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I finally got the Corvette I've been waiting for for nearly 30 years. So I am new to Corvette ownership and this forum. The corvette that I got is a nearly unmolested '74 454 coupe that was in storage for years and only has 67,000 miles on it.
The only thing that appears to be missing is the Astro Ventilation plenum. The underside of the vents were closed off with a painted piece of aluminum.
My question is, Does it work well enough to go through the trouble to track down the pieces and reinstall the system?
I was also thinking of fabricating a custom plenum and attaching a computer base fan that would be run off of a photocell mounted on the back deck to ventilate the interior when it is parked in the sun.
You would think that they would have installed the parts on all the cars....and have the vents open on an a/c car when the control was set to vent...but noooo.....only on non a/c cars.
There are some vacuum parts and/or cables involved, so it would be a challenge to incorporate on an A/C car. I'm considering some sort of door arrangement that would be operated manually.
I tested the whole idea by removing the two plates and found a couple of problems that may only apply to convertibles. First, you need lots of air volume out of the vents to create enough positive pressure in the cabin to overcome the high pressure area right behind the top. Second, all the seals on the top have to be PERFECT to allow the cabin to pressurize.
Basically on mine, it just sucks in warm air (we're talking hot right now) once I start moving. On a coupe, the area behind the rear glass might be low pressure and it would work better. I used small streamers hanging down over the openings to check airflow in or out.
When I first bought the car I was scrathing my head trying to figure out how it could possibly work and figured it must have been removed. Thanks for enlightening me.
Last night I told my Wife that the car has lied to me twice now. The first is a running battle as to whether or not the door is actually a jar or not (bad switch) and now that it has Astro Ventilation when it never did.
She said "That settles it the car is a Male." I told her that I disagreed and ran away as fast as posible since it would be an argument that I couldn't possibly win. :banghead:
thanks for that. How can I tell if I have the astro ventilation?
If you have an air con car there is no Astro Ventilation other than it says you have on the windows! I have an AC car with most of the AC missing so I took the blanking plate off the vents and leave them open.
I like the computer fan idea to exhaust more air from the cabin but I'm considering using the vent fans they use to get air into race car cabins and put them where the kick panel doors would have been in a non a/c car. Refitting all of missing air con to my car is beyond my budget at least for the time being.
...how do I find out if my 1974 with A/C have astro ventilation?...
Astro-Ventilation is nothing more than a trade name for GMs fresh air vent system for early C3s. All 68-75s had Astro-Ventilation. AC cars had Astro-Ventilation but used different ducting for cool air handling which non-AC cars did not use. Door glasses have Astro-Ventilation scripts.
Last edited by Easy Mike; Feb 26, 2016 at 07:39 AM.
Astro-Ventilation is nothing more than a trade name for GMs fresh air vent system for early C3s. All 68-75s had Astro-Ventilation. AC cars had Astro-Ventilation but used different ducting for cool air handling which non-AC cars did not use. Door glasses have Astro-Ventilation scripts.
Thanks Easy Mike, that helps a lot. I need to replace the driver side window on my 74 with AC. should I get the window with or with out
the Astro-Ventilation. I saw an article that said they installed all
the 74's with windows that had the Astro-Ventilation script on them.
I have to say that this forum has been great for info that is
otherwise hard to find.