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Value of Roof Scoops by Phirewire
Started on: 03-14-2016 07:48 PM
Replies: 10 (747 views)
Last post by: dobey on 03-19-2016 10:49 AM
Phirewire
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Report this Post03-14-2016 07:48 PM Click Here to See the Profile for PhirewireClick Here to Email PhirewireSend a Private Message to PhirewireEdit/Delete MessageReply w/QuoteDirect Link to This Post
I found a set of Indy Scoops for the decklid vents. Curious what they are worth, I think price is a bit high but want to get feedback.
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Report this Post03-14-2016 08:15 PM Click Here to See the Profile for randyeClick Here to visit randye's HomePageClick Here to Email randyeSend a Private Message to randyeEdit/Delete MessageReply w/QuoteDirect Link to This Post
Value in terms of functionality or value in terms of money?

Functionally, those over the roof scoops are *counterproductive* to the cooling air flow engineered into the Fiero design. In that regard, they aren't worth squat.

In terms of value in dollars, I'd say they are worth whatever you can get for them.

[This message has been edited by randye (edited 03-14-2016).]

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Report this Post03-14-2016 08:15 PM Click Here to See the Profile for DanyelClick Here to visit Danyel's HomePageSend a Private Message to DanyelEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Phirewire:

I found a set of Indy Scoops for the decklid vents. Curious what they are worth, I think price is a bit high but want to get feedback.


Hello
First of all Indy Scoops dont go over the decklid vents .... it is a single scoop in the middle of the deck lid ....Over the Roof scoops are what you want.... but there has been MANY arguements about these trying to force air down a vent that was designed to exit hot air .... anyways these usually sell for 200 to 400 for a pair ...... would I put them on a fiero... NAH not me ... fiero conceptors uses these vents as extraction not INSERTION

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Danyel

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Report this Post03-15-2016 10:11 AM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by randye:

Functionally, those over the roof scoops are *counterproductive* to the cooling air flow engineered into the Fiero design. In that regard, they aren't worth squat.



Keep in mind they were designed for the 84 Fiero that has SOLID side covers and CENTER decklid vent.
When used in that application - they can actually be functional (unlike the Indy roof scoop).
On my Indy, left side has a hole in panel to match open top air cleaner I mounted under it.
Right side has air ducted toward front of engine.




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[This message has been edited by fierosound (edited 03-17-2016).]

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Report this Post03-15-2016 09:40 PM Click Here to See the Profile for DKcustomsSend a Private Message to DKcustomsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Over-the-roof scoops are functional, especially if you get some sort of vent in the decklid, as shown above with the 84 decklid or another custom vent

In my opinion, and others will disagree, even with the scoops and an 85-88 decklid, air can still be vented underneath the car at speed, however not as likely if you are mostly in city traffic
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Report this Post03-16-2016 12:24 AM Click Here to See the Profile for randyeClick Here to visit randye's HomePageClick Here to Email randyeSend a Private Message to randyeEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by DKcustoms:

Over-the-roof scoops are functional, especially if you get some sort of vent in the decklid, as shown above with the 84 decklid or another custom vent

In my opinion, and others will disagree, even with the scoops and an 85-88 decklid, air can still be vented underneath the car at speed, however not as likely if you are mostly in city traffic


Those roof scoops force air in *against* the direction that the airflow was engineered to go.
Adding the roof scoops STOPS the cooling air coming UP out of the OEM vents at highway speed AND creates a static high pressure zone of air within the engine compartment that defeats any cooling airflow design. The air from the scoops into the engine compartment cannot overcome the even higher pressure, high velocity, mass of air flowing *under* the chassis rearward that acts as a barrier. As an analogy, it is similar to trying to blow air into a coke bottle.

Pay particular attention starting at 0:40 in this video:



You can put them on your Fiero because you think they *look* cool, but the engineering, design and documented testing prove that they DO NOT function how you assume they do.

If you really want *functional* scoops that enhance the cooling air flow through the engine compartment, use a good set of fender *side scoops* and duct them as low as possible into the engine compartment. This takes advantage of the low pressure area at speed just behind the rear window and the high pressure area inside the engine bay to cause the air to flow *upward* out of the OEM decklid vents at a higher velocity and pressure.

[This message has been edited by randye (edited 03-16-2016).]

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DKcustoms
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Report this Post03-16-2016 11:53 PM Click Here to See the Profile for DKcustomsSend a Private Message to DKcustomsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Like I said before, if you add some sort of vent into the decklid in collaboration with the scoops, you will have adequate, better than factory, cooling with the extra airflow.
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Report this Post03-17-2016 02:00 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Air flow over the deck lid and vent(s) only part of the issue here...
Very short... Air off the roof hits the deck ~1/2 way back or more depending on car speeds. Allot of air goes off the back, some "rolls" to rear window at shown in second vent in video above. (String used affects testing and he's video.) This happens at very low speeds too. Starts at 1-2mph.

