Which custom tunes for me

[Jackpine]

Originally Posted by apdanos

I object to this. I ordered a custom 87 performance tune and my mileage decreased by 3-4 mpg. That is 75 to 100 miles per tank. For me that is 3-4 round trip days to work. My driving habits did not change at all. Needless to say I have been running on the canned 87 tow tune. I was going to ask this in a new thread until I found this one: Is it possible to run the canned 93 performance tune with 87 octane and lowering the timing by 3.00 without causing any damage or having any trouble?

Bill has advised NOT to use low octane gas in a high octane tune. There are changes in the fueling strategy in addition to the timing changes. You DO risk some damage if you do that.

I'm VERY surprised at the "mileage decrease" you got. Is it possible your Tire Size (TS) or Gear Ratio (GR) is wrong in one of the tunes? Either one would strongly effect your perceived mileage (without actually changing the actual mileage much at all). Have you verified that your Gryphon speed matches an independent speed reading like a GPS? (Or that your odometer reading matches a measured distance?)

If you got a mileage drop like you say, I think you are the only one on the forum who did so. I know my mileage increased by about 0.5 mpg with custom tunes compared with canned, and canned was better than stock.

- Jack