The injector is still maxed out at 100 % so it makes no difference. I am trying to figure out why im hitting 100% injector duty cycle showing on my powerfc. Megasquirt support forum msextra duty cycle over 100%. Figure 2 theoretical injection map the ecu is part of a closed loop control system. Oct 11, 2008 you have the injector size set to 900 instead of and have an overallfuel trim added of 25%, this is probably why it is showing you are at 100 % duty cycle. Under most conditions, fuel is injected when the intake valves are closed, which helps with fuel atomization and efficiency. I was hitting around 120% duty cycle under high boost. Robbie mcqueen from wolf ems shows us how a fuel surge problem may be caused by installing the wrong type of injectors.
I would recommend takign this back to the tuner to have them fix this. A 50% duty cycle indicates the current to the motor is being switched on and off in equal time. Injector output 1 duty cycle will show the fuel injector duty cycle for output 1 which is what you were looking for. I assume that duty cycle is measured off of the entire two strokes of the combustion cycle. There seems to be some common confusion that running an injector at a duty cycle in excess of 80% has a tendency to be bad for the injector, and that it can possibly overheat the injector. In an automotive electronic fuel injection system, voltage pulses supplied to the fuel injector valve solenoid control the fuel injector valve at a. The user can input what percentage of the fuel flow they want the third set of injectors to contribute.
Now it could be that you have too much fuel up there and that you shouldnt be up at at 100 %, but even if you are 20% too rich, you are out of injector. Did buick size the stock fuel injectors at 100% duty cycle. This great video will show you how to set up and view injector duty cyle using hp tuners 3. I decided to do a datalog today and everything looks good no excessive af learning, no knock issues, correct boost levels except the injector duty cycle, which went as high as 109% during a 3rd gear pull. I have been reading about injectors and idc and it got me thinking about the 100 % idc. An injector in an engine turns on and off very quickly to control the amount of fuel delivered. A 100 % duty cycle indicates that the motor is operating at full voltage and amperage. Yep, i wanted to verify that injector duty cycle is a accurate measure before going with larger injectors and a return system with afpr. Holley efi 16 injector setup 8 cylinder engines setup of 8. Injector hp calculator dynostats share your horsepower. Note that the pwm frequency of the distributed pwm 50% duty cycle in the drawing above is.
The user must log operating data while the engine is running, download the data to a pc. View profile view forum posts view blog entries administrator join date dec 2009 location connecticut posts 24,637. Rpm 60 revs per second rpm 120 cycles per second by cycle i mean four strokes 120 rpm seconds per cycle maximum time available for injectors to squirt fuel injector duty cycle is the actual time the injector is open, divided by the total time available. Injector duty cycle the amount of time available between injector pulses is based on engine rpm, or more specifically, on engine cycles. At 100% duty cycle, the injector would be on constantly. Injectors will go static at about a 92% duty cycle and should be sized for an 80% duty cycle to leave some wiggle room. Duty cycle is the amount of time that the fuel injectors are switched on. Injector size in cc duty cycle in % number of injectors. At this point, the second set will turn on, and will linearly increase until both sets reach 100 % duty cycle at the same time. Injector duty cycle above 100 % if this is your first visit, be sure to check out the faq by clicking the link above.
Power wise once you hit 100 % you wont lose power but if you fit larger injectors you will make more peak power. The injector model is a mathematical description of the dynamic response of the fuel injector. Dec 29, 2009 on the next run this dropped the max duty cycle down to 94% right before the 12 shift at 5730 rpm. Going from 97% duty cycle to 100 % could cause afr to jump because of the dead time being eliminated if the injectors are just being held open. My duty cycle numbers were low which i find just means the injector is sized properly or a little large in my case. So the clock that operates the injectors must be faster than the input signal from the ecm, which tells the injector to change states and the physical attributes of the. Romraider view topic boost surge and injector duty.
Fuel injector duty cycle limitations must also be considered. Most injectors will max out at 80% duty cycle and this is the accepted industry standard. You have the injector size set to 900 instead of and have an overallfuel trim added of 25%, this is probably why it is showing you are at 100 % duty cycle. For example, if a motor runs for one out of 100 seconds, or 1 100 of the time, then, its duty cycle is 1 100, or 1 percent. Fuel injector duty cycle some engine tuners will tell you that if your car has a duty cycle of 80%, you have a possible gain of 20%. Injector duty cycle refers to how long the injector needs to be open flowing fuel in order to supply the required amount of fuel.
L92 injector duty cycle over 100% with new intake minimal. So, technically, the engine only needs a 19 lbhr fuel injector to support 300 hp, but this will require that the injector is at nearly a 100 % duty cycle in order to achieve this horsepower level. But either way your running almost at the injector max. Electrical motors typically use less than a 100 % duty cycle. Outboard synthetic 2stroke oils synthetic formulation burns cleanly.
