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GabrielKnight
27-07-2009, 17:51
What is the dial on the right of dash supposed to show? I never had one on my normal Clios.

I assumed it was some sort of rev meter to give you an idea how much petrol / power is being gobbled up so never paid to much attention. Then today I noticed it was up to 5 (500/5000/50000?) when on the motorway even with no foot on the pedal. So, what is the point of it?

Sorry for my cluelessness :oops:

Justin..
27-07-2009, 18:00
Oil pressure

GabrielKnight
27-07-2009, 18:17
No no, furthest to the right, more right than the speedometer.

DaneC
27-07-2009, 18:17
Lol super newb!

webby
27-07-2009, 18:18
No no, furthest to the right, more right than the speedometer.

u eman rev counter? lol if so its how many revolutions your engine is making per minute. if u were in 5th at 5k rpm, u were speeding :lol:

DaneC
27-07-2009, 18:18
It is a rev counter dude, you don't need your foot on the pedal for the engine to turn...

Justin..
27-07-2009, 18:21
Foookin LOLZ

webby
27-07-2009, 18:23
Foookin LOLZ

be nice now....













hahahahahaha :lol:

GabrielKnight
27-07-2009, 18:24
But what is the actual benefit of it? Is it just to show you how much strain the engine is undergoing? Surely you can tell this from the engine noise?

No need to take the piss. I've just never driven a car that has one b4.

webby
27-07-2009, 18:25
proper divers use the engine noise mate so ur on to a winner!

DaneC
27-07-2009, 18:31
http://images.yuku.com/image/pjpeg/b0a1623a3b0453a6217123a91d5c7b70ca6575ae.jpg

webby
27-07-2009, 18:35
quality but be nice.

DaneC
27-07-2009, 18:37
I don''t mean to be nasty, just surprises me the first car you drive with a rev counter is a Williams! What else have you had?

MatrixGuy
27-07-2009, 18:40
My willy was the first car i had with a rev counter. lol. :lol:

First car being a Ford KA :shock:

webby
27-07-2009, 18:42
should have learnt (not that its the "law") about it in driving lessons for a start. and it is surprising that a willy owner does not know what a rev counter is and what its for. saying that, we are all here to learn about our awsome cars!

busterhymes
27-07-2009, 18:44
its very worrying :shock:

16v_paddy
27-07-2009, 18:44
:lol: :lol: :lol:

It's a useful thing to have as it can help to see how your engine is behaving, for instance, if you know exactly how your engine sounds at say 4,500 rpm and the rev counter is saying something different - you was either wrong to start with or there is a problem somewhere.
Another use is to use it in conjunction with your oil pressure gauge, you'll know what pressure it should be at with certain amounts of revs & temperatures (over time) and you'll quickly notice if somethings changed

Allan
27-07-2009, 18:47
you will also be able to tell your clutch is slipping when it hits 8k and your not moving :P

16v_paddy
27-07-2009, 18:58
you will also be able to tell your clutch is slipping when it hits 8k and your not moving :P

I can usually tell from the smell & smoke :lol:

queegan
27-07-2009, 19:12
mateys taking the piss aint he got to surely cant believe he owns a car and doesnt know wot a revometer is shouldnt of been aloud a license how did u learn to change gear when doin your test u deffo takin the piss my gran nows wot a revometer is and shes 90 years old :rotflmao:

Wobba
27-07-2009, 19:16
Rev meters are useful with performance cars.

Engines have powerbands, where they are at their most efficient. When racing, for example, it's useful to a driver to know when ragging the shit out of the upper rev limit is not worth it as some engines, F7R included, are not delivering as much power/torque. When this is the case they simply change gear to keep the engine in it's 'sweet spot', unless they need to hold onto a gear longer in conditions where changing gear costs too much time (this is one reason why modded ECU's have chips with higher rev limits).

People also install rev lights which can be programmed to show when its a good idea to change gear. These are set to be dependant on the RPM (revolutions per minute) of the engine.

