I just purcahsed my first diese ruck on friday and i just love it. It is an 04' 2500HD 4x4 crewcab Chevy with the LLY. I am getting 16.1 miles after the third tank on the highy. Is it true i will gain about 2-3 more mpg by 20-30K miles? Also what would yall recomend doing to get the best fuel effeciency out of this truck. I was thinking of the Edge juice w/attitude, but wasn't sure. I really don't care much about speed i just want to get the best MPG as possable as I am still in college and money is now slimmer than it was a week ago ;)





Thanks - Canoli

Quad claims his tuner will give the best fuel mileage out of any tuner on the market for the LLY.


www.quadzillapower.com (http://www.quadzillapower.com)


I don't know if it is true or not.

If money is an issue, keep the $400-800 and buy fuel or fuel additive.


It will take a long time to get your with a couple of mpg???


Edited by: Kennedy

You will get the absolute best fuel economy, hands down, when it's parked.

http://www.dieselplace.com/forum/smileys/hihi.gifEdited by: motovet

You will get the absolute best fuel economy, hands down, when it's parked.


That's not true. I get 0mpg when parked. http://www.dieselplace.com/forum/smileys/smiley2.gif

Canoli,

I have about 8,500 on my LLY and have not noticed any improvement in fuel milage from break-in yet. I am still holding out to see some improvement as the truck gets some more miles on it.

I've tried Stanadyne Performance Plus fuel additive, which may have given me about .2 of a gallon improvement. I suspect it would be more if the fuel had a lower centane number.

There is a current thread going on now where the owner of an LB7 said he is getting a 1 mpg improvement with the Edge, but another poster said he lost 1 mpg. Form all the posts I read, I would figure about .5 mpg from the Edge, maybe a little more, depending if you can keep your foot out of it after getting the additonal power.
I do not think you can justify the cost of the Edge on fuel savings.

Some folks say they are getting better milage with an after market 4" exhaust and and air intake system. Then again, other say they got no improvement. I would hope to see at least 1/2 mpg gallon or more. Again, I do not think the fuel saving alone can justify the cost.

There is a thread on blocking the EGR valve. Many are saying they are getting 1/2 mpg or more improvement. I tried it and didn't get any improvement. You might want to try it since cost is not an issue. The thread does list other advantages, such as less soot, after blocking the EGR valve.

GM came out with a computer update for the LLY around Sept. 10th. A few people have reported a slight increase in fuel milage after having the computer software updated. Tell your dealer that you get an engine knock when accelerating while the truck is warming up, and it also has a low speed surge. This fix modifies the injector balance rates and is covered by GM warranty.

The very best thing you can do to improve milage is to be a smooth driver. It takes a lot of fuel to get this heavy truck moving. Driving habits appear to be a very big variable in the fuel milage.

Many folks have stated fuel milage drops like a rock as your speed exceeds over 70 MPH or 2000 rpm. There is post somewhere tracking MPG at various speeds. 1800 rpm seems to work for most.

This truck has so much power that is fun to romp on it. It takes a lot of self-control to drive for milage rather than fun!

Good luck with your new truck and your studies.

The student dilemma - beer or diesel, hmmm.

You got me there Max power.http://www.dieselplace.com/forum/smileys/smiley32.gif

Mine seems to take on fuel when parked. Guess the only time it is parked is when being fueled up....http://www.dieselplace.com/forum/smileys/smiley36.gif

What if someone is syphoning fuel out of your tank, while parked? Huh? Huh? http://www.dieselplace.com/forum/smileys/smiley17.gif

Thanks for the help guys. I might wait till it gets some more miles on before i do anything to it. Is there any kind of break in procedure for this truck as the dealer never told me anything about breaking this engine? When do you think it would be a good time to start adding performance accessories? I was thinking of this kit that has Juice w/attitude, AFE intake and MBRP exhaust, but wasn't sure how loud the exhaust is. I am not big on loud exhaust on diesel trucks, i like it quiet. Here is the link to the kit i was thinking of.


http://www.apdieselperformance.com/duramax_performance_combo (http://www.apdieselperformance.com/duramax_performance_combo.htm) .htm


Let me know what you think - Canoli

I'm not aware of anything that will provide a significant improvement in fuel mileage other than tire air pressure, driving habits etc. Just about everything out there from fuel filters to air induction systems etc claim an increasre though. If there really is some form of device that really would increase mileage I'd like to see it myself.

