hood scoop sag

[chopthebass]

Do you guys ensure that the front top of the hood scoop has same curvature as the hood? Mine has sagged, so I was wondering whether to heat up with hairdryer and try to bend the other way? I can make sure fixing holes achieve the same. I'm not to impressed with the hood quality.

http://i1252.photobucket.com/albums/hh562/cobra427427/Cobra%20Build/IMG_0248_zpsefget9j9.jpg (http://s1252.photobucket.com/user/cobra427427/media/Cobra%20Build/IMG_0248_zpsefget9j9.jpg.html)

[GoDadGo]

Just scoot the sides in a bit and it will create an arch. Tape in in place and make sure you like the positioning before you drill any holes. Measure 2,3,4 or 5 times before you drill or cut anything. Also, remember to use your CLECO fasteners. Should you want to upgrade to an aluminum piece, you can find one at Finish line accessories. They are about $250.00, but a small price compared to the finished product. Good Luck!

[2bking]

Like GoDadGo said, just squeeze it and the middle will rise. Measure the overall width with the curvature you like and mark it on the hood before starting to drill. A lot of builders trim the lip off the inside and round the edges to make it have a more aero look. (I did also.) It also makes it look more like the original scoops.

[Jeff Kleiner]

As the others have said it will spring/arch upwards when the sides are squeezed inward a bit and secured. I cut most of the turned down lip off of the ABS ones I do.

In case you are wondering here is how I lay out to cut the hood.

http://i269.photobucket.com/albums/jj43/jkleiner/Steve%20J/100_4863.jpg

http://i269.photobucket.com/albums/jj43/jkleiner/Steve%20J/100_4861.jpg

http://i269.photobucket.com/albums/jj43/jkleiner/Steve%20J/100_4869.jpg

This leaves the hole smaller than the inside of the scoop so that you have a good area for the flange to lay on and cover the opening. It will keep all of the fasteners nicely inside the underside inset and allow a bit of "wiggle room" for getting the scoop right on the centerline.

Jeff

[chopthebass]

Hey Jeff. That's interesting. I set the hole out exactly as manual - 19" from front, 8" from sides etc, and I matched your corner radii (by luck!). However, when the scoop is positioned (as per manual) the rivet holes in mid-point of rear scoop radius are right on edge of hole! So, I had to move scoop back 3/4". Not an issue with the looks though. The manual says 4" from front, and good job I did this as moving 3/4" still meant the opening was under the scoop.

[Gumball]

My Mk3 has the earlier fiberglass scoop, so some of this won't apply, but I did quite a bit of work on both my scoop and hood. I cut off the molded-in scoop and added a separate rivet-on scoop (actually #4 stainless button head screws). But, both the hood and the scoop received quite a bit of attention.

I filled most of the hole in the hood to make the opening look more like the original cars and to help direct more air into the turkey pan. Some builders used to add a small lip of a couple inches under the leading edge of the scoop, but I added something along the lines of 8" - 10" total.

The outside of hood during final bodywork to smooth the patch:

http://i845.photobucket.com/albums/ab15/CCRsAC/1sandinggaphood_zps77f47b7b.jpg (http://s845.photobucket.com/user/CCRsAC/media/1sandinggaphood_zps77f47b7b.jpg.html)

This view shows just how far back under the scoop the hood extends before the opening:

http://i845.photobucket.com/albums/ab15/CCRsAC/HoodScoopSandedHSRF4_zps7f1a1983.jpg (http://s845.photobucket.com/user/CCRsAC/media/HoodScoopSandedHSRF4_zps7f1a1983.jpg.html)

I also did quite a bit of shaping of the side flange and the front edges - and like Jeff, I also removed most of the lip along the opening and left only a small rounded edge:

http://i845.photobucket.com/albums/ab15/CCRsAC/Graduation/IMG_20150614_173007998_zpskibeunpl.jpg (http://s845.photobucket.com/user/CCRsAC/media/Graduation/IMG_20150614_173007998_zpskibeunpl.jpg.html)

Not sure if this is needed with the newer scoops that are made out of SMC, but the original FFR version that was molded into the hood was more like a ski jump than the scoops on the original cars, which followed the contour and downward slope of the hood. To correct the scoop contour issue, I sliced a pie-shaped piece out of each side that was 3/4" of an inch or so at the front down to an 1/8" hole that I drilled at a point about 2/3rd the way down the side. I then used a small tab of aluminum and some clecos to pull the top down so that the pie-shaped slice was now a consistent 1/8" separation that I fiberglassed together.

