1st SETUP injectors (flowrate, rate modifier, Min pulse width, PW adder)

Discussion in 'Tuning' started by cobalt123, Dec 5, 2009.

  1. cobalt123

    cobalt123 Platinum Member

    Likes Received:
    Jul 18, 2009
    Tyler Texas
    cant take credit
    Edit: If you have a good tune then keep it. If you want to learn how to tune then just so you know your starting from scratch here. you cant take info I have here and make one change to your current tune and expect that it will run better. It is souly up to you to get it right. the steps I providing are how to go about building your own tune. not fix or make a tune you have better that someone else provided you. the tune your running took countless hours to perfect. they minipulated numbers to obtain the same goal I have. good drivealbility with performance. the end result is the same but how we get there can be different and that is ok.

    Please dont change one factor in your tune and expect it to run better. it will affect the VE and PE and MAF, Etc. You have to do every step I am providing to build your tune. More segments will be provided. As well this is just based on my research so if you have a different way that works for you that is great. This is just how I approach tuning. hopefully it will help you. This may seem obvious but always have your WB on the car and monitor it. Bottom line I am not responsible for your tune.

    1st SETUP injectors (flowrate, rate modifier, Min pulse width, PW adder)

    Flow rate

    I have calculated the G/Sec I wanted in the injector flow rate table. problem encountered was the the PCM table has a max value of 8 that you can put in so I recalculate the table of what I wanted and put in values based on 8 being the max. this is what I came up with.

    New values for flowrate rate table for 60lbs/rated with 43.5 fuel PSI

    7.303 7.381 7.458 7.548 7.622 7.697 7.771 7.856 7.929 8.000 8.071 8.154 8.224 8.293 8.362 8.441 8.508
    8.575 8.642 8.719 8.784 8.849 8.924 8.988 9.051 9.114 9.187 9.249 9.310 9.372 9.443 9.503 9.563

    New values that can be put into table with 8 being max value. (PCM limted)
    Injector Flow Rate vs. KPA VAC
    6.110 6.175 6.239 6.314 6.377 6.439 6.501 6.572 6.6330 6.693 6.752 6.821 6.880 6.938 6.995 7.061 7.118
    7.174 7.229 7.294 7.348 7.403 7.465 7.519 7.572 7.624 7.685 7.737 7.789 7.840 7.899 7.949 8.000

    just kept it linear.

    Rate modifier
    put at 1.19. in the Flowrate modifier VS. Voltage for all values. this will increase the Injector flow rate beyond the the 8 PCM limit in the IFR VS KPA vac table.

    It will look like this in HPT


    Minimum Pulse width and PW Adder

    Pulse width is all that needs to be changed from GMS2 #'s. I researched to what is needed for Siemens injectors. Any injector can be done similarly you just need the specs.

    According to HPT the Adder table is associated to the Short Pulse Limit.

    here are specs for Siemens
    - Turn on time @ 14volts = 1.14ms
    - Turn off time at 600kpa = 0.85ms
    - gain = 0.11 ms/mg
    - offset = 0.055ms

    Pulsewidth - the time it takes the injector to complete one complete cycle to turn on and turn off.
    so, 1.14ms + 0.85ms = 1.99ms

    EDIT for Insert of additional tip

    I found setting it worked well with adder values at 0 and min. pulse width at 0.094. You experiment with this and you may find that 0.9 or 0.8 is a good value for the Minimum pulse width as that is all I had seen. Higher minimum pulse width will make it difficult to get AFR at low air flow to be leaner than 11 to 12 afr (aiming for 14.7)


    Adder the injector pulse = minimum wdith allowed
    I found if set up to provide a minimum of half of full pulse width then your idle ran rich and at any RPM at 28MAP you ran to rich. the pulse width to provide 14.7 was 0.9. I just set it to 0.094 like GM did for GMS2. worked out very well.

