Has any body drove a 2006 Duramax with the 6 speed trans and been
able to come up with a MPG figure yet?

I get 18mpg driving to work and back. I havent hauled my trailer yet to see how much that affects it.

16.8 on the first tank from the dealer. Around town and freeway combined. 400 miles on the od.

I am at 515 miles now, 14.7 on the first tank from the dealer and 15.0 mpg
on the second tank. Both tanks were mixed highway/city, and even the
highway involved some stop n go here on the California "freeways"...

I have got 1300 miles on it now and mixed city/highway I get 19 mpg! for those of you that go by what the dic system tells you do the math by hand. my thingy in the dash says I am geting 18mpg but when i figure it out its allways atleast one more mpg. also the thing in the dash tells you how much fuel I used its allways off to. I think thats why the mpg is allways a little off.

http://personal.linkline.com/rlockyer/2500Gas.xls
Updated regularly.

You should factor in .0387 increase in tire size in your spreadhseet.

Is it just me or does there seem to be virtually no diff in MPG's between the LLY's with the 5 speed and the LLY's with the 6 speed?

I wouldn't expect in town or mix of in town and highway mileage to be much different. I'm curious to see what highway mileage at 70 is with the 6 speed on something other than flat ground.

Towing 14,500 combined, got 9.7 mpg on two fillups hand calculated all freeway in sixth gear with cruise set at 74 on pretty flat ground across Indiana. That is figuring a 7% correction factor for the larger tires. DIC has been 1.5 - 2.0 mpg low even with stock tires.

There must be something wrong w/ mine then,am getting 14.3 mpg mixed driving,and the DIC seems to be pretty close when you calculate it yourself. Are your trucks 4x4 too? 550 miles on truck,no modifications,yet.

You should factor in .0387 increase in tire size in your spreadhseet.
I did. If you look at column G, beginning on line 8, I multiply column F by 1.078 to correct. Prior to line 8, I had the stock VW tires on.

There must be something wrong w/ mine then,am getting 14.3 mpg mixed driving,and the DIC seems to be pretty close when you calculate it yourself. Are your trucks 4x4 too? 550 miles on truck,no modifications,yet.
Yes, mine is a 4x4.
Mileage will improve as you get more miles on it.
Note that my first tank where I got 19 was an extended highway run, but since it was also the break-in period, I kept speeds at or below 65. Every 5 miles or so, I'd pull down an off-ramp and drive a few circles through a parking lot, idle for a few minutes, then get back on the road.

The subsequent tanks that are down around 15 are a mix of mostly city or heavy freeway traffic with a few 15 mile 70mph runs thrown in.

Yes, mine is a 4x4.
Every 5 miles or so, I'd pull down an off-ramp and drive a few circles through a parking lot, idle for a few minutes, then get back on the road.


Why ??

Read the break-in procedure in the owner's manual.
They do recommend keeping it to 55, but the important thing is to avoid extended runs at a constant speed.
That tank was an all-highway trip from Claremont to Camarillo, over to Bakersfield, and back to Claremont.
Did it all on one tank too... I would have had to have gassed my Tundra in Bakersfield :)

I'll buya used truck anytime from you rich..lol
someone besides me who follows proper break-in :cool2:

I'll buya used truck anytime from you rich..lol

LOL!
125k on my '03 Tundra traded on the Silverado... 7 quarts in, 8k later, 7 quarts out. Mobil-1 5w30 and M1-301 filter. Never lost a drop of fluid that I didn't let out, and never made a noise that it didn't make when brand new.
Easily still had another 150k left in it.

One of my techs told me that if I ever sell my dirtbike, he wants it.
He doesn't care if it's 10 years from now... he still wants it :D

The key is to hammer on it for short bursts and back way off after. Heats the killer. If you baby them too much you'll end up with a mutt.

The key is to hammer on it for short bursts and back way off after. Heats the killer. If you baby them too much you'll end up with a mutt.

I agree. Put it in first, keep it in there, and open the throttle until you reach the redline, then, completely let off the throttle and let the engine guide you back down till idle - don't touch the brake. This way, your cylinder becomes worn evenly across the whole rpm band.