This pic shows the slice, but the width of the surrounding flange and the front edge are not yet the final profile that I used - still a work-in-progress at this point:

http://i845.photobucket.com/albums/ab15/CCRsAC/Hoodscoop4_zps5e33b5b6.jpg (http://s845.photobucket.com/user/CCRsAC/media/Hoodscoop4_zps5e33b5b6.jpg.html)

Before and after pics of my scoop:

http://i845.photobucket.com/albums/ab15/CCRsAC/FrontPassThreeQuarter.jpg (http://s845.photobucket.com/user/CCRsAC/media/FrontPassThreeQuarter.jpg.html)

http://i845.photobucket.com/albums/ab15/CCRsAC/Graduation/IMG_20150614_172553889_zpsshrcoy8g.jpg (http://s845.photobucket.com/user/CCRsAC/media/Graduation/IMG_20150614_172553889_zpsshrcoy8g.jpg.html)

And here is the scoop profile on CSX3049, one of the original S/C cars, which was my goal.....

http://i845.photobucket.com/albums/ab15/CCRsAC/CSX3049/img_4290-1.jpg (http://s845.photobucket.com/user/CCRsAC/media/CSX3049/img_4290-1.jpg.html)

[mikeinatlanta]

Some good advice here, but to directly answer your question:
Assuming the scoop is made from either polyester or vinylester fiberglass. You can permanently deform it with heat, however, you must be very careful to not get it too hot and damage the resin. I suggest using a heat lamp or IR heater rather than a blow dryer or heat gun. You will want to heat the scoop to no hotter than about 210. Keep an eye on the temp using a non-contact IR thermometer. I suggest cutting a 2x4 with a concave curve with a slightly tighter radius than you want and clamping the scoop into it with vice grips. You then want to heat the whole mess up for a few hours. After cooling you will get some spring back, but the shape will be much closer to the final shape you are after.

If the scoop is made from plastic, it is thermoplastic so forget everything I just said.

[Jeff Kleiner]

If the scoop is made from plastic, it is thermoplastic so forget everything I just said.

That's exactly what the original poster's scoop is ;)

After having done several of both FFR's old 'glass scoops and the plastic ones they started supplying a few years ago I prefer the plastic; much closer to "ready to go" as delivered.

Jeff

[mikeinatlanta]

Yep, if thermoplastic reforming is mucho risky for total part melt down.

EDIT: For clarification. Most thermoplastic parts of this type are not cast, but made by thermoforming sheet stock. Thermoformed sheet stock will always retain just enough memory that when reheated it will attempt to go back to its natural flat state, and any stretched areas will attempt to shrink back to original size. Without a mold and vacuum, putting more curve into it will be very difficult. Best to bow it up like others have suggested.

[PaulW]

Hey Jeff. That's interesting. I set the hole out exactly as manual - 19" from front, 8" from sides etc, and I matched your corner radii (by luck!). However, when the scoop is positioned (as per manual) the rivet holes in mid-point of rear scoop radius are right on edge of hole! So, I had to move scoop back 3/4". Not an issue with the looks though. The manual says 4" from front, and good job I did this as moving 3/4" still meant the opening was under the scoop.

I had exactly the same issue with mine. As you said just scooted it back a bitand solved the problem.

[chopthebass]

Got it mounted with Clecos, and squeezed the front closer to create a curve. Jeff was bang on with using 8.5" instead of 8" from sides.

I would amend the manual to say 2.5" from rear, not 1.5".

FFR, please take on board some of the numerous issues highlighted on the Forum! Thanks