Useless Car Facts

Slidey

Was having a bit of a ponder today and was thinking of a thread where people could put up interesting (if slightly nerdy) car facts they think others may not know.

To start here is 2 VW ones.

The new Caddy will not work the wipers with the bonnet even slightly open.

On MK2 golfs and Jettas it is possible to turn on the window wipers and heater motor without having the key in the ignition.
Put the headlights on, move the wiper stalk to the on positon and pull the stalk to flash the lights.
Power will back feed to the wiper motor and heater fan and turn them on.

It is also possible to get a digital rev counter reading on a MK3 golf dash but I have since forgotten how to do it
Any other useless facts out there?

Berty

Volkswagen Audi Group(VAG)'s use 14.5 Volts in their License plate 38mm festoon bulbs instead of the standard 12 Volts.

Slidey

Hino and Isuzu trucks use Left Hand thread nuts and studs to hold on the wheels on the LHS of the vehicles. Not knowing that can be a bitch! :pac:

EPM

wiper thing is the same on leons. Also, if you flick the wiper for one sweep just after you turn the car off the wipers move to a horizontal position as opposed to their natural vertical one. Oh and if you hold down the one sweep button it starts sweeping at the at the fastest speed as long as its pressed down...handy for stubborn bird sh1t...probably the same on all VAG cars

Slidey

Thought of another one.

You cannot get genuine clutches for an LSD in a 325i Sport, however the clutch kit for a V6 capri fits and you have enough to do another diff left over!

scudster

On BMWs, if you have the wipers on normal speed while driving and then you stop, they automatically go into intermittent mode until you move off again. Same with high speed selection, it will revert to normal speed when you stop.
On Seat Leons (mk 1 anyway and prob on alot of VAG cars) if you want extra fuel capacity, there is an expansion tank which can be filled if you press the fuel pump nozzel to the left when the tank is nearly full. Probably not advisable in a hot climate tho!

EPM

Thats expansion tanks interesting. Gonna try it next fill up see if mine has it...i did notice a few weeks ago though i got 57 litres in...when the tanks 55...and there was some juice already in there...could be it or a dodge pump...

Mr Benevolent

You can turn the radio on in a Meriva without needing the keys in the ignition.

EPM

the VW Bora runs on sports suspension compared to the golf...

Carawaystick

scudster wrote: »

On BMWs, if you have the wipers on normal speed while driving and then you stop, they automatically go into intermittent mode until you move off again. Same with high speed selection, it will revert to normal speed when you stop.

renault lagunas do this too. and they put on the rear wiper if you select reverse gear while the front wipers on.

L1011

scudster wrote: »

On BMWs, if you have the wipers on normal speed while driving and then you stop, they automatically go into intermittent mode until you move off again. Same with high speed selection, it will revert to normal speed when you stop.

Same on top-end spec Fiats.

Confab wrote: »

You can turn the radio on in a Meriva without needing the keys in the ignition.

Never owned a car which this doesn't work?

Mostly useless fact: The fuel light on a Fiat Panda 100HP comes on when, with even relatively spirited driving, you have 100km left. The car only has a 35l tank so you can see this is a bit conservative...

EPM

Carawaystick wrote: »

renault lagunas do this too. and they put on the rear wiper if you select reverse gear while the front wipers on.

Leon does these too. Old focus used do the reverse thing too. Very handy actually. Radio on both came on without key. I think the focus one flashed 1 hour when you did it

Stevie Dakota

BMW E34's had no variable setting for the wiper intermittent speed, but if you switched the wipers between intermittent and off and back again you could set the intermittent gap yourself to whatever you wanted. In 8 years of ownership I never really got the hang of it!

Slidey

Mk3 Golfs were the same...

Great job

maidhc

The Mercedes 190e autobox starts from a standing start in second gear by default.

The Capri MkII and Mercedes 190e both have the indicator stalk on the right hand side despite being largely destined for the l/h drive market.

On the Capri MkII if you turn off the ignition the indicator stalk acts as a parking light switch, e.g. right indicator = r/h parking light.

