Reverse hood scoop

NICO · Post by **NICO** » Tue Jul 26, 2005 9:09 pm

what hood scoop should i use? sti, forster, wrx new or old, and impreza 1st.

i need some help, what scoop would suck the heat out and make the car look good.

azn2nr · Post by **azn2nr** » Tue Jul 26, 2005 10:38 pm

NICO · Post by **NICO** » Wed Jul 27, 2005 5:58 am

azn2nr you think the sti one would work well takeing the hot air out.

BAC5.2 · Post by **BAC5.2** » Thu Jul 28, 2005 1:58 am

None of the above were designed to remove heat from the engine bay, so there's a good chance that it won't matter which you choose as neither will work.

With a hood scoop facing as it was designed to face, your still flowing air through the engine bay and out underneath the car.

91White-T · Post by **91White-T** » Thu Jul 28, 2005 2:25 am

No scoop. Heat will rise out big hole in hood.

evolutionmovement · Post by **evolutionmovement** » Thu Jul 28, 2005 5:02 am

A reverse hood scoop would be more likely to pull in air than draw it out. It may even work like a cowl induction system. Holes in the hood would work best, especially in an area where the air flow over the hood would be smoothest so the Bernouli Effect would help draw air out of the engine compartment.

Steve

dscoobydoo · Post by **dscoobydoo** » Thu Jul 28, 2005 8:08 am

If you look at the JDM WRX and our 2.5 rs's, their hoods are optimal for a flat 4 turbo engine. They have the vents placed above the heads, and the scoop for air through the intercooler and down and out. That way you have heat going up and out and cool air going down.

Now, if you want to do it right, but a set of the vent covers and have a body shop install them, and keep your scoop facing forwards. A reverse scoop will not do anything, in fact, the little vacuum it created by facing that way is no where near as good as the ram air effect by it facing forwards.

Just my two cents.

jamal · Post by **jamal** » Thu Jul 28, 2005 8:54 am

speed holes are the only way to go.

NICO · Post by **NICO** » Thu Jul 28, 2005 11:55 pm

so its a bad idea then, i just want the heat to come out. what i was thinking the air in the front gets pushed in and then the scoop sucks down the air, it must make a mess under the hood.

Post by **Legacy777** » Fri Jul 29, 2005 3:07 am

You're creating low pressure zone behind the scoop. It's going to create an "eddie" and won't draw any air out.

You need to create a venturi type setup that draws hot air out of the engine bay.

NICO · Post by **NICO** » Fri Jul 29, 2005 7:59 am

should i just leave my factory gc hood alone?

Subtle · Post by **Subtle** » Fri Jul 29, 2005 11:31 pm

The baffles in the old Legacy scoop probably restrict the flow to under the hood.However, with the chimney it is clearly designed to vent heat when the car
is stopped.
On most cars one of the high pressure areas is center and just in front of
the windshield, which assists airflow into the scoop for top mounted IC.

With a front IC, the concern is too much pressure building up from the
scoop and resisting the flow from the front of the car, but I doubt that
my old one is doing very much of that.

Some venting at the low-pressure area just behind the front of the hood
would be of interest, but how do you keep the rain out--Vancouver gets
some rain.

Bob(normally aspirated engines suck)

snowjob · Post by **snowjob** » Sat Jul 30, 2005 1:23 pm

I've got a 02 wrx on mine that works really well, it keeps things pretty cool under the hood

Bane · Post by **Bane** » Mon Aug 01, 2005 5:58 am

Nico, if you could do a reverse scoop oriented towards the front of the car (ie. after the rad, but before the engine) that might vent some of the heat... that makes sense to me, but practical application wise i don't know.

One of my favorite "looking" hoods is the Erebuni one pictured for the 2000+ Legacy...

it's reverse scoop followed by bugeye hood scoop.

considering you have no scoops now, the other option is to go with a standard gci8 style hood... try a used one off the 2.5rs or outback sport.

here's one, that looks kinda cool, though it's functionality might be in question lol.

anyway good luck with it dude, give me a shout when you change it, and i'll swing by and take a look. Hopefully i should have round 1 of my mods in place this week.

