I'm wondering if the configuration of active/inactive cylinders always remains fixed, or do they randomly alternate to assure equal use over a period?

 

That is a really good question. Hope someone knows.

 

Per the following Acura press release, I believe the rear cylinder bank is always deactivated.

Acura | Press Releases Article | Acura.com

Scroll to the section where it discusses the V6 engine....

I also saw this graphic on Temple of VTEC:



And here's the link where the graphic is:

The Temple of VTEC - Honda and Acura Enthusiasts Online - Articles - Well they stood up to the plate!: 3.5L 6-cylinder i-VTEC Motors

 

Thanks for the pictorial... but it leaves the questions as to whether the pictured configuration is immutable!

Also... Should I understand that the V6 has an intermediate stage where 4 cylinders are operative --- but just on "new" productions?

 

If you read the press release link provided (and I hope you did - it doesn't leave much in the way of questions unanswered - why the exclamation point?) Acura was pretty specific -- while VCM is active, the rear bank is disabled and the front bank left enabled: "During startup, aggressive acceleration, or steep ascents — any time high power output is required — the engine operates on all six cylinders. During moderate-speed cruising and at low or moderate engine loads, the system operates just the front bank of three cylinders.".

Unless their press release intentionally left out info on the possibility of altering which cylinders are disabled, I'd say it's pretty clear cut -- it's the rear bank that's disabled (therefore it's immutable). Given the detail in the release, I doubt Acura left it out.

ps. the graphic I provided shows a 4-cylinder mode -- the TLX does not incorporate this functionality. It's either all 6 cylinders, or the 3 front cylinders. I only provided it to show the the 6 vs the 3 mode; I should have been more specific. I made an assumption it was already known.