Can someone explain something?

ljt · 24 Dec 2006 at 21:25

right mishima... best way I can explain it is as follows;

Petrol/diesel is the fuel that keeps your engine ticking over, when you engage the engine by putting it in a gear and press the accelerator (throttle) fuel is injected into the engine and revs faster, and goes forward

for example if your going along at 60 mph in 5th gear with your foot on the accelorator your injecting fuel into the engine to keep it going. if you then leave it in gear but take your foot off the accelerator you'll eventually slow down and the engines rpm will drop and you'll stall because no fuel is reaching your engine so it cant keep ticking over.

If you press the clutch down while in gear, or go into neutral (either is coasting) and you let go of the accelerator you'll never stall, why? because the engine injects fuel into the engine so it can keep running

hence coasting isnt fuel efficient

hope this makes sense!

Scarfacé · 24 Dec 2006 at 21:33

mishima said:
Now you aren't even reading what im posting..

I didn't say it wouldn't consume any fuel I just said it would consume less fuel being in neutral (coasting). You're right I'm not in full control of the vehicle, neither is the old man who's 82 who lives a few doors away from me.

AHHHHHHH!!!! *CRIES*

OK. Last try.

If you're coasting IN GEAR you're using ZERO fuel... how can you possibly use less than ZERO fuel?

I'm going to refrain from posting further in this thread to prevent me going insane.

Tommy B · 25 Dec 2006 at 16:37

A car is not designed to be driven in neutral. It's common sense.

When you're in neutral, and the engine is on, the car assumes you are about to drive off and thus begins injecting fuel. Or so that's what I've gathered.

Malachy · 25 Dec 2006 at 16:58

the complete lack of understanding and knowledge of how a car works in a motors forum amazes me :/
so much bs in this thread for both arguments

how does your car know if its in gear or neutral? it doesnt there is not a gear position sensor you car has no idea whether it is in gear or not so this has no bearing.

i explained how it all workis in an above post /yawn

aftershxck · 25 Dec 2006 at 17:04

So when you're at a traffic lights on even ground, you should keep it in 1st or put it in neutral ...?

If at traffic lights on uneven (uphill) ground, should you just have brakes on and neutral or 1st gear/brakes on or 1st gear at biting point?...?

Malachy · 25 Dec 2006 at 17:06

aftershxck said:
So when you're at a traffic lights on even ground, you should keep it in 1st or put it in neutral ...?

If at traffic lights on uneven (uphill) ground, should you just have brakes on and neutral or 1st gear/brakes on or 1st gear at biting point?...?

uhm im not here to teach you how to drive,

however neither situation will be ANY different in fuel consumption which is what the thread is asking about.

although generally the later will wear your clutch repeatedly and holding your car on your footbrake has a good chance of warping your disks

Scarfacé · 25 Dec 2006 at 17:11

Malachy said:
holding your car on your footbrake has a good chance of warping your disks

a) Many people, including myself have explained the correct answer in this thread, people just decide not to bother reading.

b) Using the brakes when the car is stationary will warp brake discs? O RLY?! Now who's talking the "BS".

Malachy · 25 Dec 2006 at 17:13

Scarfacé said:
a) Many people, including myself have explained the correct answer in this thread, people just decide not to bother reading.

b) Using the brakes when the car is stationary will warp brake discs? O RLY?! Now who's talking the "BS".

it has the potential to, especially if you have been doing heavy braking previously. how's that for BS!

Scarfacé · 25 Dec 2006 at 17:23

Malachy said:
it has the potential to, especially if you have been doing heavy braking previously. how's that for BS!

The only time you'll ever etch a brake disc is with some seriously hot brakes. Nothing that you'll come across on the roads in day to day driving, ever.

Telling people not to hold their car on the foot brake because they might "warp" their discs... don't be so silly!

dirtydog · 25 Dec 2006 at 17:26

Malachy said:
it has the potential to, especially if you have been doing heavy braking previously. how's that for BS!

