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Horse Power - I thought I understood it

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Old Jul 24, 2010 | 04:28 PM
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Default Horse Power - I thought I understood it

I regard the speed a car get from 0-60-100 and so on as QUICK
The higher the speed a car goes the FASTER.

So quick = Acceleration
Fast = Top speed.

Where is horse power more important then?

I accept its got to be for both quick and fast but if cars are purely running 0-60 times can there be big differences in BHP yet not the same proportional differences in 0-60 times.

I'm thinking about cars that already have large BHP to start with such as GTR AMG RS4 etc vs supercars etc

And is it the same for top end speed? I appreciate that then its all about wind resistance and exponential some thing or other. And gear ratio.

Can anybody explain this more simply.

This all cropped up because a colleague at work's Brother has a 911which has 400 plus BHP but its not that much quicker then my Impreza STI PPP with theoretically should have 305BHP.

My old Impreza was a standard WRX with only 220BHP and was loads slower than my STI.

In short my STI feels more than 85BHP quicker than my old WRX but the 911doesnt then feel like its 95plus BHP quicker than my STI.

My colleague says the extra horses only matter at the top end then and that 0-60 times make the extra horses not important.

I thought I understood all this but...

I haven't a clue.
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Old Jul 24, 2010 | 05:02 PM
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Don't forget about Torque too
Sorry I cant help ..not clever enough.. but isn't it also to do with the Power/ Weight ratio ?
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Old Jul 24, 2010 | 05:53 PM
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Weight must be a factor too ... 400hp in a 911 won't be enough to beat a lighter scoob running 400hp as well although the 911 will probably be faster at the top end as it's a slippery shape

TX.
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Old Jul 24, 2010 | 05:55 PM
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Torque and gear ratios too ! To use your terms, My classic is 'quicker' than my NewAge, but my NewAge is 'faster' than my Classic.
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Old Jul 24, 2010 | 05:56 PM
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And remember the scoob will have the traction off the line over the 911,but after there both rolling,the scoob will lose more of its bhp to the wheels than the 2 wheel drive 911.
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Old Jul 24, 2010 | 05:57 PM
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there are 4wd 911's
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Old Jul 24, 2010 | 07:45 PM
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Torque is the answer,the ability of the engine to push the car forward.I have 320bhp power comes in 3,500 rpm all the way to 7000 rpm,my friend runs 300 hp Skyline power comes in 5000 rpm up t0 7500 rpm.If we do side by side 0-60 my Scooby bogs slightly then rockets away,he scream away tyres smokin TC off TC on I beat him all the way to a fine !!!
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Old Jul 25, 2010 | 09:01 AM
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the best way to describe torque and bhp is think of someone punching you.
the bhp is how fast you can throw a punch.
the torque is like how hard you get hit
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Old Jul 25, 2010 | 10:04 AM
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BHP is an illusion, Torque is a reality. think of it like arm-wrestling, it's the torque that gets you past your opponents resistance threshold, and it's the illusionary BHP, that slams his arm on the table...
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Old Jul 25, 2010 | 11:28 AM
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HP = Torque in ft/lbs x RPM ÷ 5252. Really it is all down to torque, power is derived from it.


Some explanations here and here.

Last edited by Saint AAI; Jul 25, 2010 at 11:31 AM. Reason: Added Links
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Old Jul 25, 2010 | 11:32 AM
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How is it then that an Integra Type R is fast/quick with pretty low torque?

TX.
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Old Jul 25, 2010 | 12:01 PM
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I appreciate what you mean in terms of Torque and have experienced different levels of torque in my car driving life.

But BHP must be the origins of torque tho, or am I wrong

So lots of BHP will still push a car with little torque?

What if a car had loads of torque and little horse power?

I'm just guessing here.

Last edited by Dan W; Jul 25, 2010 at 12:05 PM. Reason: Torques - I sound like clarkson
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Old Jul 25, 2010 | 12:06 PM
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....oooch me head hurts
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Old Jul 25, 2010 | 12:09 PM
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Originally Posted by badboyz666
....oooch me head hurts


Mine too. But I started this so cant grumble
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Old Jul 25, 2010 | 02:14 PM
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A 400 bhp 911 is probably a 4wd turbo. It weighs more than 1570KG.

A 54 plate STI weighs around 1470KG.

The Porsche gears are probably on the long side as at the top end it is the far faster car.

J.
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