Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #16  
Old 07-19-2007, 11:41 PM
Registered User
 
Join Date: Dec 2006
Location: beautiful Bucks Co, PA
Posts: 961
Quote:
Originally Posted by Matt L View Post
You're trying to tell me that racers use logic for all of their decisions?

If they thought a dead chicken under the hood made them run a tenth of a second faster per lap, there would be chicken buckets under all of their hoods.
I made a living building, preparing and sometimes driving race cars for over 10 years. Logic always prevailed over dead chickens.

Reply With Quote
  #17  
Old 07-20-2007, 12:24 AM
Registered User
 
Join Date: Oct 2005
Posts: 4,263
Quote:
Originally Posted by Chas H View Post
I made a living building, preparing and sometimes driving race cars for over 10 years. Logic always prevailed over dead chickens.
Argon in the tires would almost certainly be better than nitrogen. The same gas laws apply, but the larger molecule will leak even less.

But racers don't use argon. That's an expensive gas. Nitrogen is dirt-cheap.
Reply With Quote
  #18  
Old 07-20-2007, 12:38 AM
Puck's Avatar
Registered User
 
Join Date: Jul 2007
Location: Brandon, Mississippi
Posts: 18
But racers don't use argon. That's an expensive gas. Nitrogen is dirt-cheap.[/quote]


Not in Mississippi it ain't!! And my wife has 4 tires to prove it!!LOL
Reply With Quote
  #19  
Old 07-20-2007, 12:45 AM
Registered User
 
Join Date: Dec 2006
Location: beautiful Bucks Co, PA
Posts: 961
Quote:
Originally Posted by Matt L View Post
Argon in the tires would almost certainly be better than nitrogen. The same gas laws apply, but the larger molecule will leak even less.

But racers don't use argon. That's an expensive gas. Nitrogen is dirt-cheap.
Leakage of this sort is not an issue in racing. If it was, argon would be used.
Reply With Quote
  #20  
Old 07-20-2007, 08:44 AM
Registered User
 
Join Date: Jul 2003
Location: Northern Virginia
Posts: 1,076
Reality

Night air is even better than nitrogen or argon. Makes you go faster.
__________________
2009 E320 Bluetec 117,000
1995 E300D 306,000 Sold
1996 Ford Taurus LX 130,000 Sold
1985 300TD Still 225,000 Sold
2016 Ford Fusion 24,900
Reply With Quote
  #21  
Old 07-20-2007, 10:08 AM
MB, love..hate..love..
 
Join Date: Apr 2003
Location: NB Canada
Posts: 1,173
What happens when the tire loses pressure and you're not near a nitrogen source, say on a trip? Can compressed air be mixed to inflate to pressure?
__________________
1986 560SL
2002 Toyota Camry
1993 Lexus
Reply With Quote
  #22  
Old 07-20-2007, 10:16 AM
waybomb's Avatar
Registered User
 
Join Date: Nov 2002
Location: St. Joe, MI; Manitowoc, WI
Posts: 1,553
Ya, for free too! Our atmosphere is somewhere around 78% N2.
__________________
Thank You!
Fred
2001 E430 Sport, 204,000 miles
1997 C280 Sport, 144,000 miles
1991 300SL, 189,000 miles
1987 420SEL, 149,000 miles
1986 190e 2.3 16v, 151,000
1968 W30 442, 78,000 miles
1988 46' US1 Cougar, 3 supercharged 572's
http://s4.photobucket.com/albums/y145/waybomb/
Warming the globe, 24 cylinders at a time
And I want a 126 wagon! Point me to one!
Reply With Quote
  #23  
Old 07-20-2007, 11:13 AM
865sp300e's Avatar
Talent Scout
 
Join Date: Feb 2005
Location: Yardley, PA
Posts: 318
Quote:
Originally Posted by Matt L View Post
You're trying to tell me that racers use logic for all of their decisions?

If they thought a dead chicken under the hood made them run a tenth of a second faster per lap, there would be chicken buckets under all of their hoods.
If they used helium would that make the car lighter?
Reply With Quote
  #24  
Old 07-20-2007, 11:20 AM
I told you so!
 
Join Date: Jun 2002
Location: Motor City, MI
Posts: 2,853
Quote:
Originally Posted by forp View Post
... The reason is the moisture content...
I guess I could take advantage of the sunny, dry, -10F days of January here and exchange all the air in my tires with a regular compressor and achieve the same thing (or better).

