Acceleration of the car

I came across the following figure from a thread in CarWale (Thanks to Binoy Thomas). But I did not understand this quite well. All I understand is that Linea takes 6.12 seconds to touch 60kmph speed from halt. But what I did not understand is that, how do they test it. i.e., Is it something like, I just keep on pressing the accelerator to the bottom of the car in first gear to check or I need to change the gear in various intervels?

Fiat Linea:

0-60kmph = 6.12sec

0-100kmph = 15.04sec

Well, what they most probably do is accelerate quickly whilst also changing gears at the required shift points. That needs a professional driver to do correctly. Also the quoted times are IMO based on multiple attempts (averaged, I guess).

Rohit,

 Thanks for answering me. But if I do not change the gear from 1st will I not get more acceleration? (Sorry if I sound stupid)

Yes you will but you won't get any appreciable top speed (15kmph max) without excessive (and possibly harmful) revving. The most common gear selection for max. acceleration is 3rd - reach that gear as quickly as possible and then accelerate as much as you want...but eventually you will have to upshift to 4th or 5th gear in the interest of the engine's health.

@rohit  thank you for the info nice buddy .

Great explanation. Thanks Rohit. It means, the figures given are achieved by the experts and we probably can expect around 10% variation. Isn't it?

The speed tests reported in magazines or the brochure are under certain controlled conditions which are seldom found during regular driving. So a variation is to be expected...whether 10% or more or less, I'm not sure of...though, I'd expect more.

Yes. You are right. Thanks for the info.

Acceleration tests are usually done on a 1/4 mile (or longer) drag racing track or some other section of smooth, flat, straight road.  MT cars are normally run at full throttle and shifted at or near redline.  For AT cars, they usually just smash the accelerator to the floor, which has the same effect.  AT times will generally be more consistent.

Sometimes they also abuse the cars to get faster times.  For MT, common tricks are dropping the clutch with the engine at high rpm at the beginning of the run and power shifting.  Power shifting means changing gears without taking your foot off the accelerator.  There isn't as much that can be done with AT, though revving up the engine and starting the run by releasing the brake pedal is common and has about the same effect as dropping the clutch.

Mike,

 Thanks for the explanation. I have more questions.

1) What are MT and AT cars? Do they mean Mileage test and Acceleration test?

2) I can change the gear only with my clutch fully engaged. My understanding is that, no use of pressing accelerator when clutch is pressed. (In my experience, car has generated big sound for nothing and no acceleration power). How does it help acceleration?