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Discussion Starter · #1 ·
I have a 2009 GMC 4 door 4x4 Duramax that I just put a 6" lift with 35" tires on. As much as I love it, The fuel milage sucks bad. What can I do to get better milage without having to go to the extent of removing the DPF and risk voiding my warranty?
 

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wont that make it worse cuz it will be higher rpm's?
 

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If you are concerned about mpg you have made a mistake. Big heavy tires eat horsepower and mpg. I can't comment on the gear change but it would certainly help towing. Motor would actually lug with 35's and stock gearing. They look great though. A good tuner can help but the tires will still be hurting mpg.
 

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I think it all boils down to the lift and big tires.
It takes power to move the biger tires.....Good luck.
 

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Discussion Starter · #6 ·
yeah, Im sure that did not help but I really didnt notice a big change from factory to now. It still has plenty power and will still pull the tongue off of any trailer that dares latch on the bumper. What can I say, I went from a slow azz 2002 1500 HD with a 6.0 gas that was lifted. Average anywhere between 12-14 depending on how heavy my shoes are that day. Just thought there may be some type of programmer or chip that I could get to help out a little. Any advice in this direction or something not so expensive would be greatly appreciated.
 

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Going to larger tires has the same effect as changing your gear ratio with factory tires.
Remember what it was like riding a 10spd bike trying to start off in 5th gear? Thats basically what you've done by adding 35's. I have'em gas mileage will get better with more miles on the eng but not much...
 

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If you are worried about voiding your warranty, don't put on a programmer. Once your warranty has expired, get rid of the DPF and get a programmer at that time. Bigger exhaust wouldn't hurt either.
 

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There's definitley programmer options that will help a good bit with mileage. But they all pretty much involve removing your DPF and the rest of the stock exhaust system. This in turn will void your warranty. A lot people don't have a problem ditching their warranty, and if you're one of them, then this is the route I'd recommend. You can see anywhere from a 2-5mpg improvement with a tuner and turbo back exhaust system.

We've got several different packages, or I could put together a custom package for you if you're interested :)

The other thing I'd recommend trying, is using 5th gear on the highway, and locking out 6th (shift into manual mode and select 5) 6th gear and 35's will give you way too low of rpms to get good mileage. Once you get in the sweet spot rpm wise in 6th gear you'll be going to fast to get good mileage. So try 5th for a tank of highway driving and I bet it improves some.

Let me know if you'd like to know more about the programmers. There's some great setups out there that are proven to give you a good mileage increase as well as some extra power.

-Jesse
 

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There's definitley programmer options that will help a good bit with mileage. But they all pretty much involve removing your DPF and the rest of the stock exhaust system. This in turn will void your warranty. A lot people don't have a problem ditching their warranty, and if you're one of them, then this is the route I'd recommend. You can see anywhere from a 2-5mpg improvement with a tuner and turbo back exhaust system.

We've got several different packages, or I could put together a custom package for you if you're interested :)

The other thing I'd recommend trying, is using 5th gear on the highway, and locking out 6th (shift into manual mode and select 5) 6th gear and 35's will give you way too low of rpms to get good mileage. Once you get in the sweet spot rpm wise in 6th gear you'll be going to fast to get good mileage. So try 5th for a tank of highway driving and I bet it improves some.

Let me know if you'd like to know more about the programmers. There's some great setups out there that are proven to give you a good mileage increase as well as some extra power.

-Jesse
It's funny you say that I had to take a trip 3wks ago to Louisville Ky empty and back empty and tried that coming back and it actually cut my milage about .5 mpg .....???? I sure though it would work....
 

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Well at least you know now right :) Even with the 285's on my truck, if I'm going 50-55, I get better mileage in 5th than 6th. But once the speed goes up, I get better mileage in 6th. So it'll be different for each truck. But it's sure worth a try.
 

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Honestly my 35's and lift dont cut down my milage too much just a little but nothing that some tuning wont fix
 

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Discussion Starter · #14 ·
Honestly my 35's and lift dont cut down my milage too much just a little but nothing that some tuning wont fix

I dont drive my truck everyday because I have a work car so my truck only has 6,000 miles on it right now. but if i just wanted to put a programmer that would also come with a dash pod to read other things like boost ect.. until I get closer to end of warranty, what would you recommend?:
 

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Only 6000 miles? Park the work car and drive the DM !!!! LOL

Ok, seriously, keep up the maintenance. ESPECIALLY keep an eye on the air pressure in your tires. I would also drive it around the block a couple of times a week, so the tires don't get flat spots. Bias plys were bad about it, but radials get flat spots too, just not as bad. Fuel stabilizer. ANY programmer will void the warranty at most dealerships. Even if you are just wanting to use it for gauges, try to convince the dealer of that...Good luck! LOL
 

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Discussion Starter · #16 ·
Only 6000 miles? Park the work car and drive the DM !!!! LOL

Ok, seriously, keep up the maintenance. ESPECIALLY keep an eye on the air pressure in your tires. I would also drive it around the block a couple of times a week, so the tires don't get flat spots. Bias plys were bad about it, but radials get flat spots too, just not as bad. Fuel stabilizer. ANY programmer will void the warranty at most dealerships. Even if you are just wanting to use it for gauges, try to convince the dealer of that...Good luck! LOL

LOL, I know, I love to drive it, but work wont pay the fuel bill for that one.
On the other hand, I had no idea that a programmer alone would void the warranty, thanks for informing me. So, I guess if anything you do as far as programs or chip, you void the warranty so i might as well take the risk and go off with the dpf like everyone has been telling me.
Thanks for letting me know that!
 

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Put an exhaust on it and an air intake and a turner
 
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