There is no ram air effect below 120mph. It'* proven to be a myth, time and time again.

You don't have a 'tank' of air. It'* your individual runners that are drawing air, and the #5 and #6 are alot more apt to be able to draw that air. Path of least resistance. Just like water and electricity.

The developed flow behind the TB plate is pointing torward it.

so no one never did compare the insert of the dorman upper to the gm i like to know if i can expect the same power

Of course the plenum is a tank of air. That'* it'* purpose...to be a tank of air that feeds the individual runners.
If you want to compare the plenum full of air to water, call it a full basin with 6 equal drains. If compared with electricity, a battery with 6 equal leads connected to it. No one gets an advantage.

If you read the thread, you'll see that I'm making the point that ram air is somewhere between "highly unlikely" and "impossible" for explaining the hypothesized "advantage" to cylinder 6, and for the very reason you stated.

You are saying there is a constant pressure differential inside the UIM between the "front" (or TB end) and the "rear" (PCV end)?

I can see there being higher pressure inside the plastic "throat" behind the TB, but there is no way this high pressure "zone" extends as far inside the UIM as runner 6. Even if it did, it would provide no more "advantage" to cylinder 6 than it would have before I cut them down.

Ultimately, if cut-down runners were causing "smoked plugs" or leanness in specific cylinders, we'd be reading alot about that on forums from HV insert owners.

The air has to turn to enter the HV insert, and alot of R&D went into developing and tuning it. Do you know if the runner openings are even the same size in it?

We're giving the best advice to you that we can based on our knowledge and experience.

The UIM isn't designed to be a reservior. It'* designed to create a specific-length runner for each cylinder.

Drop the pressure thing for a second and think about the direction of flow.
That runner is basically a pocket for the air coming through the neck into the plenum.
Originally, the air shot into the plenum and probably lost a good amount of the inertia given by it'* original flow direction before it even got to the runners. Now, it still has whatever inertia it has through the TB and UIM neck POINTED at that runner.

In the HV insert, the flow has the inertia pointed in the direction of the UIM neck and moves over the first 2 runners. In your case, the inertia is pointing toward the wall of that #6 runner.

I'm not convinced the HV insert does give even cylinder filling but it doesn't have the neck pointing at 1 runner. If all goes planned with my next header setup, I will be able to find out. (6 egts)

I'm not trying to come off as if your idea suks or anything like that. This and variations of it are just things that I have thought about for the past couple years. Things I've said in here are all things I've thought to myself at one point or another.

I mean your car isn't going to blow up or anything, it'* not like your dumping a lot of money into this, and it'* not like you can't just swap the stock or a variation back in very easily. So, by all means go for it.
I was just putting that out there to think about and possibly remedy.

Like many zzp products (e.g., the Powerlog), it seems to me that alot of user "guinea-piggage" went into the HV insert before it arrived at it'* current iterative version

I really do appreciate the comments...though the difference between advice and criticism is all in the timing

I know that the UIM creates specific runner lengths. But I maintain that it also acts as an air reservoir.

No offense taken. This is the only car enthusiast site I've ever been involved in where newbies don't get insta-flamed just for having ideas, and actual debate takes place. That'* why I like it!

I probably won't have much more to add to this thread until I get around to on-car testing. That'll be some weeks into the future, because first I've got to:

As far as the "advantage" to #6, the only way to settle whether there is one or not is testing. There can be plenty of hypothesis and theory to support either argument.

We'll just have to wait and see. :P