Hood question
Bio}{azard
10-20-2006, 01:40 AM
I have a Cowl-induction hood on my vega right now, and would like to know the principle behind the hood, does it let air in, or out? And if it lets air in, what kind of hood should I look for that lets it out?
TheSilentChamber
10-20-2006, 07:20 AM
They're mainly just for clearance for taller carbs/filters, but some logic on the induction could come from the fact that a point of high pressure is usually at the base of the windshield.
curtis73
10-20-2006, 04:17 PM
Yes, cowl induction works by letting air IN. There is an area of high pressure at the base of the windshield.
There is probably not anywhere on your hood that you could use to let air OUT, since there is a huge area of low pressure under the car. Air is being sucked out of the engine compartment and completely replaced every few seconds anyway.
Why do you ask?
There is probably not anywhere on your hood that you could use to let air OUT, since there is a huge area of low pressure under the car. Air is being sucked out of the engine compartment and completely replaced every few seconds anyway.
Why do you ask?
Bio}{azard
10-20-2006, 06:44 PM
Our radiator doesn't seem to be working as well as we need at the moment (210 degrees in 50-60* weather), and can't get a bigger one, so might as well ask about what we can to cool it by other means.
curtis73
10-21-2006, 12:57 AM
tell us more about the setup; stock? souped up? electric fans or belt? engine, year, mileage, etc.
Cooling issues are almost always a simple fix, so lets rule out the obvious stuff before adding more airflow.
keep in mind, too, that adding airflow down through the hood will reduce airflow through the radiator and could make things worse. Since almost anywhere on the hood is higher pressure, you'll almost always be removing airflow (a little) from the radiator.
Cooling issues are almost always a simple fix, so lets rule out the obvious stuff before adding more airflow.
keep in mind, too, that adding airflow down through the hood will reduce airflow through the radiator and could make things worse. Since almost anywhere on the hood is higher pressure, you'll almost always be removing airflow (a little) from the radiator.
Bio}{azard
10-21-2006, 01:59 AM
'74 Vega, '77 231 Buick V6
New cam,
High compression pistons
Four barrel intake manifold
Edlebrock carburator
Single core alluminum radiatior
and duel electric fans
6 months old but it looks like this
http://img.photobucket.com/albums/v601/Biohhazard/Engine.jpg
New cam,
High compression pistons
Four barrel intake manifold
Edlebrock carburator
Single core alluminum radiatior
and duel electric fans
6 months old but it looks like this
http://img.photobucket.com/albums/v601/Biohhazard/Engine.jpg
UncleBob
10-21-2006, 03:33 AM
Get a fan shrowd on that thing. That'll double your cooling effeciency right there.
That is the most common grevious error people make on cars. Fan shrowds are extremely important for air flow over the radiator.
That is the most common grevious error people make on cars. Fan shrowds are extremely important for air flow over the radiator.
Bio}{azard
10-21-2006, 12:40 PM
Remember, that pic is old, and we now have duel Electric fan and a single core radiator.
Moppie
10-21-2006, 03:40 PM
Remember, that pic is old, and we now have duel Electric fan and a single core radiator.
Can you show a pic of that set up?
Are the fans shrouded?
And, does the new single core offer as much surface area as the old one?
Iv seen a few cases were people have replaced an old multicore steel radiator with a new single core all flash and shiny aluminuim one, added lots of fans, and then discovered that the car over heats.
Usualy because all the fans they added to the back inhibbit air flow, or the radiator is to big for the front of the car, and there isn't airflow right accross its front face.
Usualy going back to a smaller multicore radiator solves the problem, as all its surface area is then expose to air flow.
Can you show a pic of that set up?
Are the fans shrouded?
And, does the new single core offer as much surface area as the old one?
Iv seen a few cases were people have replaced an old multicore steel radiator with a new single core all flash and shiny aluminuim one, added lots of fans, and then discovered that the car over heats.
Usualy because all the fans they added to the back inhibbit air flow, or the radiator is to big for the front of the car, and there isn't airflow right accross its front face.
Usualy going back to a smaller multicore radiator solves the problem, as all its surface area is then expose to air flow.
TheSilentChamber
10-21-2006, 04:48 PM
Steel radiator eh?
curtis73
10-21-2006, 05:04 PM
I don't mean to offend, but I always get a kick out of people who say things like high compression, electric fans, and single row radiator in the same setup.
You need at least a dual core radiator, ditch the electric fans, and how much compression are we talking about?
The electric fans don't move enough air, period. If you are GM with a million dollar R&D budget designing an electric fan to cool a 200-hp stocker, that's different. Then at highway speeds they block more air than they move. Think about it; you took off a belt fan that takes as much as 13 hp to drive and replaced it with twin 1/8 hp motors.
You need at least a dual core radiator, ditch the electric fans, and how much compression are we talking about?
