Some track do give corrected time, bassically its just a guess. Like dynoing, its close but its just math so I am sure you can find correction formulas.

http://www.wallaceracing.com/altitudecorrection.htm

This is just one of them.

I just realised why drag times are probably not corrected for altitude.

A drag time has two components. The reaction time which is independant of altitude and the actual run which is influenced by altitude.
A full run though, is these two components added together. You can't apply altitude correction to the reaction time component.

Skin.

your reaction time is almost always one of the major causes of the slower total time. That comes with practice to most. The next thing i would look at is when you are shifting winding it out all the way in RPMS is not always the faster way.

your reaction time to the tree does not count towards your ET if thats what you mean by reaction time

if you have a slow reaction to the green light...you will definetly lose time overall in the 1/4

Reaction time has nothing to do with 1/4 mile time...clock does not start until you roll/break the beam. Technically, you don't react to the green light. Reaction time is actually how well you have anticipated the green light.

First off, the word for all drag strips is ELEVATION, Not ALTITUDE. When your wheels are on the ground, it is ELEVATION, even when you are parked on top of a mountain at ELEVATION and a plane is flying through the valley BELOW you at ALTITUDE.

That settled, your reaction time has no bearing on your Elapsed time or your top speed at the end. The only thing your REACTION time has to do with is how soon you get the wheels rolling and break the beam, hopefully quicker than the guy beside you. If you react slower than him, but if you still are getting it on when you finally start rolling, your ET and time will be at your best (if you do it right) although the guy beside you with an EQUAL ET and speed will have beaten you because he had a quicker reaction time.

Ok i have to ask the question.

If commonly posted / quoted 1/4 mile times are from green light then it includes reaction time component which cannot be altitude corrected, yes ? That would be my point.

Try this:
http://www.howtodragrace.com/category/practice-tree

or this one:
http://www.dragracers.org/reaction.html

Skindiver Skindiver...you still used the word 'Altitude.' Didn't you read anything I wrote?

Old writer.

When speaking of 'correcting for altitude' we mean QNH or pressure altitude. We dont refer to it as "correcting for elevation" or 'pressure elevation'. Your GPS will not tell you your elevation either It will only refer to your altitude ASL. On a GPS with a barometer your altitude will vary hourly. Your elevation however, as expressed as the vertical relationship between two fixed points will never vary.

Atmospheric pressure varies on any give day and time. Planes do not measure the distance from the ground or the sea up to their location to determine their altitude. They measure atmospheric pressure which generally decreases with altitude. However my pressure altitude and yours, even if you are sitting in your chair at the same elevation as i am may be different simply because its hotter here than at your pad. 1013.5 is the mean pressure at sea level and all planes will adjust their QNH based on this mean once they reach their flight level so that even if they fly through areas of differing pressure that will fly a constant height ASL and maintain separation.

Pressure altitude will affect vehicle performance because there is less air for combustion at higher altitude than at sea level.

Not to sound patronising by supplying you with some basic info you most probably already understand but I am not referring to the mean published numerical meters of height as found in an atlas (elevation) that a location is above sea level. We are talking about the pressure altitude at a given instant at any location.

As such we refer to it as altitude, not elevation.

Skin.