Can someone explain altitude change to me?

KillaKev702

New Member
Mar 26, 2009
28
0
1
Las Vegas, NV
Ok so I went to "The Strip" tonight at LVMS, which is at 2,100 feet above sea level where I ran a best time of 15.0 at 95 mph :notnice:. I was talking to a guy in the pits and he said that it's the altitude change, thats why I was running slower than used to. Back in VA at Richmond Dragway, which is at 74 feet above sea level I ran a best of 14.2 at 100 mph :nice:.
So here is my question, is something wrong with my car or is it altitude? since my old best time I've added 3.90s, FRPP c springs, and an MGW. Also if it is altitude what causes this change?
 
  • Sponsors(?)


Nightfire

15 Year Member
Dec 1, 2002
3,268
148
133
TX
Obviously the more air an engine is able to suck into its chambers, the better it performs. The higher up you go in elevation, the air becomes less and less dense. In other words, the higher up you go, the air gets less and less (as simply as I can put it). With less air, you get less performance.

Have you ever heard about how mountain climbers need to wear oxygen masks? Its because the amount of oxygen decreases the higher up you go. Cars need oxygen too ;)
 

Stumbaugh

Member
May 13, 2010
903
13
19
Russellville, Ar
Obviously the more air an engine is able to suck into its chambers, the better it performs. The higher up you go in elevation, the air becomes less and less dense. In other words, the higher up you go, the air gets less and less (as simply as I can put it). With less air, you get less performance.

Have you ever heard about how mountain climbers need to wear oxygen masks? Its because the amount of oxygen decreases the higher up you go. Cars need oxygen too ;)
Very well said my friend. Just like he said, Higher up you go, the less air there is. Car's need air to perform good.
 

N8Dogg98

10 Year Member
Apr 4, 2005
3,871
242
184
38
MN
The atmospheric pressure drop is what causes the air to be less dense. So lets suppose your car made 300 HP at sea level. Average sea level pressure is 14.7 psi, now if you were to take your car to 10,000 feet above sea level the average pressure is approximately 10.1 psi. That means your car would make 300*(10.1/14.7) = 206 HP at 10,000 ft above sea level (assuming temperature and humidity were the same).

It's the same concept with forced induction. That same car at sea level with 10 PSI of boost would make 300*((10+14.7)/14.7) = 504 HP
 

KillaKev702

New Member
Mar 26, 2009
28
0
1
Las Vegas, NV
Have you ever heard about how mountain climbers need to wear oxygen masks? Its because the amount of oxygen decreases the higher up you go. Cars need oxygen too ;)
ok that makes sense but do my times make sense? should I be running that much slower from a 2000 ft elevation change? also I didnt mention before that my 60 ft times were pretty much the same as usual if that helps.
 

Dark04GT

10 Year Member
Apr 27, 2008
739
65
49
NC
ok that makes sense but do my times make sense? should I be running that much slower from a 2000 ft elevation change? also I didnt mention before that my 60 ft times were pretty much the same as usual if that helps.
Your times make sense. I would expect you to run high 14's at that altitude if you had a run just like your 14.2. At 2000 ft your are running at an atmospheric pressure of 13.6 psi versus the sea level 14.7 psi. You lost power over the entire range of RPM's because less air = less boom. Roughly you lost about 13-14 peak hp with that altitude.
 

KillaKev702

New Member
Mar 26, 2009
28
0
1
Las Vegas, NV
There are websites available that will calculate your da and "correct" your times.
I did check somne of them out and thanks to those I've stopped worrying about something being wrong with my car. According to this calculator ( DA Calculator - Density Altitude Calculator - DragTimes.com ) my car would be running 14.102 @ 102.019 MPH @ sea level.
I'm not liking this higher altitude, now I feel like I'm gonna be dumping a bunch more money in my car to get better ETs :shrug: oh well...
 

bhuff30

Founding Member
Dec 11, 2001
6,035
35
129
Olathe KS
Adjusting for DA is a funny thing. Yes, you lost power, but I would be surprised if you really ran as fast as that website claims you could. It says my 88 is a consistent high 11 second car at sea level, and it really isn't!

That assumes you have perfect traction and could perfectly plant the extra power if you had it. And even at sea level, it i rare for the temperatures to really be at standard conditions, of 59*F and 0% humidity.
 

ran260gt

New Member
Sep 7, 2005
365
0
0
DA is one of the reasons why if you get a new mod you should go to the track a few times to see if you got any HP or faster from that mod !

To many morons get a mod like a T/B or plenum or pulleys or what ever, then run one time at a track, run a slower time then before the new mod, and then go on a forum and bash the said mod for being a waste of money and makes your car slower, thats why when you get a new mod you have to run at the track a few times before posting an opinion !

DA is funny like that, you can run a 13.0 on friday and a 13.4 the next friday !
 

d98gt

Founding Member
Mar 14, 2002
4,505
59
204
SE Texas
Adjusting for DA is a funny thing.
And even at sea level, it i rare for the temperatures to really be at standard conditions, of 59*F and 0% humidity.
We get lucky to get negative da here in the winter at HRP:hail2: That is why running at the track during our summers here is pointless to some; the car can be half a second slower.
 

3ponyshow

Founding Member
Jun 26, 2002
319
1
18
62
Las Vegas
I did check somne of them out and thanks to those I've stopped worrying about something being wrong with my car. According to this calculator ( DA Calculator - Density Altitude Calculator - DragTimes.com ) my car would be running 14.102 @ 102.019 MPH @ sea level.
I'm not liking this higher altitude, now I feel like I'm gonna be dumping a bunch more money in my car to get better ETs :shrug: oh well...
I know what you mean about the frustration. Moving here from NY with it's almost sea level tracks and cooler air made a huge difference in performance. Not only do we have the disadvantage of altitude over most other tracks, but also the extreme heat which has just as much of a negative affect. Don't let it discourage you. Everyone you line up against is in the same position. When you see other's times from other places, just remember you're not comparing apples to apples. Performance mods here are still mods.
 

