My 69 has the cowl hood with a working "flapper" set-up and switch to open under full throttle. Why not have it open all the time? It sure seems like you don't get a lot of air around that valve when it's closed which is most of the time and with the air cleaner sealed to the hood that's all the air the engine draws from. It obviously is enough to run the motor but it seems like under cruise and anything under full throttle you're really restricting the air for the engine.

Unless someone can tell me why not to, I'm removing mine. I don't drive in the rain which is the only reason I could come up with.

Jody

I put about fifty thousand miles on my 67 with the fresh air hood. No air valve and no problems at all!
My buddy disconected his, he got mad at the air valve stuff for some reason or other.
I'll bet there are more Camaros running around without the valve than with.
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Chev 350 Can-Am Vintage Racer

i bet it had to do with cold engine performance-drivability and emissions.the same reason most cars had the hose that went from exhaust manifold to the snorkel on aircleaner-it really helps when it is cold out. but, in reality, how many old camaros like that get driven in the snow? not a lot, i'd wager..i personally would get rid of it real fast on any car i ever got.

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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16" IROC wheels

I would be willing to bet that all of the camaros built and sold in 69 when the system was designed got driven in the cold, and 99 percent of them owned in areas tha have snow got driven in snow. It's only now 30 years later that the owners keep them locked away for 5 months a year. All of the air you need to operate the car comes in thru the snorkel under the hood. Every car (except the high performance large displacement engins that were equipped with open element air cleaners) in the late 60's came with basically the same air cleaner setup with a single snorkel. Automatics had the air preheater valve in the snorkel to preheat the air on startup to help low speed drivability when cold.

There is no increase in air brought in by the cowl induction hood until you build up the high pressure area at the base of the windsheild. The only way to have that high pressure area built up is to be traveling at some speed.

The cowl induction hood was designed to provide cold air to the carb under full throttle and high speed conditions.

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Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11

I don't have the flapper at all with no problems. Of course, until I seal off the base, I'm not getting the full benefit but anything to enhance better breathing and air density is goodness.

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Rick Dorion
69 RS Conv,355,M20,4.10's

Thanks guys. I removed mine. Actually forgot about the snorkel on the stock assembly as I don't have the stock air cleaner on the car. I'm going to seal the base to the bottom of the hood and that requires the removal (in my opinion) of the flapper for air intake under normal (non full-throttle) conditions.

Thanks again.

Jody

Is there anyone out there that runs the open cowl induction and DOES run in the rain and snow??? Sounds like you might have, David (rain at least). I need some cool air to my intake, and am looking at either making a cowl induction hood, or using a forward facing scoop, but don't REALLY want to set up a door on it. Any thoughts?

My 69 has the GM cowl induction hood, and has no problems. I have recently converted mine over to Big Block. It has no flapper, cage, etc. I have no problems. Keep this in mind, there is alot of heat coming out of that opening in the hood. Where does that heat run? Right into your cowl in front of the hood, and right into the car through the Astro Ventilation system. My car is very hot to drive in the summer. Just something to keep in mind.

I'm running mine open, also. Besides dumping heat into the interior of your car, it also puts EVERY smell that's in the engine compartment inside with you. Oil, anti-freeze, leaking exhaust (such as a burned header gasket), whatever, the smells all come inside the cars interior.

Well, I have a 1983 T/A with the hood cowl on it. The vaccuum sensitive swith that opens it under full throttle failed, so I tied it open. Since I was going to drive in the rain and snow, I worried about the moisture getting in, so I took the whole mechanism off to see how it worked. I found that it has a reservoir with drain holes at the bottom, and that the air must travel through an awkward route so that any moisture would be dropped into the reservoir and drained out into the engine bay. I also worried about water getting in when washing the car, so I checked inside the air cleaner box right after washing and saw no trace of any water. I no longer drive my car in the nasty weather, but when I did, it ran just fine with the flap open at all times, and I actually seem to get a bit better gas mileage with it propped open like that.

Hope this helps,
BW

Thanks guys
Am going to go with the Harwood 4" cowl for my 87 and had some concerns about wet conditions. Wont take it out in the rain but you never know how weather changes while at work. Also have no heater/defrost and thinking the cowl may even help keep the windshield from condensing up on those 4 a.m.going home from work nights. Not to worried about fumes since "everything" under the hood is new. Was wondering if I could set up a flapper that I could close from inside the car just in case I needed it, kinda like a manual choke cable on the dash? Hmmm.
Bob

I am certain you could rig it up that way, but you really don't need to. If a high pressure hose doesn't flood the cowl when it is open, then a rain shower certainly shouldn't either.

