Port Nozzle Depth?

Has anyone done any experimenting on port nozzle depth?

I'm using the bodies that are 2-3/4" in over all length. About 3/4" of the tip protrudes into the port.

Correct me if I'm wrong, but the notch cut in the tip atomizes fuel as it leaves the body by bouncing the fuel off of the 45 degree angle cut into the tip.

So, what I'm trying to contemplate and process in my mind is whether the extra depth is really needed.

It would seem to me, that having it up higher would be less disruptive in air flow.

It would also seem that having it high in the runner could also cause a possible imbalance in valve cooling due to the fuel being higher in the port.

But, all I have is conjecture and theory. Does anyone have any actual data on whether a longer or shorter body is of benefit?

 

More theory for ya...

Do you insert the nozzle further into the runner and disrupt the airflow...

or

Insert it shallow and possibly have the atomized fuel hit the runner wall and puddle.

EDB

 

Just for grins why don't you hook your fuel pump up to a drill motor and run it connected to a nozzle. It might supprise you what the spray pattern from the nozzle looks like. I all engines there will be some puddeling around both the intake and exh as they are closed. Think about what happens in the overlap with the piston comming up to TDC and both valves are open! In A-fuel engines it is pretty much common practise to point the flow from the down port nozzles at the side of the runner. I have also heard of some that point down nozzles back up the port. Under any of these conditions the volume of fuel being discharged is so great that there is not much room left for air flow.

 

Which side of the runner? Could you elaborate a bit more? The down nozzles are typically straight shotgun nozzles with screens, or something else? Thanks.

 

Correct me if I'm wrong, but isn't A/Fuel naturally aspirated nitro? I'm talking about a blown alky application.

When both valves are open, you simply push boost and fuel straight through.

I had thought about converting the bodies to the straight screens as well. Right now I'm running whats in the photo below, which has no screen.

 

we have done some exspermenting with this and alot of the hard hitters told me to turn the bodys facing up towards the blower that way it atomizes better so we tryed it...and yes we left them facing up seem to work better..Dave

 

But what about the length? How far do the bodies protrude into the air stream?

 

...interesting!

I wouldn't want to try that NA.

EDB

 

I don't see why it would matter if it was N/A or blown.

Where do you think the fuel comes from when a carb is bolted on top?

 

works well with turbo's too


ash

 

My comment was in regard to aiming the nozzle up instead of down...

EDB

 

So was mine.

 

Why does it seem that more alky blown motors inject in the intake manifold runners vs injecting right by the intake valve like so many NA motors?

 

Give it a try and see if it works. I don't believe it will.

EDB

 

I have seen a past world champs pro mod engine apart and he had 2 nozzles in the top and 1 from underneath in the intake .

 

Barry and Todd Paton is the one who told me to point them up..It seems to work well

 

Nozzel placement

Manifold nozzles should protrude the minimum into the port and of course should face into the manifold and not at the valve. Injector nozzles should face out the injector and not down into the blower. These are not huge gains but are dyno proven --- 50+ hp and are used by most of the quick runners . Its called atomization !!!!

 

With this changed atomization,,,
Is it safe to simply reverse them and not change the fuel settings or does a guy need to give it more or less fuel?

 

On an other post Mike Canter said that the blower would cause the nozzle not to flow as good with all the boost, I said noway, but now i can see what was said could be right with the nozzle facing the blower. plus all that dyno talk is not right, unless there's a fan used that can put out 250 mph wind blowing into the hat.

 

WJ,

Let me see if I fully understand your question. Are you wondering if you can simply remove the additional tip portion so less is in the runner? Is your theory that having it reduces effective port size and essentially disrupts flow?