Vent Rear of the Hood

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SpeedThrills

SpeedThrills

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I have a lift-off glass hood. I'm thinking of venting under hood heat by raising the back of the hood a bit. Has anyone tested this? There's no cowl seal, so maybe it won't matter much? I know they used to look for that seal on Stock Eliminator cars. I guess "forgetting" to install it helped.
 
The base of the windshield is actually a high pressure zone. Open the under dash vents air comes in.


Lifting the back of the hood might change that?

But you also might be pushing engine smells / exhost fumes I to the car?


Not saying it's a good or bad idea just thinking through the what ifs
 
I've got a lift off 6 pack hood on my Satellite. My pins on the rear are adjusted so that there is some clearance between the clips and the scuff plates. At rest , the hood sits even with the fenders in terms of height. At speed , the back of the hood "floats".
 
Did that in the 60's-70's. Common practice. On my 67 Dart had to do that because the air cleaner was rubbing the hood frame.
Does it help ? can't say for sure. Does vent under hood temps.
 
Something I have been toying with, what is the greatest source of heat in the engine compartment? The headers or manifolds. 600+ degrees, isn’t it easier to just keep the heat in the exhaust stream, at least until it’s under the car. Thermal Ceramic coating inside and out the headers or manifolds.
 
forphorty said:
I've got a lift off 6 pack hood on my Satellite. My pins on the rear are adjusted so that there is some clearance between the clips and the scuff plates. At rest , the hood sits even with the fenders in terms of height. At speed , the back of the hood "floats".
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That's a great idea! I didn't really want it raised at rest. I just adjusted mine. I had about an extra inch of adjustment. I can also move the pin brackets up some, and/or make longer brackets.
I'll have to use a hairpin type clip. The ones I have turn sideways and look like they'll prevent it from lifting.

Before:
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After:
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Dana67Dart said:
The base of the windshield is actually a high pressure zone. Open the under dash vents air comes in.


Lifting the back of the hood might change that?

But you also might be pushing engine smells / exhost fumes I to the car?


Not saying it's a good or bad idea just thinking through the what ifs
Click to expand...
Yes, I'm aware of the high pressure zone. One reason that I want to do it. I don't know if the under hood pressure will be greater.
I'm not worried about fumes, it's mostly a track car. But with forphorty's idea, it should only lift at speed.
furrystump said:
Something I have been toying with, what is the greatest source of heat in the engine compartment? The headers or manifolds. 600+ degrees, isn’t it easier to just keep the heat in the exhaust stream, at least until it’s under the car. Thermal Ceramic coating inside and out the headers or manifolds.
Click to expand...
I agree, a lot of it is about heat. Coatings are out of my budget. Wraps are a mess. I currently have an open element air cleaner. I'm saving my money to get a cold air set up like Spectre or RamAirBox.
Part of the reason I want to vent the hood, other than to cool under hood temps, is to maybe relieve under hood pressure that could allow mph to increase?
So maybe the combination of the two (cold air and venting), will be better than one or the other.
 
My $10 ram air. Cordoba air filter and the tube was from a Dodge Omni.
Not pretty but really worked.

IMG_0434.jpg
 
Darter6 said:
Did that in the 60's-70's. Common practice. On my 67 Dart had to do that because the air cleaner was rubbing the hood frame.
Does it help ? can't say for sure. Does vent under hood temps.
Click to expand...
Did that also on my 71 Nova and 72 V8 Vega. On the Vega I just had to pop the hood and leave it hooked on the safety latch because it opened at the windshield. Like you said, a very common practice back then. :thumbsup:
 
oldkimmer said:
Search cowl induction for your answer. Lots of Chevies had it. Kim
Click to expand...
Thanks Kim. Yes, I am well aware of Chevys cowl induction. Two things with this car I’m working on, I don’t want a scoop of any kind (it’s a street/strip car), and I definitely don’t want a Chevy scoop!
 
put gills in the fenders like the early E bodys,...70s Z28 and trans am's!! that help reduce under hood pressure lot more than cracking hood at the highest pressure point on the car will!
 
I just took a test ride trying out my "floating hood". Works great! Thank you @forphorty !!

I made longer mounting brackets for the rear pins and shortened the bump stops accordingly. I filed the holes in the hood bigger so that it floats without restriction. I also changed the type of clip, because what I had (post 6) would've turned sideways and limited the amount of float.

One thing I thought of while driving; if I were doing it to help cooling in stop and go traffic, I would have it float full-time. But this car is just a cruiser and strip car. As is, it starts rising at about 37 mph, and is firmly against the pins at about 48. Sometime, I'll test it at the track with it pinned tight, and then floating, to see if there's anything measurable.
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Are you using a PC or a phone, if phone apple or Android
 
Can you see pics in post 6?
I'm doing what I always do: email pics from my Apple phone to my Chromebook, copy and paste from my email to the thread. I can see them on the thread on my phone, and Chromebook thread.
I'll get back tomorrow. Bedtime!
 
Now if you reverse the pin lengths front to rear you have a full width air grabber hood :rolleyes:
 
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In the book "We Were The RamChargers" Tom Hoover stated that the 65 Hemi hood scoop
did little as far as engine performance.But it sure helped with under hood temperatures.

IMG_2731.jpg
 
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