6.4 hp
 

This interesting post was at challengertalk.com. Dealer claims the 6.4 is rated at 475 hp.

"My fiance and I took a walk around a sale event here in Southern Oregon and I had a chat with one of the sales/marketing guys from Lithia Chrysler Jeep Dodge in Medford.

He told me that they had started receiving info on the 2011's, and specifically I asked about the 6.4L HP rating. He told me that initial tests on test cars and power plants have indicated that the 6.4L is going to be rated at 475 HP and 470TQ. However, he also said something interesting in that he said this is based on the engine running at 65% capacity of power, that it has been tuned down to get maximum engine life (and warranty claims) down.

According to him and a Chrysler rep that was there from Auburn Hills, the first 6.4L SRT8's tested in April weren't detuned (and running at 90% capacity), and were putting out 505 HP. Chrysler's warranty and legal stepped in and determined that they could reduce potential claims by 30% if they tuned it down to 450. A compromise was met at 475.

He did say the SRT10 was briefly reconsidered two months ago, but it was not in true testing. He did not say anything confirmed about the 5.7L being underrated, but he just kind of smiled when I mentioned I put down 332 RWHP on the dyno on a stock motor and that something wasn't right. He did mention that "The 5.7L is a very surprising motor isn't it? We have that poor motor so tamed down".

Interior materials and color scheme is changing, specifically in gauge design, but the overall interior isn't changing. He did mention at least as it stands now most of the 2011 parts are interchangeable with 2009/10's."

Very cool info. 65% sounds low, and clearly there will be some room to squeeze out more power, but I'm sure every street engine is tuned down from max power for reliability reasons.

I'm interested in what tuning to "100%" capacity would look like in an engine. Is it the state of tune like what you have on a top fuel dragster, where it's max power or flame out every time you launch? For a daily driver, given the sometimes lax maintenance of the average owner (not to cast aspersions on any of the fine enthusiasts here, but referring to the public in general) it would be a bad idea to warranty an engine that was tuned within an inch of its life.

I am just guessing but tuning would probably just be numbers lowered in the engine computer. i.e. you have less advance, less fuel in the injection,
and with VVT on the 6.4L have it cut back as well.

I bet if you beefed up the internals then you could get more HP from the engine without reducing engine life but you would need a more intimate knowledge of the engine.

To achieve peak power from the 6.4 you would probably need a new cam, new intake, and new heads.

Leftlane News has a spy photo of the 6.4 in a Jeep Cherokee SRT. See:

http://www.leftlanenews.com/jeep-gra...okee-srt8.html

That is what I meant by "beefed up the internals " but you can get more
power by improving the computer engine variables and that is just software and is cheap.

Super Stock
 

Just to whet your appetite, here is a video of the 6.4 in the 2008 Super Stock Concept. It ran the quarter in 11.53 sec. @114 mph.


http://www.youtube.com/watch?v=AU-eRJqBOac

Will the 6.4 be available at the beginning of '11 production or at the end.

I applaud them on doing this. It means that they will have a competitive model on the market that people who like to have a powerful car for when it is needed but not have a use the full potential all the time will have an engine that may outlast the competition's engines, but at the same time, people who want the full potential can get it in aftermarket upgrades.

ya thats right...