The electric fans don't move enough air, period. If you are GM with a million dollar R&D budget designing an electric fan to cool a 200-hp stocker, that's different. Then at highway speeds they block more air than they move. Think about it; you took off a belt fan that takes as much as 13 hp to drive and replaced it with twin 1/8 hp motors.
Moppie
10-21-2006, 06:05 PM
Steel radiator eh?
Ok, then, steel frame, top and bottom tanks, with copper fins, all covered in black paint. Feel better?
Ok, then, steel frame, top and bottom tanks, with copper fins, all covered in black paint. Feel better?
Moppie
10-21-2006, 06:16 PM
Think about it; you took off a belt fan that takes as much as 13 hp to drive and replaced it with twin 1/8 hp motors.
Hmmm, except that belt driven fan used 13hp because of its very ineffcieant design, and while the little electric motors might use less power, they still flow more air at low speed, and when stopped.
A radiator fan is only of any use when the car is stopped, or running at very low speed. Above about 30-40mph they start to become completly useless, and at 60mph they do nothing, if of a poor blade design will infact hamper air flow.
At low speed a belt driven fan dosn't realy move a lot of air because its speed is tied into engine speed. Over gear it to make it more effective and at high engine RPM it ends up turning at dangerous speeds, or simply puts to much resistance on the system.
An electric fan is not worried about engine speed, and so can provide excellent air flow when the vechile is stationary. HOWEVER, a cheap fan is a waste of time, it needs to be a high quality one, and it needs to have a blade design that is able to spin freely in the air flow at speeds above 60mph, or else it will rstrict air flow to much. Also, the thermostat that turns the fan on and off, should be set to come on a little higher than the engines operating temp at speed, so the fan motor is turned off and dosn't inhibbit air flow at high speed.
Usualy when useing electric fans you only cover half the radiator with the fan, and its usualy a fan that is just big enough to cool the engine when the vechile is stationary.
Leave as much as a radiator exposed to free airflow as possible, and let that do the cooling job when traveling at speed.
The radiator needs to be just big enough to fill the open space behind the grill. A bigger radiator won't do anything if its extra surface area is hidden behind body structure, or bumper parts, or headlights etc.
In most cars a smaller 2 or 3 core will cool better than a single core thats twice as big.
Hmmm, except that belt driven fan used 13hp because of its very ineffcieant design, and while the little electric motors might use less power, they still flow more air at low speed, and when stopped.
A radiator fan is only of any use when the car is stopped, or running at very low speed. Above about 30-40mph they start to become completly useless, and at 60mph they do nothing, if of a poor blade design will infact hamper air flow.
At low speed a belt driven fan dosn't realy move a lot of air because its speed is tied into engine speed. Over gear it to make it more effective and at high engine RPM it ends up turning at dangerous speeds, or simply puts to much resistance on the system.
An electric fan is not worried about engine speed, and so can provide excellent air flow when the vechile is stationary. HOWEVER, a cheap fan is a waste of time, it needs to be a high quality one, and it needs to have a blade design that is able to spin freely in the air flow at speeds above 60mph, or else it will rstrict air flow to much. Also, the thermostat that turns the fan on and off, should be set to come on a little higher than the engines operating temp at speed, so the fan motor is turned off and dosn't inhibbit air flow at high speed.
Usualy when useing electric fans you only cover half the radiator with the fan, and its usualy a fan that is just big enough to cool the engine when the vechile is stationary.
Leave as much as a radiator exposed to free airflow as possible, and let that do the cooling job when traveling at speed.
The radiator needs to be just big enough to fill the open space behind the grill. A bigger radiator won't do anything if its extra surface area is hidden behind body structure, or bumper parts, or headlights etc.
In most cars a smaller 2 or 3 core will cool better than a single core thats twice as big.
GreyGoose006
10-21-2006, 10:58 PM
^^^
well put.
well put.
curtis73
10-23-2006, 02:01 AM
An electric fan is not worried about engine speed, and so can provide excellent air flow when the vechile is stationary. HOWEVER, a cheap fan is a waste of time, it needs to be a high quality one,
I agree with that completely, but we don't know if his problems are stationary or moving.
Typically if its hot on the highway with electric fans, I blame the fans for blocking airflow. If its hot while stationary (where electric fans do their best work) I suspect not enough fan.
Either way in this case, I feel strongly that its the electric fans. When someone says "overheat" and "electric fan" in the same sentence its almost always the culprit. Either they're restricting air flow on the highway, or they're not providing enough flow while stationary.
Of course the single row radiator doesn't help either. Bio.. you could have a three-core copper brass radiator built from scratch for about $400. They would use GM tanks and a good Modine high-efficiency core and it would cool MUCH more efficiently than your single core aluminum.
I agree with that completely, but we don't know if his problems are stationary or moving.
Typically if its hot on the highway with electric fans, I blame the fans for blocking airflow. If its hot while stationary (where electric fans do their best work) I suspect not enough fan.
Either way in this case, I feel strongly that its the electric fans. When someone says "overheat" and "electric fan" in the same sentence its almost always the culprit. Either they're restricting air flow on the highway, or they're not providing enough flow while stationary.
