I have some Sunbird Turbo hood vents that I am going to be installing on my 85 GT. I have never done a bodywork project like this before. (knowing where to place them, getting them lined up appropriately, measuring & cutting the holes in the front hood, etc...) I would like to see a few pics of those who have done this. (Grand Am & Firebird vents are also welcome) Also, do you have any pointers/suggestions on the install? (especially on how to determine where to place them in the front of the hood / spacing, etc.)`
I used a different style vent... but the best advice I can give you is first, make sure the entire vent is behind the radiator (I know, seems obvious), and don't go back so far that you're cutting into the area that seats on the rubber seal of the spare tire compartment.
[This message has been edited by Patrick (edited 08-07-2022).]
I don't particularly like the "Glue-on" look of a lot of the vents. I prefer where the vent is ducted into the hood a bit. I also really like using the Defrost (Dash) vent as the grill for a hood vent- possibly combining it with a slight "tunneling".....
[This message has been edited by cvxjet (edited 08-07-2022).]
In a nutshell, you'll notice that with all of the vents shown above, the opening is no higher than the top of the headlight doors. Keep your vents between the headlights and you'll be fine. Basically follow the curves where the trunk seal sits that I marked in green. You can see the area between the headlights where you can cut and still be in the radiator area and not in the spare tire area.
[This message has been edited by IMSA GT (edited 08-07-2022).]
I completely understand why qwikgta installed the vents where he did, as it looks great! However, if I was to have used those style vents, I think I personally would've mounted them as far back as possible... as I wouldn't want any part of the vents to be in front of and/or on top of the radiator. It's the pressure build up behind the rad and in front of the spare tire compartment that needs to be reduced. This image sort of shows approximately where I'd try locating the rear mounting holes.
Originally posted by Patrick: I think I personally would've mounted them as far back as possible... as I wouldn't want any part of the vents to be in front of and/or on top of the radiator. It's the pressure build up behind the rad and in front of the spare tire compartment that needs to be reduced.
The area above, beside, and behind the radiator are all the same high pressure area (this is why headlight covers pop up). Vents in any of these directions/areas can help reduce the pressure build up and be effective vents.
The area above, beside, and behind the radiator are all the same high pressure area (this is why headlight covers pop up). Vents in any of these directions/areas can help reduce the pressure build up and be effective vents.
There are two factors in play here... reducing overall air pressure build up under the nose, and effectively venting hot air (as opposed to air that hasn't gone through the radiator yet). I installed my hood vents more to aid with cooling than to prevent front end lift. (I seldom go fast enough for there to ever be an issue!)
I want as much vented air as possible to have gone through the radiator.
Yes, it's conceivable that their placement doesn't make any discernible difference in the cooling effect of the vents... but I don't know for sure, which is why I lean towards moving the vents rearward of the radiator as far as they can go.
[This message has been edited by Patrick (edited 08-09-2022).]
Originally posted by Patrick: There are two factors in play here... reducing overall air pressure build up under the nose, and effectively venting hot air (as opposed to air that hasn't gone through the radiator yet).
Venting the high pressure zone (from any area) creates a pressure relief, which caused more more air movement behind the radiator, which aids in air flow through the radiator (assuming the top and sides of the radiator are still sealed to force air through vs. allowing it to pass around the radiator).
The two factors pressure and airflow (velocity) are directly linked.
The two factors pressure and airflow (velocity) are directly linked.
Agreed.
quote
Originally posted by fieroguru:
Venting the high pressure zone (from any area) creates a pressure relief, which caused more more air movement behind the radiator, which aids in air flow through the radiator (assuming the top and sides of the radiator are still sealed to force air through vs. allowing it to pass around the radiator).
Fieroguru, I always appreciate your opinion... even on the very rare occasion (like this one ) where I don't agree with you. It makes zero sense to me to reduce the high pressure zone in front of the radiator (instead of behind it) in regards to helping to cool the radiator/coolant.
Does not the high pressure zone in front of the radiator aid in air velocity through the radiator, especially when pressure relief is accomplished by way of the added vents behind the rad?
I'm sorry, but I don't see any advantage whatsoever in reducing the high pressure zone in front of the rad as opposed to behind it. Actually, I'll go further and say that IMO it's detrimental in regards to helping to cool the rad. As far as reducing front end lift, I'd say it's a wash either way.
The top and sides of the radiator are sealed to keep the front/face of the radiator at a higher pressure (when the car is driving) and force the air through the radiator (and not allow it around it) - this allows the radiator to cool w/o the use of the fan above 35 mph. The back, top, and sides of the radiator are all part of the same space and at the same pressure that can be vented to increase airflow through the radiator. Air will change directions to take the path of least resistance, so any opening in this combined area will reduce the high pressure in the back, top, and sides of the radiator and create additional air flow through the radiator (through the radiator is the primary path into this high pressure zone)
Think of it like your house and the radiator is in the open door to your deck and the prevailing wind is pushing air through the radiator. There will be some breeze when you open it, but opening any other door or window on any of the 3 other sides of the house will increase the air flow through the door. Even if it has to flow down hallways, up stairs, under doors, etc.
