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Thread: SOTF Tuning

  1. #61
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    Maybe some people here can test it and get back to us with some tips on creating a tune that can work with the switch and are unhappy with the optimal tunes. Some insight on how to custom tune and leave the switch installed would be great!

  2. #62
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    It?s just using the switch to trick the ecm to think it?s at a different altitude and thus uses fuel quantity limits based on what it perceives to be at for altitude. That?s really all it is.

  3. #63
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    Jim P, is there any way to force the ECM to use the Transient tables at all times, even when you're cruising at steady state?

    Also, in VCM Scanner, there's a PID that seems like it should be indicating which air density table is "currently in use", but it doesn't seem to work (at least for my 05). I was wondering if you knew off the top of your head when the Transient tables are generally used?

    It seems to me that the Transient tables would be used any time you weren't cruising steady state, but with the way the stock injection timing tables are set up and how my truck responds (with transient tables being fairly aggressive in terms of injection advance BTDC, which tends to cause a lot of low-boost smoke on my truck at my high elevation - and much less aggressive injection timing in the low air density tables, which results in a much cleaner running truck), it makes me wonder if it takes a much larger Pedal Request Delta to push the tune into the Transient tables. I would have thought I was using the Transient tables any time I took off from a stop, but that must not be the case, since the truck runs so clean if I leave the low-density table alone (with negative timing numbers).

    I wonder about all this because if I change my Low-Density tables to reflect timing values more along the lines of the Transient and High-Density tables, I get a ton of low-boost smoke on acceleration from a stop, before the turbo spools. But if I set the Low-Density table to be more similar to stock timing values in the spool-up region (where injection timing is more like -6* BTDC), the truck runs SOOOOO much cleaner. On the flip side, I seem to be experiencing a loss of MPG by doing so.

    Any insight you might be able to provide would be greatly appreciated! Thanks.
    Last edited by B00STJUNKY; 07-30-2020 at 09:41 PM.

  4. #64
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    Quote Originally Posted by B00STJUNKY View Post
    Jim P, is there any way to force the ECM to use the Transient tables at all times, even when you're cruising at steady state?
    Check out the table I point out in this thread. It?s the table that regulates what table is used at what air density.

    https://forum.hptuners.com/showthrea...Altitude-Tunes

    I?ve rarely observed the ?transient? table used, Cummins calls this table ?Alpha?. I?ve seen low air density used at key on engine off, after a first start when the engine is cold but most of time I?ve only observed high air density tables being used as long as a multiplier table wasn?t kicking in due to coolant temps or something.

  5. #65
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    Quote Originally Posted by Jim P View Post
    Check out the table I point out in this thread. It?s the table that regulates what table is used at what air density.

    https://forum.hptuners.com/showthrea...Altitude-Tunes

    I?ve rarely observed the ?transient? table used, Cummins calls this table ?Alpha?. I?ve seen low air density used at key on engine off, after a first start when the engine is cold but most of time I?ve only observed high air density tables being used as long as a multiplier table wasn?t kicking in due to coolant temps or something.
    Am I missing something here or is this table not available on the 2003 ECU?

  6. #66
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    Not available on the 2003 and early 2004, different ecms and operate different to varying degrees

  7. #67
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    Has anyone has the chance to actually look into a log file of his tunes. It seems that on the two highest tunes it's commanding 2900us of injector. Now correct me if I'm wrong, not only is that the absolute max you would ever want to push an injector, but I thought if all possible you really don't want to get above ~2200us on any setup for fears of EGT, smoke, and just overall fueling issues?

  8. #68
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    Max pulsewidth you would want to go on a stock 5.9 is 3200us...

  9. #69
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    Now if you have access to a dyno you can go lower on pulsewidth and higher on timing and achieve same power, but you will need to use a dyno to find the limit of what you can push for timing.

  10. #70
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    Quote Originally Posted by Jim P View Post
    Now if you have access to a dyno you can go lower on pulsewidth and higher on timing and achieve same power, but you will need to use a dyno to find the limit of what you can push for timing.
    Okay good to know. I just remember the guy from Firepunk always saying he does not like ever going above 2200us.

    On an 03 5.9 with 100hp(~37% over) injectors and a compound setup with an s475 on the big end what would be a general reasonable area to see the injectors and timing at at WOT on a max effort?

  11. #71
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    Given stock max pulsewidth is what, 1850 or so microseconds? 2200us is a pretty light weight tune, ideal for a tow tune.

    For the 03 question that would be better answered by Dom if he sees this and chimes in, he?s got way more experience with the 03-04 trucks than I do. But I?m going to say likely in then neighborhood of 2700us and 32 degrees of timing to be on the safer side.

  12. #72
    100hp Injectors I will usually not go above 2800uS and that's only if we're keeping revs around 3400ish. A lot of times I will be down in the 2550-2700 range and run out to 3800rpm. Timing between 32 and 34 depending on how spicy I'm feeling.

    I think I know what post he's referring to from firepunk and what Lavon had said was that on big injector trucks (Think like 250% overs and above) He likes to be below 2000uS. And I agree with that, because on big injector trucks you're typically spinning 4500rpm as well.