Another NOOB question =(

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Jan 25, 2008 | 01:22 PM
  #1  
I purchased my used 2005 G35 Coupe (Automatic) about a couple of months ago and I'm loving the vehicle. This purchased was made in the Sacramento, CA area and I reside in Reno, NV near Lake Tahoe. When I bought this car and whenever I'm in California, this car performs like a champ...very spirited. However, when I'm back in my hometown of Reno (located in the mountains), the car feels somewhat sluggish. I understand that when I'm in the Bay area or southern Cali, the altitude allows the car to breathe better...in turn it performs better. Is there anything I can do to get the car to breathe better in the upper elevations (4000 ft. elevation)?

Do I need to get something flashed or reprogrammed to make the computer think that its at a lower elevation? If so, can someone point me in the direction to get this done? I want my car to feel the same it does in lower elevations.

Thanks for all your help.
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Jan 25, 2008 | 02:41 PM
  #2  
boost it and you won't have that problem....lol

but really it's because the air is so much thinner that your engine has to suck in more. don't really think its something you can really fix.
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Jan 25, 2008 | 02:50 PM
  #3  
Up in the mountains the air molecules are spaced the same amount just there is less air pressure at sea level the air pressure is 14.7psi. While the computer should compensate for this it will not add the performance you will be looking for it will just make the engine run safer so nothing will happen to it. I am not sure what your setup is but if you have a stock intake run a cold air intake. A cold air intake will keep the heat from your engine away from the air, and in doing so it will make the air molecules closer together so you can pair up more parts of fuel to parts of air. That is just something you can do. PM me if you want and we can go over it a little more.
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Jan 25, 2008 | 03:25 PM
  #4  
Quote: Up in the mountains the air molecules are spaced the same amount just there is less air pressure at sea level the air pressure is 14.7psi.
That's not correct... taking the composition of air to be constant as you increase altitude (not entirely precise, as the ratio of O2 molecules to Oradical species decreases, but close enough for our purposes), the mole fraction of oxygen is equal as you increase altitude. Therefore as atmospheric pressure decreases from 14.7 psi, the partial pressure of oxygen also decreases.

Looking at the ideal gas law, PV=nRT --> V= nRT / P, the equivalent volume of oxygen must increase as its partial pressure decreases as n, R and T are constant. Therefore the O2 molecules are actually spaced further apart!

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Jan 25, 2008 | 03:35 PM
  #5  
this helps explain things abit

http://www.2-stroke-porting.com/altiden.htm
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Jan 25, 2008 | 03:45 PM
  #6  
Quote: That's not correct... taking the composition of air to be constant as you increase altitude (not entirely precise, as the ratio of O2 molecules to Oradical species decreases, but close enough for our purposes), the mole fraction of oxygen is equal as you increase altitude. Therefore as atmospheric pressure decreases from 14.7 psi, the partial pressure of oxygen also decreases.

Looking at the ideal gas law, PV=nRT --> V= nRT / P, the equivalent volume of oxygen must increase as its partial pressure decreases as n, R and T are constant. Therefore the O2 molecules are actually spaced further apart!

Yea you are right sorry about that everyone!
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Jan 25, 2008 | 04:04 PM
  #7  
Quote: That's not correct... taking the composition of air to be constant as you increase altitude (not entirely precise, as the ratio of O2 molecules to Oradical species decreases, but close enough for our purposes), the mole fraction of oxygen is equal as you increase altitude. Therefore as atmospheric pressure decreases from 14.7 psi, the partial pressure of oxygen also decreases.

Looking at the ideal gas law, PV=nRT --> V= nRT / P, the equivalent volume of oxygen must increase as its partial pressure decreases as n, R and T are constant. Therefore the O2 molecules are actually spaced further apart!


Thanks everyone! So in reality there's nothing I can do to compensate for the altitude and how my car performs? LOL...I need to move to sea level.
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Jan 25, 2008 | 04:07 PM
  #8  
Quote: That's not correct... taking the composition of air to be constant as you increase altitude (not entirely precise, as the ratio of O2 molecules to Oradical species decreases, but close enough for our purposes), the mole fraction of oxygen is equal as you increase altitude. Therefore as atmospheric pressure decreases from 14.7 psi, the partial pressure of oxygen also decreases.

Looking at the ideal gas law, PV=nRT --> V= nRT / P, the equivalent volume of oxygen must increase as its partial pressure decreases as n, R and T are constant. Therefore the O2 molecules are actually spaced further apart!

Glad you jumped on that! I was reading 88G35's post and was like "No, no, no!"

See? We can learn about a lot more than just cars here on G35driver.com!
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Jan 25, 2008 | 04:10 PM
  #9  
Quote: Thanks everyone! So in reality there's nothing I can do to compensate for the altitude and how my car performs? LOL...I need to move to sea level.
Breathing mods may help a bit, simply because they will get a larger volume of air into the engine than you otherwise would. Even though that air has the same distribution of oxygen as it did before, there will simply be more air. Not even sure it would help much, but breathing mods are inexpensive, sound good, and add HP anyway!

Oh, and forced induction would certainly solve that "sluggish" feeling!

Or a 75 shot of Nitrous Oxide...
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Jan 25, 2008 | 04:56 PM
  #10  
Ok thanks guys I get it I wont post anymore about tech questions.
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Jan 25, 2008 | 05:06 PM
  #11  
Quote: That's not correct... taking the composition of air to be constant as you increase altitude (not entirely precise, as the ratio of O2 molecules to Oradical species decreases, but close enough for our purposes), the mole fraction of oxygen is equal as you increase altitude. Therefore as atmospheric pressure decreases from 14.7 psi, the partial pressure of oxygen also decreases.

Looking at the ideal gas law, PV=nRT --> V= nRT / P, the equivalent volume of oxygen must increase as its partial pressure decreases as n, R and T are constant. Therefore the O2 molecules are actually spaced further apart!


NERD ALERT! NERD ALERT!!


jk I'm a biology major
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Jan 26, 2008 | 03:48 AM
  #12  
danngg...feels like im in class..lol
all scientific..haha ><;;
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Jan 26, 2008 | 10:12 AM
  #13  
Quote: That's not correct... taking the composition of air to be constant as you increase altitude (not entirely precise, as the ratio of O2 molecules to Oradical species decreases, but close enough for our purposes), the mole fraction of oxygen is equal as you increase altitude. Therefore as atmospheric pressure decreases from 14.7 psi, the partial pressure of oxygen also decreases.

Looking at the ideal gas law, PV=nRT --> V= nRT / P, the equivalent volume of oxygen must increase as its partial pressure decreases as n, R and T are constant. Therefore the O2 molecules are actually spaced further apart!

UUMMM, What?
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Jan 26, 2008 | 12:26 PM
  #14  
I live at about 5,400 feet. At this elevation, there is only about 83-84% of the oxygen in air as there is at sea level. That does affect performance.
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