Car faster than prescribed acceleration?

I put my foot down from stationary the other day when the road was empty, it did 0-60 in just over 5 secs, while the specs say 7.4 secs. Are cars usually faster than their prescribed specs? I would have thought they would be the "top limit" specs to try and make it look good to potential buyers.

Update - had to get out onto the A1 from a petrol station exit today. Full tank of fuel, shopping in the back, 0-60 in well under 6. To be honest, I'm surprised I didn't notice it earlier - you really don't need much pressure on the accelerator anyway. I probably drove it for a month before I actually pushed it down more than 1/3rd.

(edited 8 years ago)

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Reply 1

Talon

Are you sure you weren't counting too quickly?

Reply 2

Doones

Or 60km/h not 60mph...

Also the quoted 0-60 is actually usually for 0-62 (0-100 km/h)

Reply 3

XMaramena

Original post by Talon

Are you sure you weren't counting too quickly?

Original post by jneill

Or 60km/h not 60mph...

Also the quoted 0-60 is actually usually for 0-62 (0-100 km/h)

Lol no, my dad was in the passenger seat, used the stopwatch on his phone. And definitely 60 MPH.

2mph wouldn't make much difference I think :P

haven't tried it in manual yet, could get even faster because it has to restart the engine when it's been stopped as well.

Reply 4

Doones

Original post by XMaramena

Lol no, my dad was in the passenger seat, used the stopwatch on his phone. And definitely 60 MPH.

2mph wouldn't make much difference I think :P

Can be 0.5 sec or more difference.

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Reply 5

Potally_Tissed

It's 0-62 that's measured, and speedometers typically overstate your speed by anywhere up to about 5%, so your indicated 60 was probably closer to 57 in reality. So you're probably 4 or 5 mph off a comparable time, especially so if you'd need another gear change in there.

Reply 6

XMaramena

Original post by Potally_Tissed

Ah - the speedometer actually is the opposite on this car. I know they are supposed to show it a bit faster than you're actually going, but on this car the analogue speedometer will show 56 or 57 when you're doing 60. (At least according to Garmin and Google Maps) Maybe someone made a mistake in the factory.

But the main speedometer is digital and probably has a half second delay on it. So if anything, in this case, it's the opposite.

I'll update this thread if there's a time I have to pull out quickly again, I'll do it up to 65 or 70, we can see what happens :smile:

Reply 7

Talon

Original post by XMaramena

This isn't right - the speedometer should never show less than your actual speed. Is the tyre/wheel size combination you have approved by the manufacturer? If it is out, it will affect the accuracy of the speedometer.

Reply 8

mphysical

Original post by XMaramena

How did you calibrate this? GPS speed is only accurate on straight flat roads at a steady speed over a mile or so. You also need clear skies away from wooded areas. A lot of averaging takes place with GPS.

Reply 9

XMaramena

Original post by Talon

Original post by mphysical

Don't know anything about tyre wheel combinations, it's new, straight from the factory.

Because I can be on cruise control for ages down the motorway, sitting at 70. The digital speedo reads 70. The on-board Garmin reads 70. Google maps on my phone reads 70. The analogue speedo reads roughly 65. And they'll sit steadily at that until I alter the cruise control.

Downhill?

Original post by Supersaps

Downhill?

lol no, actually it was slightly uphill

Reply 12

XMaramena

Empty day today, empty roads - went from standstill to 70mph (went past into 73-75 for a moment before coming back down).

Was hoping to keep the handbrake on for a quick launch but it seems the handbrake automatically disconnects as soon as accelerator is pushed. No matter, there was still a little wheelspin on the wet conditions. Was also on the flats (at least, less than 1% incline) as far as I know.

It hit 60 in 5.22 seconds, 70 in 5.96. This was with a 310lb payload.

So definitely, faster than the specified target of 0-60 in 7.4 seconds.

(edited 8 years ago)

Reply 13

Economistician

Original post by XMaramena

What car is this?

Reply 14

XMaramena

Original post by Economistician

What car is this?

C220 Executive Bluetec, '15 plate new.

Maybe the specs are just for the C Class in general, using the basic C200 as an example.

(edited 8 years ago)

Reply 15

CAElite

Some manufacturer numbers are a bit off. My Skoda Fabia VRS used to be like this. Manufacturer listed 9second 0-60mph. Some reviewers measured it in late 7.Xs. None where higher than 8.5seconds. Personally I got solid 8s out of mine. The power at the wheels was also slightly off, mine was running 136bhp at the wheels from an engine that was supposed to get 130bhp at the crank (~111whp) before I got it mapped.

Reply 16

Doones

Original post by XMaramena

You can't handtime to 100ths of a sec.

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Reply 17

XMaramena

Original post by jneill

You can't handtime to 100ths of a sec.

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Reply 18

Good bloke

You must be getting used to changing the clutch by now.

Reply 19

mphysical

Original post by XMaramena

You can't handtime to 100ths of a sec.
??

Meaning:

Quote from http://www.physicsatweb.com/
Hand-operated stopwatches have an accuracy that is limited by the delay between your eye seeing the moment to start, your brain issuing command to start and your finger pressing the start button. This delay is known as your reaction time.
Typical human Reaction Time is approximately 150 to 300 milliseconds (or 0.15 to 0.30 seconds).