The key is to hammer on it for short bursts and back way off after. Heats the killer. If you baby them too much you'll end up with a mutt.
Hence, actually getting off of the freeway, cruising around, stopping to cool, then hitting the onramp to get back up to speed.

Rich, I did read the manual and followed instructions(mostly),also,truck has not gone more than 45 miles on freeway at a time yet,has also not gone over 65 mph. will just have to wait and see,thanks for the replies,never been over 1900 rpm

I think some people need to remember, a good diesel engine( like the duramax or Cummins) requires up to 20-50K miles to get completely broken in. You will not see your best MPG till after 20K miles.

trout

I think some people need to remember, a good diesel engine( like the duramax or Cummins) requires up to 20-50K miles to get completely broken in. You will not see your best MPG till after 20K miles.

Thanks for reminding me... I need to input another receipt and update the spreadsheet.

Thanks for reminding me... I need to input another receipt and update the spreadsheet.

And I thought I was the only one who kept a spreadsheet. I missed one reciept and it kills me everytime I look at it. Maybe, I need help.:D

If the DIC reads low, then I'm really happy with my new 06. It only has 64 miles on it so far, but the DIC is showing 14, all city miles.

Mine almost always reads a little low. "Fuel used" is typically 1 to 2 gallons higher than what I am actually able to push into the tank.

Worked out great today.... normally, my 76 station cuts off at $50 and I have to scan again to get that last $5 in. Of course, manually controlling with all of the foaming in the neck is a pain.

At Valero today, the pump clicked off from the foam. I let it settle, the restarted. It had just restarted when the pump went into the "I'm almost at $50 limp mode" and it ever so gently filled the neck with no foaming. Looked inside and there it was... perfectly clear #2 about 5" down from the edge.

About 15.8 gallons, DIC said I had used 16.4.

And I thought I was the only one who kept a spreadsheet. I missed one reciept and it kills me everytime I look at it. Maybe, I need help.:D
LOL!
Check this one out:
http://personal.linkline.com/rlockyer/TundraGas.xls

Nearly 3 years there. Some of the entries look fishy, IE, 26 gallon tank appearing to take 28 or more... that's because when I cruise through a place like Vail, Co or Barstow, Ca and gas is $0.50 higher than I know it is 100 miles down the road, but I'm not really sure I can make it another 100, I'll drop in 5 gallons.

The two or three times that it took over 25 gallons means that I would not have made the last 100 miles :D

If I lose a receipt, it's not the end of the world. I always reset Trip-A, so I can always back off to get the actual mileage. I use my debit card, so my online banking screen shows the purchase amount. Generally, the price isn't going to be different than if I drive back to the station to look. Math takes care of the rest.

My wife it terrible about keeping receipts... always has a few missing. The problem is, I need her vehicle records for income taxes... thankfully, not after next week (she's getting out of real estate and her part time route job watering plants).

70 MPH in 6th with 265's yeilds how many RPM's?:think:

Well I filled up today and the DIC is reading low, by hand I got 15.32 on the first tank of fuel. This is all city driving, with the A/C on, so I've very happy so far.

70 MPH in 6th with 265's yeilds how many RPM's?:think:

Not sure, I have 245's :( , but at 70 I was running 1800 rpms. IIRC 80 mph was 2000.

Not sure, I have 245's :( , but at 70 I was running 1800 rpms. IIRC 80 mph was 2000.
Ditto.
No matter the tire size (within reason), 70 will be 1800 unless the speedo is recalibrated.
Since we can't yet get a tuner for the '06, I doubt anyone is calibrated.

I'll have to compare the GPS with the tach and see what I'm actually turning with my 285's.

And I thought I was the only one who kept a spreadsheet. I missed one reciept and it kills me everytime I look at it. Maybe, I need help.:D

Do you guys really pay that much attention to fuel/mpg
Why? If it's the truck you bought and you enjoy driving a 6500lb+ vehicle around.
Fill her up enjoy the ride, pull her into the station and do it again.

