I got the plastic side air intake scoop from the Fiero store for my birthday. You know that one that replaces that vent and has nice chromed Fiero letters on the side. Does it do anything for performance besides look diffrent? It looks like it would grab a bit more air when cruising down the highway. It would be feeding an 86 Iron Duke. Just curious.

Curly

I am curious to know about the scoop too. I recently installed the same scoop on my car. It went on easy, but I am still curious. It is basically a ram air scoop, so it would ne nice to know. The gaps seem to not be the best, so there may be some blow by but it would still be nice to know. BTW, pardon the incoherence. I got my wisdom teeth removed 15 minutes ago.

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It looks different from the stock vent. No real performance gain, unless you modify the entire air introduction piping.

Modify how? A straight pipe up to the air cleaner? A chamber around the air cleaner of a CRX cold air intake?

Tell me more. I want my 3.4 to breath better when I actually install it

On my V6 I bought the smallest plastic hood scoop from Summit I could find and cut it down until it fit over the side scoop area. Then I glassed it in and smoothed it out until it looked factory. I put a piece of mesh in it and it turned out nice looking and far more functional than the factory hole.

No, not in anyway. A car does not travel fast enough to have any benefit from an "Ram Air." This scoop is for looks only, as the Fiero has a well-designed air intake system already.

So you mean the scoop did nothing ? I mean it was sticking out there "scooping" up the air ? Well at least it looked cooler than the factory one in my opinion.

Yeah my thoughts are it's for looks only. Thought I would ask I might be pleasently surprised. Anyway for a little something diffrent that takes 5 minutes to install I would say still worth it.

quote Originally posted by Fastback 86: No, not in anyway. A car does not travel fast enough to have any benefit from an "Ram Air." This scoop is for looks only, as the Fiero has a well-designed air intake system already.

Huh?? Not fast enough for "ram air"? I think you mean "ram air" in the aeronautical sense. Which is correct it does not compress air.
But in terms of the automotive sense, yes ram air works fine.

The side scoop does allow a little increase in power at highway speeds because it allows the air/fuel to flow into the head chamber.
The "mod" folks talk about is the water seperator plate in the air box behind the scoop, It can be knocked out for a slightly better flow path.

In theory, yes, it has an effect. In practice, the effect is negligible because the scoop isnt airtight and the intake is restrictive in a way that air buildup wont happen.

Ram air would be much more effective by running a pipe from the engine to the front behind the radiator with a large mouth. (Very large opening plus lots of intake volume equals a very good ram air system)

quote The side scoop does allow a little increase in power at highway speeds because it allows the air/fuel to flow into the head chamber.

Since it took me a bit to figure this out, what he means is that the scoop will push the air into the combustion chamber instead of using flywheel energy to pull it in. So in this sense you get a small amount of extra power.

[This message has been edited by AP2k (edited 10-15-2007).]

quote Originally posted by AP2k: In theory, yes, it has an effect. In practice, the effect is negligible because the scoop isnt airtight and the intake is restrictive in a way that air buildup wont happen.

What does air "build-up" have to do with "flow"?

quote Originally posted by AP2k: Since it took me a bit to figure this out, what he means is that the scoop will push the air into the combustion chamber instead of using flywheel energy to pull it in. So in this sense you get a small amount of extra power.

Yes. When the piston hits bottom, flow into the cylinders normally stop. (No displacement, no flow) But with a ram air scoop you have a positive flow pushing the air. Since the piston only displaces the volume of the cylinder that travels within, The positive flow will push a little air into the head chamber area. allowing a small bit of air/fuel more than normally would be in the cylinder. It doesn't compress the air, it just fills the head chamber with a little extra mixture. (about 51cc's, The size of the head chamber volume.) This increases efficiency resulting in better throttle response and a slight improvement in power and MPG.

[This message has been edited by Oreif (edited 10-15-2007).]

quote Originally posted by AP2k: Ram air would be much more effective by running a pipe from the engine to the front behind the radiator with a large mouth. (Very large opening plus lots of intake volume equals a very good ram air system)

Sorry, but you're wrong on both counts. A long duct and/or a large mouth => poor pressure recovery ... and pressure recovery is what "ram air" is all about. A system as you describe it would have far poorer performance than the stock Fiero cold air intake.

