alright guys here's my question, i was wondering how the injector duty on the commander is measured, does it do its calculations sowly off your the input thru the commander/datalogit (for example you input 850/1300s and it does it calculations to show you your injector duty and different loads etc)
or does it do its calcualtions on injector duty of its readings

basically to simplize it, if i input 850/1600s thru the commander and i really have 550/850 injectors, when it gives me my injector duty cycle, will it give it back 2 me as if i have 850/1600 injectors or 550/850 injectors......

i ask this cuz as you know sometimes injectors dont flow as well as they used2 when they were brand new so your 550 injector may not flow 550cc anymore after 80k, 2 me its seems very easy 2 blow your motor becuz of old/dirty injectors that arent flowing wat the pfc expects them 2......
any help would b greatly appreciated..

-dj

 

As far as I know, you might not want to imput them as 850/1600 because at the same HP level, you duty cycle will be much lower with the 850/1600, and it may be WAY TOO LOW for your 550/850 combo to dump enough fuel for your engine requirements.


You need to monitor your A/F ratios and maybe over duty your 550/850 combo to get you by for now (if your injectors really aren't flowing too well). Another option would be to crank your boost down until you get bigger injectors and can trim down your duty cycle %.

Definition of DUTY CYCLE: percent of time that your injector is open. At 80%, your injector is open %80 of the time, and closed for 20%, then opened for 80% and closed again for 20% etc. So if your cycle is lasting one second (only for example) then your injector would be open .8 seconds, and closed .2 seconds before it opens again for the next squirt (.8 seconds again).

Some of this you may already know, but hope I was of assistance.

 

thanx 4 the responce, i was only using 550/850 as an example my current fuel setup if\s 850/1300s, but on the 1300 injectors i couldnt c clearly but it looked lik 1200 was carved into it, but the seller told me they were 1300 injectors, so iam just a little bit worried that i actually have 850/1200 injectors, even though 850/1300 is what was entered into the powerfc, so iam worried bout running lean because i dont have that extra 1000cc that the powerfc thinks i have

-dj

 

Duty cycle of the injector will be what the PFC directs and displays, regardless of injector size. Fuel delivery is a different story.

 

thanx u

-dj

 

And also to add, 1300's are always modified 1200's, so it would make sense that you have 1200 stamped into the injector. Not that it wouldn't hurt to have them flow tested though. Trust no one.

 

You could also send them in to be cleaned and flow tested at RC or equivalent.

It would be piece of mind that you do have the right injectors and they would be running at near assigned values.

You have read about the issues with the 1300s correct? To high of a reported failure rate for me!