Do you guys really pay that much attention to fuel/mpg
Why? If it's the truck you bought and you enjoy driving a 6500lb+ vehicle around.
Fill her up enjoy the ride, pull her into the station and do it again.
Maintenance tracking. I always know exactly what was done and when... especially if you don't want to trust the onboard computer to tell you when to service things... nothing like thinking you're okay, and getting halfway out on a vacation and the engine going into limp wanting an oil change and fuel filter.

Ditto.
No matter the tire size (within reason), 70 will be 1800 unless the speedo is recalibrated.
Since we can't yet get a tuner for the '06, I doubt anyone is calibrated.

I'll have to compare the GPS with the tach and see what I'm actually turning with my 285's.

My guess would be around 1650 RPMs at 70 with your 285s.

Ya... about 7.8% off, which would be 140 rpm off of 1800.

Now if I could only keep it down to 70 TAS instead of IAS :D

Do you guys really pay that much attention to fuel/mpg
Why? If it's the truck you bought and you enjoy driving a 6500lb+ vehicle around.
Fill her up enjoy the ride, pull her into the station and do it again.

I've been tracking my '02 since day 1. My reason is to monitor the engine performance. I drive around 80-90 miles per day. I want to drive at the sweet spot to max MPG. Tracking the mileage is also a good way to monitor injectors. If one is getting ready to take a dump, you should see you mileage dropping.

FYI...my '02 six speed has 130k trouble free miles. I replace the fuel filter every 12k miles and run Primrose in every tank. I still have a huge :) on my face every time I drive it.

MaxRock

Is the consensus that GM added another gear to the Allison, but no one sees a clear improvement in highway mileage yet? I get 18 MPG on my '02 Crew Cab 4x4, long bed dually. Anybody doing substantially better with the extra gear in the Allison?

Confused?

I wonder when GM is going to realize some people want improved mileage. We all don't need more and more and more H.P.! How about choices GM? Some guys want a race car in a pickup truck, fine! Other people want medium towing power with 25 plus MPG! Are the "Big Three" going to wait for a foreign company to do as in the past?

:confuzeld What gives??? I was green with envy when after taking delivery on my truck, to hear of a 6 speed ally coming out... After what I've read so far, my shade of green is fading.

Ya, I'm disappointed in the 6sp MPG to I have a few months until I go truck shopping I'll see what happens. But I don't want a used diesel, so I could still end up with a gasser. Not that I have a problem with the MPG really, I just expected to see an increase.

I'm having 2nd thoughts about getting rid of the '02 Duramax on my avatar. I wanted to get away from the dually and upgrade to a 6 spd, crew cab, 4x4 short bed, but now I'm wondering if it will be worth the cost. All I will gain is a little better ride and some more power I don't really need. My '02 looks like new, so what's the point! Maybe I'll put the savings into the tank instead.

Keep in mind that none of the 6spds are really broken in.
I've got a little over 3k and about 100 hours on mine.

I wonder how the 6 speed holds in cruise? I remember when trucks would kick-down to 4th after looseing just 2 MPH. How does the new combo do?

Up and over the grapevine out of LA and back in at 70-75... I don't think it even dropped back into 5th (not towing).
The Tundra cruise was hyperactive.

For an unofficial, could get 2 dmaxes (pre '06 and an '06) and drive them side by side with cell phone communication to compare instantaneous mileage. Better to check after they are more broken in.

Up and over the grapevine out of LA and back in at 70-75... I don't think it even dropped back into 5th (not towing).
The Tundra cruise was hyperactive.

That's good to hear! That's one thing I like about the Dmax. My '01 Cummins was always hyperactive too! My '02 Dmax holds cruise control great at over 12k lbs, with the camper on! (See avatar) Got a ticket on cruise control at 89 MPH near Fallon/Reno Nevada with camper on. Just rolling along "instead" of using the cruise. Just listening to a CD, digesting Reno Prime Rib! Officer was a nice guy and wrote me for 10 MPH over the speed limit. $50. and no point against my license! I owe that cop one! Thank you Mr. Policeman! Best break I got since I was 18 flying around with a '56 Chevy!
:lol:

My '02 Dmax drove about the same from about 5k miles to now 51k miles as to mileage (18 MPG) and same power. My '01 Cummins was a dog until about 8K and then improved. Common sense says mileage and power such get better after break in! A lot of bearings all the way to the rear wheels have to break in, but is seems to be less a factor than 20 years ago.

