Impreza -OB / RS- Hood Scoop install - no cutting required.

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wtdash
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Impreza -OB / RS- Hood Scoop install - no cutting required.

Post by wtdash »

I bought a '98 (?) RS hood scoop from a vendor on RS25.com for $30 to see what I could do to get it to fit. But I did NOT want to cut my hood.

Here's what I ended up doing....


The bottom of the stock RS scoop looks like this:
Image

I cut off all the attachment pins so the scoop would sit flat, and since I only had $30 invested wasn't worried if it didn't work out:
Image
Image

The scoop still had the fuzzy, weather-strip type seal around the edge so I wasn't putting the scoop's plastic directly on my stock hood.

On each end of the scoop are 2 mounting screw holes. I drilled 2 corresponding holes in the stock hood that are NOT visible above and don't interfere w/the stock scoop's re install (if ever needed). These actually help center the scoop and pull it down flush to the hood. EDIT: I looked again @ the b4/after pics and I had to bend down/up the tabs on each end - don't recall which - but it's thin metal and was easily done w/a pair of pliers:
Image



Full view:

Image

In the center of the scoop I drilled a hole that matches up w/one of the stock scoop's mounting holes...w/the use of a bracket - see above. The bracket was just an extra piece I had.


When I tried the scoop w/just these 3 mounting points - both sides and the front - the back section would start to flutter @ speeds above 40mph, so I knew I'd have to find a way to attach it to the hood - NON-permanently.

I bought some magnet strips thinking I could stick one side to the scoop and the magnet would hold it.
Image

The magnet strips were really weak....very little magnetism. Not sure if it was the 'ebait' brand I bought or just the nature of the product. Adding to this issue, the scoop's rear edge is not flat (obviously) as it rises to create the 'scoop'. I ended up using some 3M double-sided tape to 'build-up' the edge, just inside the weather strip seal.

After 2-3 layers on top of the magnet strip I left on, there was enough contact to hold the scoop in place. After some testing, it appears to work fine and keep the scoop flush w/the hood....even @ triple-digit speeds. I'm NOT sure what will happen when the temps get warm as it's been <40 here since I installed this.

Finished product - It sits ON vs. IN the hood like other scoops, but I don't think it looks terrible as is:
Image
Image
Image

One other issue to deal with is there is a lot of space between the top of the hood and the back of the inside of the scoop. It seems like to me the air won't flow as smoothly down into the TMIC. In fact it's what may cause the scoop to want to lift off the hood. It's somewhat visible in this pic:
Image

EDIT: Cut a piece of thin aluminum - used a piece of heater ducting - about 21" x 4.5" that I attached to the back of the original scoop's mounting holes and is pushed up under a lip on the bottom of the scoop - where the scoop's opening support brackets attach. This should help force the air down to the TMIC.

Pics (poor lighting):
Image

Image

Image


I think an '02-03 WRX scoop would work similarly but it does have a slightly different bottom:
Image

Constructive Criticism welcome - This isn't NASIOC. :-)

Thanks,
Td
Last edited by wtdash on Wed Dec 25, 2013 5:38 pm, edited 5 times in total.
Turbo Subies:
'87 GL-10 Turbo - SOLD
'90 BJ EJ22T/DOHC & 5speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX -SOLD
'96 BD-turbo'd-SOLD
'98 SF - NA-T
wtdash
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Duct / Splitter for the TMIC

Post by wtdash »

Part 2 of this project is to figure out a way to make sure the air coming in thru the scoop gets to the TMIC. As there's no factory splitter for the Legacy (all the Legacy's used an AWIC, AFAIK), this isn't something you can buy anywhere.

I built this doo-hickey (and I'm being overly complimentary of it) to help 'til I can come up w/something better.

I bought a 4 foot section of L-shaped aluminum, cut into 3 pieces, drilled some some holes to match the stock mounting holes, attached some weather stripping used on the bottom of garage doors and came up w/this monstrosity:
Image


I used a piece of pipe insulation (also from Home Depot) that I cut in half and screwed into two of the stock scoop's mounting holes. It sits snug on the rear of the TMIC to seal it off.

What I want to do next is build something that attaches to the TMIC itself, like what ScottyS did on here:Image.

Td
Turbo Subies:
'87 GL-10 Turbo - SOLD
'90 BJ EJ22T/DOHC & 5speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX -SOLD
'96 BD-turbo'd-SOLD
'98 SF - NA-T
Legacy777
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Re: RS Hood Scoop install - no cutting required.

Post by Legacy777 »

Todd,

Looks good.

I can't tell in the picture, but where did you drill into the hood, was it at one of the tabs that are covered by the stock hood scoop?

