mike13

iTrader: (27)

I see posts with people saying their injector cycle is 114%, etc. Can you really have injector duty cyle numbers of more than 100%?

jgarza54

iTrader: (4)

Yes you can, mine is at 110% duty cycle right now and has been like that for a while.. Only thing with that, is that its only a matter of time before one of the injectors gives out.. I just ordered some bigger injectors last week, waiting for them to come in..

taman86

iTrader: (19)

im not a tuner but an injectors is desgined to flow only so much that it was made for. so a 28lb injector will only flow 28 lbs. when the computer is scanned and read, it may be saying 114% which to me means that the engine is producing so much HP or is reading the commanded load vs. the engine load and that it is commanding the injectors to perform at 114% duty cycle which obviously is beyond the actual operating limits of the injector. at that point you MUST upgrade your injectors to fullfil the requirment of the ECM commanding the injectors to perform at such duty cycle. but now let say that with the required adjustments for larger fuel injectors and the before and after, before the duty cycle of 28lb injectors was 114% and then upgrade to 36lb injectors and adjust the fueling trim, its now say 70% duty cycle, so now the ECM is happy, and the engine is happy cuz its not being starved. so i just put this in lamens terms, an actual tuner will tell you a bunch of formula's and this and that and what not. but if my lamens terms are off then please feel free to correct me.

mike13

iTrader: (27)

I understand what you guys are saying but let me ask this to help clarify my original question. Will a injector flow more fuel at a datalogged 114% than at a datalogged 100%?

Lambert695

iTrader: (17)

Your data log may show that but in reality your injector is only at 100%. It is impossible to have something over 100% which is saying that the injector is open all the time. So no it will no flow more fuel and if you are at 100% you need new injectors. 80% duty cycle is the goal.

mike13

iTrader: (27)

I understand the maximum 80% duty cycle, I'm confused on why you can have a duty cycle of more than 100%? Wouldn't the parameter be 0%-100%?

oange ss

iTrader: (50)

flow rate of an injector is based on the physical design....IDC is not a flow rate it's just the percentage of time the injector is activated or commanded open

rpm X IPW / 1200 = IDC %

mike13

iTrader: (27)

Correct so how can it be commanded open 114%?

Lambert695

iTrader: (17)

I may be wrong on this but i believe that its because Duty Cycle is basically just a calculation within the tuner. So if 100% is achieved at say 5500 rpm and your redline is 6500 then is will then be greater than 100% for the calculation but in reality the actual injector is still maxed at 100%... I may be wrong.

oange ss

iTrader: (50)

it's calculated

Scoggin Dickey

iTrader: (34)

Duty cycle is a calculation of injector pulse width vs rpm of the engine. Injector Pulse Width is a set number. Let's say 20 milliseconds is the fastest it can pulse. If your engine is at an RPM where it takes 50 milliseconds to complete a cycle (that's two revolutions, because two revolutions = 1 engine cycle) than your injector is at 40% duty cycle because 20 milliseconds is 40% of 50 milliseconds. The injector's open time is 40% of the time it takes or the engine to complete 1 cycle. Once the rpm reaches a point where it takes 20 milliseconds to complete a cycle, you are at 100% duty cycle and the injector is staying open. If the engine spins any faster, obviously the calculation passes 100% because the engine is taking 15 milliseconds to complete a cycle, but the injector pulse width is 20 milliseconds. The injector is still static open at 100%, but the calculation can surpass 100% because the engine is spinning faster than the injector can open and close.

Rudimentary explanation, but it's simply because it's calculation of injector open time vs rpm

Lambert695

iTrader: (17)

well I was pretty close.. ha