Mine is a 04 with 26,000 miles on it....I run up and down the highway at 79 mph http://www.dieselplace.com/forum/smileys/hihi.gif and I get 19.5 eveytime I check...bone stock. I must agree with the rest, I put alot of goodies on my old powerstroke and didnt see any better mpg....it did run like a bat out of $%^& though...until it quite..http://www.dieselplace.com/forum/smileys/smiley19.gif

WOW 19.5 that is awsome. Was it allways 19.5 since the first tank or did it get better with some miles on it? Is it the LLY or LB7?

I've always been one to measure every tank to verify mpgs. This not only helps to identify any problems with the vehicle but budget for fuel expenses as well. That being said, since I bought this truck my approach is moreso "push accelerator down, hold on, screw mpg's!" Just don't know what has gotten into me? Best mpg's 16 city, 19 highway at 70 mph. Stock truck! JJ http://www.dieselplace.com/forum/smileys/smiley2.gif

I bought mine used with 16,000 miles on it...it has been 19.5 since the first tank. Mine is a LB7, I have the six speed standard and at 79 mph it is turning 2700 rpm...I would LOVE to find something to make it run in the 2200 range at that speed...http://www.dieselplace.com/forum/smileys/smiley36.gif

<span ="bold">O2BFAST

all you can do is put on bigger tires or change gears IMHO. 2700 rpm is
way to high, you are lucky to get that kind of fuel economy but you
still have the LB7...



</span>

Listen to Kennedy if you want to save money. As soon as you put
something on it in the interest of 'saving fuel,' it will be all
over. You'll drop out of school to finance your Hp fix, years
later, we'll find you face down in a ditch cluthing a bottle of cetane
boost. It will be ugly. Just put the money away for books.
. . you guy still use books in school don't ya?http://www.dieselplace.com/forum/smileys/smiley2.gif



Dennis

I've got a 01 LB7 if I drive it easy keep it under 75mph usually about 19 mpg I've gotten as high as 22 using cruise no load constant 70 mph.Once you put your foot into it they can really suck it down

My 04.5 has 3300 miles on it. This past weekend we made a trip from Phoenix to Anahiem and on the DIC trip meter I got 22.4 on the way over and finished the trip at 21.4 with some in town driving. The info from the DIC was


873.8 miles 40.8 gallons 21.4 mpg.


The gallons used matches up with fuel receipts. The cruise was set at the posted speed limits until we got into Riverside.


EDIT: Truck has a camper shell and is mechanically stock.Edited by: sb62

Sweet , but I couldnt run that truck with the factory doughnutshttp://www.dieselplace.com/forum/smileys/smiley11.gifEdited by: blowinsmoke

04 w/LLY and get 24 mpg @ 55mph and drops to 16-17 mpg @ 75-80 mph, this is with 10k miles.


Bottom line save your money on mods, any improvement will be minimal at best and take years to pay off. To get good mileage GO SLOW !!!!!! Sorry but thats the facts

Canoli,

In regard to a low noise exhaust system, several people have posted notes saying the TTS system (TTSPowerSystems.Com) is fairly quiet. Try doing a search on TTS exhaust.

There was a note a couple of months ago saying MBRP has come out with a resinator that reduces the noise level. Most folks adding the MBRP system have reported that the noise level did increase somewhat with the standard system.

In regard to the LLY milage compared to the LB7, I have access to a near identical 2003 LB7 and it gets 3+ mpg better milage than my LLY. I suspect the emmision additions on the LLY has an impact on the fuel milage.

Since you are claiming about 16 mpg I did some quick math. 50k miles at 16 mpg is 3125 gallons. At 17 mpg it's 2941 for a 184 gallon difference. Even at $2.00 a gallon that's $368. Excluding the fun factor, which is tough to do, I'd buy the fuel.

