Page 1 of 12 12311 ... LastLast
Results 1 to 10 of 117

Thread: Injector Offset ?'s vs LS1 edit

  1. #1
    Lifetime Member MN C5's Avatar
    Join Date
    Mar 2005
    Posts
    376

    Default Injector Offset ?'s vs LS1 edit

    Man, all these new tables are giving me a head ache.. Pulled EFI FlashScan and LS1 Edit files to compare some of the things I'm used to working with and found the values differ substantially. Has anyone else run into this ?

    Also does anyone have an understanding of what changing the value in the table actually does? Say at 10 volts at all represented MAP values you have .5000 and at 13 volts and all represented MAP values you have
    .3000 for a table value. What change does the injector see ?

    Thanks

    Dennis

  2. #2
    Lifetime Member
    Join Date
    Jul 2004
    Posts
    306

    Default

    The injector offset table is a VERY important table to tuning in your car correct with aftermarket injectors like the 30lb SVO's, etc. Unfortunately, from most of the tunes I've seen it is also an ignored table most of the time. Even by professional tuners.

    If you ignore this table and just do the math on the IFR table for larger injectors, the math will be off and your tune will also. Most people compensate by "massaging" the IFR table and MAF table to get the desired Ltrims. Unfortunately, doing it this way just made your life 10x harder. (See below picture for IFR table I download of a tune of someones. )

    The offset table adjusts the injector pulsewidth on time based on voltage. Smaller values will increase ltrims and larger will decrease ltrims (larger commanding more fuel per pw).

    Over 2 years ago this table drove me crazy. I was trying to figure out why the math for the IFR didn't work out. Using the stock offset table with SVO injectors for example will make your tuning that much more difficult. I got it pretty close (WB AFR was only off by .1 compared to commanded AFR and all the math worked out for IFR) however, I have been refining it more lately to get it dead on.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	ifreeekkk.gif 
Views:	573 
Size:	13.9 KB 
ID:	59  

  3. #3
    Lifetime Member MN C5's Avatar
    Join Date
    Mar 2005
    Posts
    376

    Default

    Thanks John, I've got the base tune in mine now but know it can idle better than it does. I've got 735cc injectors from RC Engineering and sent them a email requesting offset values for these. I'll post their reply, Would anyone like to guess if a larger injector requires larger or smaller table values >>>

    Dennis

  4. #4
    Lifetime Member
    Join Date
    Sep 2003
    Posts
    688

    Default

    I hope someone can take the mystery out of that table

  5. #5
    Lifetime Member
    Join Date
    Jul 2004
    Posts
    306

    Default

    Quote Originally Posted by MN C5
    Thanks John, I've got the base tune in mine now but know it can idle better than it does. I've got 735cc injectors from RC Engineering and sent them a email requesting offset values for these. I'll post their reply, Would anyone like to guess if a larger injector requires larger or smaller table values >>>

    Dennis
    SVO injectors require larger offset values (say at 14V, .700 instead of stock .300 0kpa) than LS1 stock bosch injectors. RC will most likely have a single linear offset table like the Fords ECU's use. As you guys know, ours is a lot larger of a table. If someone has the ability to test the injectors vs voltage offset and make a table, that would be the best.

    What are your injectors? Lucas, etc??? I can work up an IFR table for them and get you in the ballpark for the offset table if they are SVO type injectors.

    To complicate things more, I'll also throw MAF table into the equation (you knew I was going to do this. ). If you've messed with it, the IFR table & offset table, you will most likely be hopelessly chasing your tail (tune). Now guys are change VE tables to even further complicate things.

    I was just discussing all this with Whitney actually and his car responded just like mine. Very predictable and repeatable with offset changes.

    Folks... KISS .... If you have a C5 with an 85mm screenless MAF, use a Z06 MAF table and don't touch it. EFILive provides us with the power of the table editing. Doesn't mean it's benefical to change every table you see.

    If anyone is using SVO or Accel (brand) injectors and would like to play with some offset tables and gather more data, feel free to email me your tune file and mod list.

    John

  6. #6
    Lifetime Member
    Join Date
    Jul 2004
    Posts
    306

    Default

    Note: Above example for SVO offset is assuming an SVO injector test pressure of 43.51psi and not 39.15psi.

  7. #7
    Lifetime Member
    Join Date
    Sep 2003
    Posts
    688

    Default

    What about racetronix 32's can you whip somthing up for that

    Code:
    Static Flow Rate @ 43.5PSI (300kPa) = 31.6 lb/hr = 332cc/min = 239g/m
    Static Flow Rate @ 58.0PSI (400kPa) = 36.5 lb/hr = 384cc/min = 276g/m
    Dynamic Flow Rate @ 43.5PSI (300kPa) = 6.68 gm/pulse - 2.5ms pulse width and 10ms repetition rate
    Dynamic Flow Rate @ 58.0PSI (400kPa) = 7.72 gm/pulse - 2.5ms pulse width and 10ms repetition rate
    Coil Resistance: 16.2 Ohms / High Impedance / High-Z (No ECM driver modifications required)

  8. #8
    Lifetime Member
    Join Date
    Jul 2004
    Posts
    306

    Default

    Quote Originally Posted by Dirk Diggler
    What about racetronix 32's can you whip somthing up for that
    Show me pictures of the injectors, supply some numbers off the injectors or all of the above. The more info the better. Don't know who's injectors racetronix uses as I haven't looked into it. Are they bosch injectors??? Should have a 0 xxx xxx xxx number or something like that. Sorry, I'm doing all this from memory, when I get home late tonight, I'll look over some of this stuff as it's been a while.

  9. #9
    Lifetime Member
    Join Date
    Sep 2003
    Posts
    688

    Default

    http://www.racetronix.com/621020.html

    I provided more information afte you quoted me

  10. #10
    Lifetime Member
    Join Date
    Jul 2004
    Posts
    306

    Default

    I used to have Lucas injectors years ago. If I recall, they were closer to stock function but I can't confirm that. Again memory.

    I know someone has to have the offset tables out there. Years and years ago when I was looking into this, I think it was Chris Bennight that got the original Ford numbers??????

Page 1 of 12 12311 ... LastLast

Similar Threads

  1. Injector Offset for #83 lb/hr injectors
    By turbo_bu in forum General (Petrol, Gas, Ethanol)
    Replies: 2
    Last Post: June 1st, 2009, 03:01 AM
  2. Wideband AFR rpm offset?
    By Highlander in forum General
    Replies: 0
    Last Post: June 15th, 2008, 12:34 PM
  3. Small Pulse Adjust/Low Pulse Width Injector Offset
    By N0DIH in forum General (Petrol, Gas, Ethanol)
    Replies: 0
    Last Post: September 4th, 2007, 08:05 AM
  4. Need injector offset table for 60# Motrons!
    By Redline Motorsports in forum General (Petrol, Gas, Ethanol)
    Replies: 2
    Last Post: April 7th, 2006, 01:56 PM
  5. Injector Offset error?
    By eboggs_jkvl in forum General (Petrol, Gas, Ethanol)
    Replies: 8
    Last Post: February 23rd, 2006, 09:49 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •