faster than a gt500 ?
08-09-2009, 10:12 AM
#72
6th Gear Member
Join Date: Nov 2007
Location: Montaner
Posts: 6,193
If any of you think a 4000' DA isn't gonna add an easy .5-.6 seconds to an ET in a NA car you're off yer rockers.
08-09-2009, 10:26 AM
#73
4th Gear Member
Join Date: Dec 2007
Location: TEXAS
Posts: 1,491
Dude, you're picking up a good 3 tenths with the MT tires... I guess tires could be considered 'bolt-ons' but if you don't have those, I doubt you're breaking 13s.
08-09-2009, 01:57 PM
#74
4th Gear Member
Join Date: Mar 2008
Location: Corona, CA
Posts: 1,579
08-09-2009, 02:57 PM
#76
low 12s, every bolt on you can find and maybe cams, and some weight savings. but none of that will get you anywhere unless you have the "driver mod" If you dont have that no matter what you wont get down then. It takes alot
08-09-2009, 03:35 PM
#77
5th Gear Member
Join Date: Jul 2006
Location:
Posts: 3,834
I guess you guys never took physics? (or did well in it?)
here we go: http://www.nhra.net/tech_specs/altitude.html
there is scientific data that supports air density and it's affects on engines.. it is damn close.. now, each car is different.. compresion, F/I will play a role in it.. but at 0ft elevation the air density is 14.7psi at 6000ft elevation its 11.78psi.. this isn't that difficult of a concept to grasp and the correction is darn accurate until you get into F/I then it gets a bit trickier but still can be accurate... here is a quote from someone who knows more than any of you seem to about the subject.
The true correction for FI depends on how much boost you are making. The 1/2 correction factor is accurate if you are making 14.7psi of boost, below that and you should get more correction and above you get less.
I'll use a NA car, one making 14.7psi boost and my Buick as an example making 21psi of boost.
Say that we have a day with a DA of 6000' (pretty common on a summer day in Acton). That equates to 11.78psi of air pressure. Percent loss is going to be absolute pressure up here divided by absolute pressure at sealevel
14.7psi / 14.7psi = 1 (sealevel has no power loss so no correction)
11.78psi / 14.7psi = 80.1% NA (19.9% less power for the NA car))
(11.78psi + 14.7psi) / (14.7psi + 14.7psi) = 90.07% (9.93% less power or 50% correction for 14.7psi boost)
(11.78psi + 21psi) / (14.7psi + 21psi) = 91.82% (8.18% less power or 41% correction for 21psi)
What about a 40psi dsm...
(11.78psi + 40psi) / (14.7psi + 40psi) = 94.66% (5.34% less power or 27% correction for 40psi)
How about a low boost supercharger, my GTO had 5.5psi
(11.78psi + 5.5psi) / (14.7psi + 5.5psi) = 85.55% (14.45% less power or 73% correction for 5.5psi)
the nearest sealevel track is over 1200 miles away.. yaaahh ill just go do that right away... why don't some of you guys with a little more cushion in your budget test your theory out since you are bringing no evidence to the table to contridect the correction for elevation and weather and are denying what experts are claiming.
Your car runs what it runs when you compare it to a car at the same track on the same day...if i talk to people here at my track i just say 13.5@102.. and they know thats a damn good time up here.. with people on the internet that time would suck.. and that was run at 4200ft DA.. and NHRA corrected to 12.9@107 for elevation only, not for weather.. with weather its 12.8@108.. not a great time with my mods but okay time.. i just got drag radials and as soon as the weather is clear hoping for some low 13s...
There is always errors in mathematics madcat? perhaps if you failed basic algebra... based on your sig id guess you are more of a literature guy and not much of a math/physics feller
here we go: http://www.nhra.net/tech_specs/altitude.html
there is scientific data that supports air density and it's affects on engines.. it is damn close.. now, each car is different.. compresion, F/I will play a role in it.. but at 0ft elevation the air density is 14.7psi at 6000ft elevation its 11.78psi.. this isn't that difficult of a concept to grasp and the correction is darn accurate until you get into F/I then it gets a bit trickier but still can be accurate... here is a quote from someone who knows more than any of you seem to about the subject.
