|
12-12-2019, 04:23 PM | #1 |
Senior Member
Join Date: Jul 2009
Posts: 928
Likes: 1
Liked 120 Times in 42 Posts
|
How Much Does Density Altitude Affect ET
I know very little about Density Altitude and was searching for information.
|
12-12-2019, 05:21 PM | #2 |
Junior Member
Join Date: Feb 2009
Location: Renton Washington
Posts: 35
Likes: 27
Liked 4 Times in 2 Posts
|
Re: How Much Does Density Altitude Affect ET
|
12-12-2019, 05:45 PM | #3 |
Senior Member
Join Date: Nov 2007
Location: Div. 6, Eastern, WA
Posts: 694
Likes: 2,260
Liked 219 Times in 105 Posts
|
Re: How Much Does Density Altitude Affect ET
My understanding that 1 and 2 barrels swing wider than 4 barrels and low compression wider than high compression and a stock converter (sportsman bracket) wider than a high flash converter, etc, etc, etc, etc . The really good cars may change very little with the weather.
__________________
Dave Noll, E/FS ,L/SA 6526 Last edited by Dave Noll; 12-12-2019 at 05:47 PM. |
Liked |
12-12-2019, 06:19 PM | #4 |
VIP Member
Join Date: Dec 2008
Location: Richmond Hill GA (and Port Ludlow WA)
Posts: 4,122
Likes: 1,978
Liked 2,707 Times in 853 Posts
|
Re: How Much Does Density Altitude Affect ET
While I’ve always referenced Biondo’s tips as a guide I would just point out that meticulously keeping notes on all your runs is invaluable to setting up a reliable correlation curve between DA and ET since the host of other variables (i.e. wind) can play such a huge role. I’m just now trying to explore some of the analytics of this and discover that my last year’s record keeping was painfully inadequate. You can probably guess one of my New Year’s resolutions.
__________________
Jim Carter 2340 Super Stock 2340 SST/2340 Stock |
Liked |
12-12-2019, 08:24 PM | #5 |
Member
Join Date: Oct 2017
Location: Bay City Texas
Posts: 358
Likes: 1
Liked 202 Times in 123 Posts
|
Re: How Much Does Density Altitude Affect ET
Percent of oxygen changes can have a big impact and since very few measure this the basic numbers can remain the same but the percentage of oxygen can change and have a large impact!
|
12-12-2019, 08:32 PM | #6 |
VIP Member
Join Date: Feb 2006
Location: Dela-where?
Posts: 2,116
Likes: 1,004
Liked 1,649 Times in 521 Posts
|
Re: How Much Does Density Altitude Affect ET
On my two cars basically 200 feet of altitude change equals one hundred .01 I run them a little fat so that it will be this way
__________________
KEITH MAYERS 2 X somebody many X nobody |
Liked |
12-12-2019, 10:17 PM | #7 |
VIP Member
Join Date: Dec 2001
Location: phoenix
Posts: 1,410
Likes: 53
Liked 655 Times in 255 Posts
|
Re: How Much Does Density Altitude Affect ET
That's pretty good. Im 145ft of change and. 1 ET difference. I run mine just right in the heat then when air gets good car goes lean. That gets me the 145ft average
Last edited by Jeff Stout; 12-12-2019 at 10:18 PM. Reason: More |
12-13-2019, 12:29 AM | #8 |
Member
Join Date: Aug 2016
Posts: 173
Likes: 113
Liked 62 Times in 29 Posts
|
Re: How Much Does Density Altitude Affect ET
|
Liked |
12-13-2019, 10:19 AM | #9 |
Member
Join Date: Jan 2002
Location: West Monroe, La.
Posts: 301
Likes: 9
Liked 13 Times in 7 Posts
|
Re: How Much Does Density Altitude Affect ET
My experience has been that if you run around the ideal air/fuel ratio you will see 150 ft equals .01. Or you can run lean and move higher into the 200ft area. It gets hairy as you get leaner and can do engine damage. The only time that I've seen the 300ft range is with ethanol in our bracket car. A normal ethanol car will equal the 300ft per .01 area. If you don't see these numbers or if your car isn't consistent , you probably have a problem that needs correcting.
__________________
Richard Grant 4988 STK |
12-13-2019, 11:21 AM | #10 |
Member
Join Date: Apr 2014
Location: Mesa, AZ
Posts: 491
Likes: 159
Liked 221 Times in 71 Posts
|
Re: How Much Does Density Altitude Affect ET
I've been strongly suspecting for a while that this is the case. When I stay near home I can get a pretty good idea from DA and wind but then I go to a different area, where they have those weird tall things (I think they call them trees) and suddenly I'm way off in my dial-in.
|
|
|