3900 Quick Question

[jman093]

I was reading about the 3900 engine tonight. I've really kind of liked this engine in my mother's 06 Impy. In 2006 the engine was a 242 hp LZ9 and in 2007 it was was a 233 hp LZ8 that has AFM, DoD, cyl. deactivation, etc. But I'm curious (for no reason other than I want to know) why it makes 11hp less?

I was thinking it's maybe because they did away with active intake on the LZ8 for some dumb reason. All of GM's media information you will ever see states the LZ8 used an active intake, but looking through GM service information for technicians I can't find any mention of it on the LZ8, nor do I see anything for it in wiring diagrams. I find both when looking up an 06 with the LZ9.

Does anyone know if the LZ8 does indeed used it or not?

[Joseph Upson]

I was reading about the 3900 engine tonight. I've really kind of liked this engine in my mother's 06 Impy. In 2006 the engine was a 242 hp LZ9 and in 2007 it was was a 233 hp LZ8 that has AFM, DoD, cyl. deactivation, etc. But I'm curious (for no reason other than I want to know) why it makes 11hp less?

I was thinking it's maybe because they did away with active intake on the LZ8 for some dumb reason. All of GM's media information you will ever see states the LZ8 used an active intake, but looking through GM service information for technicians I can't find any mention of it on the LZ8, nor do I see anything for it in wiring diagrams. I find both when looking up an 06 with the LZ9.
Does anyone know if the LZ8 does indeed used it or not?

I believe the power reduction has more to do with the addition of DOD to the Impala and Monte Carlo version possibly because of some unstated fragility of the system or the special lifters. Note the lower power occurs at a lower rpm as well so in some cases the engine maybe exactly the same but rated at a lower rpm producing a lower number. The non DOD 3900 for 06 and 07 is still rated at 240, the 08 SUV 240, the two 08 car options 222 and 233. It could also be as simple as a change in the tune or exhaust system or a combination of all of it.