This is fuel flow, not the duty cycle of the injectors. Injection 1 duty cycle only works when you are using this output for something other than running an injector. It will only be shown if three injector sets are used. These graphs depict the characteristics of various fuel injectors with effective pulse width in milliseconds with 19 ms being equivalent to 100 percent injector duty cycle and injector flow rate in ccmin.
Ill have to lower the base pressure to give me a large enough envelope of tuning to get a. Including but not limited to honda, acura, toyota, ford, chevrolet, dodge, ferrari, lamborghini and more. At this point, the second set will turn on, and will linearly increase until both sets reach 100% duty cycle at the same time. Just read an article in the source saying buick used. Jul 10, 2017 injection 1 duty cycle only works when you are using this output for something other than running an injector. This can also be caused by ipr orings, high pressure pump, or injector orings. Injector duty cycle, pulse width and limits related to rpm. For example, if 50% is entered, the second set will not start until the flow of the first set reaches 50% duty cycle. Duty cycle activation duty cycle of the first injector set, at which the. So, technically, the engine only needs a 19 lbhr fuel injector to support 300 hp, but this will require that the injector is at nearly a 100% duty cycle in order to. Megasquirt support forum msextra injector 100% duty.
Hey, just figuring out how to datalog for the first time. This is because a shorter duty cycle does not allow for the proper atomization of the fuel, and proper atomization is important for the proper burning of the airfuel. If the valve is pulsed on at variable durations called pulsewidth modulation, the duty cycle varies. Duty cycle activation duty cycle of the first injector set, at which the second set ramps in. A duty cycle of 0% means that the injector is not on at all, a duty cycle of 100 % means the injector is on constantly.
The problem with 100 % duty cycle is that if you are at 6000 rpm at 100 % duty cycle and you rev to 7000 well there is no possible way the injectors can deliver more fuel if the car needs it above 6000 so a lean condition can not be corrected and engine damage can result. The time during which the injector is powered or activated is called the injector pulse width ipw. This measurement is taken with the injector on 100 % of the time 100 % duty cycle, or wide open and with the fuel at a given pressure usually 43. C is brake specific fuel consumption how much fuel you are using per horsepower per hour.
Ve numbers are around 94 in that same range and there is o2% correction of. Learn me on fuel pump duty cycle discussion in enginetuning started by canucksnake, aug 30, 2010. It is impossible to physically run an injector higher than 100%. To tune the pwm pulse width modulation values for your engine, you need to know what kind of injectors you have low impedance or highimpedance. Similarly, for pulse the duty cycle will be 25% because the pulse remains high only for 14 of the period and remains low for 34 of the period. If you already have our layouts you wont need to follow the steps in this video. Mostly a limiting factor, although if you accidentally overboost for some reason and you dont have any headroom in your fuel system your engine could be toast also, running the injectors 100 % duty cycle will shorten their lifespan dramatically and can end up causing a host of other problems. If the injector has a 100 % duty cycle, it means it is open all the time injecting fuel whether the valves are open or closed. This represents the largest possible pulse width at 6,000 rpm.
Then again, it may just continue to recalculate pulsewidth end. The constants used are 160 cfm per 100 hp, and an 85% duty cycle for maximum injector pulsewidth. Diagnosing pulse width modulating fuel pumps know your parts. And the injector duty cycle is not a perfect representation of a 0 100 % scale. The number of cylinders in your engine, the base fuel pressure you will run your fuel pressure at idle, our calculator assumes a 1.
At 100 % duty cycle, the injector would be on constantly. Injector duty cycle idc is a very common term when tuning our dsms, or any fuel injector platform for that matter. The amount of time an injector is turned on and delivering fuel is known as the duty cycle. Check with your injector builder on where he thinks the maximum duty cycle is for you specific injectors. Holley efi 16 injector setup 8 cylinder engines setup of. Such a frequency never lets the injector start to close the turn off turn on cycle is so fast that the injector stays where it is. Limit maximum injector duty cycle to less than 90% for safe operation. If the injector needs a 100 % duty cycle at a particular engine speed and load to inject enough fuel, that means it is open all the time. Follow the ford service information to diagnose high pressure oil leaks or lack of pressure. The numbers in the 100 % column are based on 100 % injector duty cycle at indicated engine rpm.
