Horsepower Lies and Damn Lies
03-09-2010, 02:29 PM
#41
Members
Thread Starter
Join Date: Nov 2009
Location: SF Bay Area
Posts: 209
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2005 545i Sport 6 speed Manual
i just thought that a 50hp drivetrain loss was a little bit too much and tried to start a discussion about basic physics and thermodynamics, and how all that relates to dynos, hp measured at the wheels and at the crank, etc.....and it started flame war... and now people are saying that this is like talking to a tree. oh well.
i guess i should be much more careful in the future and restrict my posts to topics about which wheels look the best and other profound subjects.
i should never have started this thread. sorry.
i guess i should be much more careful in the future and restrict my posts to topics about which wheels look the best and other profound subjects.
i should never have started this thread. sorry.
03-09-2010, 02:36 PM
#42
Contributors
Join Date: Jul 2009
Location: Harrisburg, PA area
Posts: 804
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: SOLD...Jet Black 2008 550i M Sport with SAT, black interior. RPI exhaust and air scoop, 35% huper optik tint all around, CF roundels, flat black kidneys, Springfield Armory XD-40 jet black in glove box, charcoal filter removed.
i just thought that a 50hp drivetrain loss was a little bit too much and tried to start a discussion about basic physics and thermodynamics, and how all that relates to dynos, hp measured at the wheels and at the crank, etc.....and it started flame war... and now people are saying that this is like talking to a tree. oh well.
i guess i should be much more careful in the future and restrict my posts to topics about which wheels look the best and other profound subjects.
i should never have started this thread. sorry.
i guess i should be much more careful in the future and restrict my posts to topics about which wheels look the best and other profound subjects.
i should never have started this thread. sorry.
Really, its entertainment to me. I liked the post, and was just trying to be funny in my own way. Keep posting brother, good topic and I actually learned alot from reading it - I would have never cared before this post.
03-09-2010, 03:03 PM
#43
Contributors
Join Date: Jun 2007
Location: Washington DC Suburb
Posts: 470
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: '07 550i with SP, Nav, Logic7
OK Einstein, here is what you said "the loss in the geartrain should be a constant with respect to speed of the moving elements". However,
HP at the crank - drivetrain loss (constant according to you) does NOT equal dyno number because:
Dyno numbers vary greatly depends on several factors
Get it?
I'm done with this thread.
HP at the crank - drivetrain loss (constant according to you) does NOT equal dyno number because:
Dyno numbers vary greatly depends on several factors
Get it?
I'm done with this thread.
03-09-2010, 03:35 PM
#44
Members
Thread Starter
Join Date: Nov 2009
Location: SF Bay Area
Posts: 209
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2005 545i Sport 6 speed Manual
OK Einstein, here is what you said "the loss in the geartrain should be a constant with respect to speed of the moving elements". However,
HP at the crank - drivetrain loss (constant according to you) does NOT equal dyno number because:
Dyno numbers vary greatly depends on several factors
Get it?
I'm done with this thread.
HP at the crank - drivetrain loss (constant according to you) does NOT equal dyno number because:
Dyno numbers vary greatly depends on several factors
Get it?
I'm done with this thread.
03-09-2010, 04:56 PM
#45
Senior Members
Join Date: Jun 2007
Location: Atlanta, GA
Posts: 1,845
Likes: 0
Received 1 Like
on
1 Post
My Ride: 2008 535i:
(8/07 Build) Metallic Bronze, Beige NASCA Leather, Ventilated Seats, Sport Pkg, Cold Wxr Pkg, Logic-7 Sound, HUD, Night Vision, PDC, Split Rear Seats, NAV, Premium Pkg, Comfort Access, HD Radio, Sport Auto Trans
Current mods: M-Aero Kit, JB4, Motorcepts 6000k HID Foglamps
Umnitza ICE-Lite 10w LED 6000k AE's
1992 Camaro RS:
Fully Restored w/Custom Interior, 5.0L V8, T-tops, OEM Z28 Foglamps, Inst Cluster, & Spoiler, Custom Sound, Too many engine mods to list
Where's craigm when you need him?
I'll close my eyes and chant: BANANA-PICKLE-CARROT-PEPPER-BANANA-PICKLE-CARROT-PEPPER-BANANA-PICKLE-CARROT-PEPPER
I'll close my eyes and chant: BANANA-PICKLE-CARROT-PEPPER-BANANA-PICKLE-CARROT-PEPPER-BANANA-PICKLE-CARROT-PEPPER
03-09-2010, 04:56 PM
#46
Contributors
Join Date: Oct 2004
Location: So Cal, USA
Posts: 14,776
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 545iSMGSilver GrayAuburn Dakota LeatherLogic 7 Premium SoundSports Package
50... eh... I'm losing 76HP! thats like a full motor found in the smart car... haha
more for you guys to read..
http://www.m5board.com/vbulletin/e60...o-results.html
more for you guys to read..
http://www.m5board.com/vbulletin/e60...o-results.html
03-09-2010, 05:06 PM
#48
Senior Members
Join Date: Mar 2007
Location: North Carolina, USA
Posts: 1,517
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2008 BMW 550i
2006 BMW X3
One other factor that no one has mentioned is the lack of airflow in a dyno run. Most BMW motors, especially the M5 and other top end ones are dependent on the airflow of a moving car to feed the air in the motor and cool the intake charge. Most dyno results show significant HP losses without airflow. Some dyno ops deploy a large fan and show higher results. Dinan did an extensive article on dyno testing here: Dinan Dyno Testing
03-09-2010, 05:19 PM
#49
Members
Thread Starter
Join Date: Nov 2009
Location: SF Bay Area
Posts: 209
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2005 545i Sport 6 speed Manual
yes very good point. it makes a huge difference on cars with turbos and intercoolers.
One other factor that no one has mentioned is the lack of airflow in a dyno run. Most BMW motors, especially the M5 and other top end ones are dependent on the airflow of a moving car to feed the air in the motor and cool the intake charge. Most dyno results show significant HP losses without airflow. Some dyno ops deploy a large fan and show higher results. Dinan did an extensive article on dyno testing here: Dinan Dyno Testing
03-09-2010, 05:59 PM
#50
Members
Join Date: Oct 2007
Location: Roselle IL
Posts: 225
Likes: 0
Received 3 Likes
on
3 Posts
My Ride: 2008 BMW 550i M Sport
OMG You are so stobern. What did You wanted to do by starting this thread advice or statement? Seems like You are dissagree with every member here. It does not matter with turbo or not. Try to let's say from Illinois to Colorado. Car in higher altitude has less power and the loss is significant. Not mention temperature or humidity. Peace