Yes, mine is a 4x4.
Note that my first tank where I got 19 was an extended highway run, but since it was also the break-in period, I kept speeds at or below 65. Every 5 miles or so, I'd pull down an off-ramp and drive a few circles through a parking lot, idle for a few minutes, then get back on the road.


So, 400 miles at 75-80mph, including several WFO runs, followed by 10-15 pulls on Kennedy's Super Flow wasn't the correct way to break mine in? :eek: :muahaha:

Don't know much about diesels, but I used to build '50's/'60's small block Chevy engines for 55 to 65 Chevys and Corvettes. I found out if you babied them after the first 100 miles in break in (within reason of course) they didn't run as strong later. Is that the same with diesels? Wachathink?

So, 400 miles at 75-80mph, including several WFO runs, followed by 10-15 pulls on Kennedy's Super Flow wasn't the correct way to break mine in? :eek: :muahaha:
Uhh... I have some very good reasons for not purchasing used vehicles :D

Don't know much about diesels, but I used to build '50's/'60's small block Chevy engines for 55 to 65 Chevys and Corvettes. I found out if you babied them after the first 100 miles in break in (within reason of course) they didn't run as strong later. Is that the same with diesels? Wachathink?
Of course it's true, but what do you want... extreme performance for 50-100k or a solid vehicle that will last 300k+?

I am with you. Once you get past the price of fuel, driving one of these 6500 pound trucks is 100% pure driving pleasure. Duramax ON!!!

I am with you. Once you get past the price of fuel, driving one of these 6500 pound trucks is 100% pure driving pleasure. Duramax ON!!!


This is a fact! At $4.00/gal I'll probably just pleasure drive less.

Of course it's true, but what do you want... extreme performance for 50-100k or a solid vehicle that will last 300k+?

I'm not talking about beating the engine to death, but rather not driving it like it's made of "glass" after the first couple of hundred miles! My experience is that well built engines don't need to be driven like a hearse for 2000 miles. After a few hundred miles you can open it up for a few seconds and then slow it down! I'm I right, or wrong? Maybe diesels are different?

Okay... I misunderstood.
Ya, after a couple of hundred miles, sure... you can open her up.

I was thinking about the guys who don't even want it started at the dealership because they are afraid of improper ring seatng if they can't start it and immediately run it to the redline.

Yes... there is more than one web site that promotes this insanity as being he best way to break in an engine.

I filled up today, hand calculated 18.7 mpg with 60/40 Hwy/city driving. I still have less than 1000 miles on the truck, it keeps getting better. :D

I filled up today, hand calculated 18.7 mpg with 60/40 Hwy/city driving. I still have less than 1000 miles on the truck, it keeps getting better. :D

sweet :thumb:

Mine has dropped off a little. I was getting 16.8mpg 50/50 hwy/city now I have been getting 15.5mpg. I now have 2300 miles.

Haven't filled up yet so I don't have a hand-calc'd number, but DIC was running 16.5 after fill up Monday night through yesterday morning.
By the end of the day yesterday, it was back down to 15. The difference?
Tuesday was raining and it didn't get above 75. Yesterday it got closer to 90.

Long freeway run today... I'll see if it comes back up.

[QUOTE=RichLockyer;707141]I was thinking about the guys who don't even want it started at the dealership because they are afraid of improper ring seatng if they can't start it and immediately run it to the redline.
QUOTE]

Engines can be bad! I picked up a new pickup and as I left the stealership I heard a rod knock! I took it back I told them so! They smiled at me as if I was a dumb school teacher until I started the engine. Then their smiles went away in a hurry! This dumb school teacher had buit a few engines. Took me a week to get my truck back! Imagine if I had red lined it out of the stealership! The rod might have landed in your front yard!