In an indirect injection engine, 100 % idc seems fine because the intake valve opens only on the intake cycle and the air and fuel mixture is being sucked in the engine. The proper injector for this application is 31 lbs. Requires 12vdc, 500ma, extracted from the coax feedline via builtin bias tee. This is measured as a percent, so 50% duty cycle indicates that the injector is held open and held closed for an equal amount of time. How to tell if you are out of fuel injector using hp tunes. L92 injector duty cycle over 100 % with new intake minimal mods i recently installed a new varram ram air intake in place of the outlaw intake i had on my sierra. After the install my wot afr was pretty lean around. On a race engine i wouldnt exceed a maximum duty cycle of 80% as dynotesting on various have shown that injector duty cycle in the region of 60% to 70% produces the best power.
With the injectors you are running, and your current tune, you are hitting 18. Injector output 1 duty cycle will show the fuel injector duty cycle for output 1. Ive got 440cc injectors on a b18c 1800cc honda and a walbro 255lph pump. At 50% duty cycle, the injector is on 50% of the time. This calculator will do it for both 2 stroke and 4 stroke engines. Effective pulse width is the ipw value before any battery or ignition voltage offset values are added to compensate for delays in injector.
Providing user with dyno stats including horsepower and torque for their all motor, turbo, nos or supercharged setup. The fuel injector duty cycle idc is the percentage of time the injector is supplied with power. What was a little perplexing, was that it seemed from reading the plugs even at an afr setting of 10, the plugs read that more fuel was needed. A value less than 100% means that fuel is being taken out to correct a rich condition. Boaters subjected to smoke and fumes benefit from these lowemission properties. Dec 12, 2017 there is no such thing as 110% duty cycle if you feel inspired to help me stay motivated. Oct 29, 2007 when i hit about 5000 rpms,had unts of knock,timing was degrees,o2 at. It is a subject that many people get wrong and even many professionals seem to miss the point as well. Duty cycle at idle is normally only a few percent, rising as revs or load increases.
Idc is an aftermarket value to represent the amount of time a fuel injector is energized on, spraying fuel during an engine cycle. I havent looked too far into it to say an actual quantifiable value, but the ecu limits injector pulsewidth. Engine aspiration, turbocharged, supercharged, and naturally aspirated engines have different bsfcs see glossary of terms for definitions. Injector duty cycle idc explained eat sleep dsm mag. Properly selecting fuel injectors for your mustang or lightning. Need some help figuring out if the ve tables or what else will have anything to do with the injector duty cycle being maxed out. Dec 14, 2011 here i will attempt to dispel some widely advertised misconceptions about what injector duty cycle idc is. Duty cycle refers to how long the injector needs to be open flowing fuel in order to supply the required amount of fuel. This is great if most of your pwm is around 50% duty cycle but the pwm frequency gradually slows to 62. Talk to some of the specialist before wasting money on the wrong sized injectors. It is a widely believed notion that idc is a state of operation which dictates how long the injector is open and that an idc of 100 % would result in a statically open injector. It contains information on doing this in software versions v2, v3, and v4.
Set 3 is a user programmable table and works as follow. Thus a duty cycle of 80% means that at the engine red line the pulse duration the amount of time the fuel injector is help open is 80% of the available time. Use the fuel injector worksheet below to perform this calculation for you. So in other words, there may not be an actual ability to run 100 % duty cycle. If the injectors need to be on 100 % of the time to supply enough. Controls friction and helps prevent wear, plug fouling, ring sticking and exhaust.
Here i will attempt to dispel some widely advertised misconceptions about what injector duty cycle idc is. Chrysler injector characterization injector dynamics. Like if you connected a boost solenoid to this output. During normal engine operation, the fuel injector fires once during the four strokes of the otto cycle, which last for 2 revolutions of the engine. Tuning high flowing injectors for low pulse width operation. If the ecm tries to clock the injectors faster than the injectors can change state, then you will get a 100 % duty cycle because the injector cannot keep up, so it stays open. When dead time is close to the total low signal time of the injector cycle i assume it is going to start acting unstable. A 70% duty cycle indicates the standard controller with the ability to read some faults by monitoring the duty cycle.
Pcm can compute that 128% is required to spray the fuel mass required to meet a specific afr based on a computed cylinder airmass, but physically the injectors cannot open any further than 100 %. Considering that the injectors fire once per complete engine cycle which takes two revolutions of the crank, we can use the following equations to calculate some useful information. If you are runing over this its time to look for a larger injector. If you can tell me how its calculated, maybe i could find the setting thats wrong. I then went to the fuel pump table and allowed for 100 % duty cycle anywhere above 4000 rpm and 159 lbshr. This calculator will generate pulsewidth values for specific rpms, from idle to peak speeds. The inputs required to operate a pulsewidth modulated fuel pump system are generally produced by the engine control module ecm, the fpcm, and a fuel system. Outputs and inputs can be modified to tune the engine. How to tell if you are out of fuel injector using hp tunes 3.