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Thread: Injection Timing Assistance Requested

  1. #421
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    Quote Originally Posted by 07GTS View Post
    hpt uses 720 deg of crank rotation nice and easy
    Correct, however if HPT data for normal ECT is referenced in cam degrees it makes a big difference to eoit in the excel calculator posted in this thread, it needs to be doubled for crank degrees, other wise eoit is more advance than anticipated.

  2. #422
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    I also found a study online for injection timing

    http://citeseerx.ist.psu.edu/viewdoc...=rep1&type=pdf


    5. RESULTS AND DISCUSSION
    Figure 12 shows the consequence of injection phase (the
    crank angle corresponding to the end of injection) in terms of
    engine brake torque for 2600 rpm and full load; the results of
    both engine modeling and engine testing are compared in this
    figure. It is clear that there is a maximum brake torque part with
    the end of fuel injection between 360 to 390 ATDC.

    Figure 13 shows the entrance of fuel droplets to the
    cylinder by means of the mass fraction of fuel droplets in the
    end zone of the intake port for different injection phases 100,
    380 and 500 deg. ATDC. According to this figure when the end
    time of injection occurs at 100 ATDC most of fuel droplets
    reach to the vicinity of intake valve in the expansion stroke.
    For injection phase 550 ATDC the fuel droplets pass the intake
    port in intake stroke and some of them come back to the port
    due to the backflow from cylinder to the port and remain in the
    port after the intake valve closes; as a result, the engine torque
    reduces. For injection phase 380 ATDC the fuel droplets reach
    to the intake valve vicinity at the end of the exhaust stroke and
    the beginning the intake valve opening. As it is observed all of
    fuel droplets pass the intake port and enter to the cylinder
    during the first half period of intake stroke. This is an important strategy in designing the injector flow rate and injection timing.
    In this condition the backflow of the hot gases to the port
    causes the better atomization and vaporization of liquid fuel
    film in the vicinity of the intake valve. Also, with an entrance of
    fuel droplets at the beginning of the intake stroke, there is
    enough time for vaporization and mixing of air and fuel vapor in
    the cylinder. Consequently, the maximum brake torque occurs
    in this injection phase.

    Figure 14 shows the HC emissions (gr/KWh) for different
    injection phases. In view of the fact that the brake torque and
    as a result the maximum cylinder pressure is low in injection
    phase 500 deg. ATDC (Fig. 12) and also due to the better fuel
    vaporization in the intake port before the intake valve opening,
    the HC emissions have a minimum value at 500 deg ATDC. The
    considerable increase in fuel vaporization in the intake port for
    an injection phase of 550 deg. ATDC which cause a reduction
    in the liquid fuel film in the port is shown and is compared to
    other injection phases in figure 15.

    One of the imp ortant parameters on HC generation rate is
    the fuel entrainment in crevices and cavities existing on engine
    components like piston, cylinder head and ring. With an
    increase in maximum cylinder pressure, the amount of fuel
    which is placed in crevices increase and as a result the HC
    generation rate increases. According to the above effect, the
    HC emission has a maximum level in injection phases between
    230 to 380 deg. ATDC due to the high brake torque and
    cylinder pressure (Fig. 14). Figures 16 and 17 show the CO and
    NOx formation rates respectively. The CO emissions for
    injection phases corresponding to maximum brake torque (390
    deg. ATDC) have a minimum value because of better
    combustion and high cylinder pressure and temperature.
    Otherwise, the high temp erature of in-cylinder gas leads to an
    increase in NOx generation rate for the injection phases
    between 300 to 450 deg. ATDC. (Figure 17)
    According to the results of brake torque and exhaust
    emissions, the best injection phase as the end of injection is
    390 deg. ATDC at 2600 rpm and full load condition.

    In the next part the suitable injection phase for 2600 rpm
    and part load (MAP:40 KPa) is determined. The injection pulse
    width in this condition is 100 deg CA . The consequence of the
    injection phase in terms of engine brake torque for 2600 rpm
    and part load is shown in figure 18, and a comparison is made
    between the results of engine modeling and engine testing. As
    it is clear, the maximum brake torque occurs with an injection
    phase of 390 deg. ATDC. In this condition, the end of injection
    occurs on the first part of intake stroke, and most of the fuel
    droplets reach to the cylinder while less amount of fuel remains
    in the port as liquid fuel film. For optimum injection phase, the
    engine should have a high brake torque while the values of
    exhaust emissions are acceptable. For this means the exhaust
    emissions formation rates for HC, CO and NOx are shown in
    figure 19 for different injection phase. The results are based on
    engine testing. According to this figure, the HC emission has a
    maximum value in the injection phases between 360 to 420 deg.
    ATDC. because the maximum cylinder pressure in this range of
    injection phase is maximum. As a result, the low values of CO
    emission occur between 330 to 390 deg ATDC. Also, the NOx
    emissions have high value for injection phases between 330 to
    420 deg. ATDC

    Consequently, according to the values of engine brake
    torque and exhaust emissions, it can be concluded that the
    injection phase of 330 deg. ATDC is an optimum point as the
    end of injection at 2600 rpm and part load.




