Fuel injector size, duty cycle and the meaning of life. Fuel injector clinic uses the newest generation of bosch based injectors for all of our high impedance injector sets. However, injector rates are always specified at 100% duty cycle and some. Injector duty cycle, pulse width and limits related to rpm.
You do this by using scanning software and a program such as ls1 edit, etc. It is correctly calculated as you are opening the injector for about 25ms at 5000 rpm. Ph injector driver module injector drivers megasquirt ems. You bought your new bike and are looking to improve the power and the sound. Configuring megasquirtii or microsquirt tuning software. Megasquirt support forum msextra injector duty cycle. Dashpot adder increases the duty cycle when the throttle is lifted. Idle valve open duty follow the same steps for the closed duty value but instead the value to be found is when the engine rpm stops rising.
Ford efi system tuning inside the black box part 1 muscle. Ms3 with low impedance injectors discussion in efi tuning questions and engine management started by 1hcam. Dec 10, 2003 tim also then downloaded the free software from the megasquirt web site that would allow us to configure the computer for the engine we would be testing. Ford efi system tuning inside the black box part 1. This is the total injector events that you wish to occur for every engine cycle 360 degrees for two stroke engines and 720 for four strokes.
Injector duty cycle, pulse width and limits related to rpm youtube. There is a lot of software available to configure megasquirt, provide logging support and do real time and post run analysis to tweak the maps. Another formula to figure out maximum power per injector flow rate is. Have you tried fitting larger aftermarket injectors yet. The software application you use to tune and configure your megasquirtii. The manufacturer leaves it up to you to determine a system pressure and maximum duty. Megasquirt required fuel values and engine displacement. So, your injector is open all the time and this lead to a 100% duty cycle. The fuel injector duty cycle idc is the percentage of time the injector is supplied with power. The ve table represents a correction factor from how much fuel the megasquirt would inject if you were running a stoichiometric 14. The 15 is a constant which corresponds to the characteristics of a v8 running a 4 cycle combustion cycle. Jan 24, 2016 one of the most discussed topics with turbo conversions. So if i have a log that is showing an rpm of 6215 and injector pulse width of 22552 does that not come out to over 100% duty cycle.
Hiro, it sounds like you may have just maxed out the stock low impedence injectors on your race engine. This formula takes mass flow per unit time and converts it to mass flow per cylinder. Set fully closed to 100% duty cycle this means an open valve applying maximum pressure to the waste gate and fully open to 0% duty cycle a closed valve will send no pressure to the waste gate. As other pointed out, it depends if you are running full sequential or batch fire injection. If i was running 8 of them and planning high duty cycles, i would shift the line to 5 ohms per channel for no resistors. Not enough fuel volume to feed that engine, so at 100% injector duty cycle you fried the resistors. Significant components include u7, the 34151 fet injector driver, q2 and q7, the. Jan 12, 2016 steves megasquirttunerstudio help thread. Home rx7 techmods mods megasquirt programming the ecu ms2 this section covers programming the ms2 ecu to run the b rotary. 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. You can use the calculator below to determine injector duty cycle when engine speed and injector pulse width are known. This is your base pulse width, and it is used to scale almsot all your fueling. In order to properly install your megasquirt efi controller, you need to select and. Nov 27, 20 so if i have a log that is showing an rpm of 6215 and injector pulse width of 22552 does that not come out to over 100% duty cycle.
We start with the best base injectors available, and then optimize them for all performance applications, bringing great reliability and performance to all of our products. This will give the maximum hp possible at 85% duty cycle. Hp tuners llc, tuning and diagnostic solutions for your gm, ford and dodge based vehicle. Switching from 2 to 1 squirts would take out one injector opening time, so youd put a small dent in the duty. Once you are trying to produce more than about 25% of maximum hp your injectors are firing for longer than the intake valves are open. The easiest thing to do is to load the log file into excel export it as a csv, then create a formula in excel which applies the formula above.
Megasquirt uses all these factors to determine the fuel pulse width longer. The ph injector driver module is optimized for use with 4a peak and 1a hold low impedance fuel injectors. Discussion in efi tuning questions and engine management started by turbohwagon. Software for original version of fast fuel injection ecu grey box ecu warning. The id850, id, id0, id1700 and id2000 are currently available. This pad needs to be connected to a ground pad on the megasquirt board. The software application you use to tune and configure your megasquirt ii. At high injector duty cycles, the injector is spraying so long that it doesnt. Tim also then downloaded the free software from the megasquirt web site that would allow us to configure the computer for the engine we would. Note that these can be adjusted to limit the operational range of the valve. You have your new air filter and exhaust system ready to put on the bike, but recognize the need to change the airfuel mixture to take advantage of the increase in air flow into the engine and exhaust flow out. Fuel injector clinic high performance fuel injectors. Also i seem to remember common rail needing 5 injection events per cylinder per cycle pre injection to reduce knock, then several normal injections and a post injection to reduce emmisions.
