95 K2500 Suburban 6.5 To LLY Duramax.

[john8662]

After some carefull consideration after my last engine failure I have decided to (for a better word) junk the 6.5 entirely and retrofit a 6.6L Durabux into the Suburban.

My curiousity started when an LLY Max presented itself.

It's just the engine and transmission with engine harness, so I don't get the goodies necessary for the conversion.

Two considerations (being unfamiliar with this engine currently)

The LLY turbo from what I read/hear is lacking compared to the older LB7. Can a person adapt the LB7 turbo onto the LLY and use LB7 programming? I have access to a stock LB7 turbocharger assembly very cheap (probably free in trade).

Second, is the LLY a replacement for the LB7, or in other words, can you install an LLY in the place of an LB7 engine and an already equipped truck?

This is important because I'd consider treating the engine as though it were an LB7 verses the LLY.

I'd rather use the LB7 engine, but you make you due with what you have access to.

Input very welcome!

J

[DmaxMaverick]

The turbos and injectors are different (among many other things). With some creative programming, it could be done (as with any of these rolling IBMs). The turbo on the LLY is a computer controlled VGT (Variable Geometry Turbo), meaning if you remove it, the PCM will miss it. The LB7 turbo is a basic WG'd turbo, with the WG being controlled by boost pressure, directly from the compressor to the WG actuator, with no PCM intervention. The injectors may not be too different to get the LB7 PCM to work, but I haven't heard it being done. Add to that the LLY has EGR, also controlled by the PCM, and the different sensors, and I think the combination may be more trouble than it's worth. All 2001 and non CA 2002+ LB7s are non EGR (or cat or....). Why not shop around for an LB7?

While you are at it, get your hands on that turbo, whether you need it or not. Someone (including me) might, at some point.

And.....
At the same time, I like the idea of an LB7 with LLY heads (sans EGR), just to get the injectors/returns out from under.

[More Power]

After some carefull consideration after my last engine failure I have decided to (for a better word) junk the 6.5 entirely and retrofit a 6.6L Durabux into the Suburban.

My curiousity started when an LLY Max presented itself.

It's just the engine and transmission with engine harness, so I don't get the goodies necessary for the conversion.

Two considerations (being unfamiliar with this engine currently)

The LLY turbo from what I read/hear is lacking compared to the older LB7. Can a person adapt the LB7 turbo onto the LLY and use LB7 programming? I have access to a stock LB7 turbocharger assembly very cheap (probably free in trade).

Second, is the LLY a replacement for the LB7, or in other words, can you install an LLY in the place of an LB7 engine and an already equipped truck?

This is important because I'd consider treating the engine as though it were an LB7 verses the LLY.

I'd rather use the LB7 engine, but you make you due with what you have access to.

Input very welcome!

J

Nope, the LB7 & LLY are not interchangeable - due many changes in the engine control systems (injectors, FICM, turbo management, etc.). I suppose anything is possible, but I'd have to say no, an LB7 turbo couldn't be adapted to an LLY without a major re-write of the programming.

The LLY would be an excellent and perhaps better choice for a Suburban conversion.

I know it may be too late, but I suggest trying to buy a "package" that contains everything (or nearly everything) you'll need to make the swap. The intercooler & hoses/ducts/clamps, radiator, electronic modules, wiring harnesses/fuseblocks/junction blocks/electrical center/etc, ATF cooling lines, steering column, & various odds & ends can cost more over the counter at your local dealer than a salvage Duramax/Allison. Ask me how I know..... :(

I know of a complete & very low mile 2005 LLY Duramax/Allison/NV-263 package that includes everything mentioned in the above paragraph and more for $7500.

Jim

[john8662]

Excellent info guys!

OK, so the engines are entirely different. I had for some reason thought that the new engine could be used as a replacement at some point for older trucks.

Now that that's straight.

Greg

I'll see about getting the LB7 turbo, which would be easier to get if it was known to go on this project, but either way. I'd still like an LB7, cause it's been done kind of thing too. I'm serious about getting this project going.

Jim

Why would an LLY make a good engine conversion choice over the LB7 in a Suburban?

I haven't purchased the engine, but am very close (exhange of $ and loading).

Thanks for the tip on the combination you mentioned.

Still pondering a bit here too..

So, LLY, stuck with VGT turbo. But, I can kill the EGR stuff, which is still in my 6.2 trained mind as an absolutle necessity.

I think one of the major downsides to the LLY engine is the fuel economy, because the LB7 had shown such good economy. Fuel economy in this rig is also a MAJOR consideration for going to the 6.6L verses the 6.5L. So the Duramax needs to be fuel efficient and powerfull when needed.


