2.7 CR question/dual plugs

[kenikh]

I searched for an hour trying to answer this question. Although I found interesting info, I didn't find what I was looking for. The question:

What maximum CR is a reasonable expectation for a 2.7 motor with dual plugs? Say someone were to decide that their RS specced 2.7 needed an upgrade, what CR would that person ask for from their custom ordered JE pistons? This question is academic of course...

[Wayne 962]

Read the section on Twin-Plugging in the Engine Rebuild book. This is too complicated a question to answer in a single post. The summary is that it depends upon what gas you're planning on running, and also what your overall requirements are.

In general, I wouldn't go above 10.5:1 for a street car, although the 3.6 motors are spec'ed at 11:1 or so (although they never quite measure in at that number).

-Wayne

[kenikh]

I was planning on looking in the book, but I left it at work (what the heck is it doing there? ) I realize now that I left out quite a few details in my post. I was assuming 92 octane, EFI among other things. Nonetheless, you answered my questions as I was looking for a rough. Thanks!