Why acceleration times differ from one test to another.

[fpv_gtho]

so if I have grasped this right, rollout basically mans that you don't start timiing until the car has reached a predetermined point, even if the car has already started moving??

surely 0-60 means just that. zero to sixty

It'll affect 400m times easier than 0-60.

Another thing to consider is 60mph and 100km/h arent the same. Some people test 0-60mph, others will do 0-62mph.

[ringle]

Location of the testing is also critical as altitude, barometric pressure, ambient air temperature and track (ground surface) temperature, as well as type of surface (ie asphalt, concrete, dirty/dusty, rubbered or post rain,etc.) all will have some influence on the times recorded. Also type of fuel used (ie octane rating, detergents, etc.) will affect results from one test to another.

[taz_rocks_miami]

Location of the testing is also critical as altitude, barometric pressure, ambient air temperature and track (ground surface) temperature, as well as type of surface (ie asphalt, concrete, dirty/dusty, rubbered or post rain,etc.) all will have some influence on the times recorded. Also type of fuel used (ie octane rating, detergents, etc.) will affect results from one test to another.

Beat me to it, excelent point.

[aNOBLEman]

This is also true for GPS-based devices such as Correvits, VBoxs, DriftBoxs etc. they use no rollout and start timing the moment car moves. Most aussie mags use these devices, not drag strip timing, and I'm pretty sure the same goes for Euro and Jap mags

I know that Road & Track uses the VBox system.

[2ndclasscitizen]

I know that Road & Track uses the VBox system.

Err, godd for you?

[aNOBLEman]

Err, godd for you?

The original quote stated that Jap, European, and Aussie mags would have times about .3 seconds slower than US mags because they use GPS systems, but Road & Track is an American magazine and they use GPS as well which means that they're times should be about the same. Basically I'm saying that all US mags don't use the drag strip timing.

[Bob]

The original quote stated that Jap, European, and Aussie mags would have times about .3 seconds slower than US mags because they use GPS systems, but Road & Track is an American magazine and they use GPS as well which means that they're times should be about the same. Basically I'm saying that all US mags don't use the drag strip timing.

But according to the original post R&T 'simulates' the rollout when they publish their results. In other words, they use GPS timing and then give you the 3-60 mph time. I don't know if it's true, maybe I should write a letter.

[derekthetree]

No.
This is what happens when your at a track:
You pull up to the tree, once you cross the first beam the very top yellow light goes on. You scoot up a couple inches to hit the next beam, the second yellow light turns on and now the tree is activated. Your timed from the very moment you leave that second beam.
There is no "secret" here, its drag racing, nothing new.

So how does this lead to faster 0-60 times?

[aNOBLEman]

But according to the original post R&T 'simulates' the rollout when they publish their results. In other words, they use GPS timing and then give you the 3-60 mph time. I don't know if it's true, maybe I should write a letter.

This doesn't make sense to me because even at the drag strip the cars start from a stand still. The difference in times could be from the different amounts of grip from a drag strip to a normal track or the reaction times of the drivers.

[Slicks]

So how does this lead to faster 0-60 times?

It doesnt, the thread starter is smoking crack.

[Slicks]

This doesn't make sense to me because even at the drag strip the cars start from a stand still. The difference in times could be from the different amounts of grip from a drag strip to a normal track or the reaction times of the drivers.

Reaction time doesnt effect overall time. Its only a measure of how long it took for your car to leave the line when the light turns green. Like I said a few posts above, the 1/4 mile timer is started when you leave the line, not when the light turns green.

[woodstock827]

So how does this lead to faster 0-60 times?

when this "roll out" technique is used, you're technically measuring time going from 3-60mph, not 0-60 as some magazine claims.
Also, 60mph = 96.6kph, which would cause another ~0.1sec or more difference when compared with 0-100kph times.

[aNOBLEman]

Reaction time doesnt effect overall time. Its only a measure of how long it took for your car to leave the line when the light turns green. Like I said a few posts above, the 1/4 mile timer is started when you leave the line, not when the light turns green.

That's true. I was thinking about racing which is when it does matter.

[wanker rotary]

Car and Driver use a VBOX, they even tested a bunch of performance meters once. All of the magazines test using GPS devices, its just american magazines tend to have a lead foot on clutch engagment (they engage the clutch while running revs, not a start from idle.) A lot of mags don't do this, as it is seriously harmful in a high performance car, even more so if done everytime you are at a stoplight.