:badidea:

Mine has got the same mpg from tank 1. In town with ac I range from 13-15. On freeway over 2k rpms with ac I get from 15-17. On freeway cc-on no ac under 2000rpms 20.7mpg (best).

Ok, I am getting pretty happy now, 5 tanks of gas so far in my '06 with
the 6 speed Allison. (FYI, data kept in StarOffice spreadsheet and calculated
to 3 decimal places. Trip mileage * 1.0358 / gallons pumped. The 3.58% is
to adjust for tires from 245 stock to 265/75R16E's that I have.) As others
have said, the DIC is usually 1-1.5 mpg lower than actual.

14.71 mpg First tank, lots of around town.
15.13 mpg Around town + 128 mile freeway trip
14.67 mpg Around town + 128 mile freeway trip
19.20 mpg All freeway, cruise control used a lot 63-68mph
18.43 mpg Nearly all freeway, a few short trips as well.

Ok, I am getting pretty happy now, 5 tanks of gas so far in my '06 with
the 6 speed Allison. (FYI, data kept in StarOffice spreadsheet and calculated
to 3 decimal places. Trip mileage * 1.0358 / gallons pumped. The 3.58% is
to adjust for tires from 245 stock to 265/75R16E's that I have.) As others
have said, the DIC is usually 1-1.5 mpg lower than actual.

14.71 mpg First tank, lots of around town.
15.13 mpg Around town + 128 mile freeway trip
14.67 mpg Around town + 128 mile freeway trip
19.20 mpg All freeway, cruise control used a lot 63-68mph
18.43 mpg Nearly all freeway, a few short trips as well.

I hope things still improve for you 6-speed guys. I expected more of an immediate improvement though with the 6 speed. I can hit those numbers pretty easy with my '05.

A humble suggestion from the masses here. The 6 speed tranny, while being mated to the LLY while they use up the rest of them was actually intended for the LBZ. That giving more torque down low, may improve the mileage and take more advantage of the higher gearing at cruise. I have no proof of this theory, of course, but maybe the higher 6th gear in the new allison is not quite ideal for the LLY. Food for thought...

Bill

A humble suggestion from the masses here. The 6 speed tranny, while being mated to the LLY while they use up the rest of them was actually intended for the LBZ. That giving more torque down low, may improve the mileage and take more advantage of the higher gearing at cruise. I have no proof of this theory, of course, but maybe the higher 6th gear in the new allison is not quite ideal for the LLY. Food for thought...

Bill

Bill,

Happy first post - you have a valid point. But, it looks to me from other posts that the RPM's with the 6 speed have dropped quite a bit at cruising speed over the LLY. You would think that alone would have a more positive effect on MPG's on the exact same motor.

That said - I would think that if the LBZ posts much better MPG's that it is the difference in the motor and not the 6 speed.

I hope things still improve for you 6-speed guys. I expected more of an immediate improvement though with the 6 speed. I can hit those numbers pretty easy with my '05.

Did your '05 hit those numbers that quickly? I don't recall my '05 pickup being any better than that or as good as that for its first five tanks.

Did your '05 hit those numbers that quickly? I don't recall my '05 pickup being any better than that or as good as that for its first five tanks.

Yes it did, but I don't drive it hard either. I had a very slight increase in MPG's at around 10K - I'm at 23K now

My 04.5 didnt do that good early on but i dont drive 63-68mph on a freeway either!!

what do you think I will get driving 68mph to 70mph? Around here thats about as fast as you can go without a ticket on a lot of the highways I travel on.. :(

On my second tank of fuel I averaged 20 mpg hand calculated mixed driving. My third tank mostly highway miles averaged 21 mpg, the DIC is about 2 mpg off after comparing.


2006 CC 4X4 LLY D/A

On my second tank of fuel I averaged 20 mpg hand calculated mixed driving. My third tank mostly highway miles averaged 21 mpg, the DIC is about 2 mpg off after comparing.