If you have the right parts, you won't get any heat; if the rubber seal on the flange seals to the hood inner panel, nothing will exit through the opening at all. There are two different extensions (rings) and three different air cleaners for ZL-2, and if you don't have the right combination for your engine, carb, and intake, it won't seal to the hood.

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JohnZ
'69 Z28 Fathom Green

I put a lot of miles on my fresh air hood with no problems rain or shine. I even went skiing in it at Yosimite, but I think that was before the fresh air hood was installed.
I never got any hot air out of the hood or into the vents.

I used the correct air cleaner and seal, but left off the spacer to fit my taller old tarantula type manifold.
No water will get in there unless you stick a hose in it! There is a drain hole at the rear anyway.
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Chev 350 Can-Am Vintage Racer

I don't run the internal flapper on my Elky at all, no problems. With the air cleaner sealing to the hood cool/cooler air than engine compartment air will feed the engine at any speed! Cheap horsepower! The internal flapper restricts that air flow, I tossed it. As for fumes in the car I've had no problem since I sealed the firewall holes and repaired the floorpans.

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Life aint easy when you're fat and greasy

just reading another post about cowl induction, and thought of something. maybe the flappers are there to keep gas fumes out of the cowl vents that lead to the inside of the car? at low speeds,or just sitting there, fumes could come into the car and cause headaches and other problems, and some people don't like the smell of high octane gasoline.

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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16" IROC wheels

The air is going IN the cowl, not coming out, so I doubt any fumes would come from there. If the seal is good, then it is basically as good as running a hose from the carb out to the exterior of the hood. Personally, I think the flapper is just a gimmick. The sales guy can say "and when you really need power and stomp on it, this little flapper opens up and feeds the engine cold air!! watch this!"

if the car is parked and not running, the fumes could make their way into the interior, unless it was parked into a headwind, then i guess air would be going in, just like going down the road...but it could also be some kind of a marketing thing, i guess. or a combination of both?or how about if someone gets in their car and lights up a smoke with gas fumes in there?-BOOM...well, far fetched, but i bet the lawyers got in on that one..

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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16" IROC wheels

If you don't have a cowl induction air cleaner with it sealed to the hoodunderhood air does come out the flapper area. Under hood air is at a higher pressure under almost all normal driving conditions since the grille of the car is acting as a giant ram air scoop pushing air through the radiator and into the engine compartment. The only reason for having the cowl is to bring in COOL outside air directly to the carb. Using the high pressure area at the base of the hood is a good way to get this COOL air into the carb. Why GM didn't decide to use a ram air system is beyond me, maybe there isn't enought room in the grille area of the first gen camaros for the hoses and scoops. Or maybe it was just a continuation of the 67 and 68 cowl induction system that drew air into the carb through the cowl panel using a styling change on the new 69 body style.

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Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
My 69 Pace Car (http://www.townisp.com/~markcanning/camaro/7498pc4.jpg)

I have a home built seal to the hood on my 76, and have the valve wired open. I've driven in LOTS of snow and rain with no problems. I have a few small drain holes in the pan. It did make a small difference at high speed, but I origanally made it to get cool air to the carb. When I lived in deep snow, I always cleared the snow off before I left, or i would see chunks if ice getting pushed in. still, whenever I floor it, the flaps vibrate and if there are any leaves or snow there, they go right in, but never had any problems.

I have a coarse screen that covers my cowl opening. Leaves don't get through it, but if I start the car when there is snow over the opening, the snow magically disappears in the blink of an eye, hehe. Looks funny actually "slurp".

...well, my car has functional cowl induction and while I wouldn't go out on a limb and say I can feel the difference, it's one of those neat options you can see working. Nail the throttle and see that little flapper open! Oh sh*t! Look out for that tree!!

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- John -
69 Z/28 (http://www.camarogenerations.com/memberfiles/firestone.html)
69 Z11 (http://www.camarogenerations.com/memberfiles/firestonez11.html)
Camaro Generations (http://camarogenerations.com/) Member
WCA Member