X5 diesel vs gas at altitude in Colorado

[Aaron in Denver]

I've been lurking on the site for months now- planning to order an X5 this summer to replace a very reliable and roomy, but very boring to drive, Honda Pilot. Great info all over the site that makes choosing a configuration both easier and more difficult!

I recently drove the 35i and the 35d on consecutive days- never thought I would say it, but I found the diesel very fun to drive with all that low end torque. Seriously considering it over the gas engine.

Does anyone have thoughts on gas vs diesel in mountain driving at high altitude? My understanding is that diesels maintain power better at altitude because they run so lean anyway, though I think turbocharged gas engines are also more powerful at altitude than a normally aspirated engine because the turbo pressure can overcome the thinner air to a point.

We are in Denver, and regularly spend time in the mountains- and I hate being in the vehicle that is always downshifting and struggling on the climb to Summit County, etc. Any thoughts from Colorado owners or others in mountainous areas appreciated. Thanks!

Aaron in Denver

[CatFlap]

Turbo Diesel any day! Combined with the 8 speed auto gearbox it's superb. (And economical too)

As the cars altitude increases the reducing air pressure is effectively compensated for by the turbocharger which compresses the air before it enters the engine. The turbos compressor will be sized to provide maximum boost (and thus engine power) up to a very high altitude (up to a limit of course)

[B///MW]

I am really enjoying my new diesel X5, living at 7,200 feet.

[Hockey Guy]

We love ours. In Calgary at 3.400 feet. Had it higher up in the Rockies too. Ran great!

[Bigtop]

Turbo charging makes a huge difference at altitude. I live at 9,600ft and had an E70 4.8i, then a 50i turbo after that, the difference in available power between the two is tremendous. Now have the F15 50i and that is even better.

I have friends in Summit County who have diesel cars and they run well 99% of the time. However, if you leave the car outside overnight and it drops below -20F, it simply will not start, I don't care what make, what mix of diesel you have, at this altitude and that temperature it doesn't work. We do not get that many days below -20F anymore and you may be leaving your car in a garage so this is not an issue.

[Aaron in Denver]

Thanks all for the replies- basically confirms my thoughts. I was a little concerned about starting in sub-zero weather, but that is pretty rare here, and i can plan to have it indoors on those nights.

The only thing negative i noticed about the diesel is the "out of breath" feeling at has when passing at highway speeds, but the huge low end torque will be great in the mountains, and it is just a ball to drive.

Thanks again!

[Hockey Guy]

We started our 35d this past winter after being outside overnight at -30C = -22F. Might have even been a little colder. No issues.