Timing and the Pre/Post injection events

D

Diesel Freak

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WOW, first off, I did not know I could download a trial version of EFI Live...not only that, but I could also find a stock 2006 Program on the web!!!

This is cool!!!

anywho, I have been looking at the maps for fuel and timing, and well, I thinkI may have found why I got such crappy milage!!!

from what I can see, under ~70% load at 1900 RPM, the main injection event is retarded ~6 degrees AND the post event is retarded an additional 15 degrees further.

So, in this case, it looks like there is somewhere between 4 and 6 mm^3 of fuel being injected at 21 degrees after top dead center. That looks too late in the cycle to be of any use at all.

Is anyone else playing with this yet??? Of Have I just re-invented the wheel
 

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UGH, I hope I am wrong!!!

If this is true, and there is somewhere between 4 and 6 mm^3 of fuel being injected that late in the cycle. Then there is somewhere between 0.37 and 0.55 Gallons per hour of fuel basicly being wasted and sent down the tail pipe.
 
Well, this is definately an interesting toy!!!

Moved the bulk of the post event into the pilot event and smoothed it out.

Timing does look a little wild, so actually backed it off some and smoothed it out a little.
 

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There is a lot of reading on injection events on the interwebs. You could also go to the efilive forum.

Post injection is for emissions. Some tuners also use it to help spool a big single. Generally, around 6-9 degrees of main timing for cruising mileage is used. Or if you look on the timing calculator around 45% in the cruising area.

For power, anything over 55% timing or 25 degrees should be tested on a dyno first. I run 26 in the upper levels with a very small touch of 27 after 3600 rpms.

Sent from my LG pad
 
Diesel Freak said:
WOW, first off, I did not know I could download a trial version of EFI Live...not only that, but I could also find a stock 2006 Program on the web!!!



This is cool!!!



anywho, I have been looking at the maps for fuel and timing, and well, I thinkI may have found why I got such crappy milage!!!



from what I can see, under ~70% load at 1900 RPM, the main injection event is retarded ~6 degrees AND the post event is retarded an additional 15 degrees further.



So, in this case, it looks like there is somewhere between 4 and 6 mm^3 of fuel being injected at 21 degrees after top dead center. That looks too late in the cycle to be of any use at all.



Is anyone else playing with this yet??? Of Have I just re-invented the wheel
Click to expand...


Well put it this way, at least your truck was running very clean :p
 
Jordan Koehn said:
There is a lot of reading on injection events on the interwebs. You could also go to the efilive forum.

Post injection is for emissions. Some tuners also use it to help spool a big single. Generally, around 6-9 degrees of main timing for cruising mileage is used. Or if you look on the timing calculator around 45% in the cruising area.

For power, anything over 55% timing or 25 degrees should be tested on a dyno first. I run 26 in the upper levels with a very small touch of 27 after 3600 rpms.

Sent from my LG pad
Click to expand...

are you speaking specific to the main event?? If so, then do you back off the pilot timing as you advance the main timing??

Also, what is typical of the pilot quantity? is anyone adding fuel to the pilot event, or is it all added to the main event???

I would really like to see the 2003 305HP stock tune and compare it to the 325 HP tune in this 2006 engine. But unfortunately, the 2003 is not supported by EFI live.
 
Shut off post and I taper off pilot higher into the higher rpm to allow more for a large main injection event. Will keep the rail happily full.
You can make bigger charger light faster with some negative timing way down low also.
 
Last edited:
I also run ZERO post injection on almost all of the trucks I tune. Only use it in rare cases to help spool a large turbo.

I usually remove pilot as well after 2600rpm. This seems to work really well.
 
Thanks everyone!!! I know I am asking some pointed questions.

So far what I am thinking of doing:

Get rid of the post injection (set to Zero) above 1500 RPM in every map, this would be the base map and the four additional atmospheric reference maps.

Advance the main event to +10 Degrees BTDC in areas where it is not already greater than or equal to that advance. Will then Cut and paste the Base Maps into all additional maps, basicly making timing equivelant regardless of enviromnental conditions

In the areas where I advance the main event, then retard the pilot the same ammount.

Taper off Pilot Volume as RPM increases.

Add the volume removed from pilot to the main event.


Comments???
 
Watch your limits and limiter tables as they control if pilot is active. Remove post completely.
 
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