Trying to top the poll of the most boring or stupid question..
How powerful does a car need to be to =91push you back in your seat=92 I seem to remember the acceleration from a friends Vauxhall cavalier 2.0
Debacler
When I had my Opel Monza 180hp,that gave you quite a pull. I would assume it's mainly down to BHP, but there must be more to it than that.
Bod
Power to weight ratio is the most important factor.
My Opel Monza 3.0 pushed you back in your seat and it was known as a heavy car. It was fairly high revving though, especially compared to a mate's BMW M5.
Bod
Torque to weight really
Power to weight ratio is the most important factor.
*********************************8My GTM had 104bhp and really pushed you back in your seat.
64ft times were as good as 200bhp 4wd turbo cars, but the GTM was a mid engined lightweight GRP monocoque.My Locost had 127bhp, weighed around 500kg or thereabouts and certainly pushed you back in your seat even harder. That would also spin the driven wheels in three of the four gears if you were a bit too keen with the throttle.
I've been in light car which has well over 500bhp / Tonne and that obliterates both of the above. With its around 200bhp, it re calibrates what you think you know about fast. Acceleration really is genuinely a blur. Weight is the enemy.
I think it depends on the car you're used to. If you're used to something like a Golf SDi a fully laden double decker bus will throw you back in your seat.
There's also delivery. A Bentley Turbo doesn't push you back in the seat the same was as a Fiat Uno Turbo will, but the Bentley is a lot quicker, a lot more powerful and a lot torquier.
The force on your body is related to the acceleration of the car and the firmness of the seats. More power or less weight means more acceleration. Engine torque on its own is meaningless: you make it meaningful by factoring in the gearing, and having done that what you have is the power.
There are also psychological effects to take into account. *All* forward acceleration pushes you back in your seat, but you don't usually notice it.
A sudden increase in acceleration will thump you in the back. Maintained acceleration will keep you pushed into the seat.
My standard unmodified automatic 90HP Octavia TDI does that trick on kickdown after some cruising on A/M roads (which is for me the entertainment factor of the beast). Passengers don't normally expect it.
Bollocks not again, here comes your Physics primer.
Q: What drives a car? A: Traction force produced at tyre contact patch, according to Newton's law Force = Mass x Accel, F = M x A so Acceleration = F / M
see that's a FORCE, it's not TORQUE!
Q: What's torque? A: By definition Torque = Force x Distance so Accel = Torque / (Mass x Distance)
Q: What distance? A: The tyre rolling radius. Accel = Torque / (Mass x Rolling rad)
Which is what you should have said but you seem to have been learning bullshit from all the moronic motoring journo's and petrolheads that haven't got a Physics A level between. They think engine torque is important.
Q: So what's engine torque? A: It makes Torque at wheel = trans efficiency x final drive ratio x gear ratio x engine torque Accel = effy x Engine torque [1] x final drive x gear ratio / (Mass x Rolling rad)
Q: Phew, there must be an easier way? A: yes there is. Power = Force x Velocity Acceleration = effy x Power / (Mass x Velocity)
For Acceleration, Power [2] and Weight is everything. To talk about Acceleration produced by Engine Torque you have to know tyre size and gear ratios. Without them you know nothing about torque and acceleration. Any such comparison indicates a lack of education.
[2] There's more bad news. In a given gear the peak acceleration will be at about peak torque. But unless peak torque rpm is very close to peak power there's always a lower gear that will give better acceleration for a given road speed. Torque = power / speed. So the peak torque quoted is quite useless for performance. What it does do is make the car nice to drive in everyday use on public roads where you accept a less than startling performance for quietness and smoothness. [2] It's really more complex than just power as it's engine power - drag power. That's because the Force right up there at the start in Newton's law was really Traction force - drag force. But unless very underpowered drag isn't a major player in 0-60mph or even 1/4 mile times for most production cars.
Are you making excuses for not having any torque again?
Honestly, try something with a proper engine instead of some wheezy little Jap lump and you'll discover why people like big engines.
I have a 2L Capri. It has 130BHP, weighs 1098kg. It has roughly 100lb/ft torque.
I have a 2L Mondeo TDCi. It has 130BHP, weighs approx 1500kg. It has roughly 244lb/ft.
The Mondeo absolutely thrashes the Capri on 30-70MPH acceleration despite weighing nearly 50% more.
Explain.
You haven't given enough information for anything other than a guess, but my guess would be that the difference is largely explained by two things:
1 The diesel's power is available over a wider range of revs. You presumably quote peak power, which applies at only one speed. The petrol engine's power will fall off very quickly either side of the peak revs, whereas the diesel engine's won't. 2 In a petrol-driven car, the driver often can't be arsed to change down, but in the diesel car he doesn't have to. With a petrol engine the power is only available at higher revs, hence the need to change down. 3 (OK, I can't count). The Capri is knackered. :-)Note that the word "torque" doesn't figure in any of this.
You get my vote...
Tim
BAH! My little Jap 1 litre four cylinder does 0 -60mph in less than 3 seconds*
Fraser
Pete M wrote in news:h9r4f7$foc$ snipped-for-privacy@news.eternal-september.org:
Or turbocharged petrol engines.
I've had a fair few turbo'd petrol engines in my time. To make 'em fun they need to be either minimum of 3.0 capacity or run big boost.
Having said that, big engines with turbos are good fun.
Little four pots can be fun, but if you've never tried a 6 or 8 cylinder with a couple of turbos you don't know what you're missing. Turbos are a good cheat, but they're really not the same as a nice 7.2 V8.
If you're going to start about fuel consumption, you're wasting your time. Miles Per Gallon and Grins Per Mile are two entirely different things. Grins are priceless.
Diesel power bands are notoriously narrow, especially compared to that of any good petrol engine. Turbo diesels have even narrower useable power bands.
Try something with a proper petrol engine.
You're another diesel apologist, I can somehow sense it.
So is that Audi V6 a 2.7T or a 2.8? Or is it a Diesel? Cos I was all ready to go to work on analysis of the 230bhp 2.7T.
Right wheel drive required, that's what you have the Escort for.
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