I know 2700 rpm is ALOT when the thing red lines at 3200...when I go to pass someone I dont have much room for speed before I get up into the red...I thought when I bought it (used) it might have had 4:11 gears but in reading the 3:73 was all that was available...how about you guys, what kind of rpm's are you turning on the highway...Speed limit here is 70 so I try to stay right at 79..http://www.dieselplace.com/forum/smileys/hihi.gif

ok.. 04.5 lly 10.6K Avg for the last 5K mi 19.5 - 20.5 mpg unloaded.. use citgo + sunoco.


JJ

I do about 60 ish MPH and I am doing about 1900 RPMs. Fuel economy is everything for me, right now.

Man this thread has just blown up. I just love this site. Thanks for all the help, she goes in for the new upgrade tomorrow. I had another question though. My engine i just poundong like a cummings now. It is not near as quiet as the day i drove it off the lot. Well i say as loud as a cummings not quite but it is a lot louder than i was a few days ago. It really gets loud when the AC is on. What might be causing this? Is this normal?





Thanks - Canoli

I notice mine gets louder at times, it seems to correspond to fuel, will quiet upon fill at dirrerent station????

Might try some stanadyne, power diesel or other quality additive. Mine seems to run smoother since I tried it. JJ http://www.dieselplace.com/forum/smileys/smiley4.gif

Mine is louder when the air is on. Seems to be normal.

I'm picking up my new '04 LLY SB in Twin Falls, Hideeho on Friday and driving her back to Sun Diego over the weekend. I can only HOPE for 16-19mpg! http://www.dieselplace.com/forum/smileys/hihi.gif Lead-foot-Larry and my 12 year old cheering me on!

[QUOTE=02B12S]


ok.. 04.5 lly 10.6K Avg for the last 5K mi 19.5 - 20.5 mpg unloaded.. use citgo + sunoco.


JJ





Wow , you must drive like grandpa.http://www.dieselplace.com/forum/smileys/smiley5.gif





Canoli, might try to get the reflash for calibration done as it made a world of difference in the noise w/ac on on my truck.http://www.dieselplace.com/forum/smileys/smiley4.gif

Canoli, it was nice talking to you. Give a call anytime if there any more we can do for you. John

I generally get 16-18 mpg unless on a trip. It has been the same since new. Just turned over 25,000 miles this week.

Will I just got a phone call today from my dealer, with the good news that my baby was dropped off yesterday, so come Monday me and the wife are driving out to pick her up, the drive back is over 760 miles all interstate so I should be able to get back on here on Friday and let everyone know what kind of fuel mileage I got on the drive back.

TRY REMOVING THE CAT..I DID, NOW IM GETTING AT LEAST 20MILES PER GALLON.. I ALSO HAVE A TONNEU COVER, THAT HELPS..

Took a 240 mile round trip to Charlotte a week ago and averaged 21.5 mpg. This past Thursday pulled a 10000 pound fifth wheel on the same trip and averaged 12.5 mpg. This was from the DIC. Around town I get from 15 to 17 mpg.

If you are looking for an aftermarket 4" exhaust that doesn't make allot of noise, and has a removable Cat section Look at the ATS turbo system. Stainless steel, low noise, Full 4" through entire system. a bit pricey but well worth it.


As for mileage. With the 285 tires the corrected speed is 70 mph at 2000 RPM this is the best compromise between good fuel economy and not getting run off the road by everyone else doing 80+ on the freeway.


Empty I "can" get 19 to 20 mpg (Corrected) if I'm not going up and down too many hills.


At that same speed, pulling my Tall 10,000 lb 5th wheel I just got back from a trip that got me 11.4 MPG (Corrected)


If you can keep the RPMs under 2,000 you can get pretty good mileage. anything over 2000, and your mileage drops off QUICK.

I just purchased my 2004.5 Chevy HD 2500 DMax with Allison Tranny (Myfirst diesel). After about 450 mile I drove it on a freeway trip to Ontario and back (approximately 500 miles). According to the milage computer I averaged 21.2 MPG at an average speed of 68MPH on cruise, as indicated by the DIC.


I'm Interested in the extra 1.5 MPG with the EGR unplug, but will watch and listen for a bit longer.


I LOVE this machine!Edited by: 04DMaxHD2500