    6. CONCLUSION
    The backflow of the hot gases from the cylinder to the
    port has an important influence on fuel entrainment to the
    cylinder and fuel break up & atomization in the intake port.
    With the optimum injection timing it causes a better
    atomization and vaporization of liquid fuel film in the vicinity of
    the intake valve.
    In the optimum injection timing setup, the brake torque
    should be high enough, with acceptable values of exhaust
    emissions. In this condition, the fuel droplets should reach to
    the vicinity of intake valve at the end of the exhaust stroke or
    the beginning of intake stroke. So, all the fuel droplets pass the
    intake port and enter to the cylinder during the first half period
    of intake stroke. Under this condition, there is enough time for
    fuel vaporization and fuel vapor & air mixing in side the
    cylinder. As a result the maximum brake torque occurs in this
    injection phase, while NO and CO formation rates increase and
    decrease, respectively.
    Attached Images Attached Images

  3. #423
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    Quote Originally Posted by Gelf VXR View Post
    Correct, however if HPT data for normal ECT is referenced in cam degrees it makes a big difference to eoit in the excel calculator posted in this thread, it needs to be doubled for crank degrees, other wise eoit is more advance than anticipated.
    why are u doubling ect ? it's boundary - ECT - RPM - PW = SOI but there is a makeup degrees in there also, i found it pretty close when u factor in time from injector PW to cylinder going off actual changes in afr

  4. #424
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    Quote Originally Posted by 07GTS View Post
    why are u doubling ect ? it's boundary - ECT - RPM - PW = SOI but there is a makeup degrees in there also, i found it pretty close when u factor in time from injector PW to cylinder going off actual changes in afr
    I?m not disputing the formula or the methodology, I?m highlighting a possible calculation error due to what I highlighted In my fist post, I note that there is a difference in this table between HPT and EFILive for the E40 and possibly E38 and similar PCMS. EFILive at normal ECT is 220 degrees, HPT is reporting 110 (cam degrees?) The calculator is all in crank degrees.

    When you enter stock data into the calculator using HPT 110 norm ECT , it shows SOIT & EOIT after the inlet valve is open. I could be wrong but I think it?s accepted that OEM injects on closed valve, especially at idle.

    Double 110 to 220, and enter into the calculator SOIT & EOIT happens on closed inlet valve, similar timing as the gen3 ls1 PCM?s

  5. #425
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    im not up to what efi does as i don't use it, it may just start at a different point in the cycle and im not sure why a simple 4 stroke crank deg wasnt used like hpt, it should be on closed intake valve standard not sure why u have to add another 110 to it to get a closed valve in the spreadsheet, it should be close in the maths and if u add the makeup 30 deg it seemed to work out in mine

  6. #426
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    110 cam degrees = 220 crank degrees, it’s just a case of units displayed in the software.

    ECT extra Timing or make up pulse is also cam degrees, its doubled in efilive, which raises the question should it be included for the calculation of the normal pulse, should not i think, it is related to additional injection pulse?
    Last edited by Gelf VXR; 10-12-2019 at 07:55 AM.

  7. #427
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    Sorry for not getting back sooner. Had a whole lot going on lately. I left a pm to hopefully answer this... I would personally just use hpt's values - your going to be going by feel, smell, what your setting it up more for and how it "acts" anyway, so doesn't necessarily matter if the numbers are 100%... Once you get to playing with it, you'll understand more of what I mean by this, because depending on the circumstances of just what the build is meant for, you can wind up with some pretty different injection tables...
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  8. #428
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    I?m going to start with stock setting for base line, then reflash retarding eoit at 30* (15*HPT) intervals. I?m sure there are different methods to test at idle, I?m going to go with open loop MAF, set the MAF in the frequency range above and below where it normally idles to 7.5g/s for example to hold IPW steady, disable idle adaptive spark, use 13* stock timing, lock the TB where it normally idles at limiting the idle max area and set high the min idle flow table, and watch rich AFR, highest rpm and lowest MAP.

