Impreza -OB / RS- Hood Scoop install - no cutting required.
Posted: Fri Nov 08, 2013 12:10 am
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:
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:
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:
Full view:
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.
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:
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:
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):
I think an '02-03 WRX scoop would work similarly but it does have a slightly different bottom:
Constructive Criticism welcome - This isn't NASIOC.
Thanks,
Td
Here's what I ended up doing....
The bottom of the stock RS scoop looks like this:
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:
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:
Full view:
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.
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:
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:
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):
I think an '02-03 WRX scoop would work similarly but it does have a slightly different bottom:
Constructive Criticism welcome - This isn't NASIOC.
Thanks,
Td