Mtech8,

I can't say that I really heard the GL's diesel in the cabin, although you do hear a faint clatter just as you are coming on the pedal lghtly, but only momentarily. During steady cruising, it is quite quiet. If you hold the pedal down until the transmission shifts, as the engine appraoches max rpm, you do feel a bit of vibration through the pedal/floor but it is gone right after the shift.

For someone who needs a larger SUV but doesn't want to pay the high fueling costs, I think diesel is a great option. Performance on the GL/ML series is not great, what with the initial lag, but I'm betting BMW's twin turbo setup gets rid of this problem.

From my perspective, if you need a true 7 passenger vehcile and you don't want to drive a van, the GL is the way to go. If 5 passenger capacity is all you need and you can get by with less storage space, the X5 wins in diesel format.

Just my opinion though. :)

I got another opportunity to attend another Ultimate Drive event yesterday. On this route, there was a nice 270 degree on ramp to the freeway.

Here is my new take:

HighSpeed Acceleration
Freeway driving was a great opportunity to test acceleration. The 4.8 is definitely faster than the diesel (no real surprise). I found it much easier to hit 80 mph+ in the 4.8 (both from clearing the on-ramp, about 40 mph to 80 mph+ and from slowing to 60 mph and re-accelerating to 80 mph+).

At approximate 80 mph the 4.8 engine felt like it still wanted to go faster. The diesel on the other hand felt like it was happy cruising speed about 110kmh (~70mph). It had no problem going on beyond that point, but it just felt like more work was required of the engine.

Corning and Stability
I confirmed that both the 4.8 and the diesel were running on 19's. And that the "sports" button was activated on both vehicles. They both took the 270 degree ramp with ease at about 40+ mph. Very secure with little to no body roll. I'm sure I could have gone faster, but I wanted to be 100% certain everything was safe. Furthermore, the shaking that I previously reported was non-existent. It must have been the weather as both vehicles were very solid at high speeds. Thus as expected, the 4.8 and the diesel were the same in this category.

Engine Sound
This time the sound of the diesel engine was not as noticeable! Perhaps in my first experience, I was expecting quiet and thus found the noise loud. This time, I was expecting quiet and found it to be "not so loud". I'm not sure if there were other factors that influenced this. Maybe the warmer temperature from the second event? At any rate, in the cabin at idle the sound was definitely less audible. I even questioned myself as to what I heard at the first event. When I turned on the A/C, the A/C's blower was louder than the engine. But that was my experience. :dunno:

Fuel Economy
I started off all runs with a light foot. The 4.8 would only give me 8 mpg while the diesel gave about 12. After the first mile or so (after a few traffic lights. This course really had it all for a great test drive), I drove more aggressively, the 4.8 would still yield around 8 while the diesel gave about 11. As more cruising was permitted, the mpg's would go up to about 11 mpg for the 4.8 and 15 mpg for the diesel.

Overall Take
Granted that the 4.8 is faster than the diesel. I believe most daily commuters will be more than happy with the performance of the diesel. At regular traffic speeds, it provides the feeling of strong acceleration, quieter overall drive experience (though slightly louder idle) and most importantly much better fuel economy (thus less guilt).

I would take the diesel over the 4.8 if both were available right now. But I can't wait a few months for the introduction of the diesel. My wife is sick of my car shopping and just wants me to get something NOW! (I initally ordered a X6 but backed out of it due to a few reasons) My ordered 4.8 should be here VERY soon. I ordered mine before PUZZ and he's already driving his :thumbup: For those that can wait, give the diesel a test drive. You'll be very happy with that car.

mtech8,

Thanks for your review. I'm between a GL320 diesel and an X5 diesel. If I don't need the extra space of the GL, the X5d is the way to go for me (provided it is no louder than the GL320).

My wife is sick of the car shopping as well. She could care less if I just keep my old car as long as just stop talking about it already! :)

Every time. A big heavy car like the X5 needs torque and that is what the diesel engine delivers. People to my mind get focused on the fact that diesel engines are more economical and lose sight of the fact that diesel engines have better power characteristics for 95% of drivers...what most people want and need due to how they drive their car is power at low revs. It just seems weird to me having had to great cars with this disel engine to have to rev the engine to say 5000 rpm plus to get the performance out of a car...it almost seems outdated to me.

I honestly think the only non M car in BMW's range that is standout better than the diesel engined cars available is the 135i. The new V8 in the X6 may be another.

Diesel Tech has no doubt come on leaps and bounds in the last few years, I test drove a Merc GL 420 (4.0 turbo diesel V8) .. its longer than a Q7 but I tell you it doesnt half shift :thumbup: must be around 7.5 seconds 0-60

Couldn't have said it better myself. Think your "95% of drivers" refers to my reference to "daily commuters". Yeah. Immediate power right away at low reevs to easily change lanes and drive with.

I've driven the Mercedes ML 320 diesel and didn't think it had much passing power on the highway. I would think with the twin turbo diesel on the X5, it will be much better. I'm waiting for the X5 and passed on the Mercedes...

The Mercedes is a single turbo diesel...

Craig

The 4.8 is more capable in highway passing. But the X5 diesel also has no trouble at all. In the diesel, I easily passed the surrounding traffic trying to catch up to the BMW 550 that was tearing up the road.

I also test drove the Diesel X5 at Newport BMW @ Drive for the Cure and found it very nice.

I thought the interior noise level was on par with the V8 petrol.

Compared to the earlier petrol X5 model that has a snappy sensitive accelerator start, this diesel has a smoother, lighter pull feel. Once above 40MPH, the car really performs - pulls ahead quickly and powerful feel to above 70 MPH.

I couldn't really tell by the European display and driver's side mirror that I was driving a non US model but the diesel wins my approval even with the fuel prices so high. I can always drive down to Mexico for half price diesel, but then will I be risking a contaminated fuel ???

Yeah. With the constant rise in fuel prices. Diesel seems more and more appealing everytime I drive by a gas station.

Yesterday gas petro was 4.69 vs diesel at 5.19
Based on the driving 15,000 miles per year and the epa estimates

City
4.8i (14mpg)= $5,025.00/year
x35d (19mpg) = $4097.37/ year
Savings of $927.63/year

Highway
4.8i (19mpg) = $3702.63/year
x35d (25mpg) = $3114.00/year
Savings of $758.13/year

The interesting thing is that a lot of people are posting that they don't get what the epa estimates for the 4.8i. And that often it's lower.

Really makes me want a diesel instead.