KillaKev702

New Member
Mar 26, 2009
28
0
1
Las Vegas, NV
I know what you mean about the frustration. Moving here from NY with it's almost sea level tracks and cooler air made a huge difference in performance. Not only do we have the disadvantage of altitude over most other tracks, but also the extreme heat which has just as much of a negative affect. Don't let it discourage you. Everyone you line up against is in the same position. When you see other's times from other places, just remember you're not comparing apples to apples. Performance mods here are still mods.
Oh I know what you mean by the heat, it was about 95 degrees when I ran. I never just never thought that it could be this much of a difference compared to VA. Also your right about the other cars, I was still beating Z28's and s/c cobalts so I'm happy considering I'm pretty much stock except for gears and exhaust.
 
Thread starter Similar threads Forum Replies Date
derek2079 Could someone explain how to make my windshield nozzles spray on my 67? 1965 - 1973 Classic Mustangs -General/Talk- 2
C Can Someone Explain In Layman Terms These Obdii Codes? SN95 V6 Mustang Tech 3
nicholasm617 someone just explain the importance of these basic mods? Fox 5.0 Mustang Tech 14
9 Fuel leak? Can someone explain an efi fuel tank to me? Fox 5.0 Mustang Tech 2
Stumbaugh PTVC question. Someone please try and explain SN95 4.6L Mustang Tech 2
9 can someone explain runner volume plz 1994 - 1995 Specific Tech 20
R Can someone explain/verify this for me? 2005 - 2009 Specific Tech 15
BK_CAULEY can someone explain the advantage of coil overs? 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 10
spirockp Can someone explain my 1/4 times to me in English? Classic Mustang Specific Tech 16
Mustang5L5 Can someone explain the hydroboost setup for me? SN95 4.6L Mustang Tech 0
Boostedpimp someone please explain the difference between "draw-thru" and "blow-thru" meters Fox 5.0 Mustang Tech 5
deftsound Someone please explain this to me SN95 4.6L Mustang Tech 14
Cruizer67 Can someone explain? Classic Mustang Specific Tech 6
1987Rock I know the main differences, but can someone explain..... 1996 - 2004 SN95 Mustang -General/Talk- 18
2Tone5.0 Can someone explain this? 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 7
N Can someone explain to me about an aftercooler? Fox 5.0 Mustang Tech 5
oz Can someone explain 'Drifting' to me? 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 25
hotstang_46 can someone explain 87-93 strut, not same old?'s SN95 4.6L Mustang Tech 9
kingc Someone please explain this to me 1996 - 2004 SN95 Mustang -General/Talk- 7
carbed87 Blowby, can someone explain... Fox 5.0 Mustang Tech 22
95Vert Can someone explain the whole higher octane gas is not better thing? 1994 - 1995 Specific Tech 19
P Can someone please explain how Ford/SVT just keeps ****ing up? 1996 - 2004 SN95 Mustang -General/Talk- 21
Foxfan88 firewall adjuster... can someone explain?? Fox 5.0 Mustang Tech 9
InMyPrimeSVT Can someone explain to me LCAs? Fox 5.0 Mustang Tech 15
L Someone explain to a Brit about Trick or Treat... 1965 - 1973 Classic Mustangs -General/Talk- 21
chobracobra Someone explain timing to me Fox 5.0 Mustang Tech 19
W Can someone explain this to me? Fox 5.0 Mustang Tech 9
G Can someone explain to me what's wrong? (Clutch) 1974 - 1978 Mustang II Talk & Tech 2
darthcual TPS can someone explain what i'm looking at Fox 5.0 Mustang Tech 15
hersheyman Could someone explain the difference in gear sizes? SN95 4.6L Mustang Tech 4
S Can Someone Please Explain A Pushrod Engine. SN95 4.6L Mustang Tech 18
R Can someone explain this car to me Classic Mustang Specific Tech 11
1105 can someone explain this to me... 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 15
N8Miller Can someone explain to me a Lightning MAF on a fox body? Fox 5.0 Mustang Tech 4
Jekyl Supercharger noob. Someone please explain.. Fox 5.0 Mustang Tech 2
Must-Be-A-Stang Can someone explain.... Fox 5.0 Mustang Tech 31
OrangeMustangGt Can someone explain runner length on intakes? 1994 - 1995 Specific Tech 2
D Can someone explain to me suspension? Fox 5.0 Mustang Tech 7
S Can someone please explain Classic Mustang Specific Tech 1
Kdubslugga Can Someone Explain Lower Control Arms for me? How do they work? Fox 5.0 Mustang Tech 3
S Can someone explain why this happens????? 1994 - 1995 Specific Tech 8
MustangMatt1966 Can someone please explain these specs on my camshaft? Classic Mustang Specific Tech 8
1 Can someone explain to me how my car is still alive after 2-->1 shift??? SN95 4.6L Mustang Tech 27
M PLEASE SOMEONE EXPLAIN... Fox 5.0 Mustang Tech 1
M Someone please explain pinion angle adjust. Fox 5.0 Mustang Tech 4
R Can someone PLEASE explain.... Classic Mustang Specific Tech 8
9 Someone Explain FMU Hookup For Me Fox 5.0 Mustang Tech 3
washMO66 Can someone explain the power valve Classic Mustang Specific Tech 14
none67 can someone explain this to me.. Classic Mustang Specific Tech 5
D Someone please explain this!!!1 Fox 5.0 Mustang Tech 5
Similar threads