A suggestion, I would use some thin gauge metal and make a curved duct that attaches to the holes already in the hood to help direct air onto the scoop and won't allow it to hit the back of the scoop. You could probably shape something out of cardboard or construction paper and then cut/bend it out of metal.

If you're having a hard time visualizing what I'm saying (which I completely understand), let me know and I can try and draw something up.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

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wtdash
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Re: RS Hood Scoop install - no cutting required.

Post by wtdash »

JC,
I can't tell in the picture, but where did you drill into the hood, was it at one of the tabs that are covered by the stock hood scoop?
Yes, there's a tab on each end of the stock scoop hole....look @ the "full view" pic again and you can see where on each end it's screwed in.

I was thinking the same thing. I've got a piece of HVAC ducting that should work for that.
I bought something similar to this. It's easily bent, but should hold shape if mounted properly:
Image

Thanks for the feedback,
Td
Turbo Subies:
'87 GL-10 Turbo - SOLD
'90 BJ EJ22T/DOHC & 5speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX -SOLD
'96 BD-turbo'd-SOLD
'98 SF - NA-T
Legacy777
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Re: RS Hood Scoop install - no cutting required.

Post by Legacy777 »

Ok, I see them now.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
Lego22T
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Re: RS Hood Scoop install - no cutting required.

Post by Lego22T »

Very cool! I may have to look into this further.
'92 Legacy Sport - Daily Driver & SCCA AutoX (Class: SM)
"When in doubt, flat out!" Colin McRae 1968-2007
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Re: Impreza -OB / RS- Hood Scoop install - no cutting requir

Post by Lego22T »

I picked up a scoop from RS25.com as well and it'll be delivered today. After I make a quick run to Lowes for Speed Nuts and some peel & stick foam strips, I'll post some photos of how it turned out. I may also cover the section of the hood that sits under the scoop with some flat black vinyl I have to give the illusion that the opening is larger and mask the silver paint.
'92 Legacy Sport - Daily Driver & SCCA AutoX (Class: SM)
"When in doubt, flat out!" Colin McRae 1968-2007
kimokalihi
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Re: Impreza -OB / RS- Hood Scoop install - no cutting requir

Post by kimokalihi »

If you look at my build journal I did a similar thing with a wrx scoop. I also added some AC window unit insulation foam strips and spray adhesive glued them to my tmic so when the hood is closed it compresses the foam and creates a seal. Then I built a nasty lookin sheet metal splitter and mounted that to the hood to direct air into the intercooler and filled in the gaps with expanding foam. Not pretty but don't think any air goes around the intercooler anymore.
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Re: Impreza -OB / RS- Hood Scoop install - no cutting requir

Post by kimokalihi »

Or actually I think they might have adhesive on on side of them out of the bag and you just peel off the tape and stick it right to the tmic.
98 Metro Hatch Daily Driver :)
91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
"Your testes are close to your bottom but you still play with them all the time." Jeremy Clarkson
Lego22T
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Re: Impreza -OB / RS- Hood Scoop install - no cutting requir

Post by Lego22T »

^ That's what I was going to look for. I got the scoop on, but like everything else I add to my car it fought me. I ran out of day light so I'll have to wait until morning to snap a picture of the final result.
'92 Legacy Sport - Daily Driver & SCCA AutoX (Class: SM)
"When in doubt, flat out!" Colin McRae 1968-2007
kimokalihi
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Re: Impreza -OB / RS- Hood Scoop install - no cutting requir

Post by kimokalihi »

Home depot/lowes sells the ac window foam.
98 Metro Hatch Daily Driver :)
91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
"Your testes are close to your bottom but you still play with them all the time." Jeremy Clarkson
Lego22T
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Re: Impreza -OB / RS- Hood Scoop install - no cutting requir

Post by Lego22T »

Image

Image
'92 Legacy Sport - Daily Driver & SCCA AutoX (Class: SM)
"When in doubt, flat out!" Colin McRae 1968-2007
mike-tracy
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Re: Impreza -OB / RS- Hood Scoop install - no cutting requir

Post by mike-tracy »

Looks good on the more rounded front end of a post-face.
1992 Legacy SS 5mt, build in progress
Josh Colombo wrote: Mon Jan 14, 2002 10:23 am Wait....I'm confused now.
zeke
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Re: Impreza -OB / RS- Hood Scoop install - no cutting requir

Post by zeke »

I just did this on my 91 ss and it looks pretty good one the pre facelift in my opinion also my slanty sti intercooler is much cooler and my intake manifold is cold to the touch after some hard driving also
91 ss Ej22t dohc td04 sti Slanty haltech elite 1500
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