The Truth about Dyno Tuning

by Michael Decipha Ponthieux
Posted: 1-4-2014
Last Updated: 6-7-2015

The following applies to CHASSIS dyno's only, engine dyno's are the most accurate means of calibrating an engine and is highly recommended when possible. I recommend DEPAC Dyno Systems, for all engine dyno's. I consider DEPAC to be by far the most advanced engine dyno instrumentation available. Used by the OEM's and all the professionals that seek intricate engine information not available by any other means. IMO, any engine dyno that does not utilize DEPAC is absolutely useless.

First off I'll state the benefits and disadvantages of common tuning options.

Dyno Tuning Benefits

  • Tuner can physically listen/feel the engine
  • Engine can be monitored more carefully in a controlled environment
  • Higher HP engines can be operated safely as compared to street tuning
  • Finding MBT is much faster than having to read plugs after a pull (although should still be done)
  • MBT can be exceeded safer (with no detonation) due to less loading (true for most dyno's)
  • Part throttle timing can be closer to MBT (usually)
  • Tailpipe AFR sniffer can verify accurate AFR readings (so long as no cats are present)
  • Speedometer calibration can be verified faster (rather than counting mile markers)

    Dyno Tuning Disadvantages

  • Wheel slippage / Converter slippage can skew results
  • You can only simulate driving conditions (actual conditions will be different)
  • Dyno's cannot always accurately load an engine, bad data in = bad data out
  • Driveability issues may not be present on a dyno as they are on the street
  • You cannot dial in cold startup enrichment or air flow
  • Vehicle is not operated in its natural environment

    Street / Online Tuning Benefits

  • Actual street loading is the most accurate way of calibrating an engine (in vehicle)
  • Street / Online / Remotely tuned vehicles will have better driveability
  • Owner is not 'locked down' to a tune, ability to make their own changes (if desired - not recommended)
  • Time constraints are not a concern
  • Location is irrelvant no trailering needed
  • Vehicle is opeated in its actual enrivonment in its actual intended use
  • Tune changes can be made for any engine changes with ease

    Street / Online Tuning Disadvantages

  • May be dangerous to operate higher HP engines at WOT on the street
  • May take longer to dial in a tune completely due to communication
  • Accurate AFR data may not be available if no wideband is present
  • Part-throttle timing may not be as optimal as compared to dyno tuning (not often but in some cases)

    Track Tuning Benefits

  • Most accurate method of tuning for maximum performance
  • Only method to finding the most optimal ignition timing and AFR for a specific combo
  • 1/4 mile ET and MPH cannot be disputed

    Track Tuning Disadvantages

  • May take longer to dial in due to track's turnaround time
  • Inconsistent driver may lead to faulty tune adjustments
  • Changing track conditions can significantly affect ET and MPH

    Whats the best method ?

    There is no 'best' method. The most ideal option is up to your circumstances. I highly recommend engine dyno tuning when applicable. Often times that is not an option. For the majority of performance enthusiast, I recommend chassis dyno tuning if you have a knowledgeable tuner near you. If location constraints prohibit chassis dyno tuning, remote / online / street tuning is a highly effective alternative. Typically an online / remote / street tune will have slightly better driveability than dyno tuned vehicles only. It's not uncommon for most dyno tuners to operate a dyno tuned vehicle on the street to verify the calibration is operating as expected. In these cases, chassis dyno tuning has the same benefits of street / online / remote tuning. All tuners should give you complete unrestricted access to your tune, if they do not, you should reconsider utilizing that tuner. For those more technically savvy I HIGHLY recommend DIY tuning. However, a professional should be consulted or prepare a 'base' calibration for those inexperienced tuners that are limited by time constraints.

    Check out the Tuning Tips & Methodology for dyno tuning tips.

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