible. If functional hood vents did anything, they would have done them.

One thing the jalopnik article said was, the air had to be funneled/routed through the grill for there to be true cooling of the coolant/oil.

Hood vents would allow heat to escape, sure, but might actually hurt the flow of air through the grill itself.

I’d be careful with opening things up without computer flow testing or wind tunnnel testing. You’ll like must be throwing $$ at it and could make things worse.

PS we have the Colorado diesel beat. They’re stuck at 5k towing.

 

[kickingaz]

So, Jeep engineers were tasked with making the diesel possible with the highest tow retina possible. If functional hood vents did anything, they would have done them.

One thing the jalopnik article said was, the air had to be funneled/routed through the grill for there to be true cooling of the coolant/oil.

Hood vents would allow heat to escape, sure, but might actually hurt the flow of air through the grill itself.

I’d be careful with opening things up without computer flow testing or wind tunnnel testing. You’ll like must be throwing $$ at it and could make things worse.

PS we have the Colorado diesel beat. They’re stuck at 5k towing.

My understanding is that there have to run hotter to ease emissions. There are quite a few issues with these having power derating issues. I am not an engineer, but this issues all seems to be tied to the heat under the hood. Complicate that with the hundred-and-teen temperatures we frequently see in AZ during the summer and it could be an issue here. Jeep, like other manufacturers, will put out a product without it being 100% effective in all areas or all conditions. I bought this knowing there "could" be issues but wanted to take advantage of the 25 MPG I get with this (traded a Raptor).

 

[MPMB]

So, Jeep engineers were tasked with making the diesel possible with the highest tow retina possible. If functional hood vents did anything, they would have done them.

One thing the jalopnik article said was, the air had to be funneled/routed through the grill for there to be true cooling of the coolant/oil.

Correct; air forced through the radiator cools the fluids. A bigger radiator and/or heat exchanger is the best mechanical improvement. "Room" is a problem they don't want to solve.

Hood vents would allow heat to escape, sure, but might actually hurt the flow of air through the grill itself.

I’d be careful with opening things up without computer flow testing or wind tunnnel testing. You’ll like must be throwing $$ at it and could make things worse.

No, that's not how air works. It doesn't turn around. The "vents" on the hood are well past the break over point of the hood. If anything, an air pocket forms above that part of the hood back to the window. I have an bug shield on the front of my hood that affects the air as I have a definitive line across the window when it rains or snows. The airflow going over the hood and roof would suck air out from under the hood, which would end up pulling more air through the front. Like the original Ford GT-40.

Venting the hood would aid in heat dissipation, not actual cooling.

PS we have the Colorado diesel beat. They’re stuck at 5k towing.

The Colorado diesel is 7700/7600# iirc. I believe the ZR2 one is what you are referring to. And I haven't heard any cooling issues from the Chevy camp.

 

[@californiajeeping]

Hood vents are not going to fix your oil temps which is whats causing a derate.

Take your hood off and your oil temps wont go down. Parts surrounding the engine will probably last longer but your not changing the airflow to the radiator or coolers. The fan is pulling a 40mph wind through the engine bay that goes down and out. Fender liners that are vented most likely help a bit and a hood vent help but again that just affects the temps on the components under the hood not the engine block oil pan heads and turbo that are being baked by a 1400 degree over internally

 

[Akgladiator]

So, Jeep engineers were tasked with making the diesel possible with the highest tow retina possible. If functional hood vents did anything, they would have done them.

One thing the jalopnik article said was, the air had to be funneled/routed through the grill for there to be true cooling of the coolant/oil.

Hood vents would allow heat to escape, sure, but might actually hurt the flow of air through the grill itself.

I’d be careful with opening things up without computer flow testing or wind tunnnel testing. You’ll like must be throwing $$ at it and could make things worse.

PS we have the Colorado diesel beat. They’re stuck at 5k towing.

I dont think jeep wants spend extra money to make a vented hood for diesel gladiators. Cost vs profit!

A well design vented hood will vent heat and help with aerodynamic of the vehicle. Look at touring car racing, your answer is there!

 

[CerOf]

I dont think jeep wants spend extra money to make a vented hood for diesel gladiators. Cost vs profit!

A well design vented hood will vent heat and help with aerodynamic of the vehicle. Look at touring car racing, your answer is there!

Well, the rubicon hood is 90% there, so I don’t think $ is the reason.

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