When the shops fill tires with nitrogen, how do they flush out the original air that's in there? On a humid summer day that can leave more moisture in the tire than using conventional air during the Michigan winters. For those that understand dew points, you'd know what I am talking about.
__________________
95 E320 Cabriolet, 159K
Reply With Quote
  #25  
Old 07-20-2007, 12:07 PM
Registered User
 
Join Date: Mar 2003
Location: Southern California
Posts: 2,241
Exactly! In fact I've done just that. On exceptionally dry days near the ocean in Southern California when the dew point drops to 10F or less. I've changed the air in my tires to ensure that it is as dry as possible so condensation will never be an issue.

Someone earlier made the following statement:

"Water vapor is not an "ideal gas" and-in the context of race tires- expands in an unpredictable manner."

You need to review a basic chemstry text. Like any other gas at normal temperatures and pressures, water vapor behaves to within one percent of Boyle's Law - same as nitrogen and oxygen. If you want more exacting approximations, review the Van der Waal equations for each gas.

The problem with high humidity in tire air is that if the tire temperature drops to below the dew point, water vapor condenses to liquid and the pressure drops. If the temperature is 80 and the dew point is 60 and the tire temperature drops below 60, like sitting out overnight, water vapor will condense and tire pressure drops.

Of course, when the tire heats up again, either from the heat of the day or operation, it will evaporate again.

Nitrogen - at the cost tire shops charge - is a ripoff, but astute automotive owners should take reasonable care to ensure that tire air is as dry as possible. Most shops have driers, but you never know. If you have your own compressor, install a decent drier on it, which will catch condensation that may form as the temperature drops going through the regulator. And fill your tank on dry days.

If you just use one of those little tire filling compressors that doesn't have a tank, check and add air as required when the dew point is low.

Claims that nitrogen's leak rate is less due to different molecule size is bunk, especially when you consider that air is 78 percent nitrogen. If a tire looses more than 1-2 psi per month is has a minor leak, but you may be chasing a ghost trying to find it unless the leak rate is higher.

And check tires when they are cold and not in the sun - preferably in the morning when temperatures are coolest and before the car is driven.

Duke
Reply With Quote
  #26  
Old 07-20-2007, 12:17 PM
Zeus's Avatar
Moderating, Eh?
 
Join Date: Feb 2000
Location: Canada
Posts: 1,774
Quote:
Originally Posted by forp View Post
Our local Costco uses nitrogen in all new tires. The reason is the moisture content. The moisture in the tires expands and contracts at a higher rate than dry air(atomospheric or from a bottle). If your compressor could remove all of the moisture, you'd get the same effect. The higher the moisture content, the more the tire pressure varies with temp. It is not snake oil but a good way to help maintain constant pressure with changes in temperature.
Dan

Yep. x2. And you also get those neat little green tire valve caps. Look at me, I'm riding on nitrogen!
__________________
Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired


"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon
Reply With Quote
  #27  
Old 07-20-2007, 12:35 PM
Registered User
 
Join Date: Dec 2006
Location: beautiful Bucks Co, PA
Posts: 961
Quote:
Originally Posted by Duke2.6 View Post
Someone earlier made the following statement:

"Water vapor is not an "ideal gas" and-in the context of race tires- expands in an unpredictable manner."

Duke
'Twas I that made that statement and I'll stand by it.
Ideal gases can mixed in any ratio to form an homogenous mixture. Water vapor cannot be mixed so.
Air generally loses some water vapor as condensate when it is compressed. How much is lost is an unknown at the race track, so we have no idea how much water vapor is present inside a tire filled with compressed air. Tires filled with air in the morning could and most likely do, have a different amount of trapped water vapor than tires filled in the afternoon. Tires with different amounts of water vapor will produce different pressures when heated to the same temperature.
Reply With Quote
  #28  
Old 07-20-2007, 01:46 PM
Racekar's Avatar
Registered User
 
Join Date: Jun 2007
Location: LI, NY
Posts: 123
You do notice it in a race car. My Mazda starts at 34 psi cold and it rises to about 40-42 depending on outside air and track temp with air. With nitrogen the tires don't increase as much in pressure. At 32 psi my car slides around and is a handfull untill the pressure comes up in a few laps. With nitrogen I can start at 36 and it still rises to 42, but starting at 36 makes for a more controled first few laps.

For a street car it makes no difference, even if you do track days you can do a few laps to warm up the tires before realy getting on it.

__________________

Karl B
95 E300 D
2006 Mazdaspeed 6
2001 GMC Yukon XL
1997 Contour SVT
Mazda RX-7 SCCA race car
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

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 On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 09:10 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2023, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page