NICO · Post by **NICO** » Mon Aug 01, 2005 9:56 am

Bane nice pics, no i have 2 hoods one with no scoop and a 2.5rs one. the factory one with no scoops is so light an the 2.5rs one is working but not working becuse i dont got a top mount intercooler.

were can i get a cheap front scoop like the pics.

Bane · Post by **Bane** » Mon Aug 01, 2005 1:14 pm

sad as it sounds... try partsource or driverfx.com

here's one from Driverfx.com

non-carbon fibre is $140cdn
carbon fibre is $200cdn

http://www.7453217467431.com/products/p ... n_CA&tab=1

NICO · Post by **NICO** » Mon Aug 01, 2005 6:39 pm

thanks james

Carbix · Post by **Carbix** » Thu Jul 06, 2006 8:56 am

if you have every had a 95 sunfire you would know this. Being from a peace of yiker car i was some what taken back. In the front it uses a nagetive induction to "pull" air up to the rad leaving out bugs rain and what nots. this system would fit under the rad on the Legacy forcing cold air from the ground up and making a great negative pressure uder the car. So go to some junk yard (you cant have a junk yard with out a cavy or sunfire in it) cut the revers scoop looking thing out of the front and fit it to your car. hope u know how to weld tho...

evolutionmovement · Post by **evolutionmovement** » Thu Jul 06, 2006 9:39 pm

Do you mean, like, the airdam thing they put under the front of 'Vettes and Tauri also?

Subtle · Post by **Subtle** » Fri Jul 07, 2006 5:53 am

Last year I came across a spare Leg. scoop and this week had it reversed.

Bill cut out a rectangular section and reversed it, smoothed it out with epoxy and painted it to match the Winestone body.

The underhood is being painted with some sound deadening stuff that drys a dull medium gray. Should look better than the OEM cardboard liner and it can take up to 240 F.

Pick it up Friday afternoon.

Subtle · Post by **Subtle** » Sun Jul 09, 2006 7:08 am

Is a reverse scoop a poocs

Since I bot the car 4 years ago there has been a whistling sound at around 40mph and at above 55F air temp.

Thought it was the perspex spoiler in front of the sun roof. Sold it at a swap meet. Then I tried masking tape on the rubber rails on the roof. Nada.

Masked the scoop and the noise ended.

This was one of the reasons for the reversed scoop.

No whistling noise.

snowboarded · Post by **snowboarded** » Mon Jul 10, 2006 3:14 pm

Quick easy and free fix;

Drive arround without a hood.
http://photo-origin.tickle.com/image/11 ... 746232.jpg

NICO · Post by **NICO** » Tue Jul 11, 2006 11:36 pm

^^ ya i did that for a bit.

206er · Post by **206er** » Wed Jul 12, 2006 2:21 am

a guy at the rallycross last weekend had a forward scoop across most of the hood at the front, and a rear scoop across most of the hood at the rear.
also what you could do is put some blocks in the hood hinge to raise the rear of the hood. it looks cool on some cars, and probably works quite well to vent the engine bay heat.

Subtle · Post by **Subtle** » Wed Jul 12, 2006 6:07 am

Got the reversed scoop in.

As mentioned in an above post, originally it was designed to look like a functioning scoop, but it is mainly to vent heat from the turbine to the chimney to the air. The hand test indicated that almost all the heat was coming from the segment next to the baffle.

With the fmic it is important that air pressure from any kind of a forward-looking scoop is diminished, or even better --relieving underhood pressure. With this in mind, I did the reversal and then drilled some 5/8ths holes on the forward side of the underhood shroud.

It would be difficult to determine if the reversed scoop is actually flowing air aft at speed, but the vent holes sure are venting heat when parked--right across the opening.

It looks good and is functional++

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Reverse hood scoop

Reverse hood scoop