Anyone have reference charts or spreadsheets listing at what RPM/air flow secondaries kick in?

I'm curious about the E4ME but bet there would be plenty of interest for all the 4-barrel carbs.

 

You might find a chart or something that shows the factory setting, but then again they're adjustable.....

 

Here's what I mean by a reference chart or spreadsheet listing at what RPM/air flow secondaries kick in. For example, when pressing the gas pedal, how far does it have to pressed before the secondaries engage. For L69, LG4, and other engines using an E4ME carb, I would think secondary rods openings should be reasonably predicatable/repeatable. For example, an "F" hanger beings to raise at X,XXX RPM and XX MPH; or up until X,XXX RPM and XX MPH, only the primary rods feed the engine gas. Trouble is, as it's been pointed out before by five7kid in previous posts, that reving a carb in the crive is no way to test and actually see the secondaries open. Maybe I'm missing something but I don't know how to really observe when the secondaries open up when driving. A chart might provide some really helpful information. Or maybe someone has a tip on observing when the secondaires open?

 

On a Qjet, the secondaries are mechanically tied to the throttle linkage - like a Holley DP. They open when you pull the throttle open, always at the same place. Are you talking about the air valve? Its almost infinitely adjustable, so a table probably wouldn't be much help, especially since its operation is so heavily influenced by load/demand and other factors as well (displacement, cam, etc)

 

It's pretty irrelevant. As stated, the air valve opening will vary. It could vary from one day to the next if air density changes.

How much the primaries flow is about all you're going to be able to nail down. And that is only a rating, not the actual flow.

You really don't need to know when they're opening. All you need to do is adjust them so they operate properly, as described in the tech article. As the saying goes, if you can feel them opening, they're opening too soon (assuming you have enough stall to get in your cam & intake's powerband).

 

Air Adam, thanks for that point - the secondaries are linked and when the throttle is pressed they always open at the same point.

five7kid, thank you also for point that it's not supposed to be noticable when the secondaries start to open. I did not know that and will keep smooth acceleration in mind as a goal for carbs. Don't know why but had assumed there should be a sense of power when the secondaries opened.

But, I'm still curious at what point the secondaries open. There must be a rough rule of thumb on the limits of throttle travel that will only use the primary circuit (useful for economy driving) and also for knowing how much throttle is generally needed to open the secondaries.

 

Well, I guess we need to understand if you're talking about the throttle blades or the air valve.

Throttle blades - you can feel that as the throttle becomes harder to push.

Air valve - only as the engine can use it.

 

Throttle blades - I'm thinking that as throttle blades open, that is the when the secondaries actually engage (as large a volume of air begins pass through)