I was a the light the other day and a 1970 chevelle with a CI 'Flapper' Hood was next to me at the light. I noticed his flapper was very responsive to the slightest movement of his throttle. When he left the light the Flapper moved even though he was barely giving it gas. Is there a way (and there must be) to make the flappers that responsive. Actually looked pretty neat have the CI work at regular crusing speeds vs only at heavy or WOT.

MAC

I don't have any idea other than he might not be running a check valve. Maybe a healthy cam? (on 2nd thought, I guess I do have a couple)

LK

Probubly saw that you where looking so he had to stab the throttle a little extra? Vacuum holds it shut so low vacuum is what made it come up, so if he has a radicle cam and low vacuum it would jump up sooner. There is a flow control valve that I am just learning about here on another thread (my car did not have it, I just got it) that slows down the responce. I had disconected mine when it did not have the flow control valve as it was bending the flap more than I liked

I just repaired mine...goes up nice then closes slowly as it should. I think if you take the flow valve out, it would repsond faster?

Yes, remove the flow control valve and it will open up very fast but the only problem with that it will wear out your vacuum pod :yes:


Flow control valve:
http://www.ss396.com/mm5/graphics/00000009/sm/AXL-913_sm.jpg


VACUUM POD ACTUATOR:
http://www.ss396.com/mm5/graphics/00000009/sm/ACC-0417_sm.jpg

Yes, remove the flow control valve and it will open up very fast but the only problem with that it will wear out your vacuum pod :yes:


Flow control valve:
http://www.ss396.com/mm5/graphics/00000009/sm/AXL-913_sm.jpg


VACUUM POD ACTUATOR:
http://www.ss396.com/mm5/graphics/00000009/sm/ACC-0417_sm.jpg


sounds cool, just pic up some spare actuater pods ;)

Yes, remove the flow control valve and it will open up very fast but the only problem with that it will wear out your vacuum pod :yes:


I have owned my 70 SS 4 speed car for 10 years and 70 SS auto for almost 7 years and I do not have a flow control valve on either and have had no issues with the vacuum pod.

Some good information above, and here are some additional comments.
First, there is a good purpose for the flow control valve (or check valve). The vacuum source, which actuates the vacuum pod for the outer door, needs to come from a GOOD manifold source (coming off of one of the intake runners is good). The flow (or check) valve is basically a one way valve. It allows strong flow in only one direction and VERY weak flow in the other direction. THE VERY BEST check valves were the original factory valves. Frequently, the replacement and/or repo valves don't work as good as the originals. The check valve's function is to allow the vacuum supplying the pod to suddenly drop under power or hard acceleration conditions (when manifold vacuum drops real low). Then, as manifold vacuum returns, the check valve permits a VERY weak flow of vacuum to the pod so that it closes slooooooooooooooooooooowly. Another thing which affects the functioning of the pod is the strength of the spring inside the pod. A weaker spring won't open the door quite as quickly as a strong spring. BUT, a strong spring may prevent the vacuum source from closing the door. Not all pod springs and check valves are created equal.
Furthermore, as already mentioned, a cam profile will have a definite affect on the vacuum levels.
MOST OF THE TIME, if you do not have the check valve in the vacuum line, the outer door will open very quickly AND CLOSE very quickly. Thus, the desired effect of the opening/closing of the outer door is less than desired. The door should open quickly under strong acceleration (or heavy power conditions) and then close somewhat slowly. The slower the door closes, the better the visual effect (if that's what you like, and I do!).

Dave,
I hate to be the bearer of bad news, but ALLLLLLLLLLLLLLLLLL Cowl Induction outer doors flatten out when the pod is functioning properly with good vacuum. Sorry! That's just the way they are.

I have an ORIGINAL check valve that I use for shows. I have a repo valve that I never use because it doesn't flow like it should and I have a few of the check valves (black/white plastic) that were used on some kind of 80s or 90s GM econo 4cyl cars to control the air flow into the air cleaner. Those valves are now discontinued, but for functionality, they work as well or better than the original CI check valves. Several years ago, someone right here in CT told me about them, I bought one, it worked great, so I bought 2-3 more.

It will respond sooner on an engine with low vacuum / radical cam.
Right now mine only opens when I slam it to the floor. My next cam should solve that problem.

Tom
Thanks for all the info, do you know the part number for that discontinued piece they used in the 90's?

I know Tamraz has the repo ones on ebay for $10 plus shipping. How's the quality? Don't know.

Tom
Thanks for all the info, do you know the part number for that discontinued piece they used in the 90's?

Yep, it's 8997639.
And here it is with the box and instructions which come in the box.
http://i65.photobucket.com/albums/h219/DZAUTO/100_1187.jpg

BUMP

i've just ordred the entire CI assemby to re-hook up my CI and i will not be running a check valve. i have spare pods incase one gets damaged, but i am going to film the door on my car once finished without the control valve, and you will be able to see the diffrence here with your eyes. So how ever long it takes for the parts to get here. does anyone else have any reccomendations in reffrence to this?