Well, after almost 2 months of searching, test driving and "negotiating", I've been offered a very good deal on an '06 Dmax with the older, LLY engine. I have driven both vehicles a number of times and can't really see much of a difference. Of course, all of my test drives were solo so towing could show a difference but I would think that either one will be stronger than my 8.1 big block. The dealer is doing much better on the LLY that the LBZ, partly because there is a $1500 "dealer adjustment" on the older trucks. Does anyone have any experience towing with both GM diesels? I don't think it will matter at all with my current rig, since my 8.1 hauls it like it's a pop-up but I will be upgrading in about 3 years and I don't want to limit myself, although the tow ratings are identical with either engine. Please don't make this a GM - Dodge - Ford war, I gave them all a fair shake and GM works better for my needs. Specs are: LLY @ 310hp / 605lb-ft. Vs. LBZ @ 360hp / 650lb-ft. Both use the Allison 6 speed tranny. Thanks in advance.

LLY's have a history of overheating. Not sure how much weight you are towing, but the LBZ will not be as suseptable to overheating. I don't tow much, so the LLY is fine for me, but the dern fan goes off a bunch. There are some aftermarket things you can do to fix the problem, but whether or not they are cost effective when considering a new truck is not anything I can help with (search TXChristopher). If you want to do mods right away, then the LLY is the way to go, if not, I think the LBZ is probably a better fit.

06 LLY is dam close match to the LBZ like only minor things different so I wouldn't worry about getting an LLY... I have one cause I didn't want to take a chance on getting something brand new to the market in the LBZ...

nhcampers:

:welcome2:

Here's a thread from a member with a similar concern:

http://www.dieselplace.com/forum/showthread.php?t=87830

Earlier LLY's tend to run hot; those that tow heavy sometimes experience over heat. The '06 LLY is more like the LBZ than it is the earlier LLY's. IIRC the '06 LLY / LBZ also use the same cooling system, perhaps some of our members with technical backgorund will comment.

I tow heavy and have never over heated my LLY. That being said; I'm one of those types that wants everything exactly the way I want it. If it were me, I'd choose the LBZ.

Good luck! :)

LLY's have a history of overheating. Not sure how much weight you are towing, but the LBZ will not be as suseptable to overheating. I don't tow much, so the LLY is fine for me, but the dern fan goes off a bunch. There are some aftermarket things you can do to fix the problem, but whether or not they are cost effective when considering a new truck is not anything I can help with (search TXChristopher). If you want to do mods right away, then the LLY is the way to go, if not, I think the LBZ is probably a better fit.

he said they both had a 6-speed auto, so that makes it an 06 LLY, which is different from the 04.5-05 LLY

06 LLY and LBZ are identical engines with different programming on the LBZ for more power

he said they both had a 6-speed auto, so that makes it an 06 LLY, which is different from the 04.5-05 LLY

06 LLY and LBZ are identical engines with different programming on the LBZ for more power

From everything I read the LBZ has better cooling capacty, better sealed turbo bearings, much better fuel injectors (this is where the extra power is told to be from), different timing, lower compression, New glow-plugs reduce start time by as much as 50 percent and larger EGR tube (bad thing)

The comprehensive list of changes and upgrades to the 2006 DURAMAX 6600 includes:

* Cylinder block casting and machining changes strengthen the bottom of the cylinder bores to support increased horsepower and torque
* Upgraded main bearing material increases durability
* Revised piston design helps lower compression ratio to 16.8:1 from 17.5:1
* Piston pin bore diameter increased for increased strength
* Connecting rod “ I ” section is thicker for increased strength
* Cylinder heads revised to accommodate lower compression and reduced cylinder firing pressure
* Maximum injection pressure increased from 23,000 psi to more than 26,000 psi
* Fuel delivered via higher-pressure pump, fuel rails, distribution lines and all-new, seven-hole fuel injectors

