I have an 04 Duramax with an LB7 engine and have a couple random questions about the mods / upgrades that comprises what is now the LLY engine.


First, how serious are these modifications?


Most of what I've read on the topic seems to indicate at most intake, valve-cover, turbo, and fuel-delivery system modifications, which leads me to suspect that it might be possible to retrofit the LB7 with the LLY modifications.


Second, what problems were experienced that was the cause of these upgrades, and how frequently did these problems manifest themselves?


That's about it for now, I suppose :)


-- Ake

The differences are fairly extensive and pricey: variable geometry turbo; different cylinder heads, injectors, plumbing; EGR; PCV; fast start glow-plugs; ECM, catalytic converter.... Of course some of those are emissions equipment.


I haven't heard of anyone modding their LB7 into the LLY configuration and have no idea why anybody would do it. The variable geometry turbo is really not that impressive and any power gain from it in the LLY can easily and economically be made up in the LB7 with any number of proven aftermarket upgrades.


I would think the cost of the different parts could go well into the thousands of dollars.


Not knowing why you are asking your question, but if I had an LB7 and a few thousand dollars and wanted increase performance I would get a tranny upgrade and a box, programmer, or reprogrammed ECM.http://www.dieselplace.com/forum/smileys/smiley23.gif

I'd leave the thing alone. The little you might gain would not be worth the cost and the headaches. Sort of doubt you would notice any difference in most driving conditions and you might damage the resale or trade in value of your truck.

Primarily, it's my natural curiosity that is the basis of my query, and not of increasing the power or performance of the engine.


Knowing as little as I did about the type and seriousness of the differences between the two engines, I wanted to get more of a clear picture as to what extent one would need go to, to bring their LB7 up to the LLY specs.


Similarly, that's why I asked what problems were experienced that were the cause of the new LLY engine, and how frequently they manifested themselves. Understanding what they are and how serious / often they are encountered would help me make a more informed decision on which upgrades and mods my money would best be spent on. http://www.dieselplace.com/forum/smileys/smiley4.gif


And on that topic, what transmission mods are available for the Allison? It seems to be a very solid unit as is. Perhaps I'll research that some more.http://www.dieselplace.com/forum/smileys/smiley1.gif


-- AkeEdited by: Akephalos