Torque, BHP, 0-60 times - real world feel?

Head_The_Ball

facade wrote: »

The torque varies with engine speed, so that single figure could be when the engine has got to its maximum rpm...

Maximum torque (a measure of turning force) isn't produced at maximum revs, it will be at a maximum much lower down the rev range.

Around 2,500 to 3,500 revs is where most cars will achieve maximum torque although that varies greatly from car to car or engine to engine or petrol to diesel.

Maximum bhp (a measure of power) is usually achieved towards the top of the rev range.

https://www.google.co.uk/search?ei=Z9PQWtGlIoaXgAbpl5RA&q=torque+curve&oq=torque+curve&gs_l=psy-ab.12..0i67k1l2j0l8.19777.24241.0.26103.12.12.0.0.0.0.73.653.12.12.0....0...1.1.64.psy-ab..0.12.650...0i13k1j0i13i5i30k1j0i5i30k1j0i22i30k1j0i22i10i30k1.0.VcTgApbjGBI


Good luck with your lottery win. Will you take me for a spin when you get the Dodge Challenger SRT Demon?

John-K_3

When I was younger, and happy to sit at higher revs, I used to correctly look at peak horsepower as the number that mattered. If you are happy to sit at peak power, in a lower gear, you get good acceleration. This means that I was happy with motorbikes with little, revvy engines.

Nowadays I am happier closer to tickover, so pr!fère engines with more torque. My last car was an AMG C63, which pulled like a train from any revs, and now I have an M3, which is the same, but with a Turbo rather than a big normally aspirated engine.

So, I would say it depends on how you drive as to which will feel fastest. Real world is heavily affected by your driving style.

0-60 is not the greatest measure, either, of how fast a car feels. One with a shorter accelerator movement may feel faster than one with a long travel.

My fun car does 0-60 much faster than my M3 because it is four wheel drive, but the M3 feels like it picks up better if I just plant my foot to the floor in the gear I am driving in normally.

John-K_3

facade wrote: »

Top of my list when I become a lottery millionaire

1.8g acceleration off the line- lifts the front wheels off the floor
0-60 in 2.3 seconds
0-100 in 5.1 seconds

What's not to like?

It’s a nice car, but...

They use the drag race standard measurement of not counting the first foor or so of movement, so chopping a bit off the time, somthe figures are a bit exaggerated, and they achieve the time by making it heavily compromised for anything but the drag strip.

I really like Challengers, but I’d prefer one that was designed with the odd corner in mind.

leosayer

More BHP = faster acceleration, everything else being equal. But to achieve that acceleration you need full throttle and to rev the engine to the red line in each gear.

Generally, cars with higher torque figures will feel faster in 'normal' driving even if the 0-60 time is slower. Your Insignia may not 'feel' a lot different power-wise, compared to the newer cars.

Bear in mind that the BHP and torque figures are peak only which might only occur at a narrow rev range.

Weight also plays a part, which probably explains why your Insignia is so much slower 0-60 compared to the Audi and BMW which are lighter.

The Audi torque figure you quoted is wrong. It's 184 not 236.

daveyjp

Its also how you expect to drive the car and what type of drive you like.

We have just swapped a small capacity turbo 90bhp, for a 1.5 normally aspirated, 110bhp, but larger car.

0-60 are about the same, but the small turbo was not a car you could drive smoothly, especially around town as the turbo boost wasn't matched well to the gearbox. On the open road it was much better.

3rd wasn't quite right for a 30, but 4th took the turbo 'offline' and the car laboured and had nothing when you wanted to accelerate.

The 1.5 has a 6 speed box and it will happily take 5th at 30mph with no labouring and it just makes for a much smoother and more pleasant driving experience, rather than an 'on/off' turbo delivering power in a lump.

fishybusiness

Gear ratio's also affect how a car feels through the gears.

Closer ratio boxes will give the car a nippy/ revvy feel, but then top maybe a great cruising gear so the experience may well be based on power/ torque/ weight of vehicle/ gearing = best go drive them all.

foomanchu

Torque doesn't mean much unless you know the rate at which it is applied - give me a long enough bar and I can apply more torque than a Ferrari, I just couldn't do it quick enough to move it very fast.

Simply put;

Torque x Rate = (drum roll) Power
Power / Weight = Acceleration

So quoting torque by itself is pretty meaningless, though it can indicate where in the rpm range the power might be.

High torque low power - power low down in rev range, tailing off high rpm
Low torque high power - needs high revs to get the power
High torque high power - what you need if you want to go really fast

Head_The_Ball

foomanchu wrote: »

Torque doesn't mean much unless you know the rate at which it is applied - give me a long enough bar and I can apply more torque than a Ferrari, I just couldn't do it quick enough to move it very fast.....

Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.

Archimedes.

Herzlos

More toque will help you going up steep hills or with a heavily laden car.

So for instance, 4 passengers and a full boot will have a much more dramatic impact on the performance of the Audi than the Vauxhall.

onomatopoeia99

Lots of good info above. Gearing has been alluded to in places but one thing that needs to be borne in mind when considering 0-60 times, is that not all cars will make it to 60mph without two gearchanges. The extra gear change and having to gain the last few mph in third can have a noticeable effect, so while a reasonable indicator of performance, the time isn't in any way definitive.

foomanchu wrote: »

Torque doesn't mean much unless you know the rate at which it is applied - give me a long enough bar and I can apply more torque than a Ferrari, I just couldn't do it quick enough to move it very fast.

Torque is quoted with the length of the lever, so either lbs ft or N m.