It and the air dam have made a marked improvement on down for e in the fron. The stock nose actually generated lift per Pontiac at high speed. It really did feel bad at 90 mph.
The vent also makes a great bug deflector it blows them straight up at night.
Dear 2.5, In the words of Paris Hilton...... "That's Hot!" I would LOVE some pics of the underside to get an idea of where you cut in relation to the weatherstrip seal area. Thanks, Kit
Obviously the front radiator compartment is a positive pressure enclosure, given the headlight cover popping up with enough speed. With positive pressure, it will try to escape at ANY place. Flow matters, but pressure matters more. Think of it like a computer case. If you have a case with fans only driving air in, with a single opening unrestricted for air to escape, it doesn't matter which direction the fans are pointing within the case. Theres pressure, and it will escape through any path given. Be it through seams in the panels, or a vent. Same case with the hood vents. I will agree that the more in line with the flow the better, but with negligible real world difference.
Think of it like a computer case. If you have a case with fans only driving air in, with a single opening unrestricted for air to escape, it doesn't matter which direction the fans are pointing within the case. There's pressure, and it will escape through any path given. Be it through seams in the panels, or a vent. Same case with the hood vents.
So how is that supposed to convince me that air pressure escaping through hood vents located in front of the radiator (which would result in less air flow through the radiator than if the hood vents were located to the rear of the radiator) is not going to negatively affect the radiator's ability to do its job?
I appreciate the attempts to "set me straight", but they're not working.
[EDIT] I'm trying to understand where this disconnect is occurring in our discussions on air pressure. Possibly it's due to our individual understanding of where this high pressure area is actually occurring. I think we all agree that there is a high pressure zone in front of the radiator. I also believe there is a high pressure zone behind the radiator, due to the spare tire compartment being in the way of air flow which has not only gone through the radiator, but air flow that has also worked its way into that area through any number of small, and maybe not so small openings. In my opinion, creating an escape for the high pressure zone in front of the radiator does nothing to reduce the high pressure zone behind the radiator (in front of the spare tire compartment). Is the argument then that the high pressure zone in front of the spare tire compartment will force air forward through the radiator, and then out the hood vents located in front of the rad?
[This message has been edited by Patrick (edited 08-10-2022).]
I was going to try to draw something like that up guru, but im not much of an artist
Patrick, as is visualized in guru's drawing, the hood vents being "in front" of the radiator isnt relieving pressure from the front face of the radiator, because of the seal
With credit to fieroguru for the original drawing (nice!)... here's my view of the situation. Yes, I understand that in the original drawing, the seal perhaps looks more like it does in real life, but I've tried to alter the drawing to show how I believe it effectively functions. I could very well be wrong, but this is how I see the separation of the two pressure zones. The two short thick red lines show the relative locations of added vents positioned in front of the radiator, and/or behind it.
I'm going to have a good look-see at the front of my Formula before conceding anything. Good discussion!
[This message has been edited by Patrick (edited 08-10-2022).]
I like both of those hoods. Did either one of them require reworking of the spare tire compartment/seal?
I just had to push the leading wall back about 3/4 of an inch in a small section.
It seals and if I go back to the original hood I can just push it back in place.
No cutting or non reversible modifications were needed.
I think the key is one to make the vents molded in so they don’t look like a tape on vent. Also to get them in the right size for the style they are.
[This message has been edited by hyperv6 (edited 08-11-2022).]
i went for maximum air flow and minimum air restrictions, as well as clean air flow. Before i installed my radiator vent, Freya wud overheat easily in traffic. After installing it, it took a lot longer to overheat - cuz my fan was not working. When i fixed my fan, WOW it pushed a LOT of air. Car stays nicely glued to the pavement at any speed that i have traveled up to 90mph. Strings glued in and out of the vent show that at speed air moves thru at great velocity. i love my vent.
------------------ Astronomy says we will find a coded signal from outer space. Then we'll KNOW that life exists there, for coded signals aren't by chance.
Biology says there are coded genetic signals in every cell, but we KNOW that no intelligence created life.
I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 3800SC, 4-wheel drifts are fun!
Yes, without the radiator seal on top of the radiator this would not work. I know it worked b/c when the fan was on, and the car stopped, it pushed air out of the vents. also, when driving the air over the scoops created a Bernoulli Effect and pulled air out of the lower pressure area behind the radiator.
I put the scoops where I did b/c I didn't like the way it looked when they were higher up on the hood, I liked the way they worked with the headlight covers. when I moved them up it just looked wrong. I did move them apart, to the left/right but again, I just felt the looked better where I put them. In the end, I also didn't like the "bolt on" look and I wanted to have them integrated into the hood but went another route.
) where I don't agree with you. It makes zero sense to me to reduce the high pressure zone in front of the radiator (instead of behind it) in regards to helping to cool the radiator/coolant. 
