Power vs Torque

Andy1GP

///Member
I had difficulty finding an appropriate title for this thread, I found this very very very interesting. It goes against what I thought I understood and was really surprised. Made me think of the recent F30 320i vs F30 320d debates going on in the forum lately.

<iframe width="640" height="360" src="//www.youtube.com/embed/zZb3zm4SlKg" frameborder="0" allowfullscreen></iframe>

Especially for people that think power is always king. Only thing I can reason in my mind is gearing.

Taken from the Top Gear special "Hot Metal" The following comparison was a Mclaren SLR vs Porsche Carrera GT.

Oh and the Climax is the M3 CSL :)
 

Andy1GP

///Member
It's really worth watching the Top Gear videos, like this one "Hot Metal" Where they compare all the old cars vs the new ones. I really enjoy re-watching them :)
 

moranor@axis

///Member
Official Advertiser
in the vid it seems the Zonda was spinning quite a bit?

Jaguar XJ220 400 kW 644 N·m 0–60 miles per hour in 3.6 seconds

Zonda S 400 kW 750 N·m 62 mph (100 km/h) in 3.7 secs

same power
different torque
very similar results...
 

Sankekur

///Member
What if I told you.......that power is directly proportional to torque.........


power = (torque*2*pi*angular_velocity)/60
 

moranor@axis

///Member
Official Advertiser
Sankekur said:
What if I told you.......that power is directly proportional to torque.........


power = (torque*2*pi*angular_velocity)/60

it is :)

but a high peak Power number shows the ability of an engine to produce torque at High RPM... producing torque at higher RPM is most important when in a 'racing' situation :rollsmile:
 

Sankekur

///Member
moranor@axis said:
Sankekur said:
What if I told you.......that power is directly proportional to torque.........


power = (torque*2*pi*angular_velocity)/60

it is :)

but a high peak Power number shows the ability of an engine to produce torque at High RPM... producing torque at higher RPM is most important when in a 'racing' situation :rollsmile:

The whole discussion should be low end vs top end torque.
 

moranor@axis

///Member
Official Advertiser
Sankekur said:
moranor@axis said:
Sankekur said:
What if I told you.......that power is directly proportional to torque.........


power = (torque*2*pi*angular_velocity)/60

it is :)

but a high peak Power number shows the ability of an engine to produce torque at High RPM... producing torque at higher RPM is most important when in a 'racing' situation :rollsmile:

The whole discussion should be low end vs top end torque.

or torque curve :rollsmile:
 

Andy1GP

///Member
200kg weight disadvantage! with only 100nm more that should still equal rape in most cases. The Xj220 is simply spectacular.
 

Clownshoe

Active member
I have always believed that the best comparison for torque and power is the area under the graph. This gives a good idea of power and torque available through the rev range rather than at peak revs.
 

Zack

///Member
This is a topic that I have also found fascinating over the years. At the end of the day my opinion boils down to KW vs Torque. Putting diesels aside and just judging on petrol cars. Torque is simply fantastic. Throttle response on V6/8 and straight 6's is something hard to explain to some one that has driven 4 cyl cars all their life. Even when putting your foot down from 1500rpm you still get that pull (things like this makes me miss my XR6)

But now on the other hand, the pull you get from higher KW or turbocharged cars are also amazing. I tend to lean more towards higher KW than Torque though. Funny enough I never appreciated the supercharged V8's from Mercedes. Even though you should get best of both worlds I still feel one or the other gets compromised to balance it. Even when I drove a R33 GT-R a while back you only have KW, below 4000rpm very little response even with the straight 6. Driving with SP33DYV in the 1M the other day I realised that BMW's turbo engines actually does give you best of both worlds :rollsmile:

If you can afford it... :fencelook:
 

moranor@axis

///Member
Official Advertiser
Clownshoe said:
I have always believed that the best comparison for torque and power is the area under the graph. This gives a good idea of power and torque available through the rev range rather than at peak revs.

completely agree people get carried away with peak numbers alone when the curve is what you really want to look at an engine that produces high torque over a few RPM is not as good as one that produces slightly lower torque over a much wider RPM unless you only going to use the engine is the narrow torque peak...

best torque curve is a flat one till redline... this is very difficult to get right though :)
 

Mrcloc

New member
Clownshoe said:
I have always believed that the best comparison for torque and power is the area under the graph. This gives a good idea of power and torque available through the rev range rather than at peak revs.

Exactly! Area under the curve is everything. I was waiting for someone to mention it. Car manufacturers should quote a figure which is the area under the power curve for the power band.
 

Clownshoe

Active member
moranor@axis said:
Clownshoe said:
I have always believed that the best comparison for torque and power is the area under the graph. This gives a good idea of power and torque available through the rev range rather than at peak revs.

completely agree people get carried away with peak numbers alone when the curve is what you really want to look at an engine that produces high torque over a few RPM is not as good as one that produces slightly lower torque over a much wider RPM unless you only going to use the engine is the narrow torque peak...

best torque curve is a flat one till redline... this is very difficult to get right though :)

Vanos almost achieves this. IIRC while the max power output of the s50 e36 M3 and s54 e46 M3 was not that different the power and torque delivery was vastly improved.
 
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