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Do Cowl Hoods cool down our engine bay?

Burt4x4

Burt4x4

1 Ton First Gen
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California (Modesto area)
I don't necessarily have a cooling issue I'm just thinking of getting a 2" cowl hood in the near future. My K5's sheetmetal is "used" so this is not for good looks, though they do look cool on some rigs. Also 500 bucks plus shipping from what I have seen online..:thinking:

Do they Work? I assume more air must be able to flow/escape with a cowl. Does the engine notice? :confused:

Burt
 
I don't think you'd ever notice any difference. If you like the look, go for it, but it won't change performance in any way.
 
I put a cowl hood on my 454 and noticed it right away. The temp gauge sits lower, you can feel the hot air with your hand if you stick it up there. And if I leave my truck idle full of snow the first area to melt off is that area behind the cowl.

My temp gauge isn't precise enough to know if its 10/20/30 or whatever. But they definitely help.


Back in the day the old hot rodders with muscle cars would shim the hood hinges so the hood would sit higher in the back and allow air to escape .
 
ashman said:
I don't think you'd ever notice any difference. If you like the look, go for it, but it won't change performance in any way.
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Do you have one and didn't see a noticeable difference?
 
beags86 said:
I put a cowl hood on my 454 and noticed it right away. The temp gauge sits lower, you can feel the hot air with your hand if you stick it up there. And if I leave my truck idle full of snow the first area to melt off is that area behind the cowl.

My temp gauge isn't precise enough to know if its 10/20/30 or whatever. But they definitely help.


Back in the day the old hot rodders with muscle cars would shim the hood hinges so the hood would sit higher in the back and allow air to escape .
Click to expand...

Real world experience. VW guys always have the hoods spaced.
Or be like No hood! @Deuling
 
beags86 said:
Do you have one and didn't see a noticeable difference?
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Not on a blazer, but on a camaro. Didn't notice a difference. Not saying there was none, just not noticable.

If you're having an issue, it may help some but if not, it's just for looks.
 
ashman said:
Not on a blazer, but on a camaro. Didn't notice a difference. Not saying there was none, just not noticable.

If you're having an issue, it may help some but if not, it's just for looks.
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I have one my stepside with a 350.
I bought the truck like that so I don't have a before to compare it to. But I always wondered if it made a bigger difference on a bigger engine.
Bigger engine physically, More heat. Seems to make logical sense, but I'm not sure if it translates into the real world.
 
Swapped efi onto my buddies 70 Camaro. It has a cowl hood. Started with a plain open air cleaner. Did a bunch of base plate swapping. Added a k&n x flow filter top and stuffed the air cleaner as close as possible to the top of the hood. Marginally cooler air temp at idle. Rolling down the road, it will run within 10° of ambient temp. Made a major difference.
 
Absolutely makes a difference since it allows the hot air to escape (up and out) after its pulled in through the grill. Same can be said about hood louvers.
 
Removes heat until you are at speed. The cowl area becomes high pressure at speed. The air actually flows into the raised section. That is why the cowl induction became big. Fresh cool air that can be drawn into the intake....
 
Topp_rolmc said:
Removes heat until you are at speed. The cowl area becomes high pressure at speed. The air actually flows into the raised section. That is why the cowl induction became big. Fresh cool air that can be drawn into the intake....
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Yep. I'll leave my truck sit outside in my back driveway under a tree and leafs will collect on the back side of the cowl, when I get up to speed they get sucked onto the grill of the cowl and can literally see the pulling effect taking place. Its wicked.
 
Right On! Thanks for all the replies and opinions! My 454 runs about 198* under normal load (driving around town). 210* (if memory serves) when wheeling down the trail in summer. I think I need more air flow. I thought about the shimmed rear trick but that not so pleasing to the eye. And cutting into my existing hood but....arrggg
Thanks again and if any leads on 69-72 2" cowl hood be sure to ping me ok :-) My OEM hood has zero dents and the inside is coated with black POR-15 << that stuff is great! I coated it in 2005 and it still has a shine to it. Dries like ceramic :saweet:

ANYWAY!!
Thanks again and Happy Trails!:pimp:
Burt :waytogo:
 
Huge difference on my k5 going from stock to cowl hood. My proflo 4 gives you the inlet air temp as well as coolant temp and both dropped drastically with the new hood. Dont even need my fans now unless I'm sitting. Thing used to be around 170 no fans driving now it won't get over 160 my whole cooling system is just overkill right now
 
nmxhustla said:
Huge difference on my k5 going from stock to cowl hood. My proflo 4 gives you the inlet air temp as well as coolant temp and both dropped drastically with the new hood. Dont even need my fans now unless I'm sitting. Thing used to be around 170 no fans driving now it won't get over 160 my whole cooling system is just overkill right now
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160 is way to cool. You won't even burn the moisture out of the oil
 
nmxhustla said:
Huge difference on my k5 going from stock to cowl hood. My proflo 4 gives you the inlet air temp as well as coolant temp and both dropped drastically with the new hood. Dont even need my fans now unless I'm sitting. Thing used to be around 170 no fans driving now it won't get over 160 my whole cooling system is just overkill right now
Click to expand...
I have Edlebrock Pro-Flo also, it's the 2005 model w/hand held "brick" control module, duno what version that makes it? So I too can see air intake temp. Good tip on what to look at down the road when the swap has been done. :waytogo:
Thanks
Burt
 
At low/slow speeds I could see the heat having an escape path, I used to see that on the ram air 'scoops' on my 67 firebird. But at higher speeds the cowl area becomes a high pressure zone (hence the purpose of cowl induction) and will end up forcing air into the engine bay, maybe possibly fighting air from the grill.

I have not seen any studies on this, but it would be interesting to test w/ a yarn tuft test.
 
Topp_rolmc said:
160 is way to cool. You won't even burn the moisture out of the oil
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He's probably reading the coolant temp at the intake manifold. My BBC will be at 175 on the intake manifold and 205 at the head crawling down the trail.
 
skunked said:
He's probably reading the coolant temp at the intake manifold. My BBC will be at 175 on the intake manifold and 205 at the head crawling down the trail.
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Got two gages for Coolant temp 1 on the intake came with the pro flo, then the stock bbc one. Both stay petty damn close. Got a huge radiator so that's probably part of the problem.
 
Topp_rolmc said:
160 is way to cool. You won't even burn the moisture out of the oil
Click to expand...
Yeah it's pretty cool but it gets so damn hot in NC i had to do the overkill cooling system and now that it's cold it's too cool. I just let it run a while when I get places until it creeps past 180.
 
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