Caught doing 120mph on the motorway

[Pete317]

gruffalo said:

Pete317 said:

gruffalo said:

Between 60 and 80 mph the noise level in an A8 more than doubles so to say that you would not realise the increase in speed is hard to understand.

Read up on sound pressure levels and perceived loudness

The 5db increase in that report was over a 30 km increase, the speed we are talking about is an 80km speed increase so the 5db increase is likely to be much larger.
http://www.acousticsbydesign.com/acoustics-blog/pe...

Now for a quick quote for you taken from the above site.

Perception.
Sound studies tell us time and again that a 3dBA increase in sound level is barely noticeable to the human ear. In fact, you have to raise a sound level by 5dBA before most listeners report a noticeable or significant change. Further, it takes a 10dBA increase before the average listener hears “double the sound.” That’s a far cry from 3dB.

So the 5db increase is a noticeable or significant increase in perceived loudness what would the cb increase be for an 80km speed increase be, let's say 12db so very noticeable and at least perceived as twice as loud or more.

You said:"Between 60 and 80 mph the noise level in an A8 more than doubles", when the actual increase is 5dBA

And show me where I mentioned anything more than 20mph as a speed increase one might not readily notice under certain circumstances.

Edited by Pete317 on Wednesday 8th July 18:54

[LoonR1]

Pete317 said:

You said:"Between 60 and 80 mph the noise level in an A8 more than doubles", when the actual increase is 5dBA

And show me where I mentioned anything more than 20mph as a speed increase one might not readily notice under certain circumstances.

Edited by Pete317 on Wednesday 8th July 18:54

The decibel scale is logarithmic not linear. A 10dB increase is 10 times louder than before. Work out what 5dB is from that.

[Pete317]

LoonR1 said:

The decibel scale is logarithmic not linear. A 10dB increase is 10 times louder than before. Work out what 5dB is from that.

You've got that exactly backwards

[Devil2575]

Pete317 said:

LoonR1 said:

The decibel scale is logarithmic not linear. A 10dB increase is 10 times louder than before. Work out what 5dB is from that.

You've got that exactly backwards

Please elaborate on this point. How is that backwards?

[TREMAiNE]

I wonder what ever happened to the OP

[V8LM]

I

Devil2575 said:

Pete317 said:

LoonR1 said:

The decibel scale is logarithmic not linear. A 10dB increase is 10 times louder than before. Work out what 5dB is from that.

You've got that exactly backwards

Please elaborate on this point. How is that backwards?

Whilst 10db is 10x power, a 10db increase in sound (Sound Pressure Level) is perceived as only twice as loud.

Edited by V8LM on Wednesday 8th July 19:59

[Pete317]

Devil2575 said:

Pete317 said:

LoonR1 said:

The decibel scale is logarithmic not linear. A 10dB increase is 10 times louder than before. Work out what 5dB is from that.

You've got that exactly backwards

Please elaborate on this point. How is that backwards?

There's a wealth of material on the web which explains it. Try this for starters: "Experimentally it was found that a 10 dB increase in sound level corresponds approximately to a perceived doubling of loudness"

Edited by Pete317 on Wednesday 8th July 20:02

[pinchmeimdreamin]

So what was this thread about ??

[ZX10R NIN]

youngsyr said:

Over a week on from when I first posted on this thread, I'm still amazed that there are supposed motoring enthusiasts who claim they cannot tell the difference between driving at 70 mph and 120 mph!

I guess this is the internet though, so people will argue black is white for sh!ts and giggles.

I notice everyone is awkwardly avoiding my point on stopping distances though - anyone going to claim they cannot tell a difference in stopping distances of 1 and a half football pitches when they're driving on the motorway?

Thought not.

Stopping distances are shorter than you're quoting I've stopped from an indicated 141mph to 0mph in just over 100 yards.

Which I'm sure is nowhere near 1 & a half football pitches

Edited by ZX10R NIN on Wednesday 8th July 20:44

[youngsyr]

ZX10R NIN said:

youngsyr said:

Over a week on from when I first posted on this thread, I'm still amazed that there are supposed motoring enthusiasts who claim they cannot tell the difference between driving at 70 mph and 120 mph!

