Reflash or Chip: Which is Best for Diesel Tuning

150 150 Brooke Hamilton

Diesel Tuning, which is best

The question of which Diesel Tuning method is best’ is one we get all of the time. Given that most providers only offer one or the other, their opinions can be biased. We offer both so from our point of view, nothing to gain, nothing to lose so here is the truth.


Re-flashes are in differing ways more difficult to actually tune. They don’t tune in an logical way and that can actually represent some serious issues for trying to get good Air Fuel Ratios (AFR’s) throughout the range.

There can also be added issues whereby its common that the software used for ‘decoding’ the factory files tells us the map, but not the axis or units of measurement, and this can vary from car to car… So even when very familiar with these nuances, they can take quite a few runs to get right.

Re-flash PROS

  • Slightly more reliable
  • Certainly less fault codes
  • maintenance wins from EGR flow manipulation

Re-flash CONS

  • Not the same power potential
  • No ‘off’ or ‘aggressive tune’ tuning options
  • Difficult to fine tune

Word of Warning:

Due to a number of the points raised above, we DO NOT recommend that you have you’re vehicle flashed where it cannot be dyno’d. Ideally, you’d also choose a supplier who can custom right the file on site, as it can take many attempts to get right.

Diesel Chip:

Diesel Chips  are also a world of pain. Ranging from the very ordinary eBay chips (and many big names doing the same but with a big $$$ tag and marketing budget) to the ones worth mentioning.

At this point in time, we really only recommend that you consider only 4 options

  1. ECU-Shop
  2. HKS
  3. DTE / or rebranded
  4. Uni-chip

We recommend these as these have excellent tuning ability by being able to manipulate both Air + fuel (both rail pressure and duration) – where nearly all of the other chips will do only fuel – and usually only by one method.

If you’re considering a lesser chip due to not wanting to get maximal gains, then we STRONGLY recommend the re-flash option, as it will get better gains and will also provide you with additional maintenance benefits with less reliability risk and fewer (if any) fault codes.

To see our range of chips available – Click this link here:


If you’re after modest gains and are unlikely to upgrade Turbos or fuel systems into the future, then re-flash is the best solution for you.

If you’re looking for maximal safe gains, might consider upgrading various engines parts in the future then a high end ‘piggy back ECU’ like the ones listed would be the pick.


” As always, love to hear some comments or thoughts so make sure you post them below.”

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