2006 CC 4X4 LLY D/A

That's starting to get encouraging! I want to get a new Dmax just to drive without towing. It would nice to get some mileage with a big vehicle. 21+ would be nice.
:cool2:

That's starting to get encouraging! I want to get a new Dmax just to drive without towing. It would nice to get some mileage with a big vehicle. 21+ would be nice.
:cool2:

Then it becomes a toy and you spend those driving moments looking at all the pretty black smoke through the passenger side mirror and your 21+ becomes 16-18 and you even have a smile on your face. But you may be wiser than most and hold off on the goodies. I couldn't! :D

Then it becomes a toy and you spend those driving moments looking at all the pretty black smoke through the passenger side mirror and your 21+ becomes 16-18 and you even have a smile on your face. But you may be wiser than most and hold off on the goodies. I couldn't! :D

I guess a Dmax with a chip is more comfortable and useful than putting your money in a Corvette! The first time a guy told me about lighting up his tires with a 3/4 ton diesel I though he was nuts! Then I found this forum. Next Dmax I may just have to get a programmer. Wouldn't use it much, but every once in a while it would be fun. I've read that at the lowest setting some may even give you and extra mile per gallon if your foot is out of it on the highway. True/false?

I guess a Dmax with a chip is more comfortable and useful than putting your money in a Corvette! The first time a guy told me about lighting up his tires with a 3/4 ton diesel I though he was nuts! Then I found this forum. Next Dmax I may just have to get a programmer. Wouldn't use it much, but every once in a while it would be fun. I've read that at the lowest setting some may even give you and extra mile per gallon if your foot is out of it on the highway. True/false?

I'm running the Predator on my LB7 @ 40HP and I actually get 1 MPG more. I've ran stock (used predator to adjust speedo) for a few tanks then went to 40HP and gained. Pretty impressive. I still get about 19MPG around town... 20-21 on the highway more if I went slower. Gotta love the MANual.

I'm running the Predator on my LB7 @ 40HP and I actually get 1 MPG more. I've ran stock (used predator to adjust speedo) for a few tanks then went to 40HP and gained. Pretty impressive. I still get about 19MPG around town... 20-21 on the highway more if I went slower. Gotta love the MANual.

I assume you have bigger tires since you said you adjust for the speedo. Have you heard what the Allison 6 spd's are getting with the same Predator at 40 H.P.?

I assume you have bigger tires since you said you adjust for the speedo. Have you heard what the Allison 6 spd's are getting with the same Predator at 40 H.P.?
No aftermarket tunes for the '06....


... yet.

i was wondering if in anyway possible i could get the six speed in my 05 or just put the sixth gear in it it really needs it runnnin bout 75 on the hwy

No aftermarket tunes for the '06....


... yet.
Okay... ya, ya... I'm quoting myself here....


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Post your question again on the DiabloSport website instead.
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This is a reply to your question from 2005-09-30 02:08

CATEGORY: Predator
QUESTION: [Are there any plans to introduce a Predator for the 2006 GMC LLY Duramax
application?

Thank you.]

------------------------------------------------------------

ANSWER:
Dear Rich Lockyer,

We are in current R&D and expect release before the end of year.

Thank you for your interest in DiabloSport!
Stay tuned,
Keith, a proud member of the DiabloSport Support Team

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There ya go!

An update after my first (mild) towing trip.

Going from S.Florida to Dallas TX, pulling an empty 2000 lb trailer = 18.2 running 80 - 85 with the A/C on.

On the way back, running with a 6000 lb (total) loaded trailer = 14.6 runnin 75 with A/C.


And a side note, the water temp never moved, even in 94 degree heat, running for 22 hrs non stop. The trans temp did go up slightly in stop and go traffic, but stayed normal while driving.

Another note, going thru the tunnel on I-10, going west up the hill, the turbo sounded great! :D

im going to guess you have an open trailer put an enclosed trailer behind it and see what kind of MPG's you get.

im going to guess you have an open trailer put an enclosed trailer behind it and see what kind of MPG's you get.

No kidding, but still not bad mileage!

Yes this was a heavy open trailer, but I have an enclosed trailer on the way and will post those results as well.