Many Years ago I bought the hype that Fiero engine bay was hot... Even had a section of my cave to remove trapped heat...
Then a got a thermal couple to measure heat in engine bay to test.
Result I found Fiero is cooled to about same a weather temp that day when moving over ~5 mph.
I then remove that section from my cave and call BS. Even most engine swaps do not need extra help to remove heat.
Many say 85-87 V6 has a blower... But many forget only on when radiator fan or AC is on to help SI alt and HEI parts. Those are in "bad" places may not get enough air flow to cool and SI alt's have cooling problems to begin with.

Using Roof Scoops may help or hurt to cool the engine bay, intercooler for turbo, etc.
At stops the scoop will "back flow" from stack effect. IOW Scoops will act like chimneys.
Low speed might actual cancel air flow. Heat is trying to move up but air is pushing down.
High speed might push enough air down the scoop.
What speeds does that happen? No clue. Many things can change the results so If tested on one car might not be valid on another car.

"Easy test" Engine hot...
You would need a remote thermometer to read engine bay temp w/ car moving at different speeds to see how scoops perform.
A helper to write data temp and speed and do this before and after.
Note: You are not reading engine temp, ECT sensor does that, but Air in the engine bay.

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hyperv6
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Report this Post03-18-2016 09:28 PM Click Here to See the Profile for hyperv6Send a Private Message to hyperv6Edit/Delete MessageReply w/QuoteDirect Link to This Post
Well the under hood temps do in parts of the engine get higher as the air flow in the compartment is not like it is in a car with the engine up front with a large grille. So while the heat is not astronomical it can do some harm when changes are made.

In 85 and later they re channeled the flow and the open grills are needed to provide some flow. I know from years ago driving in the winter you can see the heat go straight back and melt the snow on each side behind the grills but not in the center as you drive. GM did it to keep a flow of fresh air through and also to remove a high pressure build up on there car. The nose on the coupes already suffered this.

With that said it is best not to use this type of scoope. Now if you want you more than no could run them on a stock engine and not really kill anything. HP is engergy and engery is heat. These engines stock are low enough powered the heat is nominal.

Now if you put in a more powerful V8 or add a Turbo that generates heat you can see a climb in oil temps and issues with failure of electronic items. The PPG cars that had a Turbo V6 would see oil temps to 300 degrees on the street and they were an issue to keep cool with no air flow. The grill in the lid was from a Lebaron Turbo and added fans helped. The electronics were moved to the trunk to make a barrier.

As for the 84 model they would not hurt as they had a different air package.
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Report this Post03-18-2016 09:34 PM Click Here to See the Profile for hyperv6Send a Private Message to hyperv6Edit/Delete MessageReply w/QuoteDirect Link to This Post
Well the under hood temps do in parts of the engine get higher as the air flow in the compartment is not like it is in a car with the engine up front with a large grille. So while the heat is not astronomical it can do some harm when changes are made.

In 85 and later they re channeled the flow and the open grills are needed to provide some flow. I know from years ago driving in the winter you can see the heat go straight back and melt the snow on each side behind the grills but not in the center as you drive. GM did it to keep a flow of fresh air through and also to remove a high pressure build up on there car. The nose on the coupes already suffered this.

With that said it is best not to use this type of scoope. Now if you want you more than no could run them on a stock engine and not really kill anything. HP is engergy and engery is heat. These engines stock are low enough powered the heat is nominal.

Now if you put in a more powerful V8 or add a Turbo that generates heat you can see a climb in oil temps and issues with failure of electronic items. The PPG cars that had a Turbo V6 would see oil temps to 300 degrees on the street and they were an issue to keep cool with no air flow. The grill in the lid was from a Lebaron Turbo and added fans helped. The electronics were moved to the trunk to make a barrier.

As for the 84 model they would not hurt as they had a different air package.
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Report this Post03-19-2016 10:49 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by DKcustoms:
Like I said before, if you add some sort of vent into the decklid in collaboration with the scoops, you will have adequate, better than factory, cooling with the extra airflow.


I've seen no evidence to support this claim. At speed, it is more likely what will happen with these scoops, is the build up of a high pressure area aft of the engine, in the engine bay, causing a bit of lift, similar to what happens in the front of a stock Fiero. The 84 decklid vent is too far forward to have any effective change to air flow performance. With the V6 or other larger engine in the bay, the flow out of a decklid vent in the same location as the 84 will also be obstructed by the engine and large intake plenums.

Having these scoops will also increase aerodynamic drag, which also means a negative impact on fuel economy and acceleration performance.
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