Roof Scoop

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Major System Category: Body (Shell)
Task: Mount the roof scoop
Parts: Roof Scoop (Optional Part)
Prerequisite Tasks: Mount the body
Additional Costs:
Time Requirement: 5 hours
Date Started: September 6, 2012
Date Completed: September 15, 2012
The roof scoop is more than just a pretty piece to add to the GTM's exotic look. It is a functional air scoop designed to force cold air into the engine bay (in motion) and to allow hot air to vent from the engine bay (at rest). It is a molded piece of fiberglass that needs to be centered on the roof of the car.

Roof scoop from the front. The opening requires trimming.

Consideration: The instructions I found for this were in threads on the Factory Five Forums. The description of the item on the FF website indicates that some body work is required.

Rough initial fit. There is a lip that anchors to the from the wind screen opening.

These are the items I have identified so far:

1. The scoop is longer than the roof, so the end will have to be trimmed. I am pretty sure this is by design.
2. The intake scoop is not open. This needs to cut out.
3. The slot in the rear of the roof (basically close to the rear portion of the roll cage needs to be cut out. I am making mine 12 x 1 inches.
4. The scoops needs to be fiberglassed to the roof.

Rear of the roof scoop. The untrimmed section overlaps the hatch .

I did my measurements. The scoop is approximately 26 inches wide. However, do not assume the scoop itself is centered. Measure from the edge of the roof line to get an approximate center, then measure a center line as well. There is a front lip that helps to position and anchor the scoop.

The slot is marked for the scoop cut out. This be covered by the  scoop when it is installed.

I moved my slot as far back as possible. I wanted to leave enough material so as not to compromise the strength of the roof line supporting the hatch. It seems very light weight right now, but once the glass is installed, it will get significantly heavier.

The scoop after excess is trimemd from the rear end of the piece.

I need to double check where the slot exits the roof on the underside, to ensure it is on the engine bay side of the rear class. The roof scoop requires two different cuts into the fiberglass prior to install.

1. The scoop's front opening.
2. The slot at the rear of the roof.

This is the front cut into the roof scoop. I suppose this could be completed after the scoop is mounted, but it is much easier to do this when the scoop is on a bench.

I mounted a cut off wheel on my Dremel. I know other builder's use a reciprocating saw for this work, and I sure it is very fast. I was more interested in precision. The battery charge on the Dremel was up for each cut. After I cleared away the excess debris, I used a drum sander (also on the Dremel) to even out the edges.

This is the slot just forward of the hatch (that's a nice even gap on the hatch, if I sat so myself). The roll  bar is visible .

The final piece for the roof scoop is bonding it to the the roof. I checked with other builders blogs and build journals (there are no instructions for this entire procedure). Most people decided to go with 3M 8115 adhesive. Most people griped about the cost of the gun (approximately $60). I think it is a good investment! Chances are there will be something that needs bonding. I got a great deal on Ebay.

1. 8115 gun.
2. 2 adhesive packs
3. 6 nozzles

This is where the center of the scoop mounts. It is around 9 inches up from the edge of the window.

The 8115 system is very easy to use. I marked the areas of the roof that would act as the mating surfaces for the scoop. I put a generous amount of bonding agent down, troweled it with a spreader and then mounted the scoop per my measurements. (I measured this one multiple times.) I used a combination of clamps and weights. In my case, 8 lbs boxes of 9mm bullets. I set them down in a train on both sides of the scoop and let it set up over night.

This area is the band between the edge of the scoop and where it is raised for air flow to the back slot. This averaged about 4-3/4 inches. This isn't necessarily cut even on both sides, so you really need to measure from the edge of the car to the raised area of the scoop.

The final thing I did was run a bead of 8115 bonding agent along the edge of the  scoop - like a caulk line on a bath tub. The final touch is to glass the scoop edges into the roof and create a seamless boundary.

She is clamped down and weighted down for the night, The instructions say 4 hours to set up if the temperature is 73 degrees or higher. We're starting to see night time temps in the fifties so, I let her sit all night long (about 18 hours total)..