Hone injectors?

[suburbanK-2500HD]

I came over this article at a web site, has anyone heard of this..??


Extrude honing means that the nozzle is rounded inside and holes
made larger for better flow. The size of the holes is determined by
the needs of the customer.
To increase 8% on a truck could mean 50HK and 5-10% lower consumption.
It can of course be increased as much as one wants, and often combined with other tuning to keep burning as normal as possible.
The major advantage of increasing the holes in the nozzles is that we can bring in more diesel at the same time, so that we can not burn far down in the cylinder which increases the exhaust temperature drastically and melt down the engine.
This is the way to do it in terms of: trucks, tractors,
boats at all where we spend a lot of power over longer periods.

[JohnC]

...To increase 8% on a truck could mean 50HK and 5-10% lower consumption.
...
The major advantage of increasing the holes in the nozzles is that we can bring in more diesel at the same time, so that we can not burn far down in the cylinder which increases the exhaust temperature drastically and melt down the engine. ...

Why would you want to melt down the engine?

(I don't understand what they are trying to say.)

Bottom line: The injectors cannot deliver more fuel than the injection pump pumps. Stock injectors are adequate for stock fuel levels and making them bigger won't, by itself, change anything.

(Later)
OK, maybe they are trying to say that the bigger holes allow more fuel to be delivered faster. This is true, but, still, if you don't increase the pump output, there isn't more fuel to deliver. Also, higher flow injectors are less efficient at atomizing the fuel when the flows are more in the normal range.

[Robyn]

I think I understand the theory here.
Get it in quick and keep the burn happening in the very upper reaches of the power stroke.

Unfortunately the pump can only flow so much so quick for any given RPM.

The IP must reach the opening pressure of the injector (POP PRESSURE) then at that point the fuel flow starts.

As the fuel flows in during the burn, the pressure steadily drops off until the injector slams shut and cuts off the flow.

Larger holes will definately change the atomizing characteristics of the injectors.

High pop pressure makes for a better, cleaner burn and helps cold starts.

Having the nozzle holes cleaned up to offer the best flow is not a bad idea but in and of itself will not make the injector flow more fuel beyond what the IP can deliver.

The duration of time that the pressure is between the Opening and closing threshold is where fuel is delivered and still the pumping chambers capacity is the limiting factor.

In theory, if the pop pressure is dropped off some and the low side pressure (Closing point) is also dropped, the flow will increase some.

The downside as mentioned is that this results in High EGT's

My feeling is that the best "Happy medium" is when the IP is set to (Or the computer program) is set to deliver the maximum amount of fuel possible at WOT, and use a well ballanced set of injectors set to pop at around 2000 PSI.

The rattle is not obnoxious and the performance is good.

Meltdown occurs for a couple reasons.
If the user has set the fuel delivery way to high and allows the EGT's to get out of control and or if the injectors are not spraying correctly and causing localized hot spots (peeing a steam rather than a fine mist)

Now, on a common rail system where full fuel pressure is a constant and the injectors flow characteristics are the controling factor in how much fuel flows the game is totally different.

A slight modification in the nozzle holes could be of significant value.
This would allow more flow during the "Pulse width".

The Rotary plunger pumps are going to force in whatever fuel is in the plungers/chambers no matter what.

The pressure starts high and then drops as the volume falls of, followed by the injector slamming shut.

Just some thoughts.

Missy