I'm happy with mine without the flow control valve.

 

How does the door function? Open when running, closed when off?

 

You can make it work that way, but to make it right, you need the inner door as well with the electric solenoid that is controlled at the accelerator pedal. The inner door is not needed though to make a functional outer door. The door is closed until wide open throttle, the it gradually closes as vacuum evens out. Door opens when the engine is shut off. It will stay closed at idle when properly set up.

 

My main goal for now is to get it mounted. So I guess in the way described would be the way to go till funds add up for the complete install.

Thanks!

 

Hey Mal, if you like you can come & take a look at my working Cowl Induction on my 71 this weekend, I am just north of you in Brookfield off of Mooreland Road & Greenfield Avenue.

Jim

A.C.E.S. 4996


Frame off red 71 Chevelle SS496 Convertible with white stripes, top & interior loaded with factory options: TH400, cowl induction, power windows, locks, cruise, tilt, top, trunk, 12 bolt 373 posi, A/C, AM-FM 8 track, power drivers bucket seat, mirror map light, trunk, hood, glove box lights, on the wheel GM air pressure gauges, Delco Jac Pac 175 (under hood vacuum powered air compressor) with under dash Delco air pressure controller/regulator, complete with Jac Pac 175 air shocks.

http://chevelle.ogleonline.com/jim.htm

1952 Chevrolet 4 door Deluxe Sedan with a 216.5ci in line 6 with the last RAJO (RAcing JOe) Power Cylinder Head designed by grandfather in the 1940's. Joe designed, built & sold all over the world performance heads during the 20's, 30's & 40's starting with the model T Ford. Joe drove in the FIRST INDY 500 in 1911 as car # 8.

Watch for my SS496 Chevelle as a pace car at Indy in 2011 (100 years after Grandpa Joe) IF THEY WILL LET ME !

 

what exactly does the inner door do? I dont have it hooked up on mine.... should I? would it flow air better?

 

Originally posted by ChevelleSS7D2:
what exactly does the inner door do? I dont have it hooked up on mine.... should I? would it flow air better?

In reality, it's only part of the gimmick, and in my opinion restricts air flow even when it's open. The real function is in the raised cowl of the hood that lets the fresh air in even without the cowl flapper.

When I bought the complete kit for mine I immediately saw the inner flapper as useless, in my opinion anyway.

For correctness, it should have it though.

I have the complete inner flapper and related hardware I'll make somebody a deal on.

 

Ok, here we are at Cowl Induction class. The course number is 101, so pay attention students!

Cowl Induction ( factory 1970 thru 1972 )is designed to funnel outside fresh cool air into the air cleaner for a more efficient running engine. With the car shut off, the outer door is spring loaded open/tilted upwards, when you start the car, engine vacuum pulls the outer door closed by a somewhat large diaphram "Pod" immediately underneath the hood so the hood is all nice & even & flat.

When you stomp on it, engine vacuum decreases & a the spring pops the door open to allow fresh air in as described above, that is the first step.

The second step is an electric switch on the gas pedal similar to a brake light switch, that operates a solenoid inside the hood that opens up a wide "flapper" door inside the hood.

So, step on it, engine vacuum drops, the outer door opens, at the same time the switch on the gas pedal opens up the inner hood door & presto, you have "High Performance".

There will be a written as well as an oral test on all of this at 0300 CDT tomorrow morning so study hard, if you fail, you will only have authority to drive a Pontiac Aztec, & I don't think any of you want that. So good Luck & may the force be with you.

Jim

 

Jim nailed it. He is better at describing it than I !! As for your question on the inner door. The only way it will really hinder the operation of the system is if it doesn't open with the solenoid operated switch. A closed inner door would restrict the air flow.

 

Hey Jim,

I would like to take you up on that offer. This would clear up all my questions. Here is my email.
smentecki@wi.rr.com Could you email me w/ a phone# and address so I can hook up with you this week, or weekend? Or is the Greenfield & Moorland deal a show? Is it possible I may have ran into you at the DeMarini's Pizza Rod nite on Thurdays awhile back?

Looking forward to hearing from you.

Steve
'71 SS350

 

Am I to understand that to make the door funtional that all one needs is the door, hinges, bolts, pod, pod bracket, flow control valve, and vac line?

If I set it up in this manner for now at idle it will remain open? Then gradually close as I accelerate correct? Correct me if I'm wrong.

Steve

 

Steve, you want the door closed at idle. Open at WOT. Then it will open when engine is off.

 

Yes I know. But as of now I don't have the air cleaner anyway. So as I descibe above, is that the way it will function till I snag the rest of the parts?

 

Well if I could read, I would have known you didn't have the air cleaner ! I missed that. I still don't think it will open at idle, will it ??

