:help: I have a 2004 LB7 and am looking to do some mods to it to improve my fuel mileage. The truck is stock (except the 285's that came on it) with 35k miles and I drive 45 mile in mountainous conditions one way to work daily. As you might expect, with fuel reaching the $3.50 a gallon mark :mad: -:t :( the cost for a month is starting to reach that of a car payment. I am looking for anything I can do to get more miles out of a gallon and not break my already deflated budget in the process. I am not really looking for more power but am definitely not opposed to it. Please help!!!!

Well, right off the bat I think your 285s are hurting your fuel economy. Those are big wide heavy tires....you might want to consider a smaller tire like say a 235/85 or even a 255/85. That way you keep some height but reduce the width (rolling resistence) and weight. Next if you are driving in mountainous areas the truck is probably downshifting a lot. When you are out of overdrive you are sucking fuel. A tuner set to a low level may help you ONLY if you are able to keep your foot out of it....and nobody can...:D , but if you can the extra power may allow the truck to stay in overdrive longer and may result in better fuel economy. But, like I say it's tough to keep the truck on say a 65hp tune when 90 or 100hp is just a turn of the knob away. And one last technique that may help is to be looking ahead for situations where you are going to have to slow considerably or stop. By doing this you can let up on the accelerator sooner and coast....instead of letting up right before impact and then jam on the air.....you can save fuel over a period of time. But it takes practice and you really have to focus until it becomes second nature. Of course change fluid and filters regularly. That's all I can think of right now.
JP

235/85 just like heartbeat said. Also put 60 psi in them not 40 like the dealer will do when you bring it in. Tires saved me 2 mpg when I had a bigger size on and went back to the original 235/85. bigger exhaust will also help

Tires for sure.

Drive in the efficency band. 1800-2200RPM. A chip can help with this if you need just little more power to hold the gear.

Thanks guys. I appreciate the info.:) I am definitely going to size down the tires soon. What about air intake mods? Performance type air filter? Cutting away sections of the factory air box for increased flow?? Which tuner would you recommend? Seems to be alot to choose from!

Thanks again!

Thanks guys. I appreciate the info.:) I am definitely going to size down the tires soon. What about air intake mods? Performance type air filter? Cutting away sections of the factory air box for increased flow?? Which tuner would you recommend? Seems to be alot to choose from!

Thanks again!


Nope, stick to the tires.

I went with the AFE Stage II with ProGuard 7 and also 4"-5" exhaust, didnt see any increase in MPG to speak of.


I'm presently hanging around the 19.5 to 21.3 range on my daily driving right now. Flat lands of Missouri/Kansas, highway & city combo. But, I am trying to see how good it will get so no fast starts, light pedal, etc.

PROPANE!!!!!!!!!!!!!

Thanks guys. I appreciate the info.:) I am definitely going to size down the tires soon. What about air intake mods? Performance type air filter? Cutting away sections of the factory air box for increased flow?? Which tuner would you recommend? Seems to be alot to choose from!

Thanks again!

If you're doing a substantial amount of highway driving, a tonneau cover may help a little. RE air intake mods, there was a study of flow/efficiency/filtering done by a DP member who essentially found that the OE AC DELCO was the best element out there (the thread is out there if you search for it). Otherwise, I have to agree that tires are going to give you the most bang for your buck. If you don't already, you could also try running a fuel additive for a while & see if that helps -- results are really variable on mileage increases. RE tuner selection, check the LB7 Electronics forum -- when you're done reading you should look like Rip Van Winkle.

Get a tdi beater and get 50mpg........

I know this sounds strange as a mod but it is a 'for real' fuel saver. Primrose 405C fuel additive.
405C does 5 things very well. 1. Raises cetane 5 to 7 points. We only need a 40 cetane for our engines to run but for every point we increase we bring a higher percentage of our fuel to be above 40. The elevation of cetane prevents pre-ignition prior to top dead center which bottom line results in a 3% to 12% reduction in fuel consumption.
2. Provides lubricity. 3. Provides water emulsion which eliminates free water from our systems which also eliminates microbials: no free water, no microbials.. 4. Provides corrosion protection. 5. Provides a high level of detergency to keep injector tips in optimum operating condition.
Additionally, fuel filter life is *significantly* extended..
George Morrison, STLE CLS

Rolling resistance
Air resistance
Mass
Air-pump resistance
Speed

Narrow, tall, highway pattern tires at high pressure suck less HP.

Airdam, drop height, keep windows up, hard bed cover.

Never carry weight you do not have to.

Exhaust restriction and intake restriction cost HP to overcome. Our intake is pretty good, a high flow muffler should show a slight gain.

Best economy will be below 2000 rpm. Theoretically, it will be at your torque peak, 1600-1800. Tall tires help this. A tuner that keeps you from downshifting will help as well, about 50HP.

