I have recently found a seller that is willing to sell me his dual over the roof scoops, the first thing that came to mind besides how it would dramastically cool the high heat of the fiero engine, was how it might also keep the heat in while you were in traffic? over all i really dont know how it will work but i figured i would ask someone who knew? so if anyone has any comments about the performance aspect of these things let me know? thanx for all help

I've never had them, but people say they don't cause any more heat.

As the Fiero was designed to let the air flow from under the car, up thru the engine compartment, and out the vents, it would appear to me that there is nowhere for the hot air to escape.

I've seen a car around here with just one, feeding the intake. If you like the look, try 'em out.

quote Originally posted by FieroBUZZ: As the Fiero was designed to let the air flow from under the car, up thru the engine compartment, and out the vents, it would appear to me that there is nowhere for the hot air to escape.

That is correct and adding just the scoops will result in a hotter compartment/running engine. You are trying to reverse the natural design flow of air to the engine compartment. The only way I've heard that these scoops will operate effectively, is if they have strong fans installed at the base of each scoop. As far as a street car goes, you've just increased the work load on the alternator, which blows away any benefit other that appearance.

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0 to 75 Audio http://www.cartsys.com/fiero/cal-engine.wav

Was the Fiero designed to purposely let air flow under then up through the engine compartment? As low as a Fiero is, and with the ground effects of the GT ( and other sport models ), I would wonder.
I figured the vents worked on a vacume princible, even drawing air (cooler) from underneath. The scoops should change it to a ram princible with a bad flow design raising the air pressure of the compartment at the air's exit to disallow complete venting of the compartment.
Did someone slip something into my coffee? I am no engineer.
I have never seen the Fiero scoop system but I would think it would only be good for air/fuel intake where it would go in one end and out another. Could work for cooling a compartment I guess but I would want exit vents behind and below the engine. I suppose the bottom of the engine compartment could be considered an exit, unless it was designed to allow air to enter.

All production cars have positive pressure between the floorpan and pavement which increases the faster you go. The Fiero design takes advantage of this by adding the cooling vents over the engine bay in an area that is slightly negative pressure at speed, which helps draw the air out of the compartment (assisted by the positive pressure underneath the car). At idle, heated air naturally rises.

To think, engineers get paid the big bucks. True, there is positive air pressure under the car which increases with speed. This is also true beside the car and above. All air is positive pressure unless it's absolute vacume. The vacume I was thinking of was one of less positive pressure.
Upon recollection, the Beatle, true air cooled, does have vents in it's decklid. It also has a shrouded lower engine compartment. I believe the shrouded design was to draw air up through the engine compartment.
I do not mean to, nor am I, arguing your point. I thank you for making me ponder as that is the only way we truely learn.
Back to the topic. I also am of the opinion that the scoops would be of visual value more than anything else. I was going to add cowl scoops to my 70 Chevy SWB Fleetside until I decided they were more form than function. If anyone thinks I should reconsider please let me know. I do like the looks.

I'd reconsider this idea. The engine compartment cooling on a Fiero is done with careful management of air pressure differences; the engineers earned their money that day. The abrupt drop off of the roofline at the rear window creates a low pressure zone, the air flow through the radiator is vented under the car creating a higher pressure zone underneath. This causes air to move from under the car up through the decklid vents.

This works very well at speed, but it's marginal in stop & go traffic. Adding those over-the-roof scoops would interfere with the natural air cooling and lead to higher engine compartemet temperatures at all times; not a good idea.

quote Originally posted by cliffw: To think, engineers get paid the big bucks.

Yep, we do, and we earn it !!! If you had to do our jobs, you'd understand why !

i have an 84 and i have put in the 85-88 side cover vents as well as keeping the original over the engine vent of the 84 - thus i have all three vents possible and am in a unique situation to comment about heat and venting issues. about 1/2 the perceived heat at rest (i cant feel it with my hand when moving) comes off the center vent. 1/3 of the heat comes off the right vent over where the battery was (i moved mine to the front). only 1/6 of the heat comes off through the left side cover. installing an over the roof air intake on the left side would make sense as that is directly behind the drivers head, and contributes the least of all three to engine cooling.
jon

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I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!

dont do it, there Ugly !!

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Rich AIM: ONE FAST 2M8
white-- 86se V6 daily driver
Gold--- 86se 355 SBC

done right they look allright.

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98 3800SC GTP motor,3.4 pulley, Getrag 5sp.
custom hood, trunk, side scoops, IRM front spoiler, 17" excel's , dk.Shadow Grey

No offense calikid but engineers allow me to earn big bucks also. I also listen to those who know less than I do. I have learned amazing things.

quote Originally posted by California Kid: Yep, we do, and we earn it !!! If you had to do our jobs, you'd understand why !

I AGREE

One flaw in a project, even if it is the builders comes back to the engineers who designed it.

revin - cool lookin scoop on that car, i might do something like that after i swap in my 4.9 - gg - first things first.
jon

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I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!

....turn the scoops backwards.ok I had to say it....and hey didnt I see a Mr. Fusion on ebay too?
Red

I said it in another thread, so I'll say it here too....

Forward facing scoops, just like these over-the-roof scoops, are used in high-performance mid-engine cars all the time. They do it by not having a trunk area and having rear facia vents or very small rear facias to let engine heat out. It's usually coupled with centered rear deck vents as well. I would be the first one to point out that the scoops wouldn't work very well on an otherwise stock fiero, but if you're willing to remove your trunk and do a custom rear facia, it is definately possible to make them work very well.

quote Originally posted by Whuffo: I'd reconsider this idea. The engine compartment cooling on a Fiero is done with careful management of air pressure differences; the engineers earned their money that day. The abrupt drop off of the roofline at the rear window creates a low pressure zone, the air flow through the radiator is vented under the car creating a higher pressure zone underneath. This causes air to move from under the car up through the decklid vents. This works very well at speed, but it's marginal in stop & go traffic. Adding those over-the-roof scoops would interfere with the natural air cooling and lead to higher engine compartemet temperatures at all times; not a good idea.

Not to hijack the thread but I was wondering where the air passing through the radiator went. I had thought that it made its way under the hood and exited at the base of the windshield... this idea led me to believe that the Fieros with hood mods to incorporate vents to exhaust the radiator heat was a really great idea. Now, if the theory of the air exiting the rad runs under the car is true, would the vents in the hood actually compromise the cooling capabilities of the car?

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Still plays with cars!

1986 Pontiac Fiero GT
1969 Porsche 912

quote Originally posted by exc911ence: Not to hijack the thread but I was wondering where the air passing through the radiator went. I had thought that it made its way under the hood and exited at the base of the windshield... this idea led me to believe that the Fieros with hood mods to incorporate vents to exhaust the radiator heat was a really great idea. Now, if the theory of the air exiting the rad runs under the car is true, would the vents in the hood actually compromise the cooling capabilities of the car?

I think it would be safe to say that the increased cooling from the radiator by adding a hood vent would make up for less flow under the car. Besides, it sure helps with the handling.

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