I knew the open trailer would do better, that's why I took it. I'm happy with the MPG I got, even if I did get hit with 3.79 a gallon fuel in Mississippi... :eek:

I was more concerned about the overheating issues some have, and again I was happy. Yes I was running light, but it was still hot out, and had to go up some hills. The fan never came on, even on startup...

I've got about 1500 miles on my truck now. First Highway trip @ 500 miles got me 19.2 mpg through the White Mountains and Franconia Notch - round trip.

The first pull of our 30' TT weighing around 9K - 9.5K lbs. got me 8.0 mpg - mostly uphill for first 80 or so miles. Overall trip [towing] was 10.2 mpg which means on the "downhill" side (which it is more downhill than uphill) I was getting around 13.2 mpg. That's the info from the DIC. No heating problems whatsoever. Engine temp stayed 1 - 1.5 marks below 210. Tranny temp never got over 158 (or so) and stayed in the 147 or so range for most of the trip. The 158 was pulling a long (uphill) grade (~4-5 miles?) prior to entering the Notch.

Love the truck!

I've got about 1500 miles on my truck now. First Highway trip @ 500 miles got me 19.2 mpg through the White Mountains and Franconia Notch - round trip.

The first pull of our 30' TT weighing around 9K - 9.5K lbs. got me 8.0 mpg - mostly uphill for first 80 or so miles. Overall trip [towing] was 10.2 mpg which means on the "downhill" side (which it is more downhill than uphill) I was getting around 13.2 mpg. That's the info from the DIC. No heating problems whatsoever. Engine temp stayed 1 - 1.5 marks below 210. Tranny temp never got over 158 (or so) and stayed in the 147 or so range for most of the trip. The 158 was pulling a long (uphill) grade (~4-5 miles?) prior to entering the Notch.

Love the truck!

Where were you in the white mountains... I snowmobile through Franconia notch all winter long.. Right out of Twin Mountain.. :ro) Bring on the snow!!

Where were you in the white mountains... I snowmobile through Franconia notch all winter long.. Right out of Twin Mountain.. :ro) Bring on the snow!!

I was actually up beyond the White Mountains in Vermont (straight up I93) around Concord, Vt. We had a seasonal site at a campground. :offtopic: :o::)

My old vehicle was a 2002 Trailblazer LTZ which got 18.5 mpg combined. I'm getting 17.6 mpg combined with the Duramax right now (about 1/2 highway and 1/2 city driving. :thumb:

I've got about 1500 miles on my truck now. First Highway trip @ 500 miles got me 19.2 mpg through the White Mountains and Franconia Notch - round trip.

The first pull of our 30' TT weighing around 9K - 9.5K lbs. got me 8.0 mpg - mostly uphill for first 80 or so miles. Overall trip [towing] was 10.2 mpg which means on the "downhill" side (which it is more downhill than uphill) I was getting around 13.2 mpg. That's the info from the DIC. No heating problems whatsoever. Engine temp stayed 1 - 1.5 marks below 210. Tranny temp never got over 158 (or so) and stayed in the 147 or so range for most of the trip. The 158 was pulling a long (uphill) grade (~4-5 miles?) prior to entering the Notch.

Love the truck!

Sounds about dead equal with my 2002 Dmax with a 30' TT across the country on I-40. About 10.5 mpg. See avatar same truck with a 30' TT.

Got about 10.8 towing to Albuquerque for balloon festival, 11.1 coming back, both trips over Kenosha Pass and Poncha Pass, pretty mild for Colorado. Towing about 6K travel trailer with all the water for dry camp at the fairgrounds. Truck will go as fast as you want towing, wanta go 75 up kenosha, just put your foot down. Best part was wife won $700 on slots, gave me half, so I bought a Honda Eu2000i at their fairgrounds Honda display. That trip in the Tahoe would have been a red line nail biter, wondering how much more it could take. With the Dmax, it was like riding on a train, it just goes, and goes.