* Fuel injectors spray directly onto glow plugs, providing faster, better-quality starts and more complete cold-start combustion for reduced emissions
* Improved glow plugs heat up faster through an independent controller
* Revised variable-geometry turbocharger is aerodynamically more efficient to help deliver smooth and immediate response and lower emissions
* Air induction system re-tuned to enhance quietness
* EGR has larger cooler to bring more exhaust into the system
* First application of new, 32-bit E35 controller, which adjusts and compensates for the fuel flow to bolster efficiency and reduce emissions

OK - be careful here. The LLY was made in 04 and 05, but it was much different than the one you are looking at. I don't know why they kept the same name. As far as all those concerns, the 06's will be the exact same engine with either the LLY or the LBZ. So, if anythign the LBZ will be more likely to overheat because of the extra power. Don't worry about that though.

I got an 06 lly, and have pulled heavy a few hundred miles so far, and this thing doesn't run any hotter than running empty. The tranny does not even get too hot.

I have asked this question here before, and it gets confusing because of the different LLY's made, but all 06's are the same, except one has more HP. I actually like the fact that I got an LLY because there is mroe of a service factor built in. Who needs all that HP anyway?

From everything I read the LBZ has better cooling capacty, better sealed turbo bearings, much better fuel injectors (this is where the extra power is told to be from), different timing, lower compression, New glow-plugs reduce start time by as much as 50 percent and larger EGR tube (bad thing)

The comprehensive list of changes and upgrades to the 2006 DURAMAX 6600 includes:

* Cylinder block casting and machining changes strengthen the bottom of the cylinder bores to support increased horsepower and torque
* Upgraded main bearing material increases durability
* Revised piston design helps lower compression ratio to 16.8:1 from 17.5:1
* Piston pin bore diameter increased for increased strength
* Connecting rod “ I ” section is thicker for increased strength
* Cylinder heads revised to accommodate lower compression and reduced cylinder firing pressure
* Maximum injection pressure increased from 23,000 psi to more than 26,000 psi
* Fuel delivered via higher-pressure pump, fuel rails, distribution lines and all-new, seven-hole fuel injectors

* Fuel injectors spray directly onto glow plugs, providing faster, better-quality starts and more complete cold-start combustion for reduced emissions
* Improved glow plugs heat up faster through an independent controller
* Revised variable-geometry turbocharger is aerodynamically more efficient to help deliver smooth and immediate response and lower emissions
* Air induction system re-tuned to enhance quietness
* EGR has larger cooler to bring more exhaust into the system
* First application of new, 32-bit E35 controller, which adjusts and compensates for the fuel flow to bolster efficiency and reduce emissions

All of these changes were made to the 2006 LLy AND the 2006 LBZ. Read the language at the beginning. All 2006's had those changes done.

The 2006 LLY is a very different engine than the 2004.5 - 2005 LLY's. THe 2006 LLY's have almost every improvement given to the LBZ with the exception of the engine programming. Look at this posting from GM regarding this. The 2006 LLY is a fine engine, with many enhancements. You can't go wrong with either engine, as long as it is a Duramax with the Allison 6 speed! Good Luck.



FOR RELEASE: 2005-08-01

2006 Duramax 6600 Turbodiesel to Deliver Class-leading Torque in a More Powerful and Refined Package



Engine output for Chevy Silverado HD and GMC Sierra HD increased to 360 horsepower and a class-leading 650 lb-ft of torque
Significant updates result in smoother, more refined operation, as well as reduced emissions
New glow-plugs reduce start time by as much as 50 percent
PONTIAC , MICH. – Later this year, GM Powertrain will introduce a new 6.6L Duramax 6600 turbodiesel V-8 (RPO LBZ) for the 2006 model year Chevy Silverado HD and GMC Sierra HD with class-leading horsepower – 360 (268 kw) at 3200 rpm and class-leading torque, at 650 lb.-ft. (881 Nm) at 1600 rpm. In addition to the power increase in the Silverado and Sierra, all 2006 Duramax engines have been significantly revised to deliver lower emissions and significantly improved quietness and smoothness in every application.