I guess this is the internet though, so people will argue black is white for sh!ts and giggles.

I notice everyone is awkwardly avoiding my point on stopping distances though - anyone going to claim they cannot tell a difference in stopping distances of 1 and a half football pitches when they're driving on the motorway?

Thought not.

Stopping distances are shorter than you're quoting I've stopped from an indicated 141mph to 0mph in just over 100 yards.

Which I'm sure is nowhere near 1 & a half football pitches

Edited by ZX10R NIN on Wednesday 8th July 20:44

Oh really, at 140 mph you cover 62 metres a second, how exactly did you stop from 140 mph in 90 metres - did you hit a brick wall?!

[youngsyr]

ZX10R NIN earlier...

[LoonR1]

anonymous said:

[redacted]

It certainly wasn't on a ZX10, unless it was into a wall

[Pete317]

youngsyr said:

ZX10R NIN said:

youngsyr said:

Over a week on from when I first posted on this thread, I'm still amazed that there are supposed motoring enthusiasts who claim they cannot tell the difference between driving at 70 mph and 120 mph!

I guess this is the internet though, so people will argue black is white for sh!ts and giggles.

I notice everyone is awkwardly avoiding my point on stopping distances though - anyone going to claim they cannot tell a difference in stopping distances of 1 and a half football pitches when they're driving on the motorway?

Thought not.

Stopping distances are shorter than you're quoting I've stopped from an indicated 141mph to 0mph in just over 100 yards.

Which I'm sure is nowhere near 1 & a half football pitches

Edited by ZX10R NIN on Wednesday 8th July 20:44

Oh really, at 140 mph you cover 62 metres a second, how exactly did you stop from 140 mph in 90 metres - did you hit a brick wall?!

This is what you get when irrelevance and ignorance meet

[ZX10R NIN]

0-100-0 mph list

Source: Drive magazine

• * states non production vehicles.

Ultima GTR >>> 10.30s (0-100mph: 5.99s)
Caterham R500 Evolution >>> 10.73s (0-100mph: 6.92s)

• *Suzuki GSX-R 1000 >>> 10.89s (motorcycle)

Ferrari Enzo >>> 10.98s (0-100mph: 6.69s)

• *Ford Focus Rally Cross >>> 11.10s (rally competition car)

Caterham R500 >>> 11.25s
MacLaren F1 LM >>> 11.50s (on bespoke race tyres)

• *MG Metro 6R4 >>> 11.60s (Group B car)

Porsche Carrera GT >>> 11.63s (0-100mph: 7.31s)
Stealth B6 >>> 11.73s (0-100mph: 6.85s)
Pagani Zonda C12S >>> 11.84s (0-100mph: 7.52s)
RUF CTR >>> 11.85s (0-100mph: 6.71s)
Mosler MT900 Photon >>> 11.95 (0-100mph: 7.45s)
McLaren Mercedes SLR >>> 12.13s (0-100mph: 7.70s)
RUF R Turbo >>> 13.10s (0-100mph: 8.50s)
Porsche 911 GT3 >>> 13.46 (0-100mph: 9.20s)
Lamborghini Gallardo >>> 13.65s (0-100mph: 9.02s)
Lamborghini Murcielago >>> 13.90s (0-100mph: 9.00s)
TVR T350 T >>> 14.00s (0-100mph: 9.95s)
Mercedes-Benz CL65 AMG >>> 14.01s (0-100mph: 9.02s)
Aston Martin DB9 >>> 14.91 (0-100mph: 10.21s)
BMW M3 CSL >>> 15.25s (0-100mph: 10.82s)
Honda NSX Type-R >>> 16.20s (0-100mph: 11.41s)
Lotus Elise 111R >>> 16.80s (0-100mph: 12.33s)
BMW M3 >>> 17.04s (0-100mph: 12.12s)
Mitsubishi Lancer EVO III FQ330 >>> 17.32s (0-100mph: 12.36s)
Porsche Boxster S >>> 17.65s (0-100mph: 13.00s)
Nissan 350Z >>> 18.72s (0-100mph: 14.25s)
Alpha Romeo 147 GTA >>> 18.76s (0-100mph: 14.10s)
Renault Megane Sport >>> 20.19s (0-100mph: 15.45s)
Honda Civic Type-R >>> 20.93s (0-100mph: 16.02s)
Mazda RX-8 >>> 21.17s (0-100mph: 16.51s)
Audi TT 3,2 DSG >>> 21.28s (0-100mph: 16.56s)
Renault Clio Sport >>> 21.95s (0-100mph: 17.01s)
Chrysler Crossfire >>> 22.08s (0-100mph: 17.30s)
Peugeot 206 RC >>> 24.36s (0-100mph: 19.66s)

All production cars were on road tyres except McLaren F1 that was on slicks.

