RandallMiller

I wondered if that really worked, what kind do you have? Back to the original post, I'm getting 13.5 mpg on mine @ 500 miles so far. What's everyone else seeing?

DPLarson

For me, synthetic oils, not just motor oil but trans and rear end gear as well. Check your air filter and tire inflation, drive at a reasonable speed. That last one is painful for me but when towing it can make a big difference. I know towing wasn't mentioned but that is how I roll so for me in the '06 6.0 'burb towing; 45 MPH = 12ishMPG, 55MPH = 11ishMPG, 65MPG=10MPG, 75MPH=9.xMPG, 80+MPH=8 or less MPG. I don't drive over 80 much when towing but I have a very stable weight distributing hitch and good properly adjusted trailer brakes. I ride smooth and level in some big open spaces. Over my last 800+ miles towing the GPS said my max speed was 81 and I'm sure that was just for a momnent. I don't remember going that fast at all on that trip. I did have to jam on the brakes HARD twice for Coyotes and Elk. No wheel lockup or trailer trying to swing out on me at all. I was actually quite impressed.

13.5 sounds about right for my '96 350 or '06 6.0 Suburbans in mixed driving. I expect 14.x on the highway with either when not towing. Maybe only 9 in all city driving in the '96, 11 in all city driving in the '06.

Oh yeah, I almost forgot, I agree with the person who said no Ethanol (gasahol). I always try to find E0, not e5, e10, e15 or e anything else. If you have an iPhone, get the free PureGas App. It shows who has GASOLINE and at what grades. It is fairly accurate. I got a bonus and found a place close to home that has low grade e0 but I still generally run mid or premium depending on conditions but regardless of grade, I always try to run no ethanol (e0) in everything. Also, if a station has e0 premium and e10 low grade, the mid grade may be e5 or it may be e10. How to tell: Look at the covers for the tanks in the ground. If they only have two tanks underground, they are mixing e0 premium with e10 low grade to make the mid grade so that makes it about e5 I guess. If they have three tanks, the mid grade is likely e10, same as the low grade. That is assuming the premium is e0 which it usually is but not always. Some of the discount stations may have 10% ethanol in all grades. The pumps should be marked.

spyncycle

The only way to save fuel is to drive something smaller.

Chickensandwich

I'm getting 19mpg from my 2001 Suburban. Used synthetic oil from day 1, now has 134k on it.

DPLarson

I've heard that before, 19+MPG in a Suburban. What?! Are you serious? I don't think I've ever seen better than 16 in either Suburban, '96 350 or '06 6.0. I use Synthetic oils and have 3.73 gears. What gear ratio do you have in this 19MPG 'burb?

Chickensandwich

Im not sure. Tell me how to check it out, and I'll tell you.

in2pro

Check your PRO codes in the glove box...

G80 Differential, locking, heavy-duty, rear
GT4 Rear axle, 3.73 ratio
GT5 Rear axle, 4.10 ratio
GU6 Rear axle, 3.42 ratio

Chickensandwich

I have 3.73 gears

Chevy03burban

Okay
I have a 03 suburban With over 150K and This is how I fix my MPG. I added a CAI (Cold Air Intake) dry filter not the oil filter, mine is made by FUJITA but hey they all are almost the same. I have a tornado inside my (CAI) intake tube facing throttle body to help with MPG. Look up www.tornado.com or tornado fuel saver. Some say it doesn't work but I'm a believer and trust me who in da heck brags about MPG in a chevy suburban??? "This GuysDoes"!!. Cat back exhaust system mine is magnaflow. Throttle body spacer. Ask, I only use Royal Purple synthetic Oil only. Guaranteed for 10K or more on oil change. So here's my story I stay in Socal Ca. My summers here are 110-120 almost daily trust me. I drove my suburban to Disneyland that's 392 miles round trip and still had a 1/4 tank of gas when I got home. Average speed 70-75mph. If $$ is an issue I say at least go with spectre or K&N CAI from pep boys 10% discount for active duty & retired. Also do a cat back exhaust system. You may still be able to get a tornado fuel Saver online also. Good Luck !!

73shark

Welcome to the forum.

Unfortunately your mpg evidence is less than anecdotal since you have no actual data. 400 miles on 3/4 tank doesn't equate to anything. No before data for comparison either.

And as for the Tornado and TB spacer, well if they really improved mpg, don't you think the mfgs would use them since they have to meet 54+ mpg by 2025? Don't forget cow magnets and water vapor injection. They were biggies back in the 70s during the energy crisis.

While a CAI has been shown to marginally increase hp, it's at the high end of the rpm band where the engine operates infrequently. By the way the GMT800 already has a CAI. While a dry filter might increase airflow slightly, the ECM soon compensates for it.

Try pure gas. I used it for over 1,100 miles and mpg improved 1.52 or 12%. Filled at the same pump every time.