Page 1 of 2 12 LastLast
Results 1 to 20 of 21

Thread: Injector Flow Rate High/Low Mult vs. Pressure tables

  1. #1

    Injector Flow Rate High/Low Mult vs. Pressure tables

    Is the fuel pressure reference directly referenced from the MAP?

    I've noticed that the ID1000 datasheet says to fill them with 1's and Siemens deka datasheet has actual numbers, both change the scale to around 20+ PSI compared to the stock 0-15psi.

    Can anyone shine some light on this?

    All the 'internet' tunes I've looked at leave these tables stock and fudge the slope numbers but that doesn't sound right.

    Any comments would be much appreciated.

  2. #2
    Advanced Tuner
    Join Date
    Aug 2012
    Location
    Melbourne Australia
    Posts
    344
    The pressure is referenced off the manifold and for the Ausy turbo fords it is 4bar above manifold pressure. ID1000 spreadsheet for a return style fuel system has 1.0 in the multipliers as you put in the pressure in the spreadsheet and it calculates all the data for you. If you look at the returnless tab then you will see the numbers for each pressure/voltage point. The deka sheet has the actual multipliers and you can use this to calculate the values at 58.015 (4bar) by interpolating the value and multiplying the values out. Here is an example that should clear it up:

    http://www.hptuners.com/forum/showth...l=1#post350786

  3. #3
    Thanks DarrylC,

    So for the 60lb Deka's, wouldn't that mean I generate new LS, HS, BP and offset table using the multipliers (interpolated to 58.15) and '1' out all the multipliers similar to the ID1000 sheet?

    Sorry, it's been a long day looking at excel. I've made my own sheet similar to the ID1000 one, but using 60lb deka data. I would just try it but it's for a mates car 300km away.

  4. #4
    Advanced Tuner
    Join Date
    Aug 2012
    Location
    Melbourne Australia
    Posts
    344
    When I get home I will click submit and you will get the deka values.

  5. #5
    Thanks,

    I've attached a spread sheet that calculates the 60lb injectors the same way the ID1000 spreadsheet does. It's currently untested but I'm hoping to try it this weekend.

    Please correct me if I'm wrong.

    Siemens Deka 60lb calc.xlsx

  6. #6
    Advanced Tuner
    Join Date
    Aug 2012
    Location
    Melbourne Australia
    Posts
    344
    timwds, what are you tuning?

    For the Ausy Fords there is no need for these values as the pressure is 4 bar or 58.015psi. These tables are for a returnless style fuel system but we use them to calculate the values for our return style system. So for the Deka you would calculate the values as:
    Code:
    				58psi		lb/hr
    ALOSL (lb/s)	0.017552	0.021361437	76.90117167
    AHISL (lb/s)	0.016741	0.020374419	73.34790992
    FUEL_BKPT (lb)	0.00003363	0.000040929	
    MINPW (ms)	1.391		
    			
    FNPW_OFFSET		
    VBAT	 Voltage Offset	58.015
    (volts)	 (ms)	(psi)
    6	2.59	3.152126295
    8	1.441	1.753750576
    10	0.921	1.120891242
    11	0.758	0.922514182
    12	0.636	0.774035646
    13	0.518	0.630425259
    14	0.409	0.497768206
    15	0.312	0.3797156
    And put them in the tune. As mentioned in that other thread you can use 0.8ms MINPW and get a much better idle, ...

    For the ID1000s you would select return style fuel system, put 58.015 and % ethanol in the tables and it will calculate the values for you. It does this from the returnless values just like the Deka ones you calculated above.

    Edit, just checked your spreadsheet and they are the same numbers. You only need to put these in the other tables you have converted to 1.0 are not needed.

    And I would try the 0.8ms minpw, makes a big difference!
    Last edited by DarrylC; 01-28-2015 at 11:02 PM.

  7. #7
    Thank you so much, I'm tuning a BF XR6T.

    So you're saying the slope mult tables in the PCM aren't used as part of the injector calculations and are just mustang leftovers or something?

    The part I was getting confused with is since these cars are "return style", the differential fuel pressure (rail to manifold) is always 58.015 PSI, hence multiplying by anything but 1 would throw things out.

    Thanks for being patient.

  8. #8
    Advanced Tuner
    Join Date
    Aug 2012
    Location
    Melbourne Australia
    Posts
    344
    Ford does the calibration for a return less fuel system where it varies the pressure in the rail to control the flow rate. As you have found this is good for us as we can determine the parameters at the pressure we run from these values. So not really a hang over from the mustang but it allows the calibration to be used on any system (with a bit of maths you can use the Ford data to calculate the GM data as well).

    It is confusing in that we have High and Low slope modifiers in the tune and I am not sure why they are there as they do not make sense so I guess it is a HP tuners issue.