Best 0-100-0 mph: Ultima GTR
Best 0-100 mph: Ultima GTR
Best 100-0mph: Caterham R500 Evo (3.60s)

The test was conducted by accelerating from 0 to 100 mph and then brake back to 0. The total 0-100-0 times include transition times (e.g. driving beyond 100 mph before starting to brake). Other tests like MotorTrend's are conducted by adding 0-100 and 100-0 times, with the acceleration and braking tests conducted separately, thus providing faster times.

[ZX10R NIN]

LoonR1 said:

It certainly wasn't on a ZX10, unless it was into a wall

Your not kidding I wouldn't have been able to hold on plus the front tyre would have folded, CL65 was the car with carbon ceramics. No crashing involved but it was sketchy.

[LoonR1]

Right. I'm now thoroughly confused.

We were talking about stopping in a specific distance from 120moh and now we've got a list of times to do 0-100-0mph.

Oh and if you can manage to do it in sub 11 seconds on a bike then I'd be impressed. In fact, I'd love to see that.

[ZX10R NIN]

LoonR1 said:

Right. I'm now thoroughly confused.

We were talking about stopping in a specific distance from 120moh and now we've got a list of times to do 0-100-0mph.

Oh and if you can manage to do it in sub 11 seconds on a bike then I'd be impressed. In fact, I'd love to see that.

My point was that a decent car won't take a football pitch & a half to stop from 120mph.

[Pete317]

ZX10R NIN said:

LoonR1 said:

Right. I'm now thoroughly confused.

We were talking about stopping in a specific distance from 120moh and now we've got a list of times to do 0-100-0mph.

Oh and if you can manage to do it in sub 11 seconds on a bike then I'd be impressed. In fact, I'd love to see that.

My point was that a decent car won't take a football pitch & a half to stop from 120mph.

Of course not - more likely more than two football pitches.
Even at 1g deceleration, which is unrealistic for a car with no downforce, the braking distance alone is 145 metres - to which you have to add 'thinking' distance.

Not that it's relevant to the discussion anyway.

[LoonR1]

ZX10R NIN said:

LoonR1 said:

Right. I'm now thoroughly confused.

We were talking about stopping in a specific distance from 120moh and now we've got a list of times to do 0-100-0mph.

Oh and if you can manage to do it in sub 11 seconds on a bike then I'd be impressed. In fact, I'd love to see that.

My point was that a decent car won't take a football pitch & a half to stop from 120mph.

Do some better maths than me and prove your point

My rough guide is that 100mph is 161kmh. Which is 161,000 m per hour, so 2683 m per minute, 44.72 m per second.

If it takes 5 seconds to stop from 100mph as most of the cars on your list do, then at a rough guess it'll take (5 x 44.72) / 2. I've divided by two to account for the slowing down to zero. I'm sure someone with a better grasp of maths will explain why that's wrong, but it's late and seems like a reasonable base assumption to me.

So that means 112 metres, so about one and a quarter football pitches

At 120mph following the above means 134 metres which is more or less bang on 1.5 football pitches.

[Devil2575]

Pete317 said:

Devil2575 said:

Pete317 said:

LoonR1 said:

The decibel scale is logarithmic not linear. A 10dB increase is 10 times louder than before. Work out what 5dB is from that.

You've got that exactly backwards

Please elaborate on this point. How is that backwards?

There's a wealth of material on the web which explains it. Try this for starters: "Experimentally it was found that a 10 dB increase in sound level corresponds approximately to a perceived doubling of loudness"

Edited by Pete317 on Wednesday 8th July 20:02

So it's not backwards at all then. Perceived loudness still increases at a faster rate than it would if it was a linear relationship.