'04 I6 cyl. compared to '05

[bugeyed]

Can one make an'04 I6 cyl. at 275 HP into an '05 I6 at 291 HP? Other than the MAS what other changes were made to the engine to get the higher HP?

[rubberman]

i thought the 05's were still at 275hp and the 06's started the 290hp range?

[bugeyed]

i thought the 05's were still at 275hp and the 06's started the 290hp range?

Well whatever,:rolleyes: I was quoting another post here. Same question: What are the changes that allow the '06 I6cyl to get more horse horsepower?

[trailblazingold]

Internal stuff, its more than just the MAF. Its in a post somewhere, if you want to do it you might as well buy a newer TB. Some late 05's had the upgraded motor and all of 06's and up have it.

http://media.gm.com/us/powertrain/en/product_services/whats%20new/06%20truck%20eng/06_PWT_%20Vortec%204200%20LL8.pdf (http://media.gm.com/us/powertrain/en/product_services/whats%20new/06%20truck%20eng/06_PWT_%20Vortec%204200%20LL8.pdf)

[bugeyed]

i thought the 05's were still at 275hp and the 06's started the 290hp range?
OK, Thanks. Not a DIY project!

[jag42420]

LL8 (excerpt from http://en.wikipedia.org/wiki/GM_Atlas_engine#LL8 )

Vortec 4200 LL8 engine in a 2006 Chevrolet Traiblazer.The LL8 (or Vortec 4200), is a straight-6 truck engine. It was the first Atlas engine, and was designed for GM's new SUV line. It displaces 4.2 L (4195 cc), with a 93 mm bore and 102 mm stroke. When introduced, this engine's power was 270 hp (205 kW) @ 6000 RPM and torque was 275 ft·lbf (373 N·m) @ 3600 RPM. 2003 saw a slight bump in power to 275 hp, while torque was unchanged. For 2006, power was increased to 291 hp (217 kW) @ 6000 RPM and torque to 277 ft·lbf (376 N·m) @ 4800 RPM with the addition of a MAF and a complete internal redesign of the engine. The Atlas LL8 was on the Ward's 10 Best Engines list for 2002 through 2005. Engine redline is 6300 RPM.

You'd pretty well have to do a complete swap, as the internals were completely redesigned in 2006 to get the extra HP. Having your heads milled and the valves replaced with larger, better flowing valves would net you about the same power level.

[ScarabEpic22]

Its not worth it to try and get the extra hp/tq that GM got from it, they redesigned a lot of internals. You are better off trading it in for a newer TB, or doing a CAI+exhaust+tune.

[Gary UT]

The internal changes were increased compression to 10.3 with new pistons, larger valves and higher lift cams. The oil squirters were done to solve the piston slap.

I wonder if the cams from an 06 will work in an 04? If they will than you should be able to change the valves and cams and get some increase.