    Specification Confirmation with source

    Coil Resistance: 12.5 Ohms / High Impedance / High-Z (No ECM driver modifications required)
    Static Flow Rate @ 43.5PSI ( 300kPa ) w/Gas: 60 lb/hr = 630 cc/min = 453 g/min
    Static Flow Rate @ 87PSI ( 600kPa ) w/Gas: 85.7 lb/hr = 900 cc/min = 648 g/min
    Gain: 0.11ms/mg
    Offset: 0.055ms
    Turn on time @ 14VDC: 1.14ms
    Turn off time: 0.85ms @ 600KPa
    Connector: Bosch EV1
    Orifice Type: Multi-orifice
    Spray Pattern: 30 Degree Spray Cone
    Factory fitted with Viton upper and lower o-rings

    From: http://www.bmotorsports.com/shop/pro...sk8h24bkdr09m6

    Now your ready to VE TUNE. I will collect info I obtained from various threads to get on to here. I cant take credit for the knowledge. just that I asked people and they had helped and it works. thanks Wiitt.

    other consideration. your WB. if you dont have one your going to need it. get a good one and purchase one that works with HPTuners. I didnt but I got it to work with my Autometer. then you need to get it error corrected. another thread to do in this series. oh well. its going to help someone

    ---------- Post added at 12:40 AM ---------- Previous post was at 12:39 AM ----------

    Ok here we go with Kennyspecs VE table tuning how to.

    The VE table and the MAF are both used to calculate fueling and they both have a “error” in them. We need to eliminate the error and get the car to shoot for a 14.7:1 AFR during light throttle and cruzing. We do now know how much error the VE table or the MAF has so we will first start out by eliminating the error out of the VE table. And by error I am meaning lean or rich.

    Step 1 Fail the MAF.

    Open up Hptuners and set the “Maf fail High” to 0
    Then set the P0103 code to “MIL on first error”
    If done correctly you should now have a check engine light on when you start your car.


    Step 2 Set up the car for open loop.

    Under fuel control OL &CL TAB there are 3 tables that need to be changed. They are adders/multipliers for fuel. We want to change them all to 1 cause the less multipliers and adders you have the easier tuning will be.
    The three tabs are

    Gas (Gear)
    Gas (P/N)
    IVT Gain

    The entire table does not need to be changed. Just change them where I have highlighted.


    Turn off DFCO

    Step 3 PE table.

    The PE table is a multiplier for fuel when the car is under high load/WOT. It determines the AFR that you get during WOT. You set the PE table to the right multiplier to give you the desiered AFR that you want at WOT and then LEAVE THE TABLE ALONE!!! You then adjust the VE table or MAF table to obtain the correct AFR. The equation for it is
    14.7/”EQ Ratio vs. RPM” = AFR at WOT

    So lets say that I want a 11.9 AFR at WOT so the value in the “EQ Ratio vs. RPM should be 14.7/ x = 11.9 x = 1.235

    So I then set the EQ ratio vs. Rpm to 1.235 across the entire range.

    (disclaimer: I am not saying that a 11.9 AFR is safe and should be used but it is what I use with my meth injection)

    I did not like how in the gmstg2 tune the car didn’t go into PE mode until above 4800 rpm so I changed some things.

    PE Enable MAP to 115kpa ~ 3 psi
    PE delay RPM 0
    PE table TPS (see table below)
    Enrichment rate 1
    Piston Protection 8000rpm

    Now the car will go into PE mode regardless of rpm. Anytime you are over 3psi the car will richen up and go into PE mode.


    Step 4 Turn off COT


    Finally its time to go drive around and tune the car!!!!

    So I assume that you have a WB 02 set up to log into HPtuners. Also you have to have a AFR% error histogram set up in HPtuners. It should log error based on your wideband. NOT based on LTFT or STFT.

    Start up car and wait till it has reached operating temp 180* F

    Start logging with hp tuners. hit the reset fuel trim button.
    Drive around nicely on a open highway hitting as many cells as much as possible. Vary the rpm and map as slowly as possible. Try to stay out of PE mode. (stay below 4psi) and I don’t bother tuning anything above 4000rpm as I don’t do any “nice” driving above 4000 rpm. These are the cells that you want to “hit”


    Once you have all the cells hit at least 20 times copy and paste by % error into the VE table. Start the car up again and restart the process. Drive around on the open highway again for about 5 mins before starting to log again. The reason for this is when you shut the car off to flash the new tune the car heatsoaks. This will throw off the tune. Driving around for the 5 mins just gets rid of the heatsoak. Now when you copy and paste by % error into the VE table you should have less error than last time. Now as you get closer to 0% error you should see that the WB gauge is closer and closer to 14.7 at part throttle driving. When you now paste the error in the VE table paste by % error half option. This just prevents you from going to far and overshooting the error. you will never get to 0% error so dont bother wasting your time. you should be able to get +-4 though.

    There ya go. Your car should be now tuned in open loop. once done this its time to tune
    the PE mode in open loop. To tune the PE mode is the same as tuning part throttle but now you are tuning at WOT. HAve fun with this. just watch out for knock and keep a eye on your AFR.next comes the maf. that will be in part 3 of the series

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