This is the chronicle of my home-made hood vent project.

I believe that form should follow function. And since the function of a hood vent is to extract hot air from behind the radiator, a bigger vent should yield more function. But at the same time, I didn't want to cut into the frame to accomodate a deep recessed scoop. And I didn't want a huge bulge sticking out the top of my hood, either.

So I reached a compromise. The idea was to build a scoop that's half recessed and half raised. I hit upon the idea of using the rear decklid as the mold. The hump in the notchback decklid is the perfect shape! The front edge of the hump can be used as the front lip of the scoop. And the back of the hump, turned upside-down, can be recessed into the hood.

So I pulled the decklid off my Fiero and went to work. I washed it twice with degreaser, then applied 4 coats of furniture wax, and finally a light coat of axle grease (just to be safe). In the photo below, you can see the glass fiber cloth being test-fitted onto the decklid hump.

Luckily, the glass fiber conformed to the shape with no problems. So I started the layup process. I used 6 layers of generic glass fiber cloth (available in hardware stores) with epoxy resin. I also used a small roller to smooth it out between layers. This helped to prevent bubbles.

The result looked like this:

Let me tell you, cracking the fiberglass loose from the mold always makes me a bit nervous. This made me especially nervous, because my decklid was at risk! After carefully working the fiberglass loose, I positioned the two pieces how they would be installed in the hood, to see how they look. The top of the photo would be the front of the hood.

I liked the way the two pieces looked, and so continued with the project.

The next step was to cut a hole in the hood. The sides are 2" from the crease lines in the hood. I'm not going to give exact measurements for the front and back edge, for a couple reasons. First of all, the location of the front and back will depend on the size of the scoop pieces you make. And second, there's some room for "artistic expression".

After cutting the hole, I tapered the edges with my angle grinder and a 50-grit sanding disc. The taper is roughly 1" wide all around. This, along with a matching taper on the scoop pieces, will help you create a seamless joint. See the diagram below.

The grinding creates a LOT of dust. You should at least wear a filter mask. Goggles and a long-sleeve shirt would help, too. You've been warned.

After cutting the hole, I test-fitted the scoop pieces inside. I found that the channel for the weatherstrip interfered with the back half of the scoop. So I had to grind it down. In the photo below, the green arrows show where I accidentally went all the way through.

If I had a chance to do this over, I wouldn't put the recessed piece so far back. That would probably eliminate the interference with the weatherstrip channel.

Now that the hood and scoop pieces are ready, it's time to bond them together. I hit the hood and scoop pieces with 100-grit sandpaper, then mixed up a batch of epoxy resin. The resin, along with a single layer of glass fiber cloth, will be used as the adhesive. The glass fiber cloth's absorbancy helps to keep the resin from draining away.

Several clamps and heavy objects were used to hold the pieces in place while the resin cured.

Here's a closeup of the joint. The transition from hood to scoop is almost seamless.

I was following you as you posted, so far so good. Want to see the finished product, when you get it done.

Kevin

Excellent idea! I'm really looking forward to seeing your progress on this.

Nolan

PS, A + for you!

[This message has been edited by Sourmug (edited 04-17-2006).]

Thanks for taking the time to post your build thread---its looking nice--waiting on the finished project like everyone else....

There isn't anything really interesting going on right now... just alot of sanding and some fill work.

Lately, I've been having problems with my resin gelling up too fast. With the sun shining down and 90°F temperature, the stuff goes ballistic. It actually melted the bottom out of a mixing cup!

So I put my resin cup in a big jar of ice-water to keep it cool. It worked! I had plenty of time to finish the layup work. And when the resin hit that hot hood, it warmed up and catalyzed nicely.

I guess you really do learn something every day.

putting the resin cup in cold water is a wonderful idea. i'll be using that trick alot now that i've learned it. + for you!

Today I cleaned up the edges of the scoop opening, along with some detail sanding. The fabrication work on the topside of the scoop is done. But the underside needs some more fiberglass. After that, I'll be in the home stretch.