[This message has been edited by Marvin McInnis (edited 10-15-2007).]

quote Originally posted by Oreif: What does air "build-up" have to do with "flow"?

Sorry, I dont know the specific engineering term for when the air pressure wont build up because it rolls out of the intake. I'm an EE, not AE.

When the pressure wave hits the intake box its going to reflect back out the way it came. Remove that and you get an ever so slightly more pressurization effect until the pressure forces the air out of the intake pipe.

quote Originally posted by AP2k: My point is that a large mouth makes more pressure because more air slows down.

And that's exactly where you're wrong. While it may seem intuitive, a converging inlet with a large frontal opening is the worst shape for pressure recovery. A diverging inlet with a small frontal opening provides the best pressure recovery. Source: NACA (the predecessor agency to NASA).

[This message has been edited by Marvin McInnis (edited 10-15-2007).]

Hey you guys, I have Ram Air!!! It says so right on the side!!!!
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Dougie Murder
85 Fiero GT
Romeoliquorstore.com
Myspace

[This message has been edited by Dougie Murder (edited 10-15-2007).]

[QUOTE]Originally posted by Oreif:

The side scoop does allow a little increase in power at highway speeds because it allows the air/fuel to flow into the head chamber.
QUOTE]


Really? I would think a scoop would have be really huge on the side of a Fiero to increase airflow at all. Like say 12" by 6", and still going thru the same size tube afterwards would limit it then too right?

[This message has been edited by 2.5 (edited 10-15-2007).]

quote Originally posted by Dougie Murder: Hey you guys, I have Ram Air!!! It says so right on the side!!!!

It's on the Internet, so it must be true.

quote Originally posted by Marvin McInnis: And that's exactly where you're wrong. While it may seem intuitive, a converging inlet with a large frontal opening is the worst shape for pressure recovery. A diverging inlet with a small frontal opening provides the best pressure recovery. Source: NACA (the predecessor agency to NASA).

Provide definition for "pressure recovery" so I know if we are both talking about the same thing. Also provide an actual source other than a link to a search engine.

Preliminary searches lead me to a report speaking of pressure recovery versus long and short rams, but they are also testing at speeds that only a handful of cars will ever reach.

quote Originally posted by Marvin McInnis: It's on the Internet, so it must be true.

Actually its on my car...so yeah it must be true :P

The previous owner put it on with a K&N intake...


This is pretty much the worst idea because the filter is right under the rear vent and when it rains, the engine is sucking in water. Not to mention all the hot air its sucking in.

As soon a I get my hands on a stock intake this scoop and k&n i have are gonzo.
or maybe if i feel adventurous I'll take a few notes from forum members who have done actual cold air intakes.
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Dougie Murder
85 Fiero GT
Romeoliquorstore.com
Myspace

[This message has been edited by Dougie Murder (edited 10-15-2007).]

the ONLY way to improve the air intake on the fiero is by adding a turbo or supercharger.

I have one, and like stated above it really doesn't do much except IMO look better, I did notice a significant increase in the intake noise with the window down, but the noise doesn't bother me.

Adding the scoop and removing the baffle in my opinion made alot of difference getting better air into the intake. I thought the whistling sound on heavy throttle was pretty cool too. In an essence, if you are shoving fresh air into a side scoop how can that not be better than a flat surface in which no air is going into it other than being pulled from the intake valves ?

I have a CRX intake and a custom built ram air scoop in the 1/4 panel. It feels quicker on the butt dyno, but considering both mods cost me $34... why the physics pissing match? who cares? $22 for the FieroStore scoop, in theory the way the stock intake is designed since it pulls air directly out of the scoop and forces it into the engine you are increasing the pressure of the air. LIKE A TURBO!! except you are pushing like .0000001psi. Drop the water bypass box, get a rodney airbox base, put on your scoop, and go have fun. Stock intake is plenty of air for a stock motor, we all know this, but a true conical filter cold air intake (CRX or WCF) makes a huge sound difference, which was worth the $33 to me.

quote Originally posted by AP2k: Provide definition for "pressure recovery" so I know if we are both talking about the same thing.

