What operates the 73/74 cowl induction flap?
Thread Starter
Instructor
Joined: Mar 2010
Posts: 228
Likes: 0
From: Evansville WI
What operates the 73/74 cowl induction flap?
I'll be honest, I have no idea if the cowl induction flap in my '73 works. I'm guessing it probably doesn't. I'd like to test it, and if need be, get it working. What triggers the flap solenoid, and where does the associated wiring run after it leaves the hood? What are the other parts of the system? Thanks for the info.
Drifting
Joined: Jan 2002
Posts: 1,645
Likes: 11
From: Schaumburg IL
I believe the same switch on the acc for trans kickdown is wired to the solenoid for the cowl induction. If the trans kicks down the circuit is good. Disconnect the plug on the solenoid and run +12 to the red wire just tap it and the solenoid should open up.
Burning Brakes
Joined: Jun 2008
Posts: 1,086
Likes: 1
From: Michigan
The switch at the top of the accelerator rod that activates the cowl solenoid gets out of adjustment easily.
As mentioned, go to WOT with the key on. You should hear the solenoid energize and the hood door open. If not do this first:
Reach up from the gas pedal, up the accelerator rod until you feel the switch. There is a cream colored stem on the right side of the switch. With your thumb push the stem up and toward the engine (push hard) until you hear a "snap". The switch is now in the self adjust position. The next time you go to WOT it will adjust correctly.
If you mess with your throttle linkage, replace the throttle cable, etc. you can do this procedure to automatically readjust the switch.
As mentioned, go to WOT with the key on. You should hear the solenoid energize and the hood door open. If not do this first:
Reach up from the gas pedal, up the accelerator rod until you feel the switch. There is a cream colored stem on the right side of the switch. With your thumb push the stem up and toward the engine (push hard) until you hear a "snap". The switch is now in the self adjust position. The next time you go to WOT it will adjust correctly.
If you mess with your throttle linkage, replace the throttle cable, etc. you can do this procedure to automatically readjust the switch.
Drifting
Joined: Mar 2011
Posts: 1,271
Likes: 1
From: PA
Even for a stock restore ? I wondered about it's need myself. I would rather keep the 73 stock but if the flap is just a gimmick that limits my performance I will delete it.. I assume once you step away from a totally stock set up it makes sense to not use the flap ? Saying just delete it seems like deleting the fiber optics on a 71 just because they are trouble and are not really needed.
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Le Mans Master
Joined: Oct 2005
Posts: 6,247
Likes: 471
From: Glen Allen, VA
my 81 Z28 had flaps on the hood that you could see open when you nailed the gas, feeding cold air directly to the air cleaner. Like mentioned above, I doubt it make one bit of difference in performance, but it was cool to look at. It must have been a similar set up to what is described above
Le Mans Master
Joined: Aug 2006
Posts: 7,431
Likes: 1,561
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
The scoop "hypos top engine performance"!
It says so right here in the original 74 brochure.
LOL
It says so right here in the original 74 brochure.
LOL
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Even for a stock restore ? I wondered about it's need myself. I would rather keep the 73 stock but if the flap is just a gimmick that limits my performance I will delete it.. I assume once you step away from a totally stock set up it makes sense to not use the flap ? Saying just delete it seems like deleting the fiber optics on a 71 just because they are trouble and are not really needed.
I can't remember any engine from any manufacturer not using a cold air intake in the last 30 years.
Here are a couple of previous discussions with some temperature readings you might find interesting.
http://forums.corvetteforum.com/c3-t...duction-q.html
http://forums.corvetteforum.com/c3-g...on-system.html
Have to make my L-48 sound fast some how "Yeah, and it even has cowl induction flaps that open up at WOT." 
