73/74 fresh air through the power bulge... Anyone out there ever try it?

[73runner]

I've been toying with the idea of making the power bulge hood functional. My idea would involve removing the trim covers and cutting out the section behind the "louvers" trim. The idea would be then to put in two covers that would pivot out under low vacuum signal or via a vacuum switch similar to the pop up air grabber set up. that would get you two 7 square inch opening to start with. From those openings i would then mount an air box to the hood where it would mate to the stock air cleaner base via a similar rubber foam set up to what you just described. The stock snorkel on the base I would section and blank off at a point just ahead of the carb. heated air inlet to allow for quicker warm ups in cold weather. Or leave the snorkel alone and do a cool air intake passage and duct between the battery and the radiator to the snorkel.


This set up would allow via the switch (or control of you left foot during rain storms etc) the "nostrils" to remain closed in bad weather.


The cool part would be that the covers would open when you gunned it like the flaring of nostrils on a wild animal.......

thats what they look lie and I bet that was the idea for them when they did it.

 

[Roadbird]

I like it! Sounds good, post some pics or illustrations of your idea?

 

[rebootej]

My uncle and i are talking about doing this to my 74. thing thats been hanging me up is how to close it, i like your idea, but i think i would want the vents open when idling, seams like she needs cooler air then. His idea was something like a manual choke cable.

 

[YY1]

I've always thought these hoods looked "snorty", and felt having all that engineering and parts content without functionality left quite a bit on the table.

I've thought several times that it might be a relatively easy project to make it functional.

Some of the challenges as I see it:

Despite the huge castings, the actual area for cutting holes is somewhat small.

Removing the entire casting to gain size for intake holes also removes a substantial amount of styling.

I figured the easiest way was just remove the small plastic ribbed inserts, drill through the thick pot metal "nostril" casting- perhaps a 1 inch by 2 inch oval per side, perhaps cut out the center brace on the underside that interferes with even putting on a taller air cleaner, and finally rout some hose between the new holes and the air cleaner element.

That would get fresh, cool air in the vicinity of the intake/air cleaner.

If you really wanted "ram air" a gasketed solution would be doable, but IMO, since the intake holes are relatively small, and not really above the "boundary layer", might not be worth the effort.

Hinged openings as described by the OP run the risk of acting like air brakes, and would need a really strong hinge, since it's length would be relatively small compared toa factory hinged A/G. Just sayin'...

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70 Super Bee and 70-74 Challenger rallye/sport hoods are much easier to make at least partially functional- simply remove the plastic trim, and you've got fresh air.

I always wondered why Cuda hoods and 73/74 RR hoods had a much less modification friendly design.

 

[rsd859]

I like the idea, My 400 would love to breathe in some fresh air. Keep us posted.

 

[Bruzilla]

I did it to one of my 73 road runners back in the 1980s. I removed the louvers and cut out the area behind them just as you are planning to do. I used a Dremel tool with a cutting bit to do it. Then I got some heavy black steel screen mesh from a hardware store and applied to the back of the inlet and fixed it in place using some JB weld-type epoxy.

I then made an airbox by taking a side out of an old Navy metal desk I found, and cut out a base that was the shape of the area under the bulge. I cut out a hole for the carb neck to fit through. Lastly I got some thick rubber padding that was about 6" high and an inch or so thick that we used on the carrier for insulation and I glued that all the way around the base plate. I put the base on the carb, then put the air filter and pie pan cover on and that held the base in place.

Next step was closing up the openings on the rear of the bulge on the underside of the hood, and I can't remember what I used to do that. I think it was some remaining pieces of sheet metal from the desk held in place with JB Weld. Anyway, when the hood was closed, the rubber insulation sealed the base plate to the hood and all the air going to the carb was being brought in through the bulge openings.

The last thing I did was mount two amber 1157-type bulbs just behind the mesh I put in the inlets. When I was racing at night, I would flip those lights on and it would make a nice orange fiery light effect coming out through the inlets and down the hood. I got a lot of compliments on that.

The one thing I didn't do was put some insulation on the base plate, which would have kept the heat from the engine from making the base plate hot and heating the outside air as it came in, but even without it I noticed a lot of difference when I was racing during hot nights in the summer. That 70 degree outside air coming in was a lot denser than the 100+ degree engine bay air.

I'm planning to do the same thing to the 74 I have now. The only thing holding me back is I have the louvers painted Steelers gold as a contrast element on the hood, and I like the look. If I can find some heavy enough mesh to paint that color that'll stand out as well as the louvers, I'll be making the bulge functional again.

 

[rsd859]

Ive gotta see some pics of how this is done!

 

[RICHIES ARMOR]

I was considering this as well. I was going to cast a set of the louvers in fiberglass so I didnt ruin the only set I have.

Anyone interested in a set? Wouldnt be too expensive to do.

Richie

 

[rsd859]

I would like to see how the fiberglass ones turn out.

 

[RICHIES ARMOR]

Ill put it on my projects list.

Richie

 

[Bruzilla]

If you do what I do, your louvers will be safe and sound. What gets damaged is the insert piece that bolts to the hood and that the louvers go into.

 

[Lowhound]

I seen something similar that was did to a bulge hood but it was on a 70 Superbee. It was actually on an older episode of My Classic Car. A lady & her husband fabricated an air box which attatched to the underside of the bulge & had another half as a base around the carb.

 

[rebootej]

richie id be interested too

 

[73runner]

Dug up some spare bulge inserts to begin Operation : "Snorting Little Bird"

You are all welcome to add to and join along on this journey

i guess because I'm an architect that went to a school better known for engineering I like to get my thinking and the problem organized. Since this is a needlessly complicated problem that I am trying to solve.... Just for the damned fun of it. (some people collect stamps.... But oooooh nooooo...not me, nothing that easy for me), I like to think through the problem first.

