The 2.8 is boosted to only 250hp, and I don't know how much more boost it can take. If it could be goosed to maybe 270-280 it would be a great option since it's already been applied to an Epsilon (9-3 Aero). The 3.2 is dead if I remember. The others would also work. That's part of the problem. GM has about 6 or 7 engines that would work. I still wonder if the LS4 could be cheaper.

Regarding your comment about the V8 overwhelming the chassis, I'd argue that anything close to 300hp from a V6 puts quite a bit of stress on the suspension as well, and the G6 would probably need some beefed up components regardless of engine. As far as the GP is concerned, I've heard the GXP's handle extremely well, and the W-body is not nearly as rigid as the Epsilon, so one would think the G6 could be made to handle the power as well.

Finally, regarding fuel economy, the LS4 in the GXP has the exact same fuel economy rating as the 2.8 and the 3.6L in the CTS (18, 27), which might change if those engines recieved a boost in horsepower. You can argue that real world economy would be different, but then you'd have to contend with the LS# series typically great real world economy as attested by many people here.

 

I was talking about using a NA 2.8 as the base, the 3.2 is being used by holden and alfa last I heard.

Its not the HP that I am talking about, its the torque steer. The detriot paper has a GP gxp for a week and got 15-16 mpg and said that the car was very hard to control under heavy throttle. And the General being cheap, they probably wouldn't even offer a LSD in the G6 either.

I feel the 3.4, 3.5 and 3.9 are akin to the motors from south korea and GM should be on a higher level. Every one in class has ohc, it spells refinement. The LS motors are a different story. I mentioned that the HO 3.6 HF was direct injection, thats a sign of really good efficieny. It probably has a CR of 11-1 or higher.

Nissan made the jump to put its VQ in anything that they could fit in it. I think it was a great move. The frontier/exterra went from 170-210 hp to 265-270hp. They basically have two V-6's now, 3.5 and 4.0. Its so simple, even if its just the 2.8 and 3.6. The mass quanties involed would lower the price per motor. I know it still wont be as cheap as a 3.5 built in china but it would be a better product and less incentives are needed to sell one.

 

The 3.9 is all aluminum. There is no reason why Gm can't get 280-300hp out of that motor, they simpoly choose not to. I thnk thay should jsut drop the 3.4, 3.5 because anywhere they fit the 3.9 can fit. I would like to see a 300hp 3.9 in the G6 GTP and a 350HP 327 LS4 in the G6 GXP. Now that would be a CLASS LEADER.

 

There is one good reason. Money. I am sure the 3.9 would be capable of 280-300 hp, but not for cheap.