Well I've had my Cortex set on the 91 Performance tune for more than a month now. I have been averaging 18mpg with 90% +/- being on the hwy at around 60mph. About a week ago I decided to go into the advanced settings for the first time, I was bored and have been very happy with the 91 tune. The only thing I've changed so far was to turn off the MDS. First thing I noticed was it seemed alot more responsive around town, then I realized I'm now getting 20-22 mpg. My driving hasn't changed in any way, and no other new mods since changing the program.

Now I just wish my Bilstein 5100's would get here so I can level the truck and put on a custom dual exhaust.

 

Just keep an eye on the mpg and make sure that's really the reason for the increase as it could be caused by other things also.

However, with your exhuast im sure it sounds better.

 

Turning the MDS off won't change the responsiveness. MDS isn't that noticeable. 22mpg in town? Nah.

 

Are you measuring the MPG or using the computer? The computer only estimates MPG and isn't as accurate as actually dividing the miles driven by the amount of gas used.

 

how do u like your cortex? i cant decide between the flashpaq or if i wanna get the cortex

 

My driving is mostly on the hwy. The 20mpg is my math, the truck comp comes up with 22 but that's after a week, only hwy miles. It will take a few more tanks of gas to come up with a good avg.

I love the cortex, very glad I went the superchips route. I hope to do the exhaust early next month.

 

I know when i started to trade my truck some time back i test drove a newer truck with MDS over a weekend and i could feel the MDS kick in and out. I was certainly something i want used to bit could notice. That was before they had tuners that could remove it. But maybe some trucks kick in and out better than others

 

I can hardly feel mine kick in and out. I installed a light that tells me, and now its a bit more noticeable. If im not paying attention then no I cant. When my exhaust had blown, man you can sure tell then!

You say your running 91 on the tuner? But are you putting 91 fuel in? Im running a bullydog right now at regular (89) cause i'm too cheap to buy 91 octane. But I have been considering paying a little more for premium fuel and bumping my tuner up a level....i still only get 17-18 highway, and like 14 in the city....

 

That's very good mileage. 2WD or 4? I'm guessing 2 - I don't know if its possible to break 20 in a 4WD.

 

just got back from road trip.
2007 5.7 quad cab 4x4 with 20" rims
K&N filter drop in
dynomax cat back
i run my tire pressure at max suggested by the tires,not the sticker inside the door.(dont care if i get a bumpy ride, i bought a truck ,not a Lincoln)
Diablo Predator on this trip tuned to 87, but running 89 octane.
On the way to my destination...i was getting upto 23 mpg, and on the way back driving into a nasty head wind i was getting about 19mpgs....my speed average was about 60mph/100kmh
driving habits are the name of the game.
in the city i get a low of 11mpg and have seen as high as 18mpg

i personally feel it could do better yet, before i put my predator in, i did see 25 mpgs, when i was doing 55mph/90kmh
all my numbers are according to the computer....and i use my reset button.
i just switched my tune to 91, ill update my milage