What car/driving related urban myths have you heard of?

[sadako]

twazzock said:

I think the headlight flashing myth comes from the US where some traffic lights do actually have a sensor to detect ambulance strobes (I THINK). Pretty sure it's a load of bks over here though...

The system in the states was only in some areas, and was set up to recieve a pulsed IR light at a certain pattern, like a TV remote. Naturally people worked this out and started building boxes that did the same thing for their cars...

[Rosun]

That urinating on the wheels makes the car go faster.

That's what the other half used to say to my lad when he was little.

In reality it meant that we didn't have the "I need a wee" speech 5 minutes after setting off.

[Megaflow]

m3jappa said:

'yea my mates dad always chucks a fivers worth of petrol in when he fills up with diesel, makes it run better'

Yea right

There is some truth in that. Diesel starts to turn to a gel/wax at about -10 deg, and starts causing problems. Add a small percentage of petrol eliminates the problem.

mattnunn said:

Myth - honda have never had a warranty claim on an engine directly attributable to the VTEC system

Truth - they have, my 2006 civic, several new engine parts aswell as several other things.

EFA...

[GC8]

mattnunn said:

MDT said:

That the MK3 golf 8v has more torque than the 16v one

is that really not true? Perhaps the 8v made peak torque lower down the revs?

More horsepower = more torque, but itll be peakier...

Perhaps this myth came about due to people not really understanding torque/bhp and their relationship?

Its certainly a more 'torquey' engine, but thats not quite the same thing.

[W41RU5]

loafer123 said:

AndyBrew said:

I've seen taxi drivers flash their lights at night when approaching traffic lights with the belief that this act turns them to green?

It does, if the set of lights have the sensor on the top.

It does work on some lights, there is a a set of traffic lights by a train bridge near my house and they stay green all the time on one side unless a car approaches, if you flash the lights from halfway down the road they turn green before you arrive

[Snowboy]

Truth – when people are arguing about what uses more fuel, they really need to clarify whether they are talking about more fuel per minute, more fuel per mile or something else.

For example.
If I am driving at 50mph I am using more fuel more minute than being stationary, but I'm using a lot less fuel per mile.

[stuwalsh]

Coasting in nuetral saves fuel. Maybe on a 1965 Morris Oxford but not on a modern ECU managed engine.

[TheEnd]

I've found if you shout "Change" at traffic lights as you come close to them, they will change.

Doing that, I've found that the lights always change within a minute or two, so they must have speech recognition too.

[tvrgit]

denniswise9 said:

Opulent said:

You mean, as you approach them, and if there is nothing on the other side of the road, then they change?

That will be detector/control loops cut in to the road.

Traffic lights do not respond to light signals.

There really is no argument to it.

There is.

I'll film it tonight.

Could you balance a packet of Birds Custard on the dash so that we know it's you?

Oh and make sure that you don't have any celebrities in your car, like Princess Anne, Simon Cowell or Jason Plato. Some signals have VIP and celebrity detectors, and that might skew the results.

Oh and make sure that the stereo is off. There are a few with Electric Light Orchestra detectors.

And don't try to use "the force" - they also have light sabre detectors.

You might also want to try the "reaching for the coffee cup" test that was mentioned earlier - that appears to work. There is also the "picking your nose" test, the "scratching your arse" test and the "reaching for a jelly baby" test that you might want to try - all of those have prompted unexpected signal changes, in my experience.

You might also want to test the "bursting for a piss" detectors which hold the light on red until you just HAVE TO go through them anyway.

All in the interests of scientific experiment, you understand.

[paranoid airbag]

Gad-Westy said:

It's still true. Nobody mentioned low revs. Any engine (or motor for that matter) has a speed with a peak efficiency. If you run the engine constantly at that speed but through a gearbox which makes the road speed lower, you will use less fuel. Hence the 'all else being equal' part.

But the point of peak efficiency varies with throttle load - if you maintained throttle load and engine speed and switched to a lower gear, you'd be producing more power than is necessary to hold a steady speed, and will therefore accelerate away from the sweet spot. Peak efficiency for a car will be the speed that minimises (power needed for the speed)*(least engine inefficiency for that power)/speed, assuming there's a gear that will let you reach the most efficient engine state for that speed. Not sure if I'm disagreeing with you tbh, just thought I'd add that.

[Zwoelf]

From today:

Laird said:

It is possible to drive over cat's eyes with the rear wheels only (note: not Tokyo Drift style, but simply due to the much wider rear track)

[twazzock]

tvrgit said:

Could you balance a packet of Birds Custard on the dash so that we know it's you?