Revometers are also useful to gauge the activity of your engine. If you want to be 'Eco-Man' for the day, you will probably want to stay under 3k RPM as it gives better fuel economy.

Knowing your RPM's is also useful when running in an engine too.

GabrielKnight
27-07-2009, 19:49
mateys taking the piss aint he got to surely cant believe he owns a car and doesnt know wot a revometer is shouldnt of been aloud a license how did u learn to change gear when doin your test u deffo takin the piss my gran nows wot a revometer is and shes 90 years old :rotflmao:

If she's only 90,I expect she can type / spell better and talk less drivel too.

GabrielKnight
27-07-2009, 19:51
should have learnt (not that its the "law") about it in driving lessons for a start. and it is surprising that a willy owner does not know what a rev counter is and what its for. saying that, we are all here to learn about our awsome cars!

I'd have a job, seeing as that the instructor's or the tester's car didn't have one.

webby
27-07-2009, 19:53
should have learnt (not that its the "law") about it in driving lessons for a start. and it is surprising that a willy owner does not know what a rev counter is and what its for. saying that, we are all here to learn about our awsome cars!

I'd have a job, seeing as that the instructor's or the tester's car didn't have one.

hehe, fair play mate im not 1 to have a dig! your here to learn the same as me :)

GabrielKnight
27-07-2009, 20:08
I don''t mean to be nasty, just surprises me the first car you drive with a rev counter is a Williams! What else have you had?
nova,
In 15 years of driving I've been insured on a Nova, Fiat Panda, Rover Metro, Ford Orion, Vauxhall Astra, Mercedes Luton van, Renault Clio mk1.

I've never had a problem knowing when to change the gears on any of these. It's obvious from what the car is telling you. I think the rev meter is more useful than not, but not as necessary as some are trying to make out.

I realised that the dial measures revs, but with little understanding of what goes on under the bonnet didn't understand that revs are still significant when no power is being applied. This is useful to know as an engine can still be under pressure at high revs even when not accelerating I guess?

1995clio16v
27-07-2009, 21:58
Lol! I thought this question was a wind up the further on I read!

:D

Wobba
27-07-2009, 22:03
This is useful to know as an engine can still be under pressure at high revs even when not accelerating I guess?

Parts are moving fast, so there is still stress on parts in the engine at high revs.

The ignition is still firing, just with a a lot less power due to the air/fuel ratio when coming off the gas so inevitably the revs drop as the combustion cannot maintain driving the mass of the crank and other parts, ergo, your revs drop and you slow down.

Personally I miss the RPM dial in inferior cars. I never know where redline is, and they all sound like death at anything over 3k so you never dare push it.

harvythehippo
27-07-2009, 22:51
its actually called a tachometer,

http://en.wikipedia.org/wiki/Tachometer

GabrielKnight
27-07-2009, 23:00
When I was at about 5k in 5th, I was doing about 95-105mph with no acceleration. I expected flooring it to make a big difference, like it would triple the the wear on the engine, but the rev meter shows it just makes a small change, teaching me something new and changing my driving habits.

1995clio16v
27-07-2009, 23:06
mateys taking the piss aint he got to surely cant believe he owns a car and doesnt know wot a revometer is shouldnt of been aloud a license how did u learn to change gear when doin your test u deffo takin the piss my gran nows wot a revometer is and shes 90 years old :rotflmao:

:shock:

GabrielKnight
27-07-2009, 23:18
its actually called a tachometer,

http://en.wikipedia.org/wiki/Tachometer

Interesting article, thanks. Stangely mostly relating to non-car vehicles despite predominate use in cars.

I don't remember an actual 'redline' on my tachometer but may be wrong. What is the theoretical redline on the Willy? Is there a feature on this car that restricts power over the redline to protect the engine?

As I say, I've never used the tachy on any car, but find 2 points of interest that aren't necesarily unique.