The Ford Mondeo was the first mass produced car sold in europe with an airbag as standard across the entire model range.

The MGF is based on a Mini Metro

Slidey

maidhc wrote: »

On the Capri MkII if you turn off the ignition the indicator stalk acts as a parking light switch, e.g. right indicator = r/h parking light.

This also has been on VW's for a long time

VolvoMan

You can fit two sets of golf clubs in the boot of an Octavia with room left to spare.

Seth Brundle

MYOB wrote: »

Never owned a car which this doesn't work?

My E39 won't allow the radio on without the key in!
My BMW will increase the radio volume slightly if you go over about 60km/h!

Esel

maidhc wrote: »

The Mercedes 190e autobox starts from a standing start in second gear by default.

Think a lot of Mercedes-Benz models have that feature?

kbannon wrote: »

My BMW will increase the radio volume slightly if you go over about 60km/h!

I have a Blaupunkt with that feature. There is a wired microphone which samples cabin noise level and adjusts the volume up or down accordingly.

bazz26

MkII Focus:

Multiple steering feedback settings including sport, comfort and standard set through the trip computer.

Full diagnostic display when pressing the trip computer and turning the ignition.

Stereo stays on for upto 1 hour without the key in the ignition.

Stereo display and odometer illumination lights up when you open the car with the central locking. It stays on for about 10 to 15 mins after you lock the car.

Global opening and closing of all windows using the remote key fob.

If the front wipers are on and you select reverse the rear wiper comes on.

No cigarette lighter or ash tray fitted in the car.

maidhc

Again on the Focus Mk1:

If the engine starts to overheat 2 cylinders will shut down making the engine a 2 cylinder aircooled (petrols only afaik)

The factory radio has a compensation setting for road speed/rpm

The 12v output at the back stays lit even with the key out, but the 12v output on the dash only works with the key at the first notch.

Mercedes Benz of the late 80s:

Even the top spec models, despite having an electric drivers seat, rlectric sunroof and electric windows had only an electric passenger mirror, which was a completely different size to the drivers side one.

maidhc

esel wrote: »

Think a lof of Mercedes-Benz models have that feature?

Very possibly!

galwaytt

First robot-built car: Fiat Ritmo
First robot-built engine: Fiat FIRE - Fiat Integrated Robotised Engine ...iirc.

Seth Brundle

bazz26 wrote: »

No cigarette lighter or ash tray fitted in the car.

I presume that was because it was ordered without the 'smokers pack'?

bazz26

kbannon wrote: »

I presume that was because it was ordered without the 'smokers pack'?

Yep, obviously the previous owner like myself wasn't a smoker.

milltown

Maybe the same on a lot of cars nowadays but I was mighty impressed to discover that if a brake light bulb goes on the E46 that the car uses the rear fog on that side as a brake light until the bulb is replaced.

BMW autos also default to 2nd gear starts btw.

rebel.ranter

In the 1980s BMW used to design the wiper arrangements differently to suit the right hand drive cars. Now they use the same wiper configuration LHD or RHD.

Stevie Dakota

milltown wrote: »

BMW autos also default to 2nd gear starts btw.

Not my E34, they start in first, and stay in sport mode (although the dash will show E for Economy) until the oil has warmed up, then it reverts to default Economy mode.

Mr.David

The contact patch that you have between tyre and road is independent of the width of the tyre. i.e. a 195 and a 295 tyre both have the same area of contact with the road

Stevie Dakota

Mr.David wrote: »

The contact patch that you have between tyre and road is independent of the width of the tyre. i.e. a 195 and a 295 tyre both have the same area of contact with the road

No way, you mean an M5 has the same contact patch as a Micra?! Get up the yard!

seanybiker

Mr.David wrote: »

The contact patch that you have between tyre and road is independent of the width of the tyre. i.e. a 195 and a 295 tyre both have the same area of contact with the road

interesting
Taking a corner on a bike (leaning over) you have more area of contact than been upright. Thats fairly obvious though.

