Worse mileage with gryphon on interstate

[Jackpine]

Originally Posted by soutthpaw

As Jack said, the Wind resistance makes such a huge difference... that's the one big reason I am not a fan of 5th wheel Trailers... they give you this huge air brake the whole time you are towing.
Also its really not possible for the rpm to be different at the same speed if the TCC is locked up... what differs is the amount of fuel needed to maintain that RPM at any given point

Nicely stated, soutthpaw!

I can also see I wasn't particularly clear with my explanation about "drag". I'm going to say it differently, and I think it will make much more sense.

If you are seeing a 10 mph headwind at 70 mph, you are moving approximately 14% faster through the air. But, the wind resistance has increased by a whopping 30.6%! A 20 mph headwind (28.6% higher airspeed) causes a 65% increase in wind drag. And, a 30 mph headwind more than doubles the wind drag.

Bottom line, even a small change in wind is going to have a large effect on fuel economy.

- Jack

[88Racing]

Everyones truck with a gryphon and canned/custom tunes will have varied mpgs. My truck did not get the gains I expected either but where I live most of the people drive 80+mph and the gas we use is not the best.
I bought my truck because it wasn't a prius or a civic.

[bossman15]

So I should always open the custom options menu and make sure the tire and gear are set right? I tried to do this on the limiter to see what it was set as and it said there was an error and froze up. Same thing happened on the tire size...idk what the deal is but I had to unplug it and plug it back in to reboot

[Jackpine]

Bossman, unless you are running non-OEM tires or gears, program the PCM without trying to customize anything, at least at first. Get to know wht the new tune feels like. And, the Gryphon needs a non-customized tune to properly set up its stock files.

I don't know why you'd get the errors though when you tried to use the Custom Options menu but there are two possibilities:

1. It was cold when you tried to do this. The PCM and the Gryphon's electronics don't like extreme cold or heat.

2. The battery voltage was low. The Gryphon has to do a lot of work when it builds an "options" file and it needs healthy battery voltage. If you have a low Amp (about 2 Amps) trickle charger, it would be good to have it connected to the battery while you do ANY programming of the PCM to insure there's sufficient voltage. Also, make sure your accessories (A/C, radio, lights, etc.) are off.

- Jack

[bossman15]

Yeah I set everything up with no custom tuning for the first week I had the tuner...I actually have 305-55-20 bfg's which is a 2650mm circum.. The tuner had it set at 2356mm so that definatly had something to do with it. I changed that and also firmed each shift up by one...is that okay to move the firmness?

[88Racing]

Originally Posted by bossman15

Yeah I set everything up with no custom tuning for the first week I had the tuner...I actually have 305-55-20 bfg's which is a 2650mm circum.. The tuner had it set at 2356mm so that definatly had something to do with it. I changed that and also firmed each shift up by one...is that okay to move the firmness?

Yes its okay to adjust the firmness on a canned tune.
Its also okay to do on a custom tune BUT SMALLER INCREASES should be used. Usually Bill gets the firmness tuned to a good feeling shift.

[bossman15]

alright cool. man i cant even wait to see what bill's got in store for me...im sure ill be blown away.