The 2006 Silverado HD and Sierra HD with the Allison 6-speed automatic transmission will be equipped with a significantly revised 310 horsepower Duramax 6600 (LLY) through the third quarter of 2005. It will be replaced in these applications in the fourth quarter of 2005, by the higher output, 360-horsepower Duramax (LBZ).

“The introduction of the Duramax diesel in 2001 represented a significant evolution in North American diesel pick-up truck market and propelled GM’s heavy duty diesel pick-up truck market share to over 25 percentage points,” said Charles Freese, GM Powertrain executive director, diesel engineering. “The introduction of the improved, 2006 Duramax turbo diesel once again sets a new benchmark to which all others will be measured.”

The Duramax 6600’s horsepower and torque increase and emissions reduction are enabled by a strengthened iron cylinder block and a lower compression ratio. 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 – while the lower compression helps reduce NOx emissions. Lower compression also helps reduce noise and vibration, making the all variants of the 6600 a quieter and smoother engine.

A revised variable-geometry turbocharger also enhances the driving experience of the Duramax 6600. Aerodynamic changes to the turbo’s vanes help tailor controlled application of turbo power for seamless and immediate response at full throttle. The turbo, which spins at up to 120,000 rpm, is high-speed-balanced, reducing vibration and resonance – and contributing to the engine’s overall smoothness and refinement. The revised turbo also helps reduce emissions, while maximum boost remains at 20 psi.

Another new feature of the Duramax 6600’s turbo system is the capability of the variable-geometry turbocharger to provide exhaust braking. This function is available on some medium-duty truck models and can replace add-on exhaust brake hardware. With the new system, braking is controlled by a signal from the engine controller and can be activated by the driver.

The comprehensive list of changes and upgrades to the 2006 Duramax 6600 includes:

Cylinder block casting and machining changes strengthen the bottom of the cylinder bores to support increased horsepower and torque
Upgraded main bearing material increases durability
Revised piston design helps lower compression ratio to 16.8:1 from 17.5:1
Piston pin bore diameter increased for increased strength
Connecting rod “ I ” section is thicker for increased strength
Cylinder heads revised to accommodate lower compression and reduced cylinder firing pressure
Maximum injection pressure increased from 23,000 psi to more than 26,000 psi
Fuel delivered via higher-pressure pump, fuel rails, distribution lines and all-new, seven-hole fuel injectors
Fuel injectors spray directly onto glow plugs, providing faster, better-quality starts and more complete cold-start combustion for reduced emissions
Improved glow plugs heat up faster through an independent controller
Revised variable-geometry turbocharger is aerodynamically more efficient to help deliver smooth and immediate response and lower emissions
Air induction system re-tuned to enhance quietness
EGR has larger cooler to bring more exhaust into the system
First application of new, 32-bit E35 controller, which adjusts and compensates for the fuel flow to bolster efficiency and reduce emissions
The Duramax 6600 also has a new intake air heater to reduce smoke and emissions during cold or light-load driving. The system features a 1000-watt grid heater located in the air intake duct, which is triggered automatically by the engine controller. It heats up the incoming air to speed warm-up of the engine.

In addition to 50 more horsepower and 45 more lb-ft of torque in the Silverado and Sierra, changes to the 2006 Duramax 6600 build on a host of improvements introduced for ’05 – improvements that bolstered an already strong foundation. The Duramax 6600 features a rigid cast iron cylinder block with induction-hardened cylinder bores; four-bolt, cross-drilled main bearing caps; forged steel, nitride-hardened crankshaft; aluminum pistons with jet-spray oil cooling; aluminum cylinder heads with four valves per cylinder; integrated oil cooler and a charge-cooled turbocharging system. Features, such as easy-access fuel filter and timing gears, reduce maintenance time and effort.

