When is to much duration?

[Jonesy]

When is too much duration 2500,3000,3500 wanting some input from anybody just to see what everybody thinks.

[Boost]

I am not sure if it's that simple.

[2007 5.9]

Typically nothing over 3300uS...

[WisconsinHick1]

I don't go over 3000us on the Duramax's.

[2007 5.9]

^^^^^ Typically on Cummins...over 3100uS ends up with a bunch of heat.

And the timing required to efficiently burn that pulse is dangerously high.

[700kenny]

I have been running 3100us fuel and 27 degrees timing with stock injectors on mine. My best combination i have come up with yet.

[DoghouseDiesel]

You have to do the math to figure out how much time you have available based on RPM and how much timing you're running. You also have to figure in injector close time, plus electronic to hydraulic delay to see how much duration you can run at a given point.

Dust off that calculator.

[06redram]

Rich do you have the formula to the math

[killerbee]

CADeg. Injector open duration can be expressed as the number of degrees that is swept by the piston. Crank Angle Degrees

[DoghouseDiesel]

Rich do you have the formula to the math


CADeg. Injector open duration can be expressed as the number of degrees that is swept by the piston. Crank Angle Degrees

Yes, I do, but it's not just one simple formula that I use. I have several of them that I built into a few Excel spreadsheets that I use in the tuning process. The way I have them setup, I basically input a few key parameters and the formulas reference data in certain locations to give me the outputs I want. These form my base parameters that I then modify to get the exact outputs.

Below is an example of one of the ones I have built when I'm using the MCC software. I have a more of these built for that simply because MCC is such a PITA to use vs EFILive. If / When EFILive decides to cover the 2010+ models, I won't have to use so many damn tools. These aren't the duration tools, but you get the idea of the complexity involved.

http://i288.photobucket.com/albums/ll189/Cumminalong/TuningTools.jpg

So yes, I do have the formulas, but simply because these are what I use this for business, I don't give these out.

[killerbee]

{SAE.RPM}*{GM.MAIN1T_DMA}*3/500000

This is a CADeg calculation from my calcpids file. Main1T is the injector open duration in uS. You can use this to build your own spreadsheet and apply your own rationality rules. The 2 main issues to avoid are early pressure spikes (HG issues) and late shutoff (oil contamination). What those numbers are are a matter of debate.

[06redram]

Yes, I do, but it's not just one simple formula that I use. I have several of them that I built into a few Excel spreadsheets that I use in the tuning process. The way I have them setup, I basically input a few key parameters and the formulas reference data in certain locations to give me the outputs I want. These form my base parameters that I then modify to get the exact outputs.

Below is an example of one of the ones I have built when I'm using the MCC software. I have a more of these built for that simply because MCC is such a PITA to use vs EFILive. If / When EFILive decides to cover the 2010+ models, I won't have to use so many damn tools. These aren't the duration tools, but you get the idea of the complexity involved.

http://i288.photobucket.com/albums/ll189/Cumminalong/TuningTools.jpg

So yes, I do have the formulas, but simply because these are what I use this for business, I don't give these out.

Thanks for the clear understanding Rich!

[DoghouseDiesel]

As for how much duration is too much....on my own truck, I only run 3000uS or slightly higher in 2 cells of the entire tune.

With REALLY larger injector trucks, I don't even come close to 3000.

[700kenny]

You have to do the math to figure out how much time you have available based on RPM and how much timing you're running. You also have to figure in injector close time, plus electronic to hydraulic delay to see how much duration you can run at a given point.

Dust off that calculator.

Was not meaning real actual timing, but 27 degree's on the timing table at 3100us. Anyone willing to put in a little time can learn how to make a tune, without the need to go that indepth.

[DoghouseDiesel]

27 degree's at how many RPM's? RPM's and your total timing equal how many uS you have available. This isn't a guessing game, it's a matter of making efficient power vs bending rods, blowing head gaskets, or windowing blocks. 27* at 2000 RPM's or 27* at 4000 RPM's?....one makes power, one starts stacking rings.

If you don't know how to figure out what you can run for timing at a given RPM, you're likely to do more harm than good.

[700kenny]

When discussing how much duration/timing, I assumed the OP was thinking about his upper cell.

[Jonesy]

Right I haven't gone over 27* of timing and thats on the upper rpm end at like 3500 rpm's and right now running 3100 also at 3500 was asking because didn't know if i could drop down to say like 2800 rpm and run 25* to 27* of timing and 2900 to 3100 on pulse. I'm new too this and dont want to cause any harm to a motor but would like to suck as much power out in the top end as I can without harm, not worried about low to mid range rpm cause time is set pretty low and I don't mess with the pulse in those range. Due to running on stock injector I just leave it at the factory setting but do plan on making minor changes in the future too it.

[DoghouseDiesel]

When discussing how much duration/timing, I assumed the OP was thinking about his upper cell.

The beauty of EFILive, you don't have to guess and assume. You analyze, adjust, tune, log, repeat.....and reference specifics.

[WisconsinHick1]

With REALLY larger injector trucks, I don't even come close to 3000.


With my 100% injectors I am currently running 2200us.