1. Acceleration seems to increase exponentially at the higher revs in a particular gear. What is the reason for this please?

2. The car sounds like it needs a 6th gear when 110 - 120mph is reached.
.

16v_paddy
27-07-2009, 23:24
The redline is just where the rev limiter kicks in to stop you blowing the engine to bits.

As for the acceleration, that's where the sweet spot is. It's when the engine is running at its peak power & torque, that particular gear is when it's best optimised. Look at the rev counter when this starts to happen so you can aim to keep the engine in that band of peak performance when blasting about on some good roads or on track :wink:

GabrielKnight
27-07-2009, 23:29
Should probly rephrase question 1 for clarification. Why does car seem to accelerate faster before a necesary gear change than just after one?

16v_paddy
27-07-2009, 23:44
For example, on my valver the peak performance kicks in about 4,000-4,500 rpm. So when I'm driving it properly down a country lane I wont use 5th gear as it'll take too long to get back up to those rpms when I'm accelerating round a bend, so I'll leave it in 4th for a fast corner since I can keep it in that powerband after braking allowing for optimum exit speed.

This is where the rev counter really comes in to play, by looking at it along with your speedo, you'll get to know what speeds you car does at particular rpm's in each gear allowing you to make a better judgement for gear selection when approaching a corner so you can exit the corner at optimum speed & acceleration.

I know my car hits the rev limiter in 4th gear at 110 mph, lets say I'm coming up to a bend at 100mph & 6,750 rpm, obviously I have to slow down, I'll judge the bend, my speed, rate of deceleration, how quick the rpm's are dropping, how brave I'm feeling, the capability of the car. If I see that the revs will drop quickly below 4,000 rpm I'll heel & toe to select 3rd bringing the engine back into it's peak performance range allowing me to exit the corner a lot faster than I could if I was in 4th gear with the same entry speed

GabrielKnight
28-07-2009, 00:04
I see. I get all of this from the engine sound, but understand it may be more reliable from the meter. What I don't fully get is the physical reason that acceleration is lower at the bottom end of a gear change compared to the higher end.

Is it because at the bottom end, the car is slower for that gear so uses more engine power to shift the weight forward whereas at the high end the car is up to speed and starts to over rev because its up to the highest speed it can cope with?

I know how how it works in reality (driving for 15 years) but not the physics behind it. I guess it all comes down to torque / speed, but can't get my head around it.

16v_paddy
28-07-2009, 00:19
More accurate is a better way to put it.

When you're getting higher up the revs you'll get to the point of peak power & torque after that point it drops off (I'm over simplifying it a bit but you get the jist) the torque mostly

Have a look at rolling road graphs, you'll see how the power & torque increases across the rev range

It's the torque that gives you the acceleration, once you've passed the point it's at it's peak the rate of acceleration will drop quite a lot, you're still accelerating but nowhere near as fast because you've passed the poit where it's at it's best for that gear

The physics of the engine (I've posted an article on here somewhere about it I think) - the pressure from the combustion in the cylinder generates a force on a pivoting point - the crank- this is torque, the horsepower is a measurement of how quickly it can generate & re-generate this force. Think of it as the bhp gets you to your top speed and the torque is how quickly it gets you there - again not entirely accurate but you get the idea

GabrielKnight
28-07-2009, 06:57
Thanks for all the help. 8)

cliokiz
28-07-2009, 08:35
LOL!

bass_direct
28-07-2009, 18:11
Welcome back sir!

zmaster2k
28-07-2009, 22:19
logged it especialy to say.....

EPIC.

and glad bass got it lol

bass_direct
28-07-2009, 23:26
8) to be fair though, makes the forum more interesting!

Jamie.
29-07-2009, 08:48
I doubt that, this is a real query.

1995clio16v
29-07-2009, 09:52
That pic from DaneC is absolutely priceless! Im saving that one! Cant stop laughing at that picture in context with the topic!

:o