Good points...

 

I bet a 3.7 liter...making 315 hp....still the same vq just slightly bigger bore and stroke..

 

Go buy an American car for that. I would rather have a much better balanced and well rounded car than arbitrary 1/4 mi. times -- especially since its primary role is as a luxury coupe.

As for the 4L v. 3.5L, from a marketing persepective the 4L would be easier to sell ("G40" is more obvious that it is "better" than the IS350 or 330i). The American public at large also seems to favor torque over RPM. So, it might actually make sense for Nissan (purely from a marketing persepective) to sell a higher output 3.5 everywhere else (to those that appreciate quality engineering) and a 4L in the U.S.

Now, developing two engines is unlikely, so they are left with the "which would sell more?" question. I will leave that up people much better qualified than me to deliberate over. But the 3.7L is a great compromise, da45king.

 

R34

 

You're kidding right? More torque? I-6 in NA form aren't the torquest engines around. Even the M3 with a staggering 11-x-x compression ratio only puts out 260 ft/lb. Inline sixes aren't known for their power, but they are very smooth and quiet. You have to have extremely high compression ratios to get decent power. That's why most powerful I-6 are blown. IS300 with 215 hp and the E46 330i with 225 hp are just two examples. With enough R&D you can make a very smooth v6, just look at Lexus and Mercedes. So I would agree about the balanced part, but the longer life I won't buy. I think a 3.8 L VQ with a 7k rpm and 325 hp is very doable.

 

I don't know the figures, but my dad used to have a 95 F150 with a 4.9L I6. That was a torque monster. He bought it purely for towing.

 

What about the new bmw I6 255hp, and I have read the the IS300 responded very well to boost. I will concede I don't know much about Japanese engines. I am learning on the fly. The G35 is the best car I have owned. It is also the 1st non American. I lie, I had a 350z for a few months before I bought the G, but they are basically the same car. Maybe it is just american engines, but an I6 has better torgue than a V8. It may just be a better torque curve. With an I6 the most of the torque is available a very low RPM's. And for engine life an American I6 will outlast an American V8. My brother had a Jeep for over 300k and he was in Moab all summer. It was still running strong when his wife totaled it.