I have done a bit of searching and couldn't find a definite answer for or against it, and was hoping to get a little insight.
From what I've gathered, the factory tune is stored on the device and custom tunes made by the device just save the changed values (or so others have deduced/guessed.) I've read speculation that this is why the modified tunes have smaller file sizes.
I'm not entirely sure what changes are saved in the individual tune files (ie: are they values, or modifiers?) and was curious as to whether or not I should be re-installing the factory tune before installing a modified tune?
An example of why it would matter would be if I had modified a shift point to +300 or something, and it saved +300 in the modified tune. When I apply the tune for a second time, does it set base+300 or does it simply increment existing+300 (in which case it would be +600 which is not desired)? Perhaps the tune stores the actual value (lets say 5500+300, so 5800) in which case it would be safe to overwrite a modified tune with a new modified tune.
Is it generally better to always roll back to the factory tune before modifying a tune, or can I just keep installing over modified tunes with new modified tunes? Would it be safe if it's just a modification to the same tune, or unsafe if I were changing from say mpg or 91 octane to a different tune like 93 octane w/ CAI?
Right now I'm running the canned 91 oct and am going to try customizing it a bit, and was wondering if I need to go back to the factory tune first.
Thanks!
Best practice for loading new tunes?
Moderator: mikel
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JonDiablosport
- Posts: 152
- Joined: Mon Sep 19, 2011 9:14 am
RE: Best practice for loading new tunes?
yes you can overwrite an existing tune without returning back to stock.
the tool makes a backup of the oem original software.
You will have no problem modifying canned 91 tune without going back to stock first. also on the +300 or so question. it will only raise 300 above what the canned tune has it set for not 300 increments.
for example if your canned tune is set to 5000 and you add 300 its now set to 5300.
Second time around you raise it to 350 . it is not going to go from 5300 to 5650 its just going to go from 5000 which the canned tune is set at plus 350.
the tool makes a backup of the oem original software.
You will have no problem modifying canned 91 tune without going back to stock first. also on the +300 or so question. it will only raise 300 above what the canned tune has it set for not 300 increments.
for example if your canned tune is set to 5000 and you add 300 its now set to 5300.
Second time around you raise it to 350 . it is not going to go from 5300 to 5650 its just going to go from 5000 which the canned tune is set at plus 350.