J

[DmaxMaverick]

I don't need a turbo at this time, but your having it an not needing it may help one poor soul from getting crunched too bad (and put some scratch in your pocket).

Realistically, the LLY could be a replacement for the LB7, but not in so may words. The replacement would be a lot less painful than most other options, and a 2003-2004 with an LLY would be more ideal, having the same multiplexed electronical system...did I mention that?

I'd still recommend an LB7. Less electronics, and no smog crap. They do have the possibility of injector issues, but you are a competent wrencher and shouldn't have a problem with that (being your own warranty dept). The power and economy possibilities with the LB7 are easier to realize, too. Some folks will argue that point, but they are the exception, not the rule. Other than the injectors, the LB7 is quite a bit less complex.

[john8662]

Greg,

Yep, the LB7 is my first choice.

The injector liability is on the back of my mind though, as I'm really looking for something to remain reliable for quite some time, which I haven't mananged to do withe 6.5 combination I've toyed with.

Plus, wrenching on an engine that wasn't designed to be in the chassis that will house it could cause some potential issues with R&R'ing certain components.

Finding an LB7 Combination with lower miles on it is also starting to become a little harder too, cause it's not everyday grandpa takes out his shiny Dmax and get's it waxed by the F250 who ran the red light leading to a nice powertrain up for grabs. :D

I may still purchase this LLY just for the sake of resale.


Ok, since I'm posting here.

What TCase options am I left with? The above mentioned Tcase with the LLY combination is electronic shift right?

I've got the 'ol manual style shifter in the floor and not the electric shift one.

Prolly another variable (but easy to change) to overcome.

I'm getting excited about this adventure that'll occur in my front driveway!

[DmaxMaverick]

The 263 is the only option. It is not "electronic", but can be either electric (push button select, and reliable) or manual. The "electronic" TC is the Autotrac, or Auto 4x4, and not available in models higher than the 2500LD, never behind a Duramax.

[More Power]

Jim

Why would an LLY make a good engine conversion choice over the LB7 in a Suburban?

I haven't purchased the engine, but am very close (exhange of $ and loading).

Thanks for the tip on the combination you mentioned.

Still pondering a bit here too..

So, LLY, stuck with VGT turbo. But, I can kill the EGR stuff, which is still in my 6.2 trained mind as an absolutle necessity.

I think one of the major downsides to the LLY engine is the fuel economy, because the LB7 had shown such good economy. Fuel economy in this rig is also a MAJOR consideration for going to the 6.6L verses the 6.5L. So the Duramax needs to be fuel efficient and powerfull when needed.


John,

The LLY has had fewer injector issues, and the injectors are easier to R&R. The VNT Garrett turbo hasn't been a problem for the Duramax - in any significant way that I'm aware of. So, the LLY gets the nod in my opinion simply because of the injector maintenance issues.

Some LLY owners have had heating issues while towing heavy. You'll not likely ever work an LLY hard enough in a 90's Suburban for this to be a concern.

The LB7 has a slight edge in power production - this might be important if you're into drag racing or sled pulling. Not that you'll be doing much of either in a Suburban. :) Will you??

Yes, the EGR can be blocked, and EFI-Live can do a lot to make it the way you want. I'd guess EFI-Live could improve fuel economy as well. But yes, a cherry LB7 would make an excellent choice as well.

GM installed the NVG-263 (pushbutton) and NVG-261 (manual shift) transfer cases in these 2500HD/3500 trucks. Plus, I'd bet the 263 could be converted to manual with not a lot of effort. I'm thinking the manual shift linkage and related parts would bolt on - after removing the electric shift components.

Jim

[dieseldummy]

If you end up with that LLY combo you will need a LLY ECM, wiring harness, TCM, and some way to make up for the BCM.

Like I've mentioned before, you can swap the LLY turbo for a LB7 unit and take care of the EGR with EFI live. You could also program the vain position to help with MPG.

The floor shift transfer case is somewhat of a rare item. Mostly installed in '01 and '02's. I have serious doubts that you will be able to find one very easily. I also think that converting the 263 to manual shift may be easier said than done. Did you ever find out if the unit your after is 2wd or 4wd?

[john8662]

Jim,

Points well made, the injector maintenance is the main reason one would consider the LLY.

No drag racing the suburban, any more...

Some of the heating issues from what I've read can be overcome, I'll just modify as needed.

DD,

The engine/transmission combination ended up being 2WD, so that means that I either need to keep looking or get it cheap and do some parts trading.

J

[More Power]

I also think that converting the 263 to manual shift may be easier said than done.


Opening the hood is "easier said than done". :D

[hogmotors]

John,
I have an 01 4WD Allison leftover because I used a 2wd transmission. I also have the TCCM(or WHAT ever....)control & harness for whatever transfer case was with mine.
Gordon