Okay I have been researching my new truck purchase and like the LBZ engine. I do have one question. In reading the press release info I have seen a couple of times the following "The lower compression reduces stress on the engine by reducing the peak cylinder firing pressure. This, in turn, allows more fuel to be burned - more fuel means more power "

Now more power is great, but wouldn't that also reduce mileage? With a $2000 (LLY) versus $500 rebate (LBZ) that extra power would be better spent in my needs for more MPG. Maybe I missed anyone discussing it (and a couple of quick searches didn't show anyone discussing that point...).

Only if you put your foot into it I would think.

You are going to get a maximum of "X" horsepower out of each ounce of fuel.
Improvements in engine efficiency will get you closer to that theoretical maximum, which will produce more power for the same given amount of fuel burned.
Likewise, "more mellow" driving will use less fuel to move the vehicle the same distance at the same speed and acceleration.

I have 2500 miles and around town 14-16 and road 17.7-18.5 or better.
Combined last fill was 346 miles and it took 18.4 gal.
But the ride and at 80-85 just a dream. 2000 rpm at 80. Crew cab short bed 4 by 4. Told my wife I always wanted a vett. but this is it. a chip and you have a family vehicle and a vett. LOVE IT.

I have 2500 miles and around town 14-16 and road 17.7-18.5 or better.
Combined last fill was 346 miles and it took 18.4 gal.
But the ride and at 80-85 just a dream. 2000 rpm at 80. Crew cab short bed 4 by 4. Told my wife I always wanted a vett. but this is it. a chip and you have a family vehicle and a vett. LOVE IT.

Best sales pitch I've ever heard!
:exactly:

I have 2500 miles and around town 14-16 and road 17.7-18.5 or better.
Combined last fill was 346 miles and it took 18.4 gal.
But the ride and at 80-85 just a dream. 2000 rpm at 80. Crew cab short bed 4 by 4. Told my wife I always wanted a vett. but this is it. a chip and you have a family vehicle and a vett. LOVE IT.
Yeah, I always told my wife I wanted a Jag. It was my dream car. Then Fart bought Jag. That's like the baby crying during foreplay.

I don't regret in the least getting this truck. Lotsa room, lotsa power, nice amenities, good ride. I'm sure there will be "bumps", but there's very few vehicles I've owned that didn't have them - maybe two others ... and both of them were GM.

I'm getting 15.2 with 5000 miles on a 06 lly 4x4 crew cab long bed with a 6 speed. Should I be concerned?

I'm getting 15.2 with 5000 miles on a 06 lly 4x4 crew cab long bed with a 6 speed. Should I be concerned?

Not sure. How fast are your driving, what is your city/highway mix, are you towing anything? Is the 15.2 your average for the 5,000 miles? or your last tank?

Yeah, I always told my wife I wanted a Jag. It was my dream car. Then Fart bought Jag. That's like the baby crying during foreplay.

If it's any consolation... Jag quality went up when Fart bought them :D
I'm getting 15.2 with 5000 miles on a 06 lly 4x4 crew cab long bed with a 6 speed. Should I be concerned?
http://personal.linkline.com/rlockyer/2500Gas.xls

Overall average 30mph... about 9200 miles at 310 hours.

06'LLY 1400mi. 379mi.on 22gal.300 hwy 65/75mph,3 1/4 mi. runs,1 dyno run,rest in town=17.22mpg(hand calc.)

How were your 1/4 mi times and what kind of numbers did you put up on the dyno?

I just bought mine last night so I haven't fueled up yet. I'll add to this thread when I have some numbers. I'm anxious to do some towing! :)

How were your 1/4 mi times and what kind of numbers did you put up on the dyno?

1st run-2wd smoked tires =22@79mph(rookie run)
2nd run-4wd=15.95sec@82.97
3rd run-4wd= 15.94sec@82.88
Dyno=265hp@559.7lbs torq.(6sp.+rev.& sp.limiter gave the dyno guy fits)
this is a bone stock 06'LLy.:)

First tank with 442 miles on the odometer, 90% city and 10% highway driving:
DIC: 15.6
Hand calculated: 15.7
2006 Chevy Silverado LT1 3500, 4X2, LBZ/6-spd Ally.