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Cummin_un_glued

Cummin_un_glued

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Sep 17, 2007
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ok i know i seen it on here somewhere but now i cant find it. there was a list of how long you had to inject fuel at any given rpm. basicly how long is seconds the piston was in the optimal range for injection. can someone please point me to that
 
I think your looking for something like injection per crankshaft rotation?

If you havent changed it then you shouldnt need to mess with it.

Only reason I've changed mine is because I've deleted my post injection.
 
no sir i'm looking for the formula for the amount of time the piston is in range for injection based on rpm
 
thanks triton but thats not it either, it was in a post on here but i've searched and searched and still cant find it. if i remember correctly it was based off of 40* of crank rotation and basicly told ya how long the fraction of a second that is there to inject fuel is at a given rpm since that window gets smaller as rpm gos up
 
Its not quite that simple....

RPM is just one of the factors.

You also have to look at total degrees of timing, before and after top dead center.

Injector size also plays a part. Not necessarilly for total time, but for the NEEDED amount of time to produce the power you want. While a set of 90 hp injectors may need, say 2600 uS to inject the desired quantity, a set of 180's may only need 2200 uS.

Pressure also comes into play.

There really isn't a hard and fast "rule" that says you need uS. You can calculate total AVAILABLE, but most of the time that number is WAY too high in any other condition except WOT.
 
Pulling with the chargers you've been talking about your looking for the largest set of nozzles running as much pressure your comfortable with, OR the Ppump boys will be a schoolin.
 
JSP yes that was what i was looking for, this isnt for my truck tho joe i'm helping a buddy with his. i feel like his pulse is too long, truck runs fine just runs hot on the pyro. i was thinking it needs the pressure brought up and the us down a little to try to cool it off some. am i thinking right?

btw its a stock injector dmax (realized now i posted this in cummins efi) and i was just looking for that link for ref not for hard numbers we were just talking about it after the pulls last night and i wanted to show it to him

here is the video of the truck from last night...

[ame="http://www.youtube.com/watch?v=l92P9STKQTY"]http://www.youtube.com/watch?v=l92P9STKQTY[/ame]

rich do you have any thoughts as to how to cool it down as far as tuning?

also JSP my pullin rigs are ppumped and where are you gonna get those chargers on so we can all see how that works out
 
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EGT's are a two way street.

Just seeing it hot on the pyro isn't the full indicator.

Just moving timing around can raise or lower what you see on the gauge, but sometimes lower on the gauge means more heat on the pistons and vice versa.

Without seeing the tune or the data log and what the truck is running, I can't really tell you where to adjust, it would just be a shot in the dark. But, looking at the video he's certainly running a ton of duration.
 
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You edit this into your calc_pids.txt to know your crank angle degrees for the dmax injection event. Then you can log it or map it in the graphs.

# ==============================================================================
# Add slot definitions here
# --------------------------------
# See sae_generic.txt for more information on "SLOT" formats
#
#Units Low High Fmt Expression
#------------ ------------- ------------- ---- --------------------------------------------------------------
*CLC-00-001
CAdeg 0 180 .2 "{SAE.RPM}*{GM.MAINBPW}*3/500000"
 
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