Yep, you're right, it's definitely BS

Scarfacé · 25 Dec 2006 at 17:31

dirtydog said:
Yep, you're right, it's definitely BS

Utter Cack said:
"the complete lack of understanding and knowledge of how a car works in a motors forum amazes me :/
so much bs in this thread for both arguments "

"i explained how it all workis in an above post /yawn"

"uhm im not here to teach you how to drive,"

Lose the ego. There's people in the motors forum who know 1000*1000^99 times the amount of information about cars than you or me. So they're not going to be fooled when you tell them there's a "good chance" of warping their discs by using the foot brake to hold their car stationary.

"andy" · 26 Dec 2006 at 02:22

lol classic thread this un

but....

you say holding his car on the bite point will wear his clutch...

and holding it on the brakes will warp his discs...

is his car made out of cheese ?

how else do you want him to stop on a slight hill at lights etc then. flinsotnes

or are cars doomed everytime we stop now

Lopéz · 26 Dec 2006 at 10:52

andy8271 said:
you say holding his car on the bite point will wear his clutch...

It does. A clutch works by pressing a friction plate (a big circular brake pad, basically) against the fact of the flywheel. When the two are locked together no wear occurs, however when the two faces are moving at different speeds (ie hill starts, holding the car on bite, pulling away in 2nd by slipping the clutch) the flywheel is spinning faster than the friction plate. The two surfaces are still in contact so the flywheel is wearing out the clutch friction plate.

So yes, holding a clutch on bite wears it out, an awful lot faster than not holding one on bite

Matt82 · 26 Dec 2006 at 13:38

its amazing how little mechanical knowledge some people have (and presumably, im afraid, they drive too)

... just do what your driving instructor told you, try not to do too much thinking for yourself if you dont think the clutch wears by holding the car stationary on the clutch.

thats one thing i look for if im buying a second hand car privately... how they treat the things. id never buy a car from someone who habitually did that

Tommy B · 26 Dec 2006 at 13:53

Matt82 said:
its amazing how little mechanical knowledge some people have (and presumably, im afraid, they drive too)

... just do what your driving instructor told you, try not to do too much thinking for yourself if you dont think the clutch wears by holding the car stationary on the clutch.

thats one thing i look for if im buying a second hand car privately... how they treat the things. id never buy a car from someone who habitually did that

Holding the clutch down when you're stationary doesn't wear it. It's only on hill starts where you hold at the biting point the damage occurs.

Malachy · 26 Dec 2006 at 13:56

Tommy B said:
Holding the clutch down when you're stationary doesn't wear it. It's only on hill starts where you hold at the biting point the damage occurs.

tell that to your clutch release bearing

Tommy B · 26 Dec 2006 at 14:16

I'm starting to get sick and tired of "experts" all contradicting themselves

My driving instructor always told me to hold the clutch down at traffic lights, remain in first gear, and simply take off again when needed. He said it's only worth using the hand break and putting the car in neutral on hills or when you're going to be waiting a long time.

Anyhow, the fact is, some people are saying that putting the gear in neutral damages the engine. Some people are saying dipping the clutch whilst stationary is OK, whilst others are saying this damages the engine etc etc. I'm confused tbh.

Gilly · 26 Dec 2006 at 14:42

Tommy B said:
My driving instructor always told me to hold the clutch down at traffic lights, remain in first gear, and simply take off again when needed.

Without the handbrake? :confused:

Whats the point?

I'm fairly sure I was told this would be a fault during the test when I was learning. Not knowing the vehicle and how to drive it.

Tommy B · 26 Dec 2006 at 14:50

Gilly said:
Without the handbrake? Whats the point?

I'm fairly sure I was told this would be a fault during the test when I was learning. Not knowing the vehicle and how to drive it.

I remember my test very clearly and the only time I used the hand break was on a hill start. I only got 4 minors, and they were for not checking the mirror and indicating too early on one occaseon.

As to your first point, I'm also confused. If I stopped at a zebra crossing, I wouldn't use neutral or the hand break, I'd dip my foot on the clutch and the other foot on the break. Then just drive off again when necessary.

It actually annoys me when my mates who have just passed their test obsessively use the hand break. I was always taught only to use it when entirely necessary. I think it's absolutely ridiculous using it at a junction, or in between having reversed and taking off again. It seems silly.

dirtydog · 26 Dec 2006 at 15:25

Hmm I did my test a long time ago now but I'm sure you had to use your handbrake at traffic lights. At least that was what my (ex-police traffic driver) instructor told me.