Of course the single row radiator doesn't help either. Bio.. you could have a three-core copper brass radiator built from scratch for about $400. They would use GM tanks and a good Modine high-efficiency core and it would cool MUCH more efficiently than your single core aluminum.
Bio}{azard
10-23-2006, 02:27 AM
I agree with that completely, but we don't know if his problems are stationary or moving.
Typically if its hot on the highway with electric fans, I blame the fans for blocking airflow. If its hot while stationary (where electric fans do their best work) I suspect not enough fan.
Either way in this case, I feel strongly that its the electric fans. When someone says "overheat" and "electric fan" in the same sentence its almost always the culprit. Either they're restricting air flow on the highway, or they're not providing enough flow while stationary.
Of course the single row radiator doesn't help either. Bio.. you could have a three-core copper brass radiator built from scratch for about $400. They would use GM tanks and a good Modine high-efficiency core and it would cool MUCH more efficiently than your single core aluminum.
Although I like the suggestion, money and space is a huge issue, mainly space. The old 2 core had about 1/4 of an inch between the electric and belt driven fans. Although the old and new radiators are on-par with width and height
The main problem is that we do not know that to do with an absolute max of:
Width 25 1/2
Height 17
and Thickness of 3 inches
I'll see if I can get pictures of my current setup
Typically if its hot on the highway with electric fans, I blame the fans for blocking airflow. If its hot while stationary (where electric fans do their best work) I suspect not enough fan.
Either way in this case, I feel strongly that its the electric fans. When someone says "overheat" and "electric fan" in the same sentence its almost always the culprit. Either they're restricting air flow on the highway, or they're not providing enough flow while stationary.
Of course the single row radiator doesn't help either. Bio.. you could have a three-core copper brass radiator built from scratch for about $400. They would use GM tanks and a good Modine high-efficiency core and it would cool MUCH more efficiently than your single core aluminum.
Although I like the suggestion, money and space is a huge issue, mainly space. The old 2 core had about 1/4 of an inch between the electric and belt driven fans. Although the old and new radiators are on-par with width and height
The main problem is that we do not know that to do with an absolute max of:
Width 25 1/2
Height 17
and Thickness of 3 inches
I'll see if I can get pictures of my current setup
TheSilentChamber
10-23-2006, 02:33 AM
Just curious, are you sure the gauge works right? Also when you installed that engine, are you sure that the hose routing is right?
Bio}{azard
10-23-2006, 02:48 AM
Just curious, are you sure the gauge works right? Also when you installed that engine, are you sure that the hose routing is right?
The gauge is correct, and the hoses are routed correctly. Or at least how the car allows
The gauge is correct, and the hoses are routed correctly. Or at least how the car allows
Moppie
10-23-2006, 04:33 AM
The old 2 core had about 1/4 of an inch between the electric and belt driven fans. Although the old and new radiators are on-par with width and height
Ok, heres were I start shouting:
DETAILS DETAILS DETAILS!!!!!!!!
A photo would help, but from what your saying it sounds like your still useing the belt driven fan with the electric fans?
And we still don't know when it over heats?
As TSC suggested it could also be a problem with the hoses, you never confirmed they were free of kinks, or sharp angles, things that like to restrict water flow.
And just how many radiators do you have in there?
Ok, heres were I start shouting:
DETAILS DETAILS DETAILS!!!!!!!!
A photo would help, but from what your saying it sounds like your still useing the belt driven fan with the electric fans?
And we still don't know when it over heats?
As TSC suggested it could also be a problem with the hoses, you never confirmed they were free of kinks, or sharp angles, things that like to restrict water flow.
And just how many radiators do you have in there?
TheSilentChamber
10-23-2006, 11:53 AM
I lightend the picture that you linked so that we can accually see the radiator. You have room to fit a massive radiator in there, your fan is a good 3-4" away from the radiator.
http://img.photobucket.com/albums/v608/thesilentchamber/Engine.jpg
From just looking at the picture, air one could be reason also, the highest point in the system is the bend in that top hose.
http://img.photobucket.com/albums/v608/thesilentchamber/Engine.jpg
From just looking at the picture, air one could be reason also, the highest point in the system is the bend in that top hose.
curtis73
10-23-2006, 12:22 PM
Agreed with the 3-4"... You could put a four-row, 4" radiator in there and still have over an inch back to a mechanical fan. A shroud, a replacement lightweight fan from Summit, and a good stock thermal clutch and your problems will go away, I guarantee it.
You just can't ask an electric fan to do the job of a mechanical. I think your problem is your insistence on using parts that don't work. I know electric fans save a couple hp, but there are no free rides. Remember, a 20amp draw can mean as much as a few hp draw at the alternator.
You just can't ask an electric fan to do the job of a mechanical. I think your problem is your insistence on using parts that don't work. I know electric fans save a couple hp, but there are no free rides. Remember, a 20amp draw can mean as much as a few hp draw at the alternator.
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