Here's a teaser pic:

This morning, I laid some putty on the hood. I'm using an Elmer's brand "fiberglass repair kit" that I bought at Lowes. It's epoxy based with a creamy texture, and is relatively easy to spread. Plus, it has a pot life of 20-30 minutes.

would you be willing to make a quick copy (just a few layers of glass ontop of what you have done) ?
I really like the idea (as i used the bubble from a decklid for a hoodscoop a few years ago) but I think i'd rather have it the opposite of the way yours is layed out so a copy would be perfect...

pretty please?

Blacktree,

Simply awesome.

You have a PM.

[This message has been edited by exoticse (edited 04-20-2006).]

Nicely done, it's looking great!

Nolan

Very cool project...

From your initial photos & descriptions, I wasn't too sure how it would look... but seeing it on the car, it's really looking good!

I too will be watching your progress!

That looks GREAT!!

Thanks to everyone for the compliments. In return, I'll give you some shots of the hood... all one color!





As you can see, the scoop has a low-key look from the front and sides (the photos exaggerate that effect). But when you look at it from the rear, it's like "HELLO!"



I still have plenty of work to do on the hood. There are some minor imperfections, and lots of pinholes from the fiberglass molding process. Plus, I still have to lay some fiberglass on the underside to fill the voids that were created when I chopped that big hole in the hood.

But I'm seeing the light at the end of the tunnel... hope it's not a freight train!

Here's one more shot of the nose. The hood scoop is a little more visible in this one.

Good idea and a nice build !

any chance of you makeing copies to sell?

I'm with crazyfieromike, would you consider selling me one.....I would not expect perfect but somthing I could start with along with a little instruction sheet to "Help us along" (yes some men read instructions!) PM me if you would like. Thanks T.J.

quote crazyfieromike said: any chance of you makeing copies to sell?

Maybe, maybe not. We'll see. Even if I do decide to make a mold, it'll have to wait until after the car is painted (and buffed, and waxed). Until then, I still have plenty of modding to do.

Great ingenuity +. Keep up the good work...

Bob

Now begins Phase 2. It's not part of the vent scoop, but is related to the hood. So I thought I'd just continue the thread.

I know what you are going to do. You are going to male a C4 Corvette style hood where the top half of the fenders open with the hood.

I was gonna do that to my last project (but a buddys GT came u for sale, so Im too busy with it at the moment... that and im considering norms hood) anyhow... Nice set up you got going on there, the lights and this C4 hood are really setting it off IMO... vents pretty inventive too... Nice work

quote cire36 said: You are going to [make] a C4 Corvette style hood where the top half of the fenders open with the hood.

That's right. So far, it's been pretty easy too. Getting the hood and fenders lined up *just right* before bonding them together was a bit tedious, but didn't require any rocket science.

I removed the fender mounting bolts beforehand, and bonded the parts together on the car. This should keep the fenders lined up with the rest of the body. After the fiberglass cures, I'll cut the fenders with my trusty Dremel along the top edge of the moulding. Then I'll be able to open the hood again.

I'll also need to do some fiberglass molding on the underside... and then alot of sanding/grinding/prep work.

[This message has been edited by Blacktree (edited 04-27-2006).]

Just a thought, would it be better to cut below the moulding, that way, the moulding can move with the hood and the lower fender retaining features can be hidden under it (the moulding) when it is closed.

Just a thought.

Thanks for correcting my spelling error.

I decided to cut along the top of the moulding for a few reasons. They will become evident as the project progresses.

Today I cut the hood free, so I could actually open it. Having a hood that opens is a good thing, right?



It's still pretty rough, lots of finish work and fine-tuning to do. More to follow...

I like it.

Hey! Now that's just NIFTY!

Nice work with the scoop and fender mod!

Did you build or buy your flush light conversation?

hey, thanx for the inspiration BlackTree

looks like masking tape and a paint stick were your alignment tools (after the fender was detached, before you glassed them to the hood) am i correct ?

[This message has been edited by 88GTFormula (edited 04-30-2006).]

very nice! I planned on making a hood vent my next project, might have to get a spare hood as I'm currently painting it

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3800 SC/IC Fiero Goin' pearl blue...