    And keep an eye on rich after flash problems

  9. #429
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    I'm going to post my specs and my settings to be used as another data point.
    2008 Corvette A6 with YANK SS3200
    LS3 w/ 4.080" Bore, 4" Stroke
    Cam Motion 230/234 @ 0.050" - 280/284 @ 0.006" - LSA 117+0 (I estimated an extra 25 degrees duration on each side of the lobes for my seat-to-seat timing)
    Using 6.2 Flex Fuel Escalade injectors and data.
    Stock heads, intake, full Z06 exhaust with single cat per side.

    Boundary:
    0 512 1024 1536 2048 2560 3072 3584 4096 4608 5120 5632 6144 6656 7168 7680 8192
    507 507 507 507 507 510 525 545 560 575 590 598 603 603 603 603 603
    Normal ECT:
    -40 -18 3 25 46 68 90 111 133 154 176 198 219 241 262 284 306
    199 199 199 199 199 199 154 109 109 64 64 64 64 64 64 64 64
    Normal RPM:
    0-512 640 768 896 1024 interpolate to 2048 2176 2304 2432 interpolate to 3200 carried to end
    120.0 122.5 125.0 127.5 130.0 140.0 120.0 100.0 90.0 0.0 0.0
    Makeup ECT is stock 30 across table
    Makeup RPM is stock 0 across table

    This keeps EOIT-FRC on a closed intake valve until around 2500 rpm and starts to delay it to about 583-585 degrees, or 32-35 degrees before IVC.
    The Normal RPM table slowly works its way up to 140 at 2,048 rpm to keep EOIT-FRC on the closed intake valve.

    My take on the makeup and also my reasoning for keeping the 64 value of the Normal ECT table and Normal RPM table is this:
    I think the makeup pulse is injected in the window between the Boundary and the normal EOIT (in my case, between 507 and 323-320 at idle).
    That gives me a 187 degree injection window for makeup pulse(s) for idle bouncing around slightly at 700 rpm. Also for quick throttle transitions.
    I think that's how it's supposed to work. So if you zero out Normal ECT at warm temps, and zero out Normal RPM table, there is no more window.
    I don't really know how it would work in a makeup pulse at that point, seeing as the Boundary is defined as "The latest possible crank angle that the injection pulse can finish for fuel to be delivered into the cylinder."

    These settings work perfect for my car, but only use them for reference as another data point. Car's exhaust smelled like unburned fuel when i targeted PPV.

    Daily driven with 231,000 miles on the car so far, nearly 40,000 on the engine.
    2008 Crystal Red Metallic Base Coupe A6 FE1. FlexFuel conversion, 418 LS3, CamMotion 230/234 117+0 cam, 11.5:1 CR, full Z06 exhaust, custom cold air box built around stock Z06 air bridge. Running Amsoil Signature Series 10w-30 and Amsoil Signature Series Fuel Efficient Synthetic ATF. Tuned by me with AEM 30-0333 WB thru HP Tuners.
    +231,XXX miles as of 12/12/19.
    Grimsley Performance, LLC on Facebook
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  10. #430
    This is amazing work to say they least! thank you to everyone whom has put this together over the years.

    I would like to ask some clarification questions with the latest v21 iteration.

    1) the port area...where is this data coming from? Cross Sectional Area? Max, min, average? Stock for a cathedral or square port? Just wanting to understand the source. I'm running stock 823 heads, so f this needs to be changed im happy to do so.
    2) similar, what is the source for the Inj distance from chamber of 152mm....ok to use for 823 heads?
    3) the recommendations in the DOCs tab..."keep SOIT after EVC to reduce fuel smell at idle"....that needs to reference the SOIT-FRC, not the actual SOIT?
    4) With the larger inj PW areas, much of the fuel is being sprayed at an open intake valve, especially when trying to target the PPV. Is there concern of 'washed oil off the cylinder walls'....or is that concern negated by the extra turbulence and such?

    I need to do some data logging for PW at WOT before i can finish my inputs, but much of the changes will come from delaying the boundary to before 540/BBDC

    ~Ryan
    Charleston, SC

  11. #431
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    ppv is only targeted more in the higher rpms where there is turbulence in the cylinder to atomize the fuel. Try to keep right around exhaust nearly closed at idle to 1500 rpms as possible
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  12. #432
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    What do you'all think for a Whippled LS3 with Cam and Whipple kit injectors? Does the large gap (no overlap) look correct? Looks like a wide gap to me, but it is a stock cam, and had to use 0.05 values since couldnt find 0.006. This is more of a test to see if I understand everything correctly and am planning a cam change in the future. Am I even close to getting it?

    my "Intake Lift At Valve" looks too big, but that's because I mult cam lift * 1.7, since it was worded "At Valve". What do you think about that? Do I just enter cam lift, or some mult factor due to rocker ratio?

