01-18-2012, 08:12 AM | #1 |
Lieutenant
110
Rep 590
Posts |
Turbo performance at altitude
Never having owned a turbo before, but will be shortly, how does driving in the mountains affect the overall performance of the 35i engine? I'm not so much concerned around northern NE but more so in the western mountains going from elevations of, say, 4000ft up to 8000-9000 feet? Either at highway speeds or slow crawls up winding canyon roads.
|
01-18-2012, 08:37 AM | #3 |
Lieutenant
63
Rep 580
Posts
Drives: G20 M340i
Join Date: Jan 2009
Location: Orlando
|
Check wikipedia tomorrow.
Although the air is thinner and easier to compress, the turbo will likely lose some power, but not nearly as much as a NA engine would. This is why you see lots of turbo engines for events such as pikes peak hill climb.
__________________
|
Appreciate
0
|
01-18-2012, 02:13 PM | #4 |
Captain
72
Rep 876
Posts |
IMHO if you live anywhere above 5000' a turbo car is the only way to go. I've driven over Eisenhower Pass (11,150') on numerous occasions and the difference between a N/A car and a turbo is night and day. I've been in 300+ hp n/a cars that required multiple downshifts to maintain speed. While I've gone over the pass in ~200 hp turbo motors that purred right up the mountain all while keeping the RPMs decently low.
I haven't driven the X3 over the pass yet but we did take it up the Mt. Washington auto road in NH and it was never at a lack of power. It pulled nicely at low rpms (this ZF 8 spd in normal mode HATES to downshift). |
Appreciate
0
|
01-18-2012, 03:00 PM | #5 | |
Lieutenant
110
Rep 590
Posts |
Quote:
|
|
Appreciate
0
|
01-18-2012, 03:26 PM | #6 |
Captain
72
Rep 876
Posts |
Yeah I think you'll be fine, you'll have more than enough power. The auto road did have some really steep places and while going up we mostly bounced between 2nd and 3rd gear always cruising around 10 mph.
With the tranny in sport mode it does a really good job of holding gears and it is still easy to manually drop down another gear and keep it there as needed. Also, unlike other manu-matics, when you manually select 3rd gear, for example, you can floor it and it will never up shift or down shift, it stays locked in that gear which is really nice and comparable to a normal manual. |
Appreciate
0
|
01-18-2012, 04:53 PM | #7 |
New Member
1
Rep 13
Posts |
I'm guessing there would be some minimal loss. I've heard for NA it's about a 3% loss for every 1000 feet in elevation and for a turbo it's more like 1% for every 1000 ft. Maybe someone else can confirm what the actual loss would be on the N55. I'm in Colorado Springs around 6000ft so I've been wondering this myself.
|
Appreciate
0
|
01-18-2012, 06:41 PM | #8 | |
Private
0
Rep 55
Posts |
Quote:
level where I live. I know my evaluation is subjective but the way the car blew through the Rockies passing everything effortlessly enforces my belief that nearly full power was available. |
|
Appreciate
0
|
01-19-2012, 12:33 AM | #9 |
Captain
135
Rep 753
Posts
Drives: 2020 X5 M50i
Join Date: Jun 2011
Location: Berthoud, CO
|
I have made several trips over the mountain passes, aforementioned Eisenhower as well as Vail and Monarch passes and enjoyed every minute of the drive. The X3 35i easily passed when ever I wanted to and in fact will run as fast as you feel safe driving. (Within the speed limits of coarse)
Lotus7, thank you for the technical explanation. I like ColoradoX3 have been curious about the technical affect of altitude on the N55 turbo engine. That said, my seat of the pants experience tells me there is little if any impact by the altitude on this engine. |
Appreciate
0
|
Post Reply |
Bookmarks |
|
|