 

It should. From the info I read anyway. From what I gather the vac is at its highest at idle, correct? Thus closing the flap. Then as you tromp the throttle vac decreases, thus opening the door, no? All I'm trying to figger out is how will it funtion in the way I describe with having only the vac pod routed to the manifold. The pod operates the hood door, correct? And the solinoid/relay operates the inner valve door, correct? The pedal switch, and relay switch operates the flapper door on the hood only while gas to the floor correct? So, I think if the pod is the only link in the operation, it should open and close as to the amount of vac that is supplied, no?

 

Here's a pretty good explanation of Cowl Induction. It's about Camaro's...but the theory is the same. I read somewhere that the flapper on the top of the hood was more of a marketing thing not so much a performance benefit. People liked the way it looked. The article explains the reason for the inside flapper.

http://www.camaro-untoldsecrets.com/articles/rpo_zl2.htm

 

Great link, and excellent reading. I realize the funtionality of the inside valve door. However, I am just starting the add-on, and will only be able to run the hood door for now. Again, the issue is: Will the hood flapper work as I describe?

Steve

 

It will function fine with just the pod hooked up..this is how both my cars are set up.

 

You are correct. The flapper opens when vacuum is low (full throttle or engine off) and closes as vacuum increases.

 

Good, I'm relieved. I can't afford the huge sum for the cleaner, and other parts right now. So, at least I will have the cool do-dad movement, even though the air is not feeding.

Thanks to all who responded.

Steve

 

Steve,
You are correct in your understanding as to what it takes to have a functional OUTER door. Because of your budget restrictions, or whatever, I agree that this would be the way to get started with a CI hood. If you want both the looks of a CI hood as well as a properly functioning outer door, you have the right idea. As your budget allows, you can always add the additional underhood parts.
All of the above is good info, expecially the CI Hood course. Study hard for the test, most people fail it the first time!

 

Hey DZ,

How exactly does the harness wire up? I cannot find for the life of me a harness color coded schematic for the accel switch/solinoid/relay deal. Can you help?

Steve

 

OK Steve,
There is a total of five parts for the complete elec portion of the CI system:
Wire harness (repo, its an excellent harness)
Gas pedal switch
Bracket for gas pedal switch (with screws)
Relay (and screws)
Solenoid (and screw)
First thing to do is install the wire harness through the firewall. The firewall has 2 square holes, one for the existing acclerator cable, and below that square hole is another square hole with a plug in it for the CI harness(remove the plug, if you have pwr brakes, the brake booster hides these holes). The CI harness has a round grommet to go into the square hole (I'm serious!) Feed the harness through the square hole (one pink, one tan wire and then 2 pink wires with connectors) and push the round grommet into the square hole.
If your car HAS a turbo 400, you already have the second and third parts (switch and bracket). The harness for the t-400 will have 2 pigtails at the switch, so you just plug the CI harness into those 2 pigtails (it doesn't matter which wire goes to which pigtail).
If your car DOES NOT HAVE a turbo 400, then you have to install the switch and bracket at the gas pedal. The bracket for the switch REPLACES the existing pedal shaft retainer (held in place by two screws) so that the switch can be installed. Then, plug the CI harness connectors to the terminals on the switch (2 pink wires with connectors, doesn't matter which plug connects to which terminal). Next, the pink and tan wires connect over at the fuse block. The pink wire connects to the IGN terminal and the tan wire just above it (the connectors/terminals are designed so that the connectors can ONLY go one way, thus, you cannot connect them wrong). The relay attaches to the firewall with screws and there is a double connector on the harness with pink/tan wires which will ONLY connect one way to the relay. The other tan wire connects to the third terminal of the relay and then goes up to the solenoid at the hood.
Did I confuse you?
If you don't have a factory assembly manual, get one. ALL of the aftermarket sources sell them (about $20 I think). There is a section in the back of the assembly manual for factory options which includes good info/illustrations for the CI hood.

 

Thanks DZ! I do have the ass-manual, and along with your detailed info, I now believe I have everything, and the knowlage to install the complete workings. I have the complete inner valve ass. coming also. Big James was kind enough to sell me one.

The one thing I do need is the correct spacers for the hood door hinges. You or anyone know where to aquire them?

Again, many thanks to you and all the guys for helping on this. It has been a wealth of info.

Steve
'71 SS350

 

Steve,
Those spacers ARE NOT available, ANYWHERE.
So, you have 2 choices, fabricate your own, or, use washers. Washers work just great, and are nearly impossible to see once the hood is installed.

BY THE WAY, ONE VERY CRITICAL THING TO REMEMBER!!!!!!!!! BE EXTREMELY CAREFUL ABOUT THE LENGTH OF THE BOLTS WHICH YOU USE FOR THE FLAPPER DOOR BRACKETS-----------------------IF THEY ARE TOO LONG, YOU WILL PUNCH DENTS INTO THE HOOD SURFACE FROM BELOW!!!!!!!!!!!!!!!!!! CHECK AND DOUBLE CHECK THE LENGTH!!!!!!