Originally Posted by Pex5
I think you may be confused by my post. The scary body roll I mentioned was in regard to the V6 Porsche Cayenne I drove. The X6 is tight as a drum
As for the engine, I'm surprised and impressed. Our car has a little bump to 315hp and 330 ft. lbs. of torque but that's not huge. The throttle tip in on this 6 is amazing - which in lay terms means you can take off from a standstill with a neck snap or like grandma or anything in between. The turbo lag is barely noticeable unlike the 5.0 (not bashing the 4.4 V8, it just doesn't use twin scroll technology like the 3.5 and M version V8 do). Raw straight line power is more than adequate. With the 8 speed, its genuinely fast on the highway. It will scoot quickly from 75 to a 100.
The most amazing surprise with our X6 is that its like a 7 series SUV compared to our prior V8 X5. There are no low frequencies that you get with the V8 (which of course has its drawbacks as well - i.e. exhaust sound) But the upside is that with the 8 speed transmission, you can cruise at 90 and feel like your hardly moving. That combined with a very smooth ride and maybe also our white interior lends a real feeling of luxury to the whole experience. Lastly, the turbo allows for enough thrust to waft the car along like a Rolls literally without breaking 1500 rpms around town (should you be in slow/cruise mode). This is something our X5 couldn't do. Even though it was a V8, the transmission and ECU were set up so that even just putting around town you'd hit 2500 rpms before a shift. So the X6 feels more regal and gets better mileage so far at least 4 mpg better in town - should improve a touch with break in. It's a great car. You will be very happy.
Couple of points/counter points here...
1. I don't see/feel lag in the V8. It makes its full torque of 450 at 1750 rpm (vs. 1300/1500 for the 35/M). What I do notice is that it will snap your neck OR crawl like a grandma, but nothing in-between. Some posts have suggested there might be a software update for this. I think that it may be due to the 8 speed trans (normally starting in 2nd gear I think, but upon heavy throttle, it will drop to 1st). I did not notice this in the X5M that I drove (or the 35i) , so I suspect the 6 speed trans might have been better suited to the V8.
2. On the V8, the exhaust (both sides) are controlled via a vacuum mounted device on one of the pipes leaving both mufflers (there are two pipes that leave each muffler to the exhaust). That is open upon cold start-up (very yummy sound) but then closed shortly thereafter. They stay closed unless you get on it. So there are no low frequency sounds most of the time. Pex, I wonder if that was a change made with the turbos? Some have said that if they force the 2nd exhaust pipe open, there is a noticeable loss in low end torque (but great sound). So it might make sense that the old 4.8 V8 did not have it.