"Pressure recovery" is standard fluid dynamics terminology. It refers to recovery of the dynamic pressure in a flowing fluid and its conversion to static pressure.

quote Also provide an actual source other than a link to a search engine.

I provided a link to the entire NASA on-line publications data base. What more could you ask for? Hint: Most of the subsonic studies, which are the only ones relevant to automotive practice, were performed prior to 1950. No, I'm not going to do all of your work for you.

You made the claim that a converging inlet with a large entrance area is best for "ram air" purposes. I said it is not, and provided a link to authoritative sources that support my position. It is now up to you to provide support for your statements. If you find anything new, I'll be glad to consider it. In the meantime, to get you started, here are some relevant links to a little light reading:

Wind Tunnel Tests of Air Inlet and Outlet Openings on a Streamline Body

An Experimental Investigation of NACA Submerged-Duct Entrances

An Experimental Investigation of the Design Variables for NACA Submerged Duct Entrances

Internal-Flow Systems for Aircraft

From the second reference cited above (Mossman et al, 1945):

"From the preceding discussion of the research, the following summary may be given:

1. Ramp Design

(a) The use of divergent walls ... improves the pressure recovery to such magnitude as to make them mandatory for all installations. The curved divergence shows the best characteristics.

(b) The ramp angle may be varied up to 10 [degrees] without incurring serious pressure losses. For a 10 [degree] ramp, the pressure losses are slightly greater than for lesser ramp angles. If a 10 [degree] ramp is used, a lesser divergence should be used than for smaller ramp angles."

[This message has been edited by Marvin McInnis (edited 10-16-2007).]

As for the fiero scoop. Your, probably, not going to go fast enough for it to make any difference. TBS, If you like the looks of it, go with it.

I may pick one up also but not for an intake. I would only use it to pull air in for the oilcooler since the engine will not be pulling it in . Intake is elsewhere....

[This message has been edited by Fieroseverywhere (edited 10-15-2007).]

quote Originally posted by Curlrup: Does it do anything for performance besides look diffrent? It looks like it would grab a bit more air when cruising down the highway.

Back to the original question ... the answer is no, but it won't hurt anything, either. If you just like the way it looks, that's OK too. The most important thing for maximum power and engine efficiency is that, just like the OEM intake, it is sucking cool air from outside the engine compartment.

Consider also that "ram air" effect, even if it were significant at Fiero speeds and easily recovered, wouldn't help any when "cruising down the highway." Mods like this (upstream of the throttle plate) can only help at or near full throttle, and they gain you virtually nothing at partial throttle, as when you are "cruising."

[This message has been edited by Marvin McInnis (edited 10-15-2007).]

Right that was my thought it just looked cool. Well anyway I just put said scoop on. Very easy two screws and away I went. Yeah with an old Duke that throttle will never be wide open. Unless I'm planning an engine swap soon. Which I am not. I like to think of the scoop like flames or stickers from JEGS or Summit. They make your car faster in you rmind but not in reality. Thanks for the in depth discussion though. My wife who is studying to be in engineer is finding this facinating.

Orief is correct there is no real theory when the cars are moving under 150mph. sometime there is a boost sometime there is not, when some devise is added to the intake this has aided many carbed cars with!!! E injectors??/ any small improvement in airflow is good ,but only in a few instance will there be seat dyno improvement ,, theory aside some time increase air flow at hi RPM will work to "lean" a slightly rich wot for increase performance(also can cause hole in piston). if your spark plugs run a darker brown or a tad black then you should OPEN up stock cold air intake <remember>dyno testing has proven the stock 2.5 & 2.8 stock cold air system to be superior to all others ALL

Oreif is right in that the scoop should provide a performance increase. However, that increase will be negligible.

The moral of this post is: buy the scoop for what it is... a cool looking scoop, and don't expect it to be something it's not.