Another *real easy* fuel efficiency mod is to use Primrose 405C fuel additive. 405C will increase fuel efficiency 3% to 12% in our Duramax engines.. It isn't strings and mirrors: 405C simply raises the cetane number 5 to 7 points. It is not that our engines need 50 cetane number fuel. It is the 2 to 3% of our fuel that is NOT 40 cetane and more like 35. By increasing the cetane number 5 to 7 points we are ensuring that 100% of our fuel IS 40 or greater, precluding pre-detonation, which then results in burning 100% of the fuel AFTER top dead center instead of 2 to 3% beginning to burn prior to TDC. Results: we get all of the energy out of the fuel charge.. More horsepower, more efficiency, better fuel economy. All for a little over 1 cent per gallon treat rate..
Hate to sound like an advertisement but 405C fuel additive is for real in providinig significant fuel savings..
George Morrison, STLE CLS

Deluca propane kit! :exactly:

Read the propane threads and email Marcdeluca about his setup. I have ran it for ahile and for appx. half the cost of the MSD/Powershot kits. He recently made a trip using almost 70% propane. He saved .05 p/gal. I have not run it this high in my truck yet 50/50 max so have saved appx. .02-.03. DO NOT ALLOW PREDETONATION THOUGH.

After Tdc?

Another *real easy* fuel efficiency mod is to use Primrose 405C fuel additive. 405C will increase fuel efficiency 3% to 12% in our Duramax engines.. It isn't strings and mirrors: 405C simply raises the cetane number 5 to 7 points. It is not that our engines need 50 cetane number fuel. It is the 2 to 3% of our fuel that is NOT 40 cetane and more like 35. By increasing the cetane number 5 to 7 points we are ensuring that 100% of our fuel IS 40 or greater, precluding pre-detonation, which then results in burning 100% of the fuel AFTER top dead center instead of 2 to 3% beginning to burn prior to TDC. Results: we get all of the energy out of the fuel charge.. More horsepower, more efficiency, better fuel economy. All for a little over 1 cent per gallon treat rate..
Hate to sound like an advertisement but 405C fuel additive is for real in providinig significant fuel savings..
George Morrison, STLE CLS


so how does that Primrose 405C work in conjunction with the Primrose 405C you metioned earlier in the thread? :)



















:joke: :lol: I'm sure you didn't realize you posted on the first page. :)

I added the bigger exhaust and K & N filter that has helped about 2 or 3 mpg

Another *real easy* fuel efficiency mod is to use Primrose 405C fuel additive. 405C will increase fuel efficiency 3% to 12% in our Duramax engines.. It isn't strings and mirrors: 405C simply raises the cetane number 5 to 7 points. It is not that our engines need 50 cetane number fuel. It is the 2 to 3% of our fuel that is NOT 40 cetane and more like 35. By increasing the cetane number 5 to 7 points we are ensuring that 100% of our fuel IS 40 or greater, precluding pre-detonation, which then results in burning 100% of the fuel AFTER top dead center instead of 2 to 3% beginning to burn prior to TDC. Results: we get all of the energy out of the fuel charge.. More horsepower, more efficiency, better fuel economy. All for a little over 1 cent per gallon treat rate..
Hate to sound like an advertisement but 405C fuel additive is for real in providinig significant fuel savings..
George Morrison, STLE CLS


It burns when it’s injected and that timing is controlled by the ECM. And Cetane rating will get it started easier when cold but isn’t going to do much for mileage as I understand it. Raising mileage by 3% to 12%? Wouldn't that mean the engine is putting out 3% to 12% of the fuel as unburned hydrocarbons without this stuff? Wouldn't that make the Duramax just about the least efficient diesel engine ever made? And wouldn't the EPA be all over GM? I notice that adding water emulsifiers voids warranty according to my owners manual. Do you sell this stuff or have stock in the company? Detonation before top dead center in a diesel?? Just questions. Please explain as I'm puzzled by your statements.

Check out some of the things the big guys are looking into to increase mileage and lower emissions: http://www.greencarcongress.com/2005/02/doe_cofunds_12_.html

What McRat pointed out will affect mileage big time.

Quad programmer did it for me. 70HP setting when towing and 110HP when cruising. Keep your foot out though. Also make sure you aren't running with the defroster on because that cycles the air conditioner which also sucks power. A couple of extra pounds running around in the bed doesn't help things either. Pay attention to traffic so you don't have to brake very much. Give her a good run on a big trailer now and then too.

You guys missed the easiest one (and the hardest to do!)

Drive 55 to 60 mph on the highway. With stock tires, and light traffic that will put my truck in the 24-25 mpg range every time. 75 mph brings it down to 17 mpg. Also, pump the tires up to the listed max. That's 80 psi on my Goodyears. In town, turn the engine off when you are waiting at stop lights. Coast up to all lights and stop signs. If you don't think you can make a light, start your coast.

If you do these things and drive like a little old lady you will get better milage. And probably get shot by the irate people behind you that want to go fast! But hey, your tombstone can list your last mpg as 25.6...

jb

Switch to Biodiesel. Increase cetane, smooth your engine, clean fuel injectors, drive with a clean conscience supporting farmers, not sheiks.

Check out these forums here for more info:
http://forums.biodieselnow.com/

I'm running all mixes of BD that I can get here in NYC, mainly B20, in my 2002 LB7. Noticing about a 10% increase in mpg, from 19.5 to 21.5mpg when I'm on B50 or better. This is only 2000 miles in though, so other factors could contribute...