fuel mileage

[depmike]

I have a hypertech tuner that I am using on my 2008 Duramax 2500 H.D. Chevy. I don't pull anything and its my first pleasure truck. If any of you use the hypertech can you tell me where you get the best mileage. Stage 1,2,or 3. I cannot get over 15mpg no matter what I do. I put a k + n air filter in, but still no luck.

[spongebob]

my 06 gets 16.5 and the bed is loaded with heavy stuff, and i have a ladder rack on..
my $.02, get rid of the k&n..unless you like cleaning and reoiling filters..it will do nothing for you, except pass more dirt into your intake..

oh, and my truck is stock, no hypertech.

[Mark Rinker]

Did you test mileage before installing the K&N? Might be interesting to clean the MAF sensor (search all Duramax forums for more info on this) and return to the stock air filter for a solid 3-5 tank test average.

Over oiling the filter can result in incorrect MAF readings, incorrect fueling, and could be the cause of your lower mileage.

...or it might just be your right foot, combined with the emissions stuff on the newer trucks.

[TJNE]

I have an 07 LBZ, stock other than a K&N filter and LT 285's. I get 14 mpg around town, I accelerate slow (seldom get above 2000 rpm's), coast to a stop and very little idle time. My wife always busts my chops for driving so slow. About 4-5 times a year I pull and 12k lbs 5th wheel and get 9-10 mpg, I live in Florida (flat land). I hear some say they get in the low to mid 20's mpg and 12-15 mpg towing with stock set ups. I would have see it to believe it. From what I have read on this forum most agree the cold air and exhaust are a waste of money, the tuners work but they void warranty. Sounds like Mr. Kennedy has the setup's but I don't know what I want to do, all the info is confussing and sometimes contradicting. So good luck.

[WyoDutch]

My 1984 GMC 6.2 4X4 is pushing 300K miles and she still runs like a charm. I never changed a thing... figuring that General Motors engineers knew more about the intake and exhaust than I did.

I'm now dealing on a 2007 Silverado 1-tonner with Duramax. I'll also stay away from tuners, cold-boxes, gee-whizzes and Jim-cracks.

I just ain't smart enough to outsmart GM's engineers.

[Mark Rinker]

My 1984 GMC 6.2 4X4 is pushing 300K miles and she still runs like a charm. I never changed a thing... figuring that General Motors engineers knew more about the intake and exhaust than I did.

I'm now dealing on a 2007 Silverado 1-tonner with Duramax. I'll also stay away from tuners, cold-boxes, gee-whizzes and Jim-cracks.

I just ain't smart enough to outsmart GM's engineers.

My Jim-crack rocks. Makes my truck go straight uphill and get 30mpg.

Some of those old 6.2s really hung together. If it went this far, it might go another 250K. You aren't CLUNKING it, are you?

[RayFong]

My bone stock '05 2500hd gets 14-15 in the city and 18 mixed highway city. I've never tested her straight highway but would guess 20? I'm running 265/75/16's. City driving I accelerate slow off trailer mode so she shift at about 1900 rpm's. Highway I drive 70 mph, on cruise. Mostly flat roads between Modesto, Ca and Merced on SR 99.

My 1985 1.25 ton CUCV gets 15 mixed and about the same city. She's running the old military 6.2 with banks turbo, lots of extra tranny cooling..lol...and I drive her 65 MPH on the highway due to high rpms. The old TH400 lacks overdrive. I am running 35's and regeared it to 3.73 to compensate for the rpms otherwise I'd be running 45 MPH on the highway.

[WyoDutch]

I bought a new 1-ton xtended cab Duramax Four-by instead of a used rig.
.
Driving (empty) the speed limit (65 in Wyoming... 70 in Montana), I got 16 mpg on the first tank, 17.3 on the second. No fuel additives in the first tank... 16 ounces of Power Service (grey) in the second... 16 ounces of Opti-lube XPD in the third.
.
Don't get me wrong... I'd install a corn chip if I could get away with it and it gave me more reliability, mileage and power... but from what I read, doing so *could* void the warranty and I just can't afford that.
.

[7072]

Hey Mark,
What did you do to make your truck get 30 mpg??? I am new to the forum, I just bought my first diesel a 2007 chevy crew cab LBZ. I have been researching this forum, and everywhere else I can read to find which tuner to get for the best fuel mileage and all I am doing is getting more confused !!!!

[DmaxMaverick]

Hey Mark,
What did you do to make your truck get 30 mpg??? I am new to the forum, I just bought my first diesel a 2007 chevy crew cab LBZ. I have been researching this forum, and everywhere else I can read to find which tuner to get for the best fuel mileage and all I am doing is getting more confused !!!!

Welcome aboard!

30 MPG isn't unheard of with a 6.2L. I can produce that reliably with my 85 under the right conditions. 20-25 MPG is typical. Not a likely goal for any post-6.2L truck (very common for 6.2L equipped cars), and certainly not with any late models. There are exceptions, of course, and many have come close (to the 20-25 mark). I can easily get 25+ MPG with my 2001, but it's a painful and deliberate process (easily overcome by convenience).

Tuners/chips are very subjective, and depend on too many variables to form any conclusions that apply to everyone. Equipment and driving habits can cause full swings in performance/economy. The best advice any of us can give you is to read up on all of your options, and choose according to your abilities, needs and conditions. What works well for me (or any individual) may be completely ineffective for you. In the end, if your goal is economy, it will take more miles to see a return on any significant mileage improvement expense than most people can/will drive the same truck.

[Mark Rinker]

Hey Mark,
What did you do to make your truck get 30 mpg??? I am new to the forum, I just bought my first diesel a 2007 chevy crew cab LBZ. I have been researching this forum, and everywhere else I can read to find which tuner to get for the best fuel mileage and all I am doing is getting more confused !!!!

Sorry for any confusion...I was joking when I made the 30MPG reference above.

Most stock Duramaxes, under average driving conditions, can get upwards of 20mpg empty with a light right foot. Your 2007 has a few EPA-mandated devices installed that consume fuel in favor (?) of lower emissions, also creating restriction to the exhaust, a real mileage killer when it comes to diesels.

Tuners are unlikely to give you more mileage with the LBZ - although they can give you More Power. Read carefully when it comes to 'chipping' the LBZ - the factory has given you about all the torque and HP that the stock Allison 1000 will handle under heavy towing duty. GM dealers are also paying much closer attention to trucks that are 'turned up' and denying warranty service on things like injectors, turbos, torque converters, etc. when they have reason to believe that the truck has been modified. "Caveat Emptor!" (LET THE BUYER BEWARE!)

My guess is you'll see 16-18mpg mixed use empty driving. You might see upwards of 20mpg on long level trips in cool weather, when you aren't in a hurry and keep your cruise RPMs under 1800...


Good luck!

[7072]

Well, You are about right on the mileage. I have checked every tank, and I get about 16.5 around town local driving. It has plenty of power, I was just looking for a little more mileage. The truck has 85,000 miles on it so I guess i still have a little bit left on the warranty.
Would it help to up grade the exhaust, although I hate to do that because I don't want the truck to be loud. Thanks

[Mark Rinker]

You can upgrade exhaust, but wouldn't expect any quick ROI on your investment.

• Buy good fuel from a high volume source
• Run synthetics in your engine, diffs
• Use a good fuel additive regularly to keep you injectors spraying
• Use a light right foot and avoid unecessary idling

Enjoy your truck!