Oh and make sure that you don't have any celebrities in your car, like Princess Anne, Simon Cowell or Jason Plato. Some signals have VIP and celebrity detectors, and that might skew the results.

Oh and make sure that the stereo is off. There are a few with Electric Light Orchestra detectors.

And don't try to use "the force" - they also have light sabre detectors.

You might also want to try the "reaching for the coffee cup" test that was mentioned earlier - that appears to work. There is also the "picking your nose" test, the "scratching your arse" test and the "reaching for a jelly baby" test that you might want to try - all of those have prompted unexpected signal changes, in my experience.

You might also want to test the "bursting for a piss" detectors which hold the light on red until you just HAVE TO go through them anyway.

All in the interests of scientific experiment, you understand.

Definitely don't sit there impatiently tapping the wheel, looking at your watch and muttering "come on, come on" as that would probably cancel out any headlight flashing/coffee cup grabbing.

[98elise]

Corpulent Tosser said:

98elise said:

martin84 said:

robsco said:

That if you run your fuel level too low, you start to suck up all the dregs at the bottom of the tank which is bad for your engine. Who made that st up?

People always buy this one but nobody ever asks where the dregs came from or how they got there. Baffling.

Or why they don't get churned up by filling the tank, or sloshing about when the car is being driven

Older cars may have rust in the tank which would provide the contaminant, water from condensation, or even just crap in the fuel when you buy it.
The more fuel you have in the tank the lower the percentage of contaminants, low fuel level,more crap being sucked into the fuel line.
Why do you think your vehicle has a filter in the fuel line ?

How does all this crud magically not get churned up when the car is filled, or when taking a corner, especially when the pump picks up from the bottom.

The simple fact is that it does, and anything large enough gets picked up by the filter. The crud does not settle in the bottom of the tank, and only get sucked in when the fuel is low.

[5lab]

GC8 said:

mattnunn said:

MDT said:

That the MK3 golf 8v has more torque than the 16v one

is that really not true? Perhaps the 8v made peak torque lower down the revs?

More horsepower = more torque, but itll be peakier...

Perhaps this myth came about due to people not really understanding torque/bhp and their relationship?

Its certainly a more 'torquey' engine, but thats not quite the same thing.

thats not necessarily true. A mid-range diesel has both more torque and less power than, say, a civic type r engine.

in this instance it is true, the 16v has a peak of 124ftlbs whilst the 8v has a peak of 118ftlbs

[Gad-Westy]

paranoid airbag said:

Gad-Westy said:

It's still true. Nobody mentioned low revs. Any engine (or motor for that matter) has a speed with a peak efficiency. If you run the engine constantly at that speed but through a gearbox which makes the road speed lower, you will use less fuel. Hence the 'all else being equal' part.

But the point of peak efficiency varies with throttle load - if you maintained throttle load and engine speed and switched to a lower gear, you'd be producing more power than is necessary to hold a steady speed, and will therefore accelerate away from the sweet spot. Peak efficiency for a car will be the speed that minimises (power needed for the speed)*(least engine inefficiency for that power)/speed, assuming there's a gear that will let you reach the most efficient engine state for that speed. Not sure if I'm disagreeing with you tbh, just thought I'd add that.

I think we are in agreement.

[matthias73]

busta said:

The noise the door makes when you shut it is an accurate indicator of the overall build quality of the car.

No no no, people listen to the sound it makes to make sure it sounds like a golf

[CambsBill]

56mph is the most efficient speed for all cars because that's what the quote the official mpg at.

[Morningside]

AndyBrew said:

I've seen taxi drivers flash their lights at night when approaching traffic lights with the belief that this act turns them to green?

1st reply. Yup, that really is the classic one all over isn't it! "But, but that module on the top is to 'read' the oncoming headlights" I have heard so many times over the years.

[Morningside]

snowdude2910 said:

The Wookie said:

That one about the $50 Porsche sold by the jilted wife... correct me if I'm wrong, but didn't exactly that happen to a radio DJ who was flirting with some celeb on the air?

Tim Shaw's wife sold his lotus for a pound after he told jodie marsh (I think could have been another similar type) he'd leave his wife for her. He did work on 5th gear for a bit (ginger bloke) but doesn't seem to anymore

Was that transaction ever carried though or was it just a publicity stunt?

[dp gumby]

if you're driving another car and have the driving other cars clause enabled on your policy, then the car must have its own policy.