Also, the most optimal solution to any problem the best solution becomes obvious when you take the problem completely apart. Over time and a bit of study, I've found that the process requires just a little organization of the problem and goals.


First, mission statement: or "to get to the moon someone's got to define the goal and limits"

The mission is to allow for cool outside air directly into the carb through the use of air intakes already molded onto the 73/74 road runner power bulge hood. This design will be for refit system of hardware with bolt on type assembly of components to limit damage to stock pieces where possible and minimize changes to the "look" of the original design. Likewise, the solution should be " period correct" Simple and elegant is better than complicated and ugly. Use of custom fabrication to be limited where possible and use of off the shelf similar parts will be maximized. The solution must be visible and visually pleasing in operation.

Problem issues: let's get a list and tackle them one by one. Feel free to contribute.

1) Getting through the stock cast insert: I started looking at the pot metal cast inserts and YY1 is correct. The allowable opening, if you take just the area behind the louver insert, it is too damned small to allow much air in. This is compounded by the fact that it will take a fair amount of " plumbing" to get the good air into the carburetor (read:Restriction).

2) Tight space: There is precious little room to work with. Will need to take careful measurements to and from. Measure and draw time....

3) Ducting: Getting from the carb to the new snorting intake will take the air over the a/c compressor and other heat sources that will need to be dealt with.

4) Rain and Snow: It rains occasionally and we drive our cars in the rain so we'll need to deal with that.

5) Warm-up drivability: Cool air is bad for cold carbs and intakes.... Especially in winter. The preheat will need to stay and be left operational.

6) Controls: Control must be provided for severely bad weather and added cool factor. How and where do we put it will need to be solved.

7) Linkages and operating systems: Motors and mechanical bits and pieces that will be required.

8) Research: This has been done in similar ways when our cars were new so let's get a period correct collection of systems together.


ok guys.. Lets do this! Pick one issue and solve it and let's work together.... Who's in?

I'll work on my own solutions and work in any applicable solutions or critiques you come up with posting as I go.

 

[rsd859]

Im in, Im more of a hands on and trial and error type of guy. This is something im interested in doing/learning/helping.

 

[Bruzilla]

Agree 100% on the duct issues, which is why I went the airbox route. Ducting makes the system too complicated and inefficient as the point of the system is getting OAT air into the carb and those ducts get hot over time and lesson the benefit. If you're getting a ram air effect, such as removing the high beams and replacing with air ducts, then that can compensate for the temp gain, but there's no ram effect from the hood due to intake height.

By the way, not to challenge you and YY, but there is plenty of room for air in those openings. I know that for an absolute certainty as I had a 550HP 440 breathing through them for a couple of years.

 

[UKPlymouth]

I enquired about this elsewhere. I have the feeling that due to the manner that airflow works, it would have very little benefit to the car. Has the impresssion that scoops need to be in the vicinity of 3" high minimum to be effective.No problems either though besides weather etc...

 

[73runner]

Ukplymouth....I agree that we would get no benefit of any positive pressure out of any air we get within the boundary air layer where the scoops are. In fact it might even be negative given their location so close to the nose and all that roiled air at speed.

But that's not really the point here... The little bit of ram air at typical speeds is also pretty negligible in comparison to intake air temp from what I've heard and read. Still working on some research on this so if I'm wrong please feel free to let me know.

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Agree 100% on the duct issues, which is why I went the airbox route. Ducting makes the system too complicated and inefficient as the point of the system is getting OAT air into the carb and those ducts get hot over time and lesson the benefit. If you're getting a ram air effect, such as removing the high beams and replacing with air ducts, then that can compensate for the temp gain, but there's no ram effect from the hood due to intake height.

By the way, not to challenge you and YY, but there is plenty of room for air in those openings. I know that for an absolute certainty as I had a 550HP 440 breathing through them for a couple of years.

No challenge felt by anything you can contribute.... Thanks. You know a lot having already done this.

I'm measuring the interior engine bay next week when I get back from a little trip with my family. Also, I think I may have licked the opening issue. Working on some sketches to cut out some ideas in cardboard. Stay tuned....

Good point on the ducting getting hot.... That was one of the issues I noted above.

I did the headlight thing on an old jaguar and it made a noticeable seat of the pants improvement in power and drivability . I live where it gets plenty hot during the spring summer and fall....so I know this will make a big difference for me... Sort of like when I drive a warmed up engine on a cool winters day....you can feel it like in your seat and hear it when you chirp the tires when and where you usually don't.....


found this link right here on this forum for similar Mopar systems...check it out for ideas (not pricing)

http://www.pgclassic.com/advanced_s...ubcat=1&keywords= &categories_id=4&azrefine=1

 

[73runner]

Here are some images for 70 and 71 air grabber set ups to add to our research.

 

[Bruzilla]

The last time I did this, I was a broke-*** Navy E-5, which was why I used a sheet metal panel cut out of the side of a junk desk for my baseplate. Like the ducting, that would get hot over time as well. I was wondering with technology today if there wasn't some material that could be used to make the baseplate that would not absorb heat?

I was also thinking of an article I read a couple of decades ago about a "who's faster?" race between a Chevelle and a Hemi Road Runner. The road runner had a fresh air system that had an ice box added to it. The owner would put ice in the box before racing, and the air would flow through it on the way to the carb. I never had a road runner with air conditioning, but it always made me think it would be cool if I did have A/C to tap a duct into the cabin system and use a vac switch to route it to the air box. I read somewhere that air from an A/C should be at like 40 degrees, so that would be flowing really cool air to the carb.