BMW X3 Forum
BMW X3 Forum
Welcome to the ultimate BMW X3 community.
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
Post Reply
 
Thread Tools Search this Thread
      01-18-2012, 08:12 AM   #1
cadman50
Lieutenant
United_States
103
Rep
590
Posts

Drives: 2012 X3 35i, 2021 X3 M40i
Join Date: Oct 2011
Location: Eastern Mass

iTrader: (0)

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.
Appreciate 0
      01-18-2012, 08:18 AM   #2
bren
user
bren's Avatar
4
Rep
229
Posts

Drives: German Camaro
Join Date: Nov 2011
Location: MD

iTrader: (0)

You will find the turbo to be advantageous over a naturally aspirated car at altitude.
Appreciate 0
      01-18-2012, 08:37 AM   #3
jsublime
Lieutenant
United_States
62
Rep
580
Posts

Drives: G20 M340i
Join Date: Jan 2009
Location: Orlando

iTrader: (1)

Garage List
2015 BMW X3 28i  [0.00]
2011 BMW 135i  [0.00]
2016 BMW M3  [0.00]
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
n55x3
Captain
72
Rep
876
Posts

Drives: n55 BMWs
Join Date: Dec 2011
Location: us - ohio

iTrader: (0)

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
cadman50
Lieutenant
United_States
103
Rep
590
Posts

Drives: 2012 X3 35i, 2021 X3 M40i
Join Date: Oct 2011
Location: Eastern Mass

iTrader: (0)

Quote:
Originally Posted by n55x3 View Post
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).
I think that Mt. Washington auto road in NH is pretty steep in some places as I've heard. I'll be driving some fairly steep canyon roads thruout the west at slow speeds and wondered if I would be losing power and have to constantly downshift or not. Seems like I have an answer now. Thanks alot.
Appreciate 0
      01-18-2012, 03:26 PM   #6
n55x3
Captain
72
Rep
876
Posts

Drives: n55 BMWs
Join Date: Dec 2011
Location: us - ohio

iTrader: (0)

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
ColoradoX3
New Member
1
Rep
13
Posts

Drives: X3
Join Date: May 2011
Location: Colorado

iTrader: (0)

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
Horsedoc67
Private
United_States
0
Rep
55
Posts

Drives: 2010 35i Z4 2011 X3 35i
Join Date: Mar 2010
Location: Ventura, CA

iTrader: (0)

Quote:
Originally Posted by n55x3 View Post
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).
Last fall I drove I-70 from Utah to Kansas over the aforementioned Eisenhower Pass with the outside air temp a warm 70-80 F making the Density Altitude considerably higher than 11,150 ft and I could discern no significant difference in the power and performance of the engine. It felt the same as it does @ sea
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
turbotoy4me
Captain
turbotoy4me's Avatar
United_States
131
Rep
752
Posts

Drives: 2020 X5 M50i
Join Date: Jun 2011
Location: Berthoud, CO

iTrader: (0)

Garage List
2015 Porsche Macan ...  [0.00]
2017 BMW i3  [0.00]
2020 BMW  [0.00]
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

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 06:39 AM.




xbimmers
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST