Self tuning w/ VT primer questions

Discussion in 'Mazdaspeed 3/6 ECU Tuning' started by VoodooJef, Jul 2, 2017.

2 users.
  1. VoodooJef

    VoodooJef My friends call me Captain Zen Greenie Member

    Dec 24, 2016
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    **Ok, to minimize the potential tangents, let`s just assume that 27 years in building and modding performance cars has given me a fair base of experience to work from here. LOL. **

    (1) built motor/BT/E85/Methanol.
    (2) setup will only differ from previous (non-forged) in the addition of a better exhaust manifold. Everything else will be exactly the same.

    I`ll be self tuning with Versatune. The plan is to get a solid base map together, put in a few revisions from street pulls, then dial it in on a dyno.

    Let`s start:

    once the base map is established, can I use the data from my previous logs as a guide in developing the new tune? Ie; can I use the previous load/timing/boost/afr readings as targets in the new tune? (no, not considering going straight to final map readings. More like mid-tune numbers).

    How big or small should my change increments be per revision? Can I make substantial jumps in the beginning or is it really mandatory to do small steps? (example: base map has a max timing advance of 4*. Can I bump that to 10* or would it be necessary to step it between 4 and 10? Again, assuming the requisite other parameters are also addressed).

    I am familiar with boost tuning. VT is load based. I`m fine with that, but it begs this: with boost tuning you keep bumping boost to make more power (again, yes, of course keeping other parameters in check along the way) until adding more boost does not make more power, you can`t maintain afr, or you hit your goal. Would I now bump load the same way instead?

    And likely the most important question I could ever ask: What makes a BAD tune? What are things to avoid that may be common to the platform?
  2. Redline

    Redline I done fucked up for the last time. BANNED Greenie Member

    Feb 12, 2016
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    I'll leave it to the VT experts, but I will tell you if it's a load-based tune, your load caps will effectively be your boost limits. In other words, if Xpsi of boosy hits Y calculated load (your load cap), the calibration will adjust WGDC to limit you to that load cap, and subsequently to that boost level, too.

    Boost-based tuning: Boost targets set the limits (simplified explanation without going into much more detail)

    Load-based tuning: Load limits set your boost limits because limiting load effectively limits boost (Calculated Load is a function of grams/sec *40 / rpm) so MAF calibrating changes calculated load. That's why a good MAF cal is an essential starting point.

    Hybrid tuning: Best of both worlds, IMHO - setup the tune to hit boost targets year-round (which means added power in cold weather), and per gear load caps are used to set ultimate load limits, like a safety net.

    Pure load-based tunes can vary the boost levels a LOT depending on ambient conditions. The stock Mazda tune is load-based and most people see anywhere between 13-15.5psi max, the key being varying ambients (cooler ambients = more oxygen density = more grams/second = higher calculated load).

    Hopefully that helps with the fundamentals. Like I said, I'm an ATR guy, and a Hybrid guy, but these principles apply to both tuning solutions. Hopefully a VT master can come in here and help you.

    Stratified's version:
    Last edited: Jul 2, 2017

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