[W126 Coupe] 0-60 times?

[Vance Rowley]

Hi Steve,

 You are absolutely correct. Good info.

Cheers,
Vance.
  ----- Original Message ----- 
  From: Steve Lemberg 
  To: Mercedes Coupes Mailing Lists 
  Sent: Tuesday, March 21, 2006 1:09 AM
  Subject: Re: [W126 Coupe] 0-60 times?


  Vance,

  The altitude compensation is for the MIXTURE only; all air breathing engines suffer from loss of pressure at altitude and the effects of density altitude.     A forced induction engine may be able to normalize the charge or it may not depending on many factors.     

  At roughly 10000 feet MSL or 3000 meters the air is half as dense as it is at sea level.    All air breathing engines start to show the effects of altitude at as little as 1500 feet or 500 meters in standard conditions sooner when it is warmer.     Standard conditions for sea level are 60 F or 15 C and the temperature lapse rate is 3.5 F or 2 C drop for every 1000 feet of elevation.    

  All air breathing engines only produce rated power at SEA LEVEL in standard conditions.     Every other situation reduces power output to some degree.     High humidity also adversely affects engine performance; the water vapor in the air displaces oxygen that would be present in dry air.    

  Cold dry air is best for air density, while hot dry air produces the least drag.    In a car the drag issue is minimal at low speeds so the cold air is preferred.    

  There are correction factors to normalize for the above and most dynos factor these into the data they provide.    The G-tech is not able to solve the problem only raw data.    The numbers could easily be .4- .5 seconds slower then sea level.

  Steve
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