So I bought a 2013 SRX a few months back, and love it. I was coming out of a 2004 Dodge Durango with a 5.7L Hemi (@335hp), so I certainly was used to some getty up and go when I put my foot in it. Of course I don't hold the SRX to quite that standard, but just to show that underpowered was not going to be something that would interest me in a new vehicle. That the 3.6L V6 in the SRX hits max torque at around 2400 rpm is certainly noticeable and pleasant.

Then the CUE in my SRX died, and the dealer needed to keep it for a few days, and kindly gave me a 2014 XTS Luxury as a loaner. Very pleasant and comfortable car, and the controls and features are very familiar to my SRX experience, so no major learning curve. Even has the same engine. No complaints here for a short-term loaner, even if it is a FWD instead of the AWD of my SRX.

But, wow, noticeably different power response. At first I was wondering if somehow it was in my head and I wasn't feeling what I thought I was feeling in the seat of my pants. But, no, wiki says in the XTS that engine doesn't hit torque max until 5200 RPM instead of 2400RPM in the SRX. In fact, according to wiki it is only in the SRX incarnation that torque maxes that low --every other vehicle GM uses it in, maxes at 4800-5200 RPM.

What's up with that? How is that accomplished. . . and why would you not want to do it in all applications where you use that engine?