A new, 32-bit E35 engine controller monitors and adjusts the engine’s operation. Designed exclusively for the Duramax diesel engine, the controller helps the injectors precisely meter fuel to the cylinders and can compensate for the variability of the injectors and fuel flow. This sophisticated, more powerful controller also can support up to five injections per cylinder and eliminates the need for an engine-mounted drive unit to fire the fuel injectors.

The new Duramax 6600 in the Silverado and Sierra heavy-duty pick-ups will be available exclusively with the new Allison 1000 6-speed automatic transmission, featuring class-first features, like tap-shift range selection mode.

In addition to the Chevy Silverado HD and GMC Sierra HD, the Duramax 6600 (LLY) is also available at varying power outputs in the Hummer H1 Alpha, Chevy Kodiak and GMC Topkick. For 2006, the Duramax is available for the first time in GM’s full-size vans, Chevy Express and GMC Savana, providing power and capabilities matched with quietness and smoothness not found in competitors’ diesel-equipped vans.

The Duramax 6600 was introduced in 2001 and was developed in a partnership with GM Powertrain and Isuzu Motors. Since its introduction, more than 650,000 6.6L Duramax diesels have been built and sold.

The Duramax 6600 is assembled at the DMAX facility in Moraine, Ohio , a joint venture between General Motors and Isuzu created specifically to produce diesel engines.


2006 Duramax 6600 Specifications (LLY, LBZ) Assembly site:
Moraine, Ohio

Applications:
Chevy Silverado and GMC Sierra 2500HD, 3500 pickups; Hummer H1, Chevy Express and GMC Savana full-size vans; Chevy and GMC medium-duty trucks

Type:
90º V-8 charge-cooled turbodiesel

Displacement (cu in/ cc):
403 / 6599

Bore x stroke (in x mm):
4.06 x 3.9 / 103 x 99

Block material:
cast iron with induction-hardened cylinder liners

Cylinder head material:
cast aluminum

Intake manifold:
cast aluminum

Exhaust manifolds:
cast nodular iron with steel pipe extension

Compression ratio:
16.8:1

Valve configuration:
overhead valve, four valves per cylinder

Valve lifters:
Mechanical roller

Firing order:
1 – 2 – 7 – 8 – 4 – 5 – 6 – 3

Fuel system:
direct injection diesel with high-pressure common rail

Horsepower (hp / kw):
360 / 268 @ 3200 rpm (2500 HD and 3500 Chevrolet Silverado and GMC Sierra) (LBZ) (Automatic transmission only) (Available beginning 4 th quarter 2005)

310 / 231 @ 3000 rpm (2500 HD and 3500 Chevrolet Silverado and GMC Sierra) (LLY) (Automatic transmission only) (Available through 3 rd quarter 2005)

300 / 224 @ 3000 rpm 2500 HD and 3500 Chevrolet Silverado and GMC Sierra (LLY) (manual transmission), Chevrolet Kodiak and GMC TopKick (LLY) and Hummer H1 Alpha (LLY)

250 / 186 @ 3200 rpm (Chevrolet Express and GMC Savana) (LLY)

Torque (lb-ft / Nm):
650 / 881 @ 1600 rpm (2500 HD and 3500 Chevrolet Silverado and GMC Sierra) (LBZ) (Automatic transmission only) (Available beginning 4 th quarter 2005)

605 / 820 @ 1600 rpm 2500 HD and 3500 Chevrolet Silverado and GMC Sierra (LLY) (Available through 3 rd quarter 2005), Chevrolet Kodiak and GMC TopKick (LLY), (Automatic transmission only)

520 / 705 @ 1600 rpm 2500 HD and 3500 Chevrolet Silverado and GMC Sierra (LLY) (manual transmission), Chevrolet Kodiak and GMC TopKick (manual transmission) (LLY) and Hummer H1 Alpha (LLY).

