Originally Posted by 1999RedXLT
Hello All,
I've read the FAQ about custom parameters and I'm not sure I understand completely. I understand that there are some parameters that are specific to the vehicle configuration, like gear ratios and tire sizes. Not really specific to the vehicle, since you CAN mount different tires or install different gears. If this happens, you want to inform the PCM.
Others are tuneable, like WOT and Rev limit. These are "electronic" limits only. They have no relation to any mechanical parts on the vehicle.
I further understand that those parameters, or their equivalents, exist in the stock tune. The Tire Size (TS) and Gear Ratio (GR) are not really in the "stock tune" but are kept in the VID section of the PCM.
It would seem like the Gryphon would load the stock gear ratios and tire sizes, even if you are doing a custom tune, then you would only have to change them if/when you change the item, like tire sizes. That would be logical, but according to Bill, it doesn't happen. As long as you load a canned tune and DON'T open the Custom Options Menu, the stock TS and GR are taken from the VID and "placed into the tune". If Bill writes a custom tune, he can set a "bit" that tells the PCM to ignore the VID and load a custom TS and GR that is included in your tune. But as soon as you open the Custom Options Menu, any "ignore" bit is bypassed and the VID values are too. Placeholder values are retrieved from some other part of the PCM and they may need to be corrected.
But as I understand it, the Gryphon, when you open the custom parameters screen, loads some default parameter that may or may not represent the configuration of your truck, even if it is stock. YES!
So you have to go and set tire size and gear ratio (anything else?) if you load any custom parameters. NO! (As long as you are happy with the way your tune performs).
While that seems suboptimum, it may be due to the architecture of the ECM or Gryphon and I'm OK with it. But when do I have to do that? Only ANYTIME you open the Custom Options menu.
Only the first time for each level? Every time I change levels? Example - If I have larger tires, and I want to enter that fact in Level 2, I open the screen and do so. Maybe I change some shift points, and other things and after I finish towing, I want to go to Level 3. First, when I go to level 3, are all my custom parameters in Level 2 saved with Level 2 so that they are there the next time I use Level 2? When I load Level 3 and open custom parameters, I'll get the defaults, right? Level has nothing to do with it. When you use the Custom Options Menu, you end up creating or modifying a SINGLE "previous settings" file. This SAME file will be applied to any Level if you open the Custom Options Menu and "Load Previous Settings". One place this could be bad is if you advance your timing 1 degree because you use 89 octane gas in an 87 octane tune, but then put 91 octane gas into a 93 octane tune. The timing advance will need to be changed, but you might want to keep the shift behavior and you certainly want the same TS and GR.
I know I can choose to get parameters from the previous tune, but I don't want them all, just the ones associated with the truck, like tire size. So if I don't want to blow away Bill's good defaults for Level 3 I have to let it load the defaults and change the things that need changing, like tire size, is that right? If all you've changed is the TS and/or GR, you won't blow away any of Bill's defaults when you "Reload Previous Settings". But, if you've given Bill your TS and GR, he'll include them in your tunes. You don't need Custom Options at all.
Sorry to be so dense, but I'd like to be sure I understand the use and storage of custom parameters.
Thanks,
Al
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