84 z28

I tried to adjust my idle screws on my 650 mighty demon carb last night. I try to get the highest vacum out of each screw but the olny way I got a good vacum was if I turned the idle screws all the way in. Now If turn all the idle screws all the way in my car should stall out right ? I left them as I had them before 1 turn out but this is really boggling my mind. I dont know if this matters or not but I also have a 1 inch open carb spacer. Any suggestions would be helpful.

sofakingdom

iTrader: (1)

Why?

What kind of intake is this?

Where are the throttle blades at idle, with respect to the transfer slots? (that is, how much of the transfer slots is showing?)

Does this carb have the idle thing in the center of it? What do they call it... Idle EZ, or something like that?

84 z28

I have a weiand stealth intake and the throttle blades are open equally primary and secondary touch more than the .020. And yes its has the idle ez on it but it dosent work worth a crap. That is adjusted out to what demon recommeds it to be for an intial setting. And why not a 1 inch spacer it creates more plenum volume and helps the air/fuel mixture. I have the

http://www.highvelocityheads.com/ss.htm

sofakingdom

iTrader: (1)

Right; we're pretty familiar with the Super Sucker.No particular reason; it's just potentially part of a combo that works in conjunction with (or against, as the case may be) the rest of the parts of the combo, to be used as a tuning aid; which is to say, the process goes something like, measure performance, install part, re-measure, compare results, which way did they go? remove part or leave part accordingly. Not, "Hey great ad copy! I'll stick one on" or "Everybody has one" or "Joe Schmoe at the track put one on his 1939 Hupmobile V-14 and picked up a second and a half, so it must be great".

Spacers tend to improve upper-RPM power by adding plenum volume to a single-plane intake (VERY important: results can be RADICALLY different on a dual-plane), which in turn reduces the amount of pulsation that the carb sees from each individual cyl's intake event, which in turn reduces the carb CFM requirements since the flow is some lower, more nearly steady-state value closer to the "VE" equation result, as opposed to being so much of a series of "peaks" (cyl fill events) which a carb must be sized for, and valleys (the time in between cyl fill events). Teh Super Sucker in particular adds the function of smoothing out the transition between the carb and the plenum, such that the air doesn't come right straight out of the carb and into the bigger volume. On the other hand, if there's no plenum, then it doesn't do that; it does something esle. Who knows what.

All that aside, I'd suggest first off, taking off the spacer, and seeing what happens.

Clearly it's idling too rich. Whatever you do, should be in the direction of getting it to idle leaner.

IIRC the Idle-EZ feature is designed to put the idle mixture roughly into a range within which the mixture screws have the proper effect. I.e., set the mixture screws to some reasonable amount, like 1¼ turn or ¾ turn or whatever; then get it somewhat close with the other thing; then dial it in with the mixture screws. What happens when you try that?

You're doing the right thing trying to set it to max idle vacuum, of course. That's the right way.

What power valve is in it? Which "Stealth" intake is it, since that's not exactly a "model", but rather a "product line"?

84 z28

I can try the carb with out the spacer and see what happens its very resposive right now. You mash the gas and its up to 6,000 in a second. And the intake I have is a weiand stealth PN#8016 http://www.holley.com/HiOctn/ProdLin...AMSM/8016.html
And the power valve in the demon is a 6.5 and I also have the stock jetting 71 primary and 79 secondary. These seems ok ?

I will try and play with the idle ez a little bit more and see what happens with tuning. i thought it would have been a good option to go with since I have a pretty big cam.

wrsjr

Could be a blown power valve.

327_TPI_77_Maro

iTrader: (8)

If your throttle blades are open too far at idle, you will be drawing fuel off the main circuit, and the idle screws will have little to no effect. That may be what's happening

redfire82

heck if it runs good, why bother trying for best vacuum?

84 z28

I think your right. I'm going to have to take the carb back off and start with the .020 open slots and see where I go from there.