The true correction for FI depends on how much boost you are making. The 1/2 correction factor is accurate if you are making 14.7psi of boost, below that and you should get more correction and above you get less.
I'll use a NA car, one making 14.7psi boost and my Buick as an example making 21psi of boost.
Say that we have a day with a DA of 6000' (pretty common on a summer day in Acton). That equates to 11.78psi of air pressure. Percent loss is going to be absolute pressure up here divided by absolute pressure at sealevel
14.7psi / 14.7psi = 1 (sealevel has no power loss so no correction)
11.78psi / 14.7psi = 80.1% NA (19.9% less power for the NA car))
(11.78psi + 14.7psi) / (14.7psi + 14.7psi) = 90.07% (9.93% less power or 50% correction for 14.7psi boost)
(11.78psi + 21psi) / (14.7psi + 21psi) = 91.82% (8.18% less power or 41% correction for 21psi)
What about a 40psi dsm...
(11.78psi + 40psi) / (14.7psi + 40psi) = 94.66% (5.34% less power or 27% correction for 40psi)
How about a low boost supercharger, my GTO had 5.5psi
(11.78psi + 5.5psi) / (14.7psi + 5.5psi) = 85.55% (14.45% less power or 73% correction for 5.5psi)
the nearest sealevel track is over 1200 miles away.. yaaahh ill just go do that right away... why don't some of you guys with a little more cushion in your budget test your theory out since you are bringing no evidence to the table to contridect the correction for elevation and weather and are denying what experts are claiming.
Your car runs what it runs when you compare it to a car at the same track on the same day...if i talk to people here at my track i just say 13.5@102.. and they know thats a damn good time up here.. with people on the internet that time would suck.. and that was run at 4200ft DA.. and NHRA corrected to 12.9@107 for elevation only, not for weather.. with weather its 12.8@108.. not a great time with my mods but okay time.. i just got drag radials and as soon as the weather is clear hoping for some low 13s...
There is always errors in mathematics madcat? perhaps if you failed basic algebra... based on your sig id guess you are more of a literature guy and not much of a math/physics feller
08-09-2009, 03:43 PM
#79
Mish-ogynist
Join Date: Nov 2007
Location: Helena, MT
Posts: 3,780
ofcourse there are other factors.. the weather and the track prep... you get guys from across the country that race at our track here and they are running 1/2 a second slower.. and DA correction is pretty accurate.. when you run at 2000ft da, adjust it, then you run again at 0da and its the same as the adjusted time then its pretty accurate..(assuming you are actually good and run consistently, my times typically dont change more than .1 even on street tires) i don't understand what point you are trying to make with your arguement?
Last edited by Mishri; 08-09-2009 at 03:47 PM.
08-09-2009, 03:48 PM
#80
6th Gear Member
Join Date: Nov 2007
Location: Montaner
Posts: 6,193
Let's not dance around this any longer. Yes you guys are doubting the NHRA's calculations. If Mishri's car runs a 13.5 and the DA is 4200' then the NHRA says it will run a 12.9 at sea level. There may be a small bit of room for variance but it's not gonna be much. So yes, the NHRA says the car will do 12.9 down in your neck of the woods.
I know what you skeptics are getting at here. Until Mishri takes his car down to sea level and runs it then you don't believe the NHRA's calculations. It remains unproven to you and yer not gonna budge on that.
So how about you drive up here and run your car? You're the ones who are doubting the NHRA in the first place. The onus is on you guys to prove otherwise IMO.
I said it before I'll say it again. If you don't think a 4200' DA is going to add up another 1/2 second or more in an NA car then you're just being stubborn about this.
I know what you skeptics are getting at here. Until Mishri takes his car down to sea level and runs it then you don't believe the NHRA's calculations. It remains unproven to you and yer not gonna budge on that.
So how about you drive up here and run your car? You're the ones who are doubting the NHRA in the first place. The onus is on you guys to prove otherwise IMO.
I said it before I'll say it again. If you don't think a 4200' DA is going to add up another 1/2 second or more in an NA car then you're just being stubborn about this.
Last edited by Riptide; 08-09-2009 at 03:52 PM.