Official support forum for megasquirt, microsquirt, ms1extra, ms2extra and megasquirt 3. For quick determination of injector size, multiply flow rate in cc per minute by the number of injectors. Once they are you can then tune wot using a wideband o2 meter and typically adjust the pe vs. He told me he was seeing around 80% duty cycle and the engine was starting to go lean as it was running out of fuel from the injectors being maxed out this. How to tune boost control in megasquirt boostvlog 3. Assuming the injectors are at or less than 80% duty cycle, then you have. Idle open and closed duty reflect the duty cycles where the valve is fully open and fully close. Injector duty cycle tuningtuners modern mopar forum. For a 4stroke, a complete stroke cycle is 720 degrees of crankshaft rotation i. Ideally, youll want the timing to be set to slightly below the timing that would give it the most power on most piston engines, this typically works out to somewhere in the 10 to 18 degree range. For example, the injector pulse width is the measure in milliseconds of how long the injector is opened for each pulse, regardless of how many times it is opened in a cycle. Yes, duty cycle in in the log is the injector duty cycle.
Car crafts giant efi test car craft magazine hot rod. Timing is a very useful tool for controlling your idle speed. For me the notion of 30 amps total injector current where you would be at 100% duty cycle and 4 ohms per channel with a saturated driver and good alternator just seams excessive. Using the test run position lower the duty value down until the engine rpm does not get any lower. If your maximum hp is correctly calibrated to a safe 80% duty cycle, your injectors are injecting well over 50% of the time on closed valves. I recently completed my second install on the same car, which i will explain later, so. Ive been running megasquirt under the radar since september 2007. The time during which the injector is powered or activated is called the injector pulse width ipw. It is impossible to physically run an injector higher than 100%. Because there is such a difference between the setup of the various megasquirt versions, each ecu has its own configuration page. Switching from 2 to 1 squirts would take out one injector opening time, so youd put a small dent in the duty cycle, but probably not enough. Dashpot adder is the percentage of duty cycle added briefly to.
Many of the settings overlap and effect one another. However, injector rates are always specified at 100% duty cycle and some nominal pressure usually 43. Duty cycle gives the percentage of time the injector is open irrespective of individual pulse duration. Ms3 with low impedance injectors page 2 efi tuning.
All you do is program how much fuel you need into the map, the computer does the rest. I found a calc online but i cant get the bitch linked into this post. Please keep in mind that this is just a guideline, the. Steves megasquirttunerstudio help thread mustang forums. The software application you use to tune and configure your megasquirtii or. Tuning high flowing injectors for low pulse width operation with. The software application you use to tune and configure your megasquirtii or microsquirt is called megatune2. Dashpot adder is the percentage of duty cycle added briefly to the valve. I had my car on the dyno the other day getting tuned, and my tuner commented at the end of the day that the reporting of the injector duty cycle seemed to be a bit out. Injectors and fuel supply megasquirtr faq main page. Now that you understand the basics of fuel delivery, you need to understand how the ecu decides the proper injector pulse width or duty cycle for the required fuel flow, to achieve the desired af. Injectors should not be used at more than 8085% duty cycle. Data match technology information sheet is currently limited to all high impedance injectors 900ccmin and larger due to the the additional cost for little benefit in smaller injector sizes.
You also need to consider how much work is required to configure the ecu. This software gives you total control over specific events that your engine needs set correctly to run properly. Basically you group your injectors, injectors 2, 4 and 6 will be fired by injector driver 1 light blue wire and 1,3 and 5 by driver 2 wires dark green wire on the right. Duty cycle gives the percentage of time the injector is open irrespective of.
The duty cycles can be a little confusing at first glance. I think another big issue would be getting the seperate ms ignition and fuel outputs to control the timing and duration of the same injector. Ive found that on the dyno, by moving the eoit closer to 34 of the way through the intake valve events give or take dependent on the cam, that you can gain quite a bit of power and torque as long as you arent over 75%80% injector duty cycle which is where the injector is basically open for far longer than the intake valve is open. Pwm idle cranking duty sets the duty cycle opening amount of the idle valve. Number of injectors is the total number of injectors megasquirt is controlling. The next to last pad is the new pad which is a ground for the lowcurrent devices on the board which is separate from the highcurrent injector grounds.
They refer to waste gate opening, not solenoid opening. Dashpot adder is the percentage of duty cycle added briefly to the valve as the engine rpm drops. Hope this clears some things up about fuel system upgrades. Megasquirt not driving injectors modified vehicle builds. Now flash software engineers have been finding more and more of these pulse width adder tables within the code that the oem engineers have. Configuring your megasquirt ii or microsquirt controller. There is no such thing as 110% duty cycle if you feel inspired to help me stay motivated. Incorrectly using andor incorrectly installing this software can cause your engine to perform at degraded levels or even stop running completely. You would also need to design your own io circuits if you adopted the megasquirt design, all this would be done for you. I am revising my thoughts on duty cycle it is the time the injector is open pw.
Megasquirt was designed by bruce bowling and al grippo in 2001. The manufacturer leaves it up to you to determine a system pressure and maximum duty cycle in order to compute the resulting flow. You can later calibrate this on your ms via megatune tuning software for the megasquirt. The ph injector driver module compensates for low voltage conditions cold weather, startup, etc.
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