Worse mileage with gryphon on interstate

[bossman15]

Did a little test on the interstate today. Cruise control at 70 for 55 miles to madison florida from tallahassee. Averaged 15.2 with my trucks stock tune. On the way back I had the tow tune with 87. Averaged 14 even at the same speed. I don't get it. It seemed like it was running higher revs with the gryphons tunes ( tried 87 tranny for a bit too). Anybody else experience this? I have a brute force cai and a super 44 catback

[cleatus12r]

You ABSOLUTELY need to compare mileage on the same route in the same direction. You would not believe the difference in economy when travelling in the opposite direction when taking a trip. The amount of average elevation change would startle you.

I used to make the same 250 mile trip just about every weekend. The trip to Billings would get me about 19.5-20 MPG. Going back to Jefferson City (just south of Helena) I was only able to get 17.5-18. The results were repeated dozens of times.

After some research, I see that the elevation of both cities differs by about 2 feet. Wow. Head wind maybe?

Lots of things to consider here. I see also that you thought your RPM was higher while using the Gryphon programming. The only three ways that the programming is going to affect are that either the gear ratio value in the Gryphon is incorrect giving your speedometer an accuracy problem and you were actually going faster than actual....

OR

The tire size selection is wrong causing the same issue......

OR

The torque converter clutch isn't applying.....

[88Racing]

The 87 oct canned tow tune runs a little richer than stock.
Figure in the CAI into the equation and that maybe where the problem is.
I agree with Cody that equal trips will show better results when try to point the finger at a cause.
Try it with custom tunes when you get them.

[Jackpine]

Head wind will absolutely KILL your gas mileage. Let's just assume you had a tail wind of about 5-10 mph on the way out. On the way back, if that turned into a 5-10 mph headwind, it would be kind of like driving 10-20 mph faster, as far as wind resistance goes, and, because drag increases with the square of velocity, the drag you would have to overcome would increase enormously. To give you some numbers, at 70 mph, the velocity effect on drag is 10,540 feet per second squared. At 80 mph (or with a 10 mph headwind), the velocity effect is 13,767 and with a 20 mph headwind, the velocity effect is 17,424. A 30 mph headwind at 70 mph gives a drag effect of 21,511 - over twice what it was at 70 with no wind!

Over a period of 1-2 weeks driving on trips, I average about 12.7 using Bill's tunes pulling our trailer (for the whole trip). But, individual fillup calculations vary anywhere from well over 14 mpg down to below 10 mpg. Some of this, of course, is downhill vs uphill, but wind plays a big part too.

Did you program the Level 2 tune without opening the Custom Options menu? Notice I said opening! If you didn't open that menu, then your Tire Size and Gear Ratio were set at what Ford put in the PCM when your truck left the factory and should have matched the stock tune values. But, if you opened that menu, but did not set BOTH the TS and GR to correct values manually, then one or both is almost surely wrong, which means your speed was different.

And, if you were fighting a headwind, your TC may have been unlocked more often.

As Cody says, either calculate the mileage using the two tunes going the same way at the same time on the same day (impossible), or, average the economy using the different tunes over a 1-2 week trip driving essentially the same route in essentially the same weather and at the same speeds.

- Jack

[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

[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

[Corey Cohron RIP]

Just a heads up...

the canned Level 2 is a tow tune. It's not written for fuel economy; it's written for more bottom end torque for pulling.

[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