Anan1

Stevie Dakota wrote: »

No way, you mean an M5 has the same contact patch as a Micra?! Get up the yard!

I think he means on the same car! If you fit wider tyres to a car the contact patch gets wider, but also shorter from front to rear.

Mr.David

Its true! Re the M5 vs Micra, the M5 contact patch will be wide and short (from front of tyre to rear) whereas the Micra tyre will be narrow but long. But they both have the same contact area!

But obviously it depends on weight and tyre pressures being equal

Anan1

Mr.David wrote: »

Its true! Re the M5 vs Micra, the M5 contact patch will be wide and short (from front of tyre to rear) whereas the Micra tyre will be narrow but long. But they both have the same contact area!

But obviously it depends on weight and tyre pressures being equal

Which they won't be between an M5 and a Micra!;)

Mr.David

Anan1 wrote: »

Which they won't be between an M5 and a Micra!;)

Ok, a micra with 10 people in it then


But yes, on the same vehicle contact patch area is independent of tyre width and depends only upon inflation pressure and corner weight

znv6i3h7kqf9ys

BMW keys. If you hold down the central locking button for ten seconds all the windows and sunroof will open automatically. Try it.

cashmni1

Engine rpm will go from 900 rpm to 1000 rpm when the car is in neutral and rolling forward (on a slope, or in traffic) in a Peugeot 406 2.0 HDi to allow you to slip it into gear when rolling forward.

Wiper functions previously mentioned - on the Focus - also all work on a Pug 206.

Radio functions previously mentioned - volume up and switch on for period of time without the key - work on VAG and Peugeot also. Peugeot has "economy mode" after a length of time without the key which will switch off interior lights and switch off the radio to save the battery. The same will happen in VAG products but I dont know what comes up on the display.

EPM

cashmni1 wrote: »

The same will happen in VAG products but I dont know what comes up on the display.

On mine nada:D

If you have elec folding mirrors on a VAG, hold down the remote key when you lock it and they fold it automatically and open again when you start the engine. They couldn't program my key though so I have to use the switch inside both times...oh the inconvenience:pac:

Also - I presume its the same with all VAG 8 button designs - on the Multi-Function wheel press the top left and top right buttons at the same time and it turns off the illumination on the wheel

maidhc

Mr.David wrote: »

But yes, on the same vehicle contact patch area is independent of tyre width and depends only upon inflation pressure and corner weight

I'm either slow or that makes no sense. if both tyres are the same diameter (say 17") and one is 5 inches wide and the other 8 inches, then surely the wider tyre has more purchase.

Anan1

maidhc wrote: »

I'm either slow or that makes no sense. if both tyres are the same diameter (say 17") and one is 5 inches wide and the other 8 inches, then surely the wider tyre has more purchase.

It's all about the weight. If you put wider tyres on a car, you spread the weight over a wider contact patch. This reduces the length of the contact patch, as the tyre is not deformed as much by the weight of the car.

Mr.David

Myth 2: A larger contact patch = more grip

Think about that, its somewhat counter intuitive!!

Pique

maidhc wrote: »

I'm either slow or that makes no sense.

No, you're not slow. It's tosh ! Hence why sports cars have wider tyres...increase the contact area and increase the grip (except for snow, when narrow tyres increase the pressure/area and cuts through the snow to the grip beneath.)


Anyhoo. 1980s BMW F1 engines used unused M10 engine blocks from the early 70s (when they produced 75bhp)that had been left sitting (outside at times) for years and had been totally de-stressed, enabling them to run high-pressure turbos on them (producing 1500bhp!!!).

Pique

Mr.David wrote: »

Myth 2: A larger contact patch = more grip

Think about that, its somewhat counter intuitive!!

Oh yeah...let me put 1" wide tyres on my car and see how it brakes !! :rolleyes:

Slidey

Pique wrote: »

Anyhoo. 1980s BMW F1 engines used unused M10 engine blocks from the early 70s (when they produced 75bhp)that had been left sitting (outside at times) for years and had been totally de-stressed, enabling them to run high-pressure turbos on them (producing 1500bhp!!!).