    Is there any point in adjusting it away from the stock 110/520 with a stock cam?

    Not sure I entered all the cam info correctly, because I'm getting different results in the older "INJECTOR TIMING TOOL GEN IV - LS2 02.10.2017" vs. newer "INJECTOR TIMING TOOL GEN IV - Black Charts-FRCv21 calculator"..

    Thanks for all who have contributed to these calculators!!

    EDIT - After looking at it a little more, looks like the numbers I came up with are for a cam with larger overlap, good practice, I guess.

    2020 10-31 Inj Timing Stock LS3 1.PNG
    2020 10-31 Inj Timing Stock LS3 2.PNG
    2020 10-31 Inj Timing Stock LS3 3.PNG
    Last edited by 10_SS; 10-31-2020 at 05:11 PM.
    2010 Camaro LS3 (E38 ECU)
    Whipple 2.9L, 3.875" Pulley, kit injectors, supplied MSD Boost-A-Pump, stock pump
    LG Motorsports 1 7/8" Headers - No Cats, stock mid pipe with JBA Axle Back
    ZL1 Wheels/Tires

  13. #433
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    Looks okay to me except for the "lift at valve." I did notice the large negative overlap but that's unsurprising using 0.050" lift numbers on a stock cam. My cam is the LPE GT9 (engine is E-Force supercharged) and even though it has no overlap at 0.050" it does have some overlap when measured at 0.006". Because of that overlap, I fiddled with the target numbers to not start injection until after EVC at idle and light throttle cruise. After learning that OEM timing purposely injected fuel on a closed intake valve, I tried that, too, but it made the smell at idle worse. What seemed to work best for me is this:
    Attached Images Attached Images
    Last edited by pannetron; 10-31-2020 at 12:31 PM. Reason: Add screen grabs

  14. #434
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    Bringing this back from the past with what "may" be additional information. I am new to tuning and have been doing a lot of reading around tuning the Gen4. In looking over the tables in my tune (E38) I have a table that I haven't seen mentioned. It is called "Makeup RPM". In my tune this is all "0"s. but what I found interesting is the table description.

    [ECM] 13340 - Makeup EOI Target vs. RPM: The target angle before the boundary that the makeup injection pulse(s) should finish.

    I think the calculation for EOIT would be Boundary-ECT-RPM+Makeup = EOIT.

  15. #435
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    Please help me to understand the following. I have been reading how to eliminate "Trailer Hitching" for about 2 months on my 12 Z-06. I have been lead to Injector timing as the issue. To solve , I have downloaded the 720 degree wheel and with my cam specs at .006, and one of the excel calculator's you guys have so graciously provided, I have marked the four points as EVO-91.5, IVO-327.5, EVC-400.5, and IVC-620.5. Boundary from the tune is 520, N.Temp @176-110, N. RPM is 25 @ 850, Makeup RPM-30 and Inj Deg-21.6 @850, and 585 @ 6500. If I understand what I read with the 73 deg. of overlap that I have , SOIT up to 1536 RPM should be at or just after EVC of 400.4 deg. To get there, it looks like 520-(110+25+30)= 355.
    1.) Do I then add to the Boundary by 45.5 Deg. to make SOIT 400.5? 2.) Do I do the same above 3K to arrive at EOIT 477 deg (IVO Max Open)? 3.) And would it follow to adjust the Boundary to allow for EOIT above 4.5K to be IVO Close @ 620.5 minus 15 to 20 degrees or 600.5 EOIT? I am sure the answers are quite simple to you and would be to me also with out the N.ETC, RPM, and Makeup RPM thrown in. They are confusing.
    Last edited by lbl866@aol.com; 1 Week Ago at 07:10 PM. Reason: misspelled word

  16. #436
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    take confusion out and just set all boundary to 520, zero out the normal rpm, and then lower the normal ect until at idle u get most rich on the trims/WB and then adjust fueling to suit so its error is minimal, then u can raise the boundary in the 1500+ cells to suit cruse and then higher if u want to above, i dont like going over 580ish at the top so can slope from your 580 up top to yours idle deg should be fine, just dont go too delayed at idle as it also gets reversion back out the intake especially if u have a late IVC, set makeup ect to 20-30 deg, makeup pulse min to 0.20 if they are not already, see how u go

  17. #437
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    Thanks for your reply. I will get on it and see how it turns out.