To Boosted2003: I bought the headlight conversion kit from Kris Munson (PFF username "kmunson56").

To 88GTFormula: Correctamundo. That kept the hood and fender parallel horizontally. I also put shims under the hood in various spots to keep them parallel vertically.

Also, I used the angle grinder on the edges of the hood and fender to create a V-shaped channel. The fiberglass was laid down in that channel. I used 3 layers of glass fiber cloth, with epoxy resin. I had to do it in 2 stages. The first stage is the two strips you see in the photo. The second stage filled in the empty spots where the tape and sticks were.

That by itself seems to be strong enough to hold the hood & fenders together. The fiberglass is actually stiffer than the fender! But I'm also going to layup some fiberglass on the underside (after grinding a similar V-shaped channel). The fenders are kinda floppy, so I may end up reinforcing them.

Tomorrow (or actually later this morning ) I'll show you why I sliced the fender along the top edge of the moulding.

EDIT: It kinda goes without saying, but I removed the radio antenna before starting the fender mod. The antenna will need to be relocated.

[This message has been edited by Blacktree (edited 04-30-2006).]

quote Originally posted by Blacktree: EDIT: It kinda goes without saying, but I removed the radio antenna before starting the fender mod. The antenna will need to be relocated.

Theres a mod several guys have done just to loose the antenna and they fill in that factory antenna hole with bondo or some other filling agent... Thery mount the antenna above the fender well... I dunno if you've seen this mod or not... But one i get an extra set of fenders, I'm gonna attempt what you did...

WHEW! Wetsanding is alot of work! But my car looks sooooooo sexy now.



Alright, back to business. Here's why I cut the fender along the top of the moulding. There are 2 things that made me decide:

1) If the side marker light is attached to the hood, it will interfere with the frame. You'd need to cut a pretty deep notch in the frame (maybe even all the way through) to make room.



2) The bottom corner of the fender, top corner of the fascia, and wheel well liner are all held together by one screw! The screw goes through the wheel well, then the fascia, and into a body nut in the fender. If the bottom of the fender remained attached to the hood, there would be nothing to hold the top corner of the fascia and the wheel well together.



I'm sure these problems could be overcome with some time & effort. But decided it wasn't worth the trouble. Besides, the black moulding will still camouflage the seams. Black is good at hiding seams.

Tomorrow I get to play with putty! YAY!

YaY, got my tom's flushmounts with Kris's covers semi fine tuned... I guess a hood mod similar to this one may be one of my next body mods... and or possibly a vent mod. on the decklid... gotta figure out a few things for the rockers though... We'll see what happens... woohoo

sorry, keep the pics. comin blacktree 'whatcha doing next?'

Well, it's been a few days since my last update. I've haven't had much time to work on the hood. But nonetheless, I've made a bit of progress.

First of all, the vent scoop is practically finished. All that's left is sanding and prep work. This involved molding some fiberglass to fill the empty spaces where the channels in the hood used to be. I crammed some styrofoam into the voids and laid on the fiberglass. Then I chopped up some paint sticks, glued them to the hood, and sanded a nice curve to match the curve of the scoop. Then I laid fiberglass (and some filler) on top. This will provide a nice transition between the underside of the hood and the upward curve of the scoop.



I also took this opportunity to work on the underside of the hood/fender mod. As mentioned before, I laid some fiberglass on the underside of the hood/fender seam. You can see the rough fiberglass seam below.


Notice that the mounting flange (where the top of the fender attached to the frame) is now gone. I chopped it out and ground the area flat.

After the seams are smoothed out, I plan on molding some more fiberglass to fill some awkward-looking spots in the fender. There's also an alterior motive here: filling in those spots will provide a flat mating surface between the upper and lower fender. I can then stick something soft in there (like weatherstripping) to keep the two panels from chaffing. In the photo below, the yellow lines outline that area.

[This message has been edited by Blacktree (edited 05-06-2006).]

Nice.

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"Anyone can make a copy of something, it may look good but it ever is the real car, make something from your imagination, something unique, something nobody has, anything is possible and, ideas can be a reality."