It looks cool if you like it. Performance wise...dont do anything more than a bi wing on a 75 hp Honda.

quote Originally posted by Marvin McInnis:...

I'm not above eating pie on subjects where I am not an authority and I thank you for the links. But dammit you cant just point to google and say "The information is out there. Look for it."

quote Originally posted by Curlrup: Yeah my thoughts are it's for looks only. Thought I would ask I might be pleasently surprised. Anyway for a little something diffrent that takes 5 minutes to install I would say still worth it.

I agree, if you like the way it looks on your car, then put it on there. As a power benefit, you won't notice any difference.
Enjoy
Gary

I went with Rodney Dickman's (rodneydickman.com) cold air intake tubing. Easy instal. Don't know if it benificial or not, but it's a more direct flow pattern than the original.
Rich
As a ps, I've never had anything but professional interaction with Rodney in the 5 yrs. I've been buying parts and upgrades from a multidude of vendors.

quote Originally posted by Blacktree: Oreif is right in that the scoop should provide a performance increase. However, that increase will be negligible. The moral of this post is: buy the scoop for what it is... a cool looking scoop, and don't expect it to be something it's not.

Putting a scoop in the incoming air stream at highway speeds is bound to increase the flow. Seven years ago I got curious and called Holley as they were still making the scoops at that time. The tech department guy told me that the scoop would produce a 2-3 HP increase when WOT is used at speeds of 60 MPH and above. I can believe this as if you stick the palm of your hand out the window at 60MPH into the air stream you will feel a good amount of pressure on your hand. That air pressure is what aids air flow going into the scoop.

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87GT 3.4 Turbo- 0-60 5.2 seconds
2006 3800SC Series III swap in progress
Engine Controls, PCM goodies,
re-programming & odd electronics stuff
" I'M ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by AP2k: I'm not above eating pie ....

That was not my intent. It's not about you or me. It's about correct vs. incorrect information.

quote But ... you cant just point to google and say "The information is out there. Look for it."

Sorry to be cranky, but I never pointed you to Google. I provided a link to the entire online NASA publications database, in part to avoid claims of withholding possible sources of contradictory information. Digging out stuff like this is what engineers do for a living, even when it's tedious, boring, and dirty.

[This message has been edited by Marvin McInnis (edited 10-17-2007).]

quote Originally posted by Marvin McInnis: Going from memory (so I may be wrong in detail), recovering 100% of the dynamic pressure at 200 mph will increase the intake air density about 2%. Since dynamic pressure is proportional to the square of the velocity, recovering 100% of the dynamic pressure at 60 mph will net you a maximum theoretical power increase of 0.18% ... which would be about 1/4 horsepower in a stock Fiero V6. If Holley has published data to the contrary, I'll be glad to consider it.

But not only are you recovering dynamic pressure, You are also increasing the amount of air/fuel in the cylinder by 51cc's which can give a 1-2hp increase. This could be why Holley has stated the gains.

I think that the small claimed HP increase comes down to harnessing the cold outside air more efficiently. The side scoop won't increase air density much but I would say that it might increase the volume. I am no expert on air dynamics but again if I put my had outside the window at 60MPH I feel a considerable amount of pressure that pushes my hand back. This same air flow must be going into that scoop and doing something- either aiding in the air flow, lowering the air temps etc.
While the debate on whether or not the Holley /Fiero Store side scoop does much for the 2.8L will go on, I can tell you that the frontal opening is too small to help a 3.4L or 3800. Accordiong to my calculations it will actually restrict a 3800SC with a 3 1/2" CAI system.

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87GT 3.4 Turbo- 0-60 5.2 seconds
2006 3800SC Series III swap in progress
Engine Controls, PCM goodies,
re-programming & odd electronics stuff
" I'M ON THE LOOSE WITHOUT THE JUICE "

Wait a minute... wait, wait, wait.....

quote Originally posted by Dougie Murder:

Dougie, Are you tellin' me that the previous owner put that scoop on the outside, but on the inside, the intake isn't even connected to it?

HAHAHAHA!!! Now THAT'S nice.