With slightly fat O2's ( 805-820 ) and 0.0 KNKR shown on Direct Scan, My injector PW shows ( 98-105 ) % static at the top of 2nd and 3rd gears. How can you have more than 100%? Is this refered to as % of injector turn on? Am I maxed on injector? I am using 55 pounders w/ a TE45A. Thanks Brian
Injector PW % staic
- Thread starter Fuelie600
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What direct scan is showing you is what pulse width is being commanded (asked for). So yes, anything over 100% is still only 100% (commanded on all the time).
It's not unusual to see duty cycles well over 100%. The computer is just calculating what it thinks it needs the fuel injectors to do, in order to obtain the desired air fuel ratio.
That's an awfly big turbo for nothing more than 55# injectors
No wonder you're hitting static.
By the time someone's engine is set up to the point where a TE45 size turbo is needed, you should be looking at substantially more injector, say, maybe 65-72#
I'm quite surprised you got that far into the 10's and are only at about 100% duty cycle.
It's not unusual to see duty cycles well over 100%. The computer is just calculating what it thinks it needs the fuel injectors to do, in order to obtain the desired air fuel ratio.
That's an awfly big turbo for nothing more than 55# injectors
No wonder you're hitting static.
By the time someone's engine is set up to the point where a TE45 size turbo is needed, you should be looking at substantially more injector, say, maybe 65-72#
I'm quite surprised you got that far into the 10's and are only at about 100% duty cycle.
Dave, Thanks for responding. I don't understand your last statement, "only at about 100% duty cycle". What should I be looking for? There are several guy,s who have gone deep into the tens with 55's. Does 100% static mean I should get larger injectors even though my O2's are on the fat side and I have 0.0 KNKR. If I could learn how to drive the car, It should run in the 10.70's with a harder launch and a 150ish 60 ft. Thanks in advance for your help! Brian
Sure, there have been lots of folks getting deep into the 10's with 55's. But did they have anything hooked up that told them what was going on to get there. They likely had to do a few tricks like upping the fuel pressure, etc. not realizing how far beyond the injectors true capabilities they were actually pushing things to get there.
IMHO, one should not tune to run the desired numbers by pushing the injectors beyond static by tuning with high fuel pressure numbers etc. We run computer controlled systems for a reason. Userping the electronic controls by old tuning methods doesn't make a lot of sense.
The reason is, once the injectors hit static (100% D.C.) you have no more control over them. You have to up the fuel pressure to "force" more fuel through them, and it's not much better than guess work at that point.
Unless you have a very sophisticated monitoring system and are also running a wideband O2 to ensure that you actually are getting what's hopped for.
You lose control of the injectors at more like 90%.
I just worked on a car and we went from 110%DC down to 85%, and the engine really started making some HP.
To understand what's going on takes an ecm bench, and WB, IMO. Spend a couple weeks, with Direct Scan, experimenting on the bench, then take what you've learned and apply it to the car.
The MAF tables Scalers, and PE stuff all does make sense.
Brian,
I think theres an important point left out in all this. What was your EGT or air fuel ratio when you were at 100% + duty cycle? You may have been rich. What was your boost pressure?
What was the weather(temp,humidity,baro)? All of these play a large roll in the A/F ratio. Your pulse may have been commanded too high to start with.
I think theres an important point left out in all this. What was your EGT or air fuel ratio when you were at 100% + duty cycle? You may have been rich. What was your boost pressure?
What was the weather(temp,humidity,baro)? All of these play a large roll in the A/F ratio. Your pulse may have been commanded too high to start with.