Fact..

Think there should be an urban myth thread started too!

maidhc

Anan1 wrote: »

It's all about the weight. If you put wider tyres on a car, you spread the weight over a wider contact patch. This reduces the length of the contact patch, as the tyre is not deformed as much by the weight of the car.

It is about ground pressure rather than weight. E.g. A tractor can run on tyres that are to all intents and purposes flat (e.g. a couple PSI). The net result is you get a machine that weighs 10 tonnes but that can drive in soft ground without damaging what is underfoot because the weight is spread over such a massive area.

It BeeMee

slideways wrote: »

Hino and Isuzu trucks use Left Hand thread nuts and studs to hold on the wheels on the LHS of the vehicles. Not knowing that can be a bitch! :pac:

I'd say all large vehicles have this, it's to do with the thread direction and the wheel direction going the same way.

On VAG cars, not only can you open the windows by holding the keyfob, but holding the Lock button for a few seconds will close them again too.

Pique

slideways wrote: »

Fact..

Think there should be an urban myth thread started too!

Hehe, someone already started it, in the middle of this thread.

I'll add to it:
Bigger exhausts actually make your car go faster (as opposed to reducing the back pressure and robbing the car of power!)
Lexus lights are THE styling mod !
The fastest vehicle on the road is a white van (no matter what speed you're doing, a white van will ALWAYS overtake you or sit on your rear bumper) :P

Mr.David

Pique wrote: »

No, you're not slow. It's tosh ! Hence why sports cars have wider tyres...increase the contact area and increase the grip (except for snow, when narrow tyres increase the pressure/area and cuts through the snow to the grip beneath.)


Anyhoo. 1980s BMW F1 engines used unused M10 engine blocks from the early 70s (when they produced 75bhp)that had been left sitting (outside at times) for years and had been totally de-stressed, enabling them to run high-pressure turbos on them (producing 1500bhp!!!).

Pique.....get you facts right before you come on here spouting rubbish, its not "tosh", its in fact 100% true.

Sports cars have wider tyres due to the shape of the contact patch. It allows for a much greater % of the cycle to cool the tyre compared to a narrow width tyre (a 225 tyre will have 45% more cooling than a 155). This in turn allows a softer compound to be used for a wider tyre, hence generating a higher friction coefficient and more grip.

As regards your "increase the contact area increase the grip" comment, as I said before the contact area is the same (assuming constant pressure and normal force) it is simply the shape of the contact area that changes.

Tosh? I think not :P

Mr.David

maidhc wrote: »

It is about ground pressure rather than weight. E.g. A tractor can run on tyres that are to all intents and purposes flat (e.g. a couple PSI). The net result is you get a machine that weighs 10 tonnes but that can drive in soft ground without damaging what is underfoot because the weight is spread over such a massive area.

Yes maidhc you are right, but we were considering cases where the pressure was constant so then the force is the determining variable in terms of contact area

Pique

Regarding the rubbish that's been posted about contact area not affecting grip and that larger tyres will reduce the pressure/area, can one of you Einsteins explain why cars that weigh a few hundred kilos and put out 1000+ bhp have huge tyres to put the power down ?



Oh and Mr.David, we should all be thankful to you for redefining the laws of physics....taking cooling of the contact area into account is truly a master stroke. I'll send you profile link to Good Year, shall I ?:D

Mr.David

Yes I can.

The frictional force generated (i.e. grip) is determined by:

F = uN

Where F is the frictional force, u is the coefficient of friction and N is the normal force (i.e. the weight of the car).

As a racing car has to be as light as possible, this limits the 'N' variable in the equation, so the frictional force will only be increased due to an increased 'u' value.

This is achieved by having a super sticky rubber compound (high 'u' value). The tyre must then be very wide so that it can be cooled. If it were narrow and made of the same compound it would simply melt and would have no durability at all.