Big Injector timing

S Phinney

Active member
Aug 15, 2008
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Quncy, Fl
In general you would run a 1450 us tune 14.5 to 15.5 degrees at 3250 rpms. The higher timing generates the excessive smoke as well. I generally on run 48 to 52 percent timing splits on the big end. Numbers are all relative to where you are in the mapping. If you run the numbers on the timing calculator you would find that you are putting too much in before TDC and would find improved results with less timimg.
 

x MadMAX DIESEL

<<<< No Horsepower
Dec 30, 2008
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In general you would run a 1450 us tune 14.5 to 15.5 degrees at 3250 rpms. The higher timing generates the excessive smoke as well. I generally on run 48 to 52 percent timing splits on the big end. Numbers are all relative to where you are in the mapping. If you run the numbers on the timing calculator you would find that you are putting too much in before TDC and would find improved results with less timimg.

That timing calculated never works on my computer. But I'm running 30 down the whole track pretty much. 3700-4500rpm is all 30 degrees when full throttle
 

GMC_2002_Dmax

The Still Master
Injector latency and pressure drop when the needle lifts off the seat has to be factored as well as pilot timing or lack of.........:thumb:

The timing calculator will figure out in theory a 50/50 split but the CADEG pid will tell you how many degrees the injector is actually dwelled open during the compression/power stroke.

The only true answer without a dyno and cylinder pressure monitoring gauge is your ears and you ass in the seat.

If you can figure out what a fuel rattle, pilot rattle or timing rattle sound like/different then you have something..........;)

Spend the time, use the map functions in the software and log it.

Good Luck
 

x MadMAX DIESEL

<<<< No Horsepower
Dec 30, 2008
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Should I be looking for a 50/50 split end result? Yes is my lbz. I guess I figured all the hot tunes would be throwing in all the fuel btdc anyways.
 

S Phinney

Active member
Aug 15, 2008
4,008
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Quncy, Fl
I wouldn't run more than 60 on the big end and in my opinion that is extreme. Too much timing and you beat out your besrings. If you are not cracking pistons and windowing blocks you are still hurting the motor.
 

x MadMAX DIESEL

<<<< No Horsepower
Dec 30, 2008
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So how can I tell what degree it would be. You'd have 90 degrees or 45 really to stay outta if it took a second per degree injection. But were talking milliseconds lol do you have any guess what a 1200 us would be timed with your 60? Would that be as little as 10* or something? I'm really not scared to pull the motor apart and replace everything that needs it. But I don't want to window a block or need to over bore really
 

x MadMAX DIESEL

<<<< No Horsepower
Dec 30, 2008
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Well i am trying to download it on an ipad now and it wont allow it. In the past it wouldnt download without like 500 errors on my computer. So maybe i just need a new computer. But "in theory" running such a low pulse, even with high timing shouldnt have many negative effects as far as pressures etc. right? Basically thinking say 30* 3000stock spray, would put more stress 30* 1500us big sticks cause its actually spraying longer. I was really jw what how much timing these 2.6 3.0 are running. I wasnt sure if it was like 20 or more like 30+, just a very curious question haha
 

Yellow Jacket

WannaBe Sled Puller
Feb 11, 2009
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Waterloo, IA
Well i am trying to download it on an ipad now and it wont allow it. In the past it wouldnt download without like 500 errors on my computer. So maybe i just need a new computer. But "in theory" running such a low pulse, even with high timing shouldnt have many negative effects as far as pressures etc. right? Basically thinking say 30* 3000stock spray, would put more stress 30* 1500us big sticks cause its actually spraying longer. I was really jw what how much timing these 2.6 3.0 are running. I wasnt sure if it was like 20 or more like 30+, just a very curious question haha

We run more than 30* and 1450us with 400% overs, but 30* and up is in higher rpms...