[Stéphane Dumas]

an article from AutoblogGreen about the EPA tests of the Silverado/Sierra hybrid who gets 21 mpg city/22 mpg highway
http://www.autobloggreen.com/2008/0...rid-gets-official-with-the-epa-21mpg-city-22m

note then the 2-mode hybrid is use with the 6.0L I wonder if it could fit with the 4.8L and the 5.3L? Also Chrysler will use the 2-mode hybrid as well for the Ram for 2010 and if they menage to get the Hemi more efficient with the 2-mode hybrid, we could see a interesting competition.

 

[jkennedy293]

note then the 2-mode hybrid is use with the 6.0L I wonder if it could fit with the 4.8L and the 5.3L?

That question was asked when the Tahoe 2-Mode came out. GM says they went with the 6.0 because it can stay longer in 4-cyl mode than the 4.8 and 5.3.

 

[eurohazard]

That question was asked when the Tahoe 2-Mode came out. GM says they went with the 6.0 because it can stay longer in 4-cyl mode than the 4.8 and 5.3.

This answer makes a lot of sense too. The 5.3, and especially the 4.8 make peak torque pretty high up in the RPM range.

 

[Randiglio]

I'm pretty sure they use the 6.0 to allow the engine to run an Atkinson cycle.
I won't try to explain try a google search.

 

[Johnny P]

I'm pretty sure they use the 6.0 to allow the engine to run an Atkinson cycle.
I won't try to explain try a google search.

Ding, ding, ding.....

It all has to do with cam timing. In order to run the engine the way they wanted, they needed the added torque of the 6.0l. The 4.8 and 5.3 don't have the necessary torque when running Atkinson cycle cam timing.