Injection Timing/Flow/duration discussion

[88Racing]

Southpaw

Good discusion topics!

Big ol'can of worms.

Lars

[Jackpine]

I THINK you knew I was kidding, I hope. Sometimes, I can sound too serious. (I blame it on my Wife - Janet will say, with a perfectly straight face that something totally hideous is "beautiful", and, because she's much more artistic than me, I'll believe her)! :o

I DO think you've opened a productive discussion topic and I hope I didn't derail it. I absolutely agree with all the points you made, and I just wish I knew more about the subject so I could contribute! But, what I know about diesels, you could put on the point of a pin.

- Jack

[soutthpaw]

yep I knew you were kidding.

[Blowby]

Injection Timing= when during the exhaust/compression stroke do we start putting fuel in the cylinder

When is the right time you ask? Let me ask what type of delivery system are you going to use, I mean in detail, since the delivery of fuel will control the point in time enough fuel enters the chamber to start ignition, the delivery system of fuel and oxygen will control the burn rate (time to complete) and the delivery system of fuel and oxygen will dictate the type of pressure and heat created in the combustion chamber to generate mechanical force on the piston and crank.

[theSLEEPER]

This is the thread I was looking for the MOST out of.

Blowby... Could you simplify your question a little? When you say "fuel delivery", do you mean the injectors? Or what?

[Blowby]

Tip hole dia, P&B ratio, oil modifications, HPO method.

[theSLEEPER]

Ok. I see what you're talking about now...

Meaning, if you were running something like Stg 2's with 80% nozzles, and stock oil, and standard 238 hybrids with 200% nozzles, and stock oil you'd want to open the Stg 2's earlier, since they're gonna take longer to empty? Or will the P&B ratio of the Stg. 2 vs. the Hybrid make the Stg. 2 empty quicker?

I'm sorry, I thought I was on track here until I started taking the ratios into account...

Blowby, who built your injectors?

[Power Hungry]

There are sooooo many variables to take into account with modified injectors that it's extremely difficult to nail down specific timing curves and flow rates. Even the difference between EDM and Extrude Honed nozzles will change flow characteristics, atomization, and combustion points.

As always, I am more than happy to share what I know (time permitting) and am actually in the process of writing an application that will take a standard calibration and uses adjustable sliders to determine calculated values such as SOI (timing), Pulsewidth, and a few other functions. This is mostly to help determine just where in the grand scheme of things we are starting and stopping the injection events to help determine if specific calibrations may be running more timing that expected and causing engine failures. However, it's also a useful diagnostic tool to see just what we should be expecting with specific modifications.

It's going to be a while before it's finished as I have other, more pressing tasks at hand. Rest assured though, it's going to raise a few eyebrows when I start running files through the scripts.