The K&N and Magnaflow can't improve what the factory already did. The ones it came with also flow good. The factory filter and exhaust was already engineered for maximum flow. Add more horsepower with cam,head work and such then you need to open up the breathing and exhaust. But not on a stock engine.

 

Since deleting the MDS and changing ECM paranmeters are you hand checking MPG? It might be off quite a bit over the readout in EVIC. I see no way that running on all eight compared too running on four mileage is unchanged. Why did they do MDS if no difference. Why does G.M. have it on many of its models? Not just trucks. I like MDS. Mine works great. It takes far less horsepower to move a vehicle thats already under way. Its physics at work.

 

Yes, I hand check. Don't even look at the EVIC. I have a spreadsheet, although I stopped keeping it up to date. It was depressing.



As for liking MDS, I have now had it on, and off. I prefer it off. Even if I do lose some MPG.

I just feel that 8 cylinder engines run better on 8 cylinders.

 

I wouldn't say it runs better but it is different. You know years back people use to remove piston,rod,lifter and push-rods on V8 engines to make then 4 and or 6 cylinders. Usually if damage to a rod or piston had occurred. Remove the damage one and one opposite it. G.M. has been fooling with cylinder deactivation since the mid 1970s on Cadillac V8,6,4. I like my MDS just fine. I just went to get a bite about 10 miles(20 round trip) away with the wife. Truck was in MDS the majority of the time. I drive with a lite foot.

 

To each their own I guess. When summer comes I may do some experimenting back and forth to see if it is worth turning it back on full time, and just using the "put in in 5" theory around town.

 

I'm convinced the truck just needs to warm up more. I usually just drive it to and from work. Take the wifes honda crv on errands. But i just drove the truck the same route I take everyday. Took the dog to the veg after work. Surprisingly the display was in the 16 going up to 17mpg. That's a big difference compared to my mid 13s I see everyday. I guess the warmer the engine gets and further you drive the better it gets. I know I hit over 20 on a 20 mile ride. Perhaps it's just this cold weather. I love my truck and just might start driving it more! I still want a programmer!!!

 

Don't worry so much about it. 13MPG is bad, so is 16, 17 and 21. You are driving a truck, not an eco car. You can only get bad MPG.

My advice, turn your EVIC off and just enjoy driving the truck! You will be much happier this way!

Oh yes, you do want a tuner!

 

Thanks gutty96. You definitely put it in perspective. I bought the truck because its a TRUCK! Trucks use a lot of gas, are more fun when loud, tow stuff, rip stuff out of the ground, and a lot more. I didn't buy it to be green. I bought it to tow my camper and take my butt to and from work. I'll quit worrying about it now and just enjoy the hemi.

 

The cold kills mileage on short to moderate trips. Same here in Georgia once temps go under 40 degrees.

 

I have had the superchips since 2010 when they added 4th gen support and immediately disabled MDS since I could not stand the sound and performance hit when it dropped into 4 cyl mode. And driving on back roads, it would shift into MDS at like 25-30 mph so it was constantly going in and out. Just not for me or my driving style and roads I drive.

As far as mileage, this winter gas sucks. Warm weather driving, I would regularly see ( on the EVIC, not hand calc'ed ) 17.6-18.2 with mixed driving. Now, I am at 13.9-14.6. This seems to be a normal seasonal pattern and it does help that I usually let the truck warm up for 5 minutes or so each morning during winter.