take a F1 car which has a is it a 2.5 L v8 so the torque cannot be much more than 250 to 300lbs of torque, but they produce 700 bhp due to reving to 20.000 rpm. I know the car has no weight and great aero, but how does this push a car to to 200 mph.

yes I know bhp is work rate, but you need torque to push you to that speed

please explain i dont get it

 

Gearing.

Basically, as the engine is turning at 20000rpm, you can gear it down, and so multiply the torque by the same factor.

The power of the engine is the single metric which you can judge it's peformance by. It takes into account the torque produced, and how quickly the torque can be produced.

The higher up the rpm range you can make torque, the better - power is what quantifies this.

 

BHP is more important that torque for top speed.

If you make lots of torque without lots of bhp it means you do it at very low rpm, which means that by the time you have put it hrough a gearbox you have LESS torque at the wheels than a car with more hp and less torque


Its TORQUE @ WHEELS that moves a car forwards, and thats a function of BHP and Gearing only and not of the engine torque figure (unless in context with RPM at which points thats what a BHP figure is!)

 

BHP sells cars and Torque wins races my arse

Bollocks spouted by people with big engines that arnt very powerful

 

You boys have just scrambled my mind

 

I understand gearing but its still does not make sense.,

so if i gear my car correclty i cauld produce more speed, whats the limit when torque takes over?

 

By itself, a torque figure is quite useless - u cant ever judge a cars pefomance with it. Power is the rate at which torque is developed - it takes into account time. The definition of acceleration is the change in speed relative to time. A torque figure is a scalor quantity, (power is vector), which is defined at an instant in time.

 

steve don't tell this to a derv owner

 

Torque just makes it nicer to drive, a turbocharged LS1 5.7 litre Chevy motor would be a lot easier to live with than a F1 2.5 V8 making less power.

Mark

 

Torque NEVER takes over. It is totally irrelevant. If you geared your car low, it would accelertate quickly - but then you would run out of revs. Ie, you could have it so at 70mph u were doing 7000rpm in 5th. The car would be very fast, but 70 would be ur top speed. Now, say that your engine could rev to 20k. The car would be very fast, but this time would have a top speed of around 180... The torque figure hasn't changed, but your Power figure now has (Power = torque x rpm)

 

Torque of what?

Takes over what?


Do you not understand what torque is or what BHP is?



Torque is a figure saying how hard something is applying a force, BHP is saying BOTH how hard its applying a force AND how often.


As an example, take cups of water used to fill a punch bowl.

The bowl getting more full = the car acceleating
The bowl getting less full = the car decelerating


BHP would say how much water is moved into the bowl, so maybe "20 litres a minute" for example, torque would just be the size of the cup, to the punch bowl it doesnt care i it gets 40 half litre cups, or 80 quarter litre cups, its still the same amount of fluid on the way in.


On that example, the faster you are trying to go, the quicker the punters are emptying the punch bowl.

So 200mph might require 80 litres of water a minute, in which case either loads of little cups, or less big cups are both the same result, the flow into the bowl (or the torque at the wheels) is still the same.

 

ding dong, cheers rick its clicked

 

Actually there is some truth in that statement.

Torque does help win races, but thats to do with being able to pull cleanly off the line, if you have to slip the cluthc till you are doing 8000rpm its not so easy to get away well, thats why V8s are good in drag racing and a formula 1 engine wouldnt be so good.

Once moving though, like you say its only bhp and gearing that really counts.

 

lol lol chip nice way for putting it

 

I might even save that one off for the next time someone asks

 

yes chip torque is bhp over time, but if you put a F1 engine in a tank i still cannot see if the gearing would help

 

It would work if you had an automatic gearbox (sod clutch slipping to 16000 rpm) with the right gearing, and that was effiecent enough not to lose half the power on the way through the transmission.

There is then the fact of course that to go anywhere the engien would HAVE to be absolutely flat out foot the floor the entire time at high RPM.

I believe that in that sort of circumstance you would be lucky to see 10 mins use out of the motor on a typical F1 map before it expired as obviously during a race it gets time to recover in bends etc as you dont hold a F1 car flat out like you do a tank (well i did last time i drove one, lol)

 

Why not? Set it so that 20000rpm in top gear is 50mph and it will go very well.

 

afterhaving a fag think yes it would work but reving a engine 20000 rev all day would not be reliable

 

For a few mins

 

By jove, i think he's got it


Thats EXACTLY the point mate.



Have a look at generator motors for example, they sit there at 3000rpm ALL day quite happily, but a smaller engine at 15,000 rpm wouldnt last as long.

 

tar peeps i think i have got it

yes i am a thick cunt

 

lol, spot on.

But, i think initially it's best for you to think about what is happening, and the theory rather than reliability and driveability - that comes after

 

Cant be that thick if you can get your head round that at midnight on a schoolnight mate

 

and after 4 cans of red stripe and 2 classes of wine

 

LEGEND!

 

Was it whilst getting a rub and tug though?

 

only when training mate

they are all old hands know

 

So which would you have you of the 2?

600bhp with 400ftlbs?

500bhp with 500ftlbs?

 

For what?

A road car? or a race car?



Obviously there is more to the engines than just those numbers, but speaking broadly, most engines make peak BHP a little after peak torque has started to drop off, so you are probably looking at 8000rpm+ for the 600bhp one and quite possible 6000rpm for the 500bhp one.

So as a road car, the 500bhp one sounds to me like a nice option, especially if it was a cosworth and you are on standard gearing.

For a trackday / race car though, the 600bhp/400lbft one would be my choice



Thats based on the 600bhp one not being too "peaky" of course, there are far more characteristics than just the peak figures obviously.

 

Don't forget that aerodynamics plays a huge factors in a F1 cars top speed

 

yeah on a road car chip.



that will do the odd track day here and there

 

Depends on how you drive it, but the 500bhp one is likely to be less laggy and more long lasting (due to not needing revving as hard), so i would probably pick that for a road car for those reasons, so depends which of the two uses matters more to you as its going to be a compromise either way.

 

responsive and drivabilty,

which is certainly is.

gotta love the noise of a scremaer pipe

 

Very interesting read.

 

600 and 400lb everyday! 400lb is still a lot of troque, and won't shag the transmission as easily!

 

How come cars with turbo diesel engines go up hills so much better than NA engines ?

 

Great topic.

 

They dont if they are similar power and you are in the correct gear in both.

You just PERCEIVE that they go up a hill better cause in the petrol you have to change down 2 gears to get any torque at the wheels.


But once both are in the correct gear, with equal power they will both climb equally well.


Petrol one woudl blow up sooner though if hill was long enough, as you are raping it at high rpm to get it to work, but until that happens, it would do the job equally well.