trevorcossie

i under stand its good to have plenty of torque but how is it produced and why does it benefit to have a nice amount regards matt

foreigneRS

it's produced by the piston moving down and turning the crankshaft. more is better than less as it can turn the wheels through the gearbox easier

alistairolsen

Torque is merely a static turning force.

cootsie

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

LHD220Turbo

iTrader: (4)

the best way to think about torque is it makes things easier (in car terms)
In simple car terms:

2 cars, 1 big steep hill

car 1 has double the torque as car 2.

car 1 will be able to go up the hill alot easier than car 2 in the same gear.

obviously there is alot of information on the net if you google the term torque; this will give you a detailed explantion. torque and horepower go hand in hand.

JTECH James

iTrader: (13)

Q what does torque actually do

A Break gearboxes

Chip

iTrader: (3)

Torque is half of the important equation that produces BHP, which is what gives a car performance.

RPM is the other half.

You want a lot of one or the other to stop a car being slow, or better still quite a bit of both.

andrewg

they say horse power sells cars torque wins races!

Chip

iTrader: (3)

Very true in drag racing when you need to hook up off the line, or in a rally car with a BHP limiting restrictor, tends to be less accurate the rest of the time though, formula 1 and touring cars etc, its all about BHP really.

mechanic28

iTrader: (5)

top fuel drag cars are 8000bhp!not sure what torque tho!

Chopshop85

iTrader: (4)

Which is why V-tech is gay. All the bhp, but about as much "torque" as a mute

escos-jim

iTrader: (1)

bhp is how fast you hit the brick wall
torque is how far you take the brick wall with you

simples

Steven_RW

Just find out what rpm it produces the BHP at and back calc the torque....

Torque is the twisting force. In our case created by the combusiton process, pushing the piston and rod down, twisting the crank.

Basically, the way I explained it myself back in the day is as follows.

Torque, the force produced by one cylinder firing once. At any given point in RPM and conditions, a cylinder volume with the right mixture will create the most power (right ignition timing etc) at a set RPM.

Lets say our little basic 100bhp polo (for random example). It will probably produce peak torque about 3,500 rpm. That is the engine rotation speed that the engine is being its most efficient (for numerous reasons).

As the RPM of the car rises above that peak efficiency moment, the torque produced by that cylinder will slowly reduce. IN my simplified view, it was just the engine moving out of its most efficient speed (ie at perfect peak torque, the engine might get 0.1 second at our example of 3,500rpm to fill the cylinder, because the inlet valve is open for .1 seconds. If you do twice the rpm, the cylinder only gets 0.05 seconds till fill, therefore it probably will not fill as efficiently (that my assumption at the time, when i was trying to get my head round it all, it will have quite a bit to do with a multiple of other variables like combustion chamber shape, ignition timing and the natural burn time of the correct fuel air mixture, inlet valve lift, inlet to exhaust valve ratios and so on but that is too complex for this and for me when I was first thinking about it all.

SO - bhp, is basically how many of those small explosions happen every second.

Obviously 100 small explosions at 95% of peak power (peak torque), gives u more go than 1 explosion at 100% of peak power. Therefore "torque" is not the be all and end all. You need a power band that is of a size that suits the conditions/situation u are using the engine.

Need to go to bed - will look at this explanation tomorrow and make sure it makes sense.

RW

Touring Car Spares

iTrader: (6)

Nope , torque is the power out of corners,without it youre way behind when it does become a BHP race on the straight .The AON Focus is a case in point , same engine all year, diferent mapping and slightly longer inlet tracts to produce the low( er ) down torque required to move the car !
This is all relevant tho , the aim is to Not dip below 6500 revs all lap !

alistairolsen

And totally wrong

alistairolsen

Now we enter the discussion not about peak torque but about the spread of torque. Distribution of toruqe gives you the power curve (rpm is a linear scale) Therefore as you say, take two engines with the same peak power and torque, but one with more torque low down and the latter will be faster,this is why big V8s make much better engines than shitey blown 4pots.

dojj

iTrader: (3)

the simplest way (although i stand to be corercted) would be to say that the torque is the amount of force inside the cylinder that's forcing the piston down and power is the speed at which you can do this many times over

which also conviniently explains why diesels have more torque than petrol engines because they produce a bigger bang per cylinder

Thrush

iTrader: (1)

I was always told that the easy, as in laymans, way to think of torque is it's power against resistance, or pressure against opposite pressure. IE, it is the power to overcome negative resistance, or more pressure than the opposing pressure force...

Is that way off, close enough, or completely irrelevant?

.Ross.

iTrader: (2)

Quote:

what does torque actually do

Torque is the Whole basis of any force in rotation.

Yup thats about the top and bottom of it right there. (I think we are on the same page anyhow )

Torque = Force x length.

Apply 1lb of weight to a 1ft wrench will = 1 ft. lb of Torque

The reason why diesels have more torque.

The throws on the crank shaft tend to be longer. Which means applying 1lb to a 1ft throw = 1 ft. lb ... 1lb to a 2ft throw = 2 ft. lb

Thats why Diesels dont rev as high as Petrol engine ..

Twice the Throw = Twice the speed per rotation. (Piston Linear motion)

I like the wiki page on torque What a load of horse shite

Rich_bloor

.Ross.

I like your explanation, can you do BHP now please. im interested in an explanation i can understand

trevorcossie

cheers guys so if you have 2 cossies say both 400bhp but one 400lbs torque and the other 320torque say would you see a difference

.Ross.

iTrader: (2)

Brake Horse Power ... MMM Missleading term TBH .. Very old school ..

Horse Power .. Unit term to describe power.

Brake Horse power is the Max power an engine can achive.

When an Engine reaches a certian RPM then the inertia of the crank helps the engine to spin. A Resistance Value is subjected onto the engine so momentum doesnt come into it. (I think ) The Max power developed by the actual Combustion bang.

(Just like lifting weights .. Its better to go slow, No momentum to help with the lift)

Thats why Petrol engines tend to have more HP than torque as they can spin like fook.

Diesels spin slower so the BHP reading is down as theres not as much Momentum but the torque is well up as the crank speed is slower over the equivlent piston Linear speed (Up and Down)(If the pistons in a petrol and diesel are going the same speed .. Up & Down the Diesel crank will be spinning slower)

Thats all i know about BHP .. Not really a factor with Big diesel engines.

Fook me .. had a few goes at describing that Two cups of Coffee and 4 Smokes as well ..

TREVCOSSIE: Dont know mate .. .. Iam sure some of the well established Tuners will be right along shortly.

trevorcossie

cheers ross its all coming together now .......

.Ross.

iTrader: (2)

Aye ... Some Rolling Road expert might pop in .. They probably know more ..

Steven_RW post is a good one (Only just noticed) .. Explains why the torque drops off and why BHP goes up (Sort of anyway)