Timing Calculator

[mstordahl]

The new timing calculator built in is cool, and with the new description makes sense too.

What I am wondering is what I should be looking for with this, is there an optimum amount of pulse before or after, or is it totally different truck to truck?

Thanks!

[dansdieselp]

Typically you want around 50% up top and less down low. The Cummins doesn't like 50 across the board as much as the Duramax does. This also depends on the size of injectors you have and turbo.

[chance cobb]

any one care to explain how this works ?

[mstordahl]

Typically you want around 50% up top and less down low. The Cummins doesn't like 50 across the board as much as the Duramax does. This also depends on the size of injectors you have and turbo.

Ok, so considering that my truck has stock sticks and injectors I should keep it in the 50%range up top and closer to 0 down low?

Thanks for the information!

[FUBAR]

This is where it'll start to turn a little grey...pretty much it leaves from here to a tuner to tuner opinion. The dyno time, trial and error, and other experience is what gives them their professional intellectual tuning ability and livelihood.

What I think will be safe to say, is to briefly explain what you're working with and you can use judgement how to tune for it. This being a stock thread, it's assumed we're using stock injectors. That being said, how do we get power out of them? Think of the basic torch concept. If we have a plate of metal, and two torches, one big, one small, and we need to heat the plate up to a certain temp., let's look how we're gonna do this. Using the big torch, it puts out more heat using LESS TIME to heat the plate up, than it would to have to stand there and hold the small torch and try to bring the plate up to the same temp.

Now of course there are A LOT of other variables that come into play in talking about a engine while tuning timing, but this fundamental theory should help start your thought process.

[FUBAR]

There's spooling the turbo to think about, fuel mileage, duration, pressure, other injection events, spraying outside of the bowl, etc, etc.

[KB3MMX]

There's spooling the turbo to think about, fuel mileage, duration, pressure, other injection events, spraying outside of the bowl, etc, etc.

^^^^ Exactly

The static timing calculator is a good reference but real timing will be affected by many variables like pre-injection(quantity&timing before main shot), fuel temps, air temps, fuel cetane, fuel pressure, etc, etc. Learning how to adjust timing takes some time and understanding of the influences involved.