460 / 624 @ 3200 rpm (Chevrolet Express and GMC Savana) (LLY)

Fuel shut off:
3250 rpm Silverado and Sierra (Heavy Duty), Kodiak and

TopKick (Medium Duty) and Hummer H1 Alpha. (LLY)

3450 rpmExpress and Savana (LLY), Silverado and Sierra HD and 3500 (LBZ)

Crankshaft:
forged steel

Connecting rods:
forged steel, stress-fractured

Additional features:
Turbocharger with charge cooling; exhaust braking (medium duty only); heated air intake; GM Oil Life System

Jeff

Sorry for the confusion nhcampers. The guys here are right about the '06 LLY being different from the one I have. I forgot that detail and jumped the gun when writing a response. The major difference between the two is basically tuning. If you are going to do some mods, that will probably not matter, so go with the best color.

Ok, another question: A couple of people on RV-Net, alluded to the '06-LLY not being as good as my current (if only for 2 more days) 8.1? Even though the LLY has slightly less HP, it has tons more torque. I can't imagine that it would be less potent than my Big Block?

The 8.1 is great engine, but it not out-tow an 06 LLY. And the fuel economy (range) when towing heavy is much better on the diesels.

If you need more power, the diesels can be turned up very easy. Even a 50HP tuner makes a huge difference in power without hurting the fuel economy.

Even with our early LLY's, we can tow 17,000lb combined at 75mph up a 6% grade without breaking a sweat.

just buy it now before jan,1,07 ,,, so you don't get stuck with extra emmisions,,im so happy with my 06 lbz i should buy an extra one now so i can have a new truck in a couple of years

I traded an 8.1 in for my LLY (again, it aint the same as the one your looking at). There is NO comparison. Twice the fuel mileage, pulls much easier (though I don't tow a whole bunch), its down right crazy fast unloaded, and its actually quieter than the gasser. Make the switch and you won't be dissapointed. The only place I think the gasser might beat the LLY is if the gasser had 4.10's and you were comparing off the line acceleration. The 8.1 could get a jump on the diesel, but once the turbo spools up (which is really quick these days), say goodbye to the big block. Hope this helps.

My 2002 LB7 out pulled my buddy's 8.1 up and down the grades of I 81 through VA and TN., each towing similar 5th wheel campers (see sig.). He noted that on the hills he could keep up at the beginning of the climb but then I would walk away from him noticably. I don't know if the 8.1's had any power increases since after the '02 model. I did like the way his big block sounded tho'.

Ed

Actually the 8.1's have lost "rated" power since '02. My 8.1 was an '02 and was rated at 345 HP. Over the next few years with more and more emissions crap, the ratings dropped to 330HP. I haven't checked lately, but I think they are still rated there. The torque ratings have also dropped from 465 to 450 lb-ft.

Who needs all that HP anyway?

:lol:

Well, again thanks to those who offered wisdom but the LLY truck I was considering, was purchased by someone else yesterday. It was to be a dealer swap and the other dealer sold it. The good news is, I signed the papers on an identical truck, but with the LBZ motor, tonight! Pick it up tomorrow afternoon, can't wait. My dealer ate "most" of the difference in cost. I will officially join the diesel world tomorrow afternoon.. See you through the smoke!

I have an 04.4 LLY and an '06 LLY. Totally different engines.... Totally different attitudes.
The 04.5 is quicker, but the 06 revs out farther.


The '06 does NOT overheat. All this truck does is PULL trailers. The lightest trailer is 12,000lbs. I have pulled 21,500+ with it.

Very good truck, but can use more power. FYI I believe only Hypertech has a programmer for the RARE '06 LLY.

Fuel economy is decent. Nothing to get all excited about though. 10 mpgs pulling 14,000 on this trip right now.

(I'm typing this at the GMC dealer while I'm getting them to change air, oil, and fuel filters.) I stopped here because I can say that it is down at least 1.0 mpg from usual.

Service on the diesel will cost plenty more than the gasser.