  9. #9
    I tried these values on the weekend, I think something is broken. I had to raise the offset multiplier to 60PSI and drop the slope values to around 69lb/h to get close to target.

  10. #10
    Advanced Tuner
    Join Date
    Feb 2010
    Location
    Perth Australia
    Posts
    480
    check your voltage offset units in the tune
    04 Velocity MKII M6 & 06 BF F6 555 ZF6

  11. #11
    Units as V vs. msec?

    I filled in the Offset vs Voltage table using the stock voltage scale and the values above. It was trying to idle at 17AFR until closed loop kicked in and added 20+ percent. I multiplied the voltage offset by the 60PSI multiplier to enlarge the values which as I understand would increase fuel.
    Last edited by timwds; 02-01-2015 at 10:35 PM.

  12. #12
    Advanced Tuner
    Join Date
    Aug 2012
    Location
    Melbourne Australia
    Posts
    344
    Post up your tune and we will have a look. As stated in another thread the car with the best idle and response was with the above values for offset, breakpoint but with both high and low slopes around 65 and minpw at 0.8ms.

  13. #13
    I'll post it tonight.

  14. #14
    Here is the tune.
    010215.hpt

    In it's current state boost is ok but idle/cruise LTFT is about 18%.

  15. #15
    Advanced Tuner
    Join Date
    Aug 2012
    Location
    Melbourne Australia
    Posts
    344
    Had a quick look and I am not sure where you are getting the data from as I cannot find a 1.3 multiplier in the tables which is what you have used for the offset calculation. However your offset is greater so it should lead to more fuel. Your breakpoint is also lower. The values look like they should work but 18% fuel trims to me indicate they may not be Deka 60s, something around a 50lb injector?

    The above figures I gave with a High and Low slope of about 65 and a minpw of 0.8ms work well in a car with Deka 60s.

  16. #16
    Advanced Tuner
    Join Date
    Aug 2012
    Location
    Melbourne Australia
    Posts
    344
    When you say the boost is ok what lambda where you getting? If it was around 0.8 (0.83?) then we are close.

    At this stage I don't have access to the car with deka 60s in it so I cannot check what the idle fuel trims are. For all I know they could have been +18, however the car idled perfectly and was responsive but I did not have a lambda gauge on it at the time.

  17. #17
    The 1.3 multiplier came from desperation to make it idle properly with out the low slope being lower than the high slope, nothing scientific.

    When the engine starts it goes straight to 17afr until closed loop kicks in and brings it back to stoich. Boost (11-12PSI) is between 11.9-11.4afr.

    The injectors were pulled from a wreck that came from a salvage auction so it's possible they aren't right. The injectors had nothing but a part number on them which I googled and found a page of 60lb siemens ebay/amazon listings and looked the same (black, plain, thin).

    The PCM had a stock tune it and wouldn't run (too much fuel), I'm guessing old mate reverted to stock using an SCT box before insurance company got it.

    Do you know of any 50lb that look like the Siemens 60lb? The part number should rule that out but I'm running out of ideas.

    Edit: Faulty fuel reg? maybe the spring has gone soft and bleeds too much at idle...
    Last edited by timwds; 02-02-2015 at 04:52 PM.

  18. #18
    I'll give 65lb slopes with your offset data a try when I have access to the car next.

    My main concern is why I'm having to deviate from the datasheet so much. I'm sure if I fudge the numbers enough it will work fine but not sure that I should if that makes sense?

  19. #19
    Advanced Tuner
    Join Date
    Aug 2012
    Location
    Melbourne Australia
    Posts
    344
    timwds I will PM you data from a couple of tunes I have for the deka 60s. They are widely different.

    Given your AFRs they are probably deka 60s, don't know if there are fake ones out there like the Bosch green giants.

    For some (most?) of the injectors Ford does not even use their own motorsport data.

    Deka 60s are notorious for being difficult to set up but there is data on them now and other people have reported they are getting good results with the Ford data. I suggest sending a PM to IH8TOADS as he spent a lot of time getting them to work well and may have some pointers. You can search the forum to find his post on it.

  20. #20
    Tuner in Training
    Join Date
    Feb 2019
    Posts
    20
    Quote Originally Posted by DarrylC View Post
    The pressure is referenced off the manifold and for the Ausy turbo fords it is 4bar above manifold pressure.
    Sorry to revive an old thread. Am I understanding correctly? This would be 4bar above gauge pressure in the manifold correct? That would be the pressure differential across the injector? This is what the the "pressure" axis is referring to?

    EDIT:

    The "differential" pressure would be the difference between the rail pressure(4bar) and gauge pressure in the manifold not 4bar above it.
    Last edited by Boody78; 08-24-2019 at 10:30 AM.