[dencobmw]

I'll be ordering a 28i next month...so excited! I live in Colorado and my only hesitation about ordering an X3 with the N20 engine is how it will perform on the highway over our high mountain passes. Vail pass is 10,662 ft (3250 m) and Trail Ridge Road, which I travel more often, is 12,183 ft (3713 m). What really stinks about going up in the mountains on I-70 is getting stuck behind a semi truck on a hill and losing all your momentum. Will the N20 be able to hold it's own up there? (I know no one has the N20 in an X3 yet). I've heard that turbos perform well at high altitude but I have no idea why.

Anyone here from Colorado (or another high altitude location) who can give me some insight on how small BMW engines do in the mountains?

Thanks.

[Jan van Zyl]

A normally aspirated engine theoretically loses 1% efficiency per 100m above sea level - for 3000m heights you will be looking at a theoretical 30% loss. Also depending on ambient temperature and other factors of course. Turbo engined vehicle may suffer 3% loss for every 10% loss of NA engine - I.e. 9% total theoretical loss @ 3000m. Your Toyota Tacoma probably not turbo charged - so you will experience something totally different with your new purchase .. you may lose momentum when stuck behind a semi - but should have more than enough oomph to pass safely.

[n55x3]

The N20 will do just fine. I ran a Subaru Legacy GT (turbo motor w/ ~250hp) up and down I70 multpile times with no issue. I could blow by trucks and slower vehicles every time i approached Eisenhower Tunnel. When altitude comes into play there really isn't anything that compares to forced induction. Plus you'll have an 8spd transmission that, when in sport mode, will hold lower gears for you so you keep your rpms up.

In contrast, I've also driven a Tahoe (NA V8 @ 285 HP) up that same stretch and it was a dog. I'm talking 2nd gear and still working hard to make it up the hill. I remember one time I went up both Monarch and Ptarmigan pass in the Tahoe and it was painful.

[tuco44]

I lived in the Denver area back in the 80s and can add my comment that the turbo engine will be fine for the high altitudes passes, far better than N/A'ed engine.

[lbjgh]

Agreed with aforementioned... the n20 28i will suit your needs much better than the previous normally aspirated 6 at that elevation.

[dencobmw]

Thanks everyone for the replies. It's true that I've never actually had any complaints about my 190HP non-turbo V6 manual Tacoma in the Colorado mountains. So I'm sure the BMW will be a whole 'nother animal. I just wanted